tested basic frame parser

Reviewed-on: #111

.github/workflows/ci.yml

@@ -1,42 +1,39 @@
-on: [push]
-
 name: ci
+on: [push, pull_request]
 
 jobs:
   check:
-    name: Check
+    name: Check build
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-      - uses: actions-rs/cargo@v1
-        with:
-          command: check
-          args: --release
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - run: cargo check --release
 
-  msrv:
-    name: Check with MSRV
+  test:
+    name: Run Tests
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: 1.61.0
-          override: true
-          profile: minimal
-      - uses: actions-rs/cargo@v1
-        with:
-          command: check
-          args: --release
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - name: Install nextest
+        uses: taiki-e/install-action@nextest
+      - run: cargo nextest run --all-features
+      - run: cargo test --doc
+
+  msrv:
+    name: Check MSRV
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@1.70.0
+      - run: cargo check --release
 
   cross-check:
-    name: Check Cross
+    name: Check Cross-Compilation
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -44,70 +41,32 @@ jobs:
           - armv7-unknown-linux-gnueabihf
           - thumbv7em-none-eabihf
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions-rs/toolchain@v1
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
         with:
-          profile: minimal
-          toolchain: stable
-          target: ${{ matrix.target }}
-          override: true
-      - uses: actions-rs/cargo@v1
-        with:
-          use-cross: true
-          command: check
-          args: --release --target=${{ matrix.target }} --no-default-features
+          targets: "armv7-unknown-linux-gnueabihf, thumbv7em-none-eabihf"
+      - run: cargo check --release --target=${{matrix.target}} --no-default-features
 
   fmt:
-    name: Rustfmt
+    name: Check formatting
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
-      - run: rustup component add rustfmt
-      - uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: --all -- --check
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - run: cargo fmt --all -- --check
 
-  check-doc:
+  docs:
     name: Check Documentation Build
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          override: true
-          profile: minimal
-      - uses: actions-rs/cargo@v1
-        with:
-          command: doc
-          args: --all-features
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@nightly
+      - run: RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc --all-features
 
   clippy:
     name: Clippy
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-      - run: rustup component add clippy
-      - uses: actions-rs/cargo@v1
-        with:
-          command: clippy
-          args: -- -D warnings
-
-  ci:
-      if: ${{ success() }}
-      # all new jobs must be added to this list
-      needs: [check, fmt, clippy]
-      runs-on: ubuntu-latest
-      steps:
-        - name: CI succeeded
-          run: exit 0
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - run: cargo clippy -- -D warnings

CHANGELOG.md

@@ -8,6 +8,201 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 # [unreleased]
 
+# [v0.12.0] 2024-09-10
+
+- Bumped MSRV to 1.70.0
+
+## Added
+
+- Added new `cfdp::tlv::TlvOwned` type which erases the lifetime and is clonable.
+- Dedicated `cfdp::tlv::TlvLvDataTooLarge` error struct for APIs where this is the only possible
+  API error.
+- Added File Data PDU API which expects the expected file data size and then exposes the unwritten
+  file data field as a mutable slice. This allows to read data from the virtual file system
+  API to the file data buffer without an intermediate buffer.
+- Generic `EofPdu::new` constructor.
+- Added generic sequence counter module.
+- Added `MsgToUserTlv::to_tlv` converter which reduced the type and converts
+  it to a generic `Tlv`.
+- Implemented `From<MsgToUserTlv> for Tlv` converter trait.
+- Added CFDP maximum file segment length calculator method `calculate_max_file_seg_len_for_max_packet_len_and_pdu_header`
+
+## Added and Changed
+
+- Added new `ReadableTlv` to avoid some boilerplate code and have a common abstraction implemented
+  for both `Tlv` and `TlvOwned` to read the raw TLV data field and its length.
+- Replaced `cfdp::tlv::TlvLvError` by `cfdp::tlv::TlvLvDataTooLarge` where applicable.
+
+## Fixed
+
+- Fixed an error in the EOF writer which wrote the fault location to the wrong buffer position.
+- cfdp `ConditionCode::CheckLimitReached` previous had the wrong numerical value of `0b1001` (9)
+  and now has the correct value of `0b1010` (10).
+
+## Changed
+
+- Minor documentation build updates.
+- Increased delegate version range to v0.13
+
+# [v0.11.2] 2024-05-19
+
+- Bumped MSRV to 1.68.2
+
+## Fixed
+
+- Removed `defmt::Format` impl for `MetadataPduCreator` which seems to be problematic.
+
+# [v0.11.1] 2024-04-22
+
+## Fixed
+
+- The default data length for for `SpHeader` constructors where the data field length is not
+  specified is now 0.
+- The `SpHeader::new_from_fields` is public now.
+
+## Added
+
+- `SpHeader::to_vec` method.
+
+# [v0.11.0] 2024-04-16
+
+## Changed
+
+- Moved `CCSDS_HEADER_LEN` constant to the crate root.
+
+## Added
+
+- Added `SpacePacketHeader` type alias for `SpHeader` type.
+
+# [v0.11.0-rc.2] 2024-04-04
+
+## Changed
+
+- Renamed `PacketId` and `PacketSequenceCtrl` `new` method to `new_checked` and former
+  `new_const` method to `new`.
+- Renamed `tc`, `tm`, `tc_unseg` and `tm_unseg` variants for `PacketId` and `SpHeader`
+  to `new_for_tc_checked`, `new_for_tm_checked`, `new_for_unseg_tc_checked` and
+  `new_for_unseg_tm_checked`.
+- `PusTmCreator` and `PusTcCreator` now expect a regular instance of `SpHeader` instead of
+  a mutable reference.
+
+## Added
+
+- `SpHeader::new_from_apid` and `SpHeader::new_from_apid_checked` constructor.
+- `#[inline]` attribute for a lot of small functions.
+
+# [v0.11.0-rc.1] 2024-04-03
+
+Major API changes for the time API. If you are using the time API, it is strongly recommended
+to check all the API changes in the **Changed** chapter.
+
+## Fixed
+
+- CUC timestamp was fixed to include leap second corrections because it is based on the TAI
+  time reference. The default CUC time object do not implement `CcsdsTimeProvider` anymore
+  because the trait methods require cached leap second information. This task is now performed
+  by the `cuc::CucTimeWithLeapSecs` which implements the trait.
+
+## Added
+
+- `From<$EcssEnum$TY> from $TY` for the ECSS enum type definitions.
+- Added basic support conversions to the `time` library. Introduce new `chrono` and `timelib`
+  feature gate.
+- Added `CcsdsTimeProvider::timelib_date_time`.
+- Optional support for `defmt` by adding optional `defmt::Format` derives for common types.
+
+## Changed
+
+- `PusTcCreator::new_simple` now expects a valid slice for the source data instead of an optional
+  slice. For telecommands without application data, `&[]` can be passed.
+- `PusTmSecondaryHeader` constructors now expects a valid slice for the time stamp instead of an
+  optional slice.
+- Renamed `CcsdsTimeProvider::date_time` to `CcsdsTimeProvider::chrono_date_time`
+- Renamed `CcsdsTimeCodes` to `CcsdsTimeCode`
+- Renamed `cds::TimeProvider` to `cds::CdsTime`
+- Renamed `cuc::TimeProviderCcsdsEpoch` to `cuc::CucTime`
+- `UnixTimestamp` renamed to `UnixTime`
+- `UnixTime` seconds are now private and can be retrieved using the `secs` member method.
+- `UnixTime::new` renamed to `UnixTime::new_checked`.
+- `UnixTime::secs` renamed to `UnixTime::as_secs`.
+- `UnixTime` now has a nanosecond subsecond precision. The `new` constructor now expects
+   nanoseconds as the second argument.
+- Added new `UnixTime::new_subsec_millis` and `UnixTime::new_subsec_millis_checked` API
+  to still allow creating a timestamp with only millisecond subsecond resolution.
+- `CcsdsTimeProvider` now has a new `subsec_nanos` method in addition to a default
+  implementation for the `subsec_millis` method.
+- `CcsdsTimeProvider::date_time` renamed to `CcsdsTimeProvider::chrono_date_time`.
+- Added `UnixTime::MIN`, `UnixTime::MAX` and `UnixTime::EPOCH`.
+- Added `UnixTime::timelib_date_time`.
+- Error handling for ECSS and time module is more granular now, with a new
+  `DateBeforeCcsdsEpochError` error and a `DateBeforeCcsdsEpoch` enum variant for both
+  `CdsError` and `CucError`.
+- `PusTmCreator` now has two lifetimes: One for the raw source data buffer and one for the
+  raw timestamp.
+- Time API `from_now*` API renamed to `now*`.
+
+## Removed
+
+- Legacy `PusTm` and `PusTc` objects.
+
+# [v0.11.0-rc.0] 2024-03-04
+
+## Added
+
+- `From<$TY>` for the `EcssEnum$TY` ECSS enum type definitions.
+- `Sub` implementation for `UnixTimestamp` to calculate the duration between two timestamps.
+
+## Changed
+
+- `CcsdsTimeProvider` `subsecond_millis` function now returns `u16` instead of `Option<u16>`.
+- `UnixTimestamp` `subsecond_millis` function now returns `u16` instead of `Option<u16>`.
+
+# [v0.10.0] 2024-02-17
+
+## Added
+
+- Added `value` and `to_vec` methods for the `UnsignedEnum` trait. The value is returned as
+  as `u64`. Renamed former `value` method on `GenericUnsignedByteField` to `value_typed`.
+- Added `value_const` const function for `UnsignedByteField` type.
+- Added `value_typed` const functions for `GenericUnsignedByteField` and `GenericEcssEnumWrapper`.
+
+# [v0.9.0] 2024-02-07
+
+## Added
+
+- `CcsdsPacket`, `PusPacket` and `GenericPusTmSecondaryHeader` implementation for
+  `PusTmZeroCopyWriter`.
+- Additional length checks for `PusTmZeroCopyWriter`.
+
+## Changed
+
+- `PusTmZeroCopyWriter`: Added additional timestamp length argument for `new` constructor.
+
+## Fixed
+
+- Typo: `PUC_TM_MIN_HEADER_LEN` -> `PUS_TM_MIN_HEADER_LEN`
+
+# [v0.8.1] 2024-02-05
+
+## Fixed
+
+- Added `pub` visibility for `PacketSequenceCtrl::const_new`.
+
+# [v0.8.0] 2024-02-05
+
+## Added
+
+- Added `len_written` and `to_vec` methods to the `TimeWriter` trait.
+
+# [v0.7.0] 2024-02-01
+
+# [v0.7.0-beta.4] 2024-01-23
+
+## Fixed
+
+- `MetadataPduCreator`: The serialization function shifted the closure requested information
+  to the wrong position (first reserved bit) inside the raw content field.
+
 # [v0.7.0-beta.3] 2023-12-06
 
 ## Added

Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "spacepackets"
-version = "0.7.0-beta.3"
+version = "0.12.0"
 edition = "2021"
-rust-version = "1.61"
+rust-version = "1.70.0"
 authors = ["Robin Mueller <muellerr@irs.uni-stuttgart.de>"]
 description = "Generic implementations for various CCSDS and ECSS packet standards"
 homepage = "https://egit.irs.uni-stuttgart.de/rust/spacepackets"
@@ -14,7 +14,8 @@ categories = ["aerospace", "aerospace::space-protocols", "no-std", "hardware-sup
 
 [dependencies]
 crc = "3"
-delegate = ">=0.8, <0.11"
+delegate = ">=0.8, <=0.13"
+paste = "1"
 
 [dependencies.zerocopy]
 version = "0.7"
@@ -34,23 +35,37 @@ optional = true
 default-features = false
 features = ["derive"]
 
+[dependencies.time]
+version = "0.3"
+default-features = false
+optional = true
+
 [dependencies.chrono]
 version = "0.4"
 default-features = false
+optional = true
 
 [dependencies.num-traits]
 version = "0.2"
 default-features = false
 
-[dev-dependencies.postcard]
-version = "1"
+[dependencies.defmt]
+version = "0.3"
+optional = true
+
+[dev-dependencies]
+postcard = "1"
+chrono = "0.4"
 
 [features]
 default = ["std"]
 std = ["chrono/std", "chrono/clock", "alloc", "thiserror"]
 serde = ["dep:serde", "chrono/serde"]
-alloc = ["postcard/alloc", "chrono/alloc"]
+alloc = ["postcard/alloc", "chrono/alloc", "defmt/alloc", "serde/alloc"]
+chrono = ["dep:chrono"]
+timelib = ["dep:time"]
+defmt = ["dep:defmt"]
 
 [package.metadata.docs.rs]
 all-features = true
-rustdoc-args = ["--cfg", "doc_cfg"]
+rustdoc-args = ["--generate-link-to-definition"]

README.md

@@ -29,10 +29,6 @@ Currently, this includes the following components:
 
 `spacepackets` supports various runtime environments and is also suitable for `no_std` environments.
 
-It also offers optional support for [`serde`](https://serde.rs/). This allows serializing and
-deserializing them with an appropriate `serde` provider like
-[`postcard`](https://github.com/jamesmunns/postcard).
-
 ## Default features
 
  - [`std`](https://doc.rust-lang.org/std/): Enables functionality relying on the standard library.
@@ -43,6 +39,10 @@ deserializing them with an appropriate `serde` provider like
 ## Optional Features
 
  - [`serde`](https://serde.rs/): Adds `serde` support for most types by adding `Serialize` and `Deserialize` `derive`s
+ - [`chrono`](https://crates.io/crates/chrono): Add basic support for the `chrono` time library.
+ - [`timelib`](https://crates.io/crates/time): Add basic support for the `time` time library.
+ - [`defmt`](https://defmt.ferrous-systems.com/): Add support for the `defmt` by adding the
+   [`defmt::Format`](https://defmt.ferrous-systems.com/format) derive on many types.
 
 # Examples
 
@@ -61,3 +61,13 @@ cargo install grcov --locked
 
 After that, you can simply run `coverage.py` to test the project with coverage. You can optionally
 supply the `--open` flag to open the coverage report in your webbrowser.
+
+# Miri
+
+You can run the [`miri`](https://github.com/rust-lang/miri) tool on this library to check for
+undefined behaviour (UB). This library does not use use any `unsafe` code blocks, but `miri` could
+still catch UB from used libraries.
+
+```sh
+cargo +nightly miri nextest run --all-features
+```

automation/Dockerfile

@@ -15,7 +15,10 @@ RUN rustup install nightly && \
     rustup target add thumbv7em-none-eabihf armv7-unknown-linux-gnueabihf && \
     rustup component add rustfmt clippy llvm-tools-preview
 
+# Get grcov
 RUN curl -sSL https://github.com/mozilla/grcov/releases/download/v0.8.19/grcov-x86_64-unknown-linux-gnu.tar.bz2 | tar -xj --directory /usr/local/bin
+# Get nextest
+RUN curl -LsSf https://get.nexte.st/latest/linux | tar zxf - -C ${CARGO_HOME:-~/.cargo}/bin
 
 # SSH stuff to allow deployment to doc server
 RUN adduser --uid 114 jenkins

automation/Jenkinsfile

@@ -21,7 +21,9 @@ pipeline {
     }
     stage('Docs') {
         steps {
-          sh 'cargo +nightly doc --all-features'
+          sh """
+            RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc --all-features
+          """
         }
     }
     stage('Rustfmt') {
@@ -31,7 +33,8 @@ pipeline {
     }
     stage('Test') {
       steps {
-        sh 'cargo test --all-features'
+        sh 'cargo nextest r --all-features'
+        sh 'cargo test --doc'
       }
     }
     stage('Check with all features') {

release-checklist.md

@@ -4,11 +4,14 @@ Checklist for new releases
 # Pre-Release
 
 1. Make sure any new modules are documented sufficiently enough and check docs with
-   `cargo +nightly doc --all-features --config 'rustdocflags=["--cfg", "doc_cfg"]' --open`.
+   `RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc --all-features --open`
+   or `cargo +nightly doc --all-features --config 'build.rustdocflags=["--cfg", "docsrs" --generate-link-to-definition"]' --open`
+   (was problematic on more recent nightly versions).
 2. Bump version specifier in `Cargo.toml`.
 3. Update `CHANGELOG.md`: Convert `unreleased` section into version section with date and add new
    `unreleased` section.
-4. Run `cargo test --all-features`.
+4. Run `cargo test --all-features` or `cargo nextest r --all-features` together with
+   `cargo test --doc`.
 5. Run `cargo fmt` and `cargo clippy`. Check `cargo msrv` against MSRV in `Cargo.toml`.
 6. Wait for CI/CD results for EGit and Github. These also check cross-compilation for bare-metal
    targets.

src/cfdp/lv.rs

@@ -1,5 +1,4 @@
 //! Generic CFDP length-value (LV) abstraction as specified in CFDP 5.1.8.
-use crate::cfdp::TlvLvError;
 use crate::ByteConversionError;
 use core::str::Utf8Error;
 #[cfg(feature = "serde")]
@@ -7,6 +6,8 @@ use serde::{Deserialize, Serialize};
 #[cfg(feature = "std")]
 use std::string::String;
 
+use super::TlvLvDataTooLarge;
+
 pub const MIN_LV_LEN: usize = 1;
 
 /// Generic CFDP length-value (LV) abstraction as specified in CFDP 5.1.8.
@@ -20,6 +21,7 @@ pub const MIN_LV_LEN: usize = 1;
 ///    this will be the lifetime of that data reference.
 #[derive(Debug, Copy, Clone, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct Lv<'data> {
     data: &'data [u8],
     // If the LV was generated from a raw bytestream, this will contain the start of the
@@ -61,9 +63,10 @@ pub(crate) fn generic_len_check_deserialization(
 }
 
 impl<'data> Lv<'data> {
-    pub fn new(data: &[u8]) -> Result<Lv, TlvLvError> {
+    #[inline]
+    pub fn new(data: &[u8]) -> Result<Lv, TlvLvDataTooLarge> {
         if data.len() > u8::MAX as usize {
-            return Err(TlvLvError::DataTooLarge(data.len()));
+            return Err(TlvLvDataTooLarge(data.len()));
         }
         Ok(Lv {
             data,
@@ -72,6 +75,7 @@ impl<'data> Lv<'data> {
     }
 
     /// Creates a LV with an empty value field.
+    #[inline]
     pub fn new_empty() -> Lv<'data> {
         Lv {
             data: &[],
@@ -81,45 +85,52 @@ impl<'data> Lv<'data> {
 
     /// Helper function to build a string LV. This is especially useful for the file or directory
     /// path LVs
-    pub fn new_from_str(str_slice: &str) -> Result<Lv, TlvLvError> {
+    #[inline]
+    pub fn new_from_str(str_slice: &str) -> Result<Lv, TlvLvDataTooLarge> {
         Self::new(str_slice.as_bytes())
     }
 
     /// Helper function to build a string LV. This is especially useful for the file or directory
     /// path LVs
     #[cfg(feature = "std")]
-    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
-    pub fn new_from_string(string: &'data String) -> Result<Lv<'data>, TlvLvError> {
+    #[inline]
+    pub fn new_from_string(string: &'data String) -> Result<Lv<'data>, TlvLvDataTooLarge> {
         Self::new(string.as_bytes())
     }
 
     /// Returns the length of the value part, not including the length byte.
+    #[inline]
     pub fn len_value(&self) -> usize {
         self.data.len()
     }
 
     /// Returns the full raw length, including the length byte.
+    #[inline]
     pub fn len_full(&self) -> usize {
         self.len_value() + 1
     }
 
     /// Checks whether the value field is empty.
+    #[inline]
     pub fn is_empty(&self) -> bool {
         self.data.len() == 0
     }
 
+    #[inline]
     pub fn value(&self) -> &[u8] {
         self.data
     }
 
     /// If the LV was generated from a raw bytestream using [Self::from_bytes], the raw start
     /// of the LV can be retrieved with this method.
+    #[inline]
     pub fn raw_data(&self) -> Option<&[u8]> {
         self.raw_data
     }
 
     /// Convenience function to extract the value as a [str]. This is useful if the LV is
     /// known to contain a [str], for example being a file name.
+    #[inline]
     pub fn value_as_str(&self) -> Option<Result<&'data str, Utf8Error>> {
         if self.is_empty() {
             return None;
@@ -135,6 +146,7 @@ impl<'data> Lv<'data> {
     }
 
     /// Reads a LV  from a raw buffer.
+    #[inline]
     pub fn from_bytes(buf: &'data [u8]) -> Result<Lv<'data>, ByteConversionError> {
         generic_len_check_deserialization(buf, MIN_LV_LEN)?;
         Self::from_be_bytes_no_len_check(buf)
@@ -151,6 +163,7 @@ impl<'data> Lv<'data> {
         MIN_LV_LEN + self.data.len()
     }
 
+    #[inline]
     pub(crate) fn from_be_bytes_no_len_check(
         buf: &'data [u8],
     ) -> Result<Lv<'data>, ByteConversionError> {
@@ -165,10 +178,10 @@ impl<'data> Lv<'data> {
 
 #[cfg(test)]
 pub mod tests {
-    use super::*;
     use alloc::string::ToString;
 
-    use crate::cfdp::TlvLvError;
+    use super::*;
+
     use crate::ByteConversionError;
     use std::string::String;
 
@@ -259,15 +272,11 @@ pub mod tests {
         let lv = Lv::new(&data_big);
         assert!(lv.is_err());
         let error = lv.unwrap_err();
-        if let TlvLvError::DataTooLarge(size) = error {
-            assert_eq!(size, u8::MAX as usize + 1);
-            assert_eq!(
-                error.to_string(),
-                "data with size 256 larger than allowed 255 bytes"
-            );
-        } else {
-            panic!("invalid exception {:?}", error)
-        }
+        assert_eq!(error.0, u8::MAX as usize + 1);
+        assert_eq!(
+            error.to_string(),
+            "data with size 256 larger than allowed 255 bytes"
+        );
     }
 
     #[test]

src/cfdp/mod.rs

@@ -18,6 +18,7 @@ pub const CFDP_VERSION_2: u8 = 0b001;
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum PduType {
     FileDirective = 0,
@@ -26,6 +27,7 @@ pub enum PduType {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum Direction {
     TowardsReceiver = 0,
@@ -34,6 +36,7 @@ pub enum Direction {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum TransmissionMode {
     Acknowledged = 0,
@@ -42,6 +45,7 @@ pub enum TransmissionMode {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum CrcFlag {
     NoCrc = 0,
@@ -69,6 +73,7 @@ impl From<CrcFlag> for bool {
 /// Always 0 and ignored for File Directive PDUs (CCSDS 727.0-B-5 P.75)
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum SegmentMetadataFlag {
     NotPresent = 0,
@@ -78,6 +83,7 @@ pub enum SegmentMetadataFlag {
 /// Always 0 and ignored for File Directive PDUs (CCSDS 727.0-B-5 P.75)
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum SegmentationControl {
     NoRecordBoundaryPreservation = 0,
@@ -86,6 +92,7 @@ pub enum SegmentationControl {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum FaultHandlerCode {
     NoticeOfCancellation = 0b0001,
@@ -96,6 +103,7 @@ pub enum FaultHandlerCode {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum ConditionCode {
     /// This is not an error condition for which a faulty handler override can be specified
@@ -108,7 +116,7 @@ pub enum ConditionCode {
     FileSizeError = 0b0110,
     NakLimitReached = 0b0111,
     InactivityDetected = 0b1000,
-    CheckLimitReached = 0b1001,
+    CheckLimitReached = 0b1010,
     UnsupportedChecksumType = 0b1011,
     /// Not an actual fault condition for which fault handler overrides can be specified
     SuspendRequestReceived = 0b1110,
@@ -118,6 +126,7 @@ pub enum ConditionCode {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum LargeFileFlag {
     /// 32 bit maximum file size and FSS size
@@ -129,6 +138,7 @@ pub enum LargeFileFlag {
 /// Transaction status for the ACK PDU field according to chapter 5.2.4 of the CFDP standard.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum TransactionStatus {
     /// Transaction is not currently active and the CFDP implementation does not retain a
@@ -146,6 +156,7 @@ pub enum TransactionStatus {
 /// [SANA Checksum Types registry](https://sanaregistry.org/r/checksum_identifiers/)
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum ChecksumType {
     /// Modular legacy checksum
@@ -167,8 +178,28 @@ pub const NULL_CHECKSUM_U32: [u8; 4] = [0; 4];
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct TlvLvDataTooLarge(pub usize);
+
+impl Display for TlvLvDataTooLarge {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+        write!(
+            f,
+            "data with size {} larger than allowed {} bytes",
+            self.0,
+            u8::MAX
+        )
+    }
+}
+
+#[cfg(feature = "std")]
+impl Error for TlvLvDataTooLarge {}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum TlvLvError {
-    DataTooLarge(usize),
+    DataTooLarge(TlvLvDataTooLarge),
     ByteConversion(ByteConversionError),
     /// First value: Found value. Second value: Expected value if there is one.
     InvalidTlvTypeField {
@@ -185,6 +216,12 @@ pub enum TlvLvError {
     InvalidFilestoreActionCode(u8),
 }
 
+impl From<TlvLvDataTooLarge> for TlvLvError {
+    fn from(value: TlvLvDataTooLarge) -> Self {
+        Self::DataTooLarge(value)
+    }
+}
+
 impl From<ByteConversionError> for TlvLvError {
     fn from(value: ByteConversionError) -> Self {
         Self::ByteConversion(value)
@@ -194,13 +231,8 @@ impl From<ByteConversionError> for TlvLvError {
 impl Display for TlvLvError {
     fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
         match self {
-            TlvLvError::DataTooLarge(data_len) => {
-                write!(
-                    f,
-                    "data with size {} larger than allowed {} bytes",
-                    data_len,
-                    u8::MAX
-                )
+            TlvLvError::DataTooLarge(e) => {
+                write!(f, "{}", e)
             }
             TlvLvError::ByteConversion(e) => {
                 write!(f, "tlv or lv byte conversion: {}", e)
@@ -228,6 +260,7 @@ impl Display for TlvLvError {
 impl Error for TlvLvError {
     fn source(&self) -> Option<&(dyn Error + 'static)> {
         match self {
+            TlvLvError::DataTooLarge(e) => Some(e),
             TlvLvError::ByteConversion(e) => Some(e),
             _ => None,
         }

src/cfdp/pdu/ack.rs

@@ -15,6 +15,7 @@ use serde::{Deserialize, Serialize};
 /// For more information, refer to CFDP chapter 5.2.4.
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct AckPdu {
     pdu_header: PduHeader,
     directive_code_of_acked_pdu: FileDirectiveType,

src/cfdp/pdu/eof.rs

@@ -15,6 +15,7 @@ use super::{CfdpPdu, WritablePduPacket};
 /// For more information, refer to CFDP chapter 5.2.2.
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct EofPdu {
     pdu_header: PduHeader,
     condition_code: ConditionCode,
@@ -24,20 +25,36 @@ pub struct EofPdu {
 }
 
 impl EofPdu {
-    pub fn new_no_error(mut pdu_header: PduHeader, file_checksum: u32, file_size: u64) -> Self {
+    pub fn new(
+        mut pdu_header: PduHeader,
+        condition_code: ConditionCode,
+        file_checksum: u32,
+        file_size: u64,
+        fault_location: Option<EntityIdTlv>,
+    ) -> Self {
         // Force correct direction flag.
         pdu_header.pdu_conf.direction = Direction::TowardsReceiver;
         let mut eof_pdu = Self {
             pdu_header,
-            condition_code: ConditionCode::NoError,
+            condition_code,
             file_checksum,
             file_size,
-            fault_location: None,
+            fault_location,
         };
         eof_pdu.pdu_header.pdu_datafield_len = eof_pdu.calc_pdu_datafield_len() as u16;
         eof_pdu
     }
 
+    pub fn new_no_error(pdu_header: PduHeader, file_checksum: u32, file_size: u64) -> Self {
+        Self::new(
+            pdu_header,
+            ConditionCode::NoError,
+            file_checksum,
+            file_size,
+            None,
+        )
+    }
+
     pub fn pdu_header(&self) -> &PduHeader {
         &self.pdu_header
     }
@@ -147,7 +164,7 @@ impl WritablePduPacket for EofPdu {
             &mut buf[current_idx..],
         )?;
         if let Some(fault_location) = self.fault_location {
-            current_idx += fault_location.write_to_bytes(buf)?;
+            current_idx += fault_location.write_to_bytes(&mut buf[current_idx..])?;
         }
         if self.crc_flag() == CrcFlag::WithCrc {
             current_idx = add_pdu_crc(buf, current_idx);
@@ -170,13 +187,23 @@ mod tests {
     use crate::cfdp::{ConditionCode, CrcFlag, LargeFileFlag, PduType, TransmissionMode};
     #[cfg(feature = "serde")]
     use crate::tests::generic_serde_test;
+    use crate::util::{UnsignedByteFieldU16, UnsignedEnum};
 
-    fn verify_state(&eof_pdu: &EofPdu, file_flag: LargeFileFlag) {
+    fn verify_state_no_error_no_crc(eof_pdu: &EofPdu, file_flag: LargeFileFlag) {
+        verify_state(eof_pdu, CrcFlag::NoCrc, file_flag, ConditionCode::NoError);
+    }
+
+    fn verify_state(
+        eof_pdu: &EofPdu,
+        crc_flag: CrcFlag,
+        file_flag: LargeFileFlag,
+        cond_code: ConditionCode,
+    ) {
         assert_eq!(eof_pdu.file_checksum(), 0x01020304);
         assert_eq!(eof_pdu.file_size(), 12);
-        assert_eq!(eof_pdu.condition_code(), ConditionCode::NoError);
+        assert_eq!(eof_pdu.condition_code(), cond_code);
 
-        assert_eq!(eof_pdu.crc_flag(), CrcFlag::NoCrc);
+        assert_eq!(eof_pdu.crc_flag(), crc_flag);
         assert_eq!(eof_pdu.file_flag(), file_flag);
         assert_eq!(eof_pdu.pdu_type(), PduType::FileDirective);
         assert_eq!(
@@ -196,7 +223,7 @@ mod tests {
         let pdu_header = PduHeader::new_no_file_data(pdu_conf, 0);
         let eof_pdu = EofPdu::new_no_error(pdu_header, 0x01020304, 12);
         assert_eq!(eof_pdu.len_written(), pdu_header.header_len() + 2 + 4 + 4);
-        verify_state(&eof_pdu, LargeFileFlag::Normal);
+        verify_state_no_error_no_crc(&eof_pdu, LargeFileFlag::Normal);
     }
 
     #[test]
@@ -282,7 +309,7 @@ mod tests {
         let pdu_conf = common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Large);
         let pdu_header = PduHeader::new_no_file_data(pdu_conf, 0);
         let eof_pdu = EofPdu::new_no_error(pdu_header, 0x01020304, 12);
-        verify_state(&eof_pdu, LargeFileFlag::Large);
+        verify_state_no_error_no_crc(&eof_pdu, LargeFileFlag::Large);
         assert_eq!(eof_pdu.len_written(), pdu_header.header_len() + 2 + 8 + 4);
     }
 
@@ -294,4 +321,48 @@ mod tests {
         let eof_pdu = EofPdu::new_no_error(pdu_header, 0x01020304, 12);
         generic_serde_test(eof_pdu);
     }
+
+    fn generic_test_with_fault_location_and_error(crc: CrcFlag) {
+        let pdu_conf = common_pdu_conf(crc, LargeFileFlag::Normal);
+        let pdu_header = PduHeader::new_no_file_data(pdu_conf, 0);
+        let eof_pdu = EofPdu::new(
+            pdu_header,
+            ConditionCode::FileChecksumFailure,
+            0x01020304,
+            12,
+            Some(EntityIdTlv::new(UnsignedByteFieldU16::new(5).into())),
+        );
+        let mut expected_len = pdu_header.header_len() + 2 + 4 + 4 + 4;
+        if crc == CrcFlag::WithCrc {
+            expected_len += 2;
+        }
+        // Entity ID TLV increaes length by 4.
+        assert_eq!(eof_pdu.len_written(), expected_len);
+        verify_state(
+            &eof_pdu,
+            crc,
+            LargeFileFlag::Normal,
+            ConditionCode::FileChecksumFailure,
+        );
+        let eof_vec = eof_pdu.to_vec().unwrap();
+        let eof_read_back = EofPdu::from_bytes(&eof_vec);
+        if let Err(e) = eof_read_back {
+            panic!("deserialization failed with: {e}")
+        }
+        let eof_read_back = eof_read_back.unwrap();
+        assert_eq!(eof_read_back, eof_pdu);
+        assert!(eof_read_back.fault_location.is_some());
+        assert_eq!(eof_read_back.fault_location.unwrap().entity_id().value(), 5);
+        assert_eq!(eof_read_back.fault_location.unwrap().entity_id().size(), 2);
+    }
+
+    #[test]
+    fn test_with_fault_location_and_error() {
+        generic_test_with_fault_location_and_error(CrcFlag::NoCrc);
+    }
+
+    #[test]
+    fn test_with_fault_location_and_error_and_crc() {
+        generic_test_with_fault_location_and_error(CrcFlag::WithCrc);
+    }
 }

src/cfdp/pdu/file_data.rs

@@ -92,16 +92,67 @@ impl<'seg_meta> SegmentMetadata<'seg_meta> {
     }
 }
 
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+struct FdPduBase<'seg_meta> {
+    pdu_header: PduHeader,
+    #[cfg_attr(feature = "serde", serde(borrow))]
+    segment_metadata: Option<SegmentMetadata<'seg_meta>>,
+    offset: u64,
+}
+
+impl CfdpPdu for FdPduBase<'_> {
+    fn pdu_header(&self) -> &PduHeader {
+        &self.pdu_header
+    }
+
+    fn file_directive_type(&self) -> Option<FileDirectiveType> {
+        None
+    }
+}
+
+impl FdPduBase<'_> {
+    fn calc_pdu_datafield_len(&self, file_data_len: u64) -> usize {
+        let mut len = core::mem::size_of::<u32>();
+        if self.pdu_header.pdu_conf.file_flag == LargeFileFlag::Large {
+            len += 4;
+        }
+        if self.segment_metadata.is_some() {
+            len += self.segment_metadata.as_ref().unwrap().written_len()
+        }
+        len += file_data_len as usize;
+        if self.crc_flag() == CrcFlag::WithCrc {
+            len += 2;
+        }
+        len
+    }
+
+    fn write_common_fields_to_bytes(&self, buf: &mut [u8]) -> Result<usize, PduError> {
+        let mut current_idx = self.pdu_header.write_to_bytes(buf)?;
+        if self.segment_metadata.is_some() {
+            current_idx += self
+                .segment_metadata
+                .as_ref()
+                .unwrap()
+                .write_to_bytes(&mut buf[current_idx..])?;
+        }
+        current_idx += write_fss_field(
+            self.pdu_header.common_pdu_conf().file_flag,
+            self.offset,
+            &mut buf[current_idx..],
+        )?;
+        Ok(current_idx)
+    }
+}
+
 /// File Data PDU abstraction.
 ///
 /// For more information, refer to CFDP chapter 5.3.
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct FileDataPdu<'seg_meta, 'file_data> {
-    pdu_header: PduHeader,
     #[cfg_attr(feature = "serde", serde(borrow))]
-    segment_metadata: Option<SegmentMetadata<'seg_meta>>,
-    offset: u64,
+    common: FdPduBase<'seg_meta>,
     file_data: &'file_data [u8],
 }
 
@@ -134,42 +185,34 @@ impl<'seg_meta, 'file_data> FileDataPdu<'seg_meta, 'file_data> {
             pdu_header.seg_metadata_flag = SegmentMetadataFlag::Present;
         }
         let mut pdu = Self {
-            pdu_header,
-            segment_metadata,
-            offset,
+            common: FdPduBase {
+                pdu_header,
+                segment_metadata,
+                offset,
+            },
             file_data,
         };
-        pdu.pdu_header.pdu_datafield_len = pdu.calc_pdu_datafield_len() as u16;
+        pdu.common.pdu_header.pdu_datafield_len = pdu.calc_pdu_datafield_len() as u16;
         pdu
     }
 
     fn calc_pdu_datafield_len(&self) -> usize {
-        let mut len = core::mem::size_of::<u32>();
-        if self.pdu_header.pdu_conf.file_flag == LargeFileFlag::Large {
-            len += 4;
-        }
-        if self.segment_metadata.is_some() {
-            len += self.segment_metadata.as_ref().unwrap().written_len()
-        }
-        len += self.file_data.len();
-        if self.crc_flag() == CrcFlag::WithCrc {
-            len += 2;
-        }
-        len
+        self.common
+            .calc_pdu_datafield_len(self.file_data.len() as u64)
+    }
+
+    pub fn segment_metadata(&self) -> Option<&SegmentMetadata> {
+        self.common.segment_metadata.as_ref()
     }
 
     pub fn offset(&self) -> u64 {
-        self.offset
+        self.common.offset
     }
 
     pub fn file_data(&self) -> &'file_data [u8] {
         self.file_data
     }
 
-    pub fn segment_metadata(&self) -> Option<&SegmentMetadata> {
-        self.segment_metadata.as_ref()
-    }
-
     pub fn from_bytes<'buf: 'seg_meta + 'file_data>(buf: &'buf [u8]) -> Result<Self, PduError> {
         let (pdu_header, mut current_idx) = PduHeader::from_bytes(buf)?;
         let full_len_without_crc = pdu_header.verify_length_and_checksum(buf)?;
@@ -190,16 +233,18 @@ impl<'seg_meta, 'file_data> FileDataPdu<'seg_meta, 'file_data> {
             .into());
         }
         Ok(Self {
-            pdu_header,
-            segment_metadata,
-            offset,
+            common: FdPduBase {
+                pdu_header,
+                segment_metadata,
+                offset,
+            },
             file_data: &buf[current_idx..full_len_without_crc],
         })
     }
 }
 impl CfdpPdu for FileDataPdu<'_, '_> {
     fn pdu_header(&self) -> &PduHeader {
-        &self.pdu_header
+        &self.common.pdu_header
     }
 
     fn file_directive_type(&self) -> Option<FileDirectiveType> {
@@ -216,19 +261,8 @@ impl WritablePduPacket for FileDataPdu<'_, '_> {
             }
             .into());
         }
-        let mut current_idx = self.pdu_header.write_to_bytes(buf)?;
-        if self.segment_metadata.is_some() {
-            current_idx += self
-                .segment_metadata
-                .as_ref()
-                .unwrap()
-                .write_to_bytes(&mut buf[current_idx..])?;
-        }
-        current_idx += write_fss_field(
-            self.pdu_header.common_pdu_conf().file_flag,
-            self.offset,
-            &mut buf[current_idx..],
-        )?;
+
+        let mut current_idx = self.common.write_common_fields_to_bytes(buf)?;
         buf[current_idx..current_idx + self.file_data.len()].copy_from_slice(self.file_data);
         current_idx += self.file_data.len();
         if self.crc_flag() == CrcFlag::WithCrc {
@@ -238,10 +272,167 @@ impl WritablePduPacket for FileDataPdu<'_, '_> {
     }
 
     fn len_written(&self) -> usize {
-        self.pdu_header.header_len() + self.calc_pdu_datafield_len()
+        self.common.pdu_header.header_len() + self.calc_pdu_datafield_len()
     }
 }
 
+/// File Data PDU creator abstraction.
+///
+/// This special creator object allows to read into the file data buffer directly. This avoids
+/// the need of an additional buffer to create a file data PDU. This structure therefore
+/// does not implement the regular [WritablePduPacket] trait.
+///
+/// For more information, refer to CFDP chapter 5.3.
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct FileDataPduCreatorWithReservedDatafield<'seg_meta> {
+    #[cfg_attr(feature = "serde", serde(borrow))]
+    common: FdPduBase<'seg_meta>,
+    file_data_len: u64,
+}
+
+impl<'seg_meta> FileDataPduCreatorWithReservedDatafield<'seg_meta> {
+    pub fn new_with_seg_metadata(
+        pdu_header: PduHeader,
+        segment_metadata: SegmentMetadata<'seg_meta>,
+        offset: u64,
+        file_data_len: u64,
+    ) -> Self {
+        Self::new_generic(pdu_header, Some(segment_metadata), offset, file_data_len)
+    }
+
+    pub fn new_no_seg_metadata(pdu_header: PduHeader, offset: u64, file_data_len: u64) -> Self {
+        Self::new_generic(pdu_header, None, offset, file_data_len)
+    }
+
+    pub fn new_generic(
+        mut pdu_header: PduHeader,
+        segment_metadata: Option<SegmentMetadata<'seg_meta>>,
+        offset: u64,
+        file_data_len: u64,
+    ) -> Self {
+        pdu_header.pdu_type = PduType::FileData;
+        if segment_metadata.is_some() {
+            pdu_header.seg_metadata_flag = SegmentMetadataFlag::Present;
+        }
+        let mut pdu = Self {
+            common: FdPduBase {
+                pdu_header,
+                segment_metadata,
+                offset,
+            },
+            file_data_len,
+        };
+        pdu.common.pdu_header.pdu_datafield_len = pdu.calc_pdu_datafield_len() as u16;
+        pdu
+    }
+
+    fn calc_pdu_datafield_len(&self) -> usize {
+        self.common.calc_pdu_datafield_len(self.file_data_len)
+    }
+
+    pub fn len_written(&self) -> usize {
+        self.common.pdu_header.header_len() + self.calc_pdu_datafield_len()
+    }
+
+    /// This function performs a partial write by writing all data except the file data
+    /// and the CRC.
+    ///
+    /// It returns a [FileDataPduCreatorWithUnwrittenData] which provides a mutable slice to
+    /// the reserved file data field. The user can read file data into this field directly and
+    /// then finish the PDU creation using the [FileDataPduCreatorWithUnwrittenData::finish] call.
+    pub fn write_to_bytes_partially<'buf>(
+        &self,
+        buf: &'buf mut [u8],
+    ) -> Result<FileDataPduCreatorWithUnwrittenData<'buf>, PduError> {
+        if buf.len() < self.len_written() {
+            return Err(ByteConversionError::ToSliceTooSmall {
+                found: buf.len(),
+                expected: self.len_written(),
+            }
+            .into());
+        }
+        let mut current_idx = self.common.write_common_fields_to_bytes(buf)?;
+        let file_data_offset = current_idx as u64;
+        current_idx += self.file_data_len as usize;
+        if self.crc_flag() == CrcFlag::WithCrc {
+            current_idx += 2;
+        }
+        Ok(FileDataPduCreatorWithUnwrittenData {
+            write_buf: &mut buf[0..current_idx],
+            file_data_offset,
+            file_data_len: self.file_data_len,
+            needs_crc: self.crc_flag() == CrcFlag::WithCrc,
+        })
+    }
+}
+
+impl CfdpPdu for FileDataPduCreatorWithReservedDatafield<'_> {
+    fn pdu_header(&self) -> &PduHeader {
+        &self.common.pdu_header
+    }
+
+    fn file_directive_type(&self) -> Option<FileDirectiveType> {
+        None
+    }
+}
+
+/// This structure is created with [FileDataPduCreatorReservedDatafield::write_to_bytes_partially]
+/// and provides an API to read file data from the virtual filesystem into the file data PDU buffer
+/// directly.
+///
+/// This structure provides a mutable slice to the reserved file data field. The user can read
+/// file data into this field directly and then finish the PDU creation using the
+/// [FileDataPduCreatorWithUnwrittenData::finish] call.
+pub struct FileDataPduCreatorWithUnwrittenData<'buf> {
+    write_buf: &'buf mut [u8],
+    file_data_offset: u64,
+    file_data_len: u64,
+    needs_crc: bool,
+}
+
+impl FileDataPduCreatorWithUnwrittenData<'_> {
+    pub fn file_data_field_mut(&mut self) -> &mut [u8] {
+        &mut self.write_buf[self.file_data_offset as usize
+            ..self.file_data_offset as usize + self.file_data_len as usize]
+    }
+
+    /// This functio needs to be called to add a CRC to the file data PDU where applicable.
+    ///
+    /// It returns the full written size of the PDU.
+    pub fn finish(self) -> usize {
+        if self.needs_crc {
+            add_pdu_crc(
+                self.write_buf,
+                self.file_data_offset as usize + self.file_data_len as usize,
+            );
+        }
+        self.write_buf.len()
+    }
+}
+
+/// This function can be used to calculate the maximum allowed file segment size for
+/// a given maximum packet length and the segment metadata if there is any.
+pub fn calculate_max_file_seg_len_for_max_packet_len_and_pdu_header(
+    pdu_header: &PduHeader,
+    max_packet_len: usize,
+    segment_metadata: Option<&SegmentMetadata>,
+) -> usize {
+    let mut subtract = pdu_header.header_len();
+    if segment_metadata.is_some() {
+        subtract += 1 + segment_metadata.as_ref().unwrap().metadata().unwrap().len();
+    }
+    if pdu_header.common_pdu_conf().file_flag == LargeFileFlag::Large {
+        subtract += 8;
+    } else {
+        subtract += 4;
+    }
+    if pdu_header.common_pdu_conf().crc_flag == CrcFlag::WithCrc {
+        subtract += 2;
+    }
+    max_packet_len.saturating_sub(subtract)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -263,7 +454,7 @@ mod tests {
         assert!(fd_pdu.segment_metadata().is_none());
         assert_eq!(
             fd_pdu.len_written(),
-            fd_pdu.pdu_header.header_len() + core::mem::size_of::<u32>() + 4
+            fd_pdu.pdu_header().header_len() + core::mem::size_of::<u32>() + 4
         );
 
         assert_eq!(fd_pdu.crc_flag(), CrcFlag::NoCrc);
@@ -290,11 +481,11 @@ mod tests {
         let written = res.unwrap();
         assert_eq!(
             written,
-            fd_pdu.pdu_header.header_len() + core::mem::size_of::<u32>() + 4
+            fd_pdu.pdu_header().header_len() + core::mem::size_of::<u32>() + 4
         );
-        let mut current_idx = fd_pdu.pdu_header.header_len();
+        let mut current_idx = fd_pdu.pdu_header().header_len();
         let file_size = u32::from_be_bytes(
-            buf[fd_pdu.pdu_header.header_len()..fd_pdu.pdu_header.header_len() + 4]
+            buf[fd_pdu.pdu_header().header_len()..fd_pdu.pdu_header().header_len() + 4]
                 .try_into()
                 .unwrap(),
         );
@@ -380,7 +571,7 @@ mod tests {
         assert_eq!(*fd_pdu.segment_metadata().unwrap(), segment_meta);
         assert_eq!(
             fd_pdu.len_written(),
-            fd_pdu.pdu_header.header_len()
+            fd_pdu.pdu_header().header_len()
                 + 1
                 + seg_metadata.len()
                 + core::mem::size_of::<u32>()
@@ -390,7 +581,7 @@ mod tests {
         fd_pdu
             .write_to_bytes(&mut buf)
             .expect("writing FD PDU failed");
-        let mut current_idx = fd_pdu.pdu_header.header_len();
+        let mut current_idx = fd_pdu.pdu_header().header_len();
         assert_eq!(
             RecordContinuationState::try_from((buf[current_idx] >> 6) & 0b11).unwrap(),
             RecordContinuationState::StartAndEnd
@@ -482,4 +673,142 @@ mod tests {
         let output_converted_back: FileDataPdu = from_bytes(&output).unwrap();
         assert_eq!(output_converted_back, fd_pdu);
     }
+
+    #[test]
+    fn test_fd_pdu_creator_with_reserved_field_no_crc() {
+        let common_conf =
+            CommonPduConfig::new_with_byte_fields(TEST_SRC_ID, TEST_DEST_ID, TEST_SEQ_NUM).unwrap();
+        let pdu_header = PduHeader::new_for_file_data_default(common_conf, 0);
+        let test_str = "hello world!";
+        let fd_pdu = FileDataPduCreatorWithReservedDatafield::new_no_seg_metadata(
+            pdu_header,
+            10,
+            test_str.len() as u64,
+        );
+        let mut write_buf: [u8; 64] = [0; 64];
+        let mut pdu_unwritten = fd_pdu
+            .write_to_bytes_partially(&mut write_buf)
+            .expect("partial write failed");
+        pdu_unwritten
+            .file_data_field_mut()
+            .copy_from_slice(test_str.as_bytes());
+        pdu_unwritten.finish();
+
+        let pdu_reader = FileDataPdu::from_bytes(&write_buf).expect("reading file data PDU failed");
+        assert_eq!(
+            core::str::from_utf8(pdu_reader.file_data()).expect("reading utf8 string failed"),
+            "hello world!"
+        );
+    }
+
+    #[test]
+    fn test_fd_pdu_creator_with_reserved_field_with_crc() {
+        let mut common_conf =
+            CommonPduConfig::new_with_byte_fields(TEST_SRC_ID, TEST_DEST_ID, TEST_SEQ_NUM).unwrap();
+        common_conf.crc_flag = true.into();
+        let pdu_header = PduHeader::new_for_file_data_default(common_conf, 0);
+        let test_str = "hello world!";
+        let fd_pdu = FileDataPduCreatorWithReservedDatafield::new_no_seg_metadata(
+            pdu_header,
+            10,
+            test_str.len() as u64,
+        );
+        let mut write_buf: [u8; 64] = [0; 64];
+        let mut pdu_unwritten = fd_pdu
+            .write_to_bytes_partially(&mut write_buf)
+            .expect("partial write failed");
+        pdu_unwritten
+            .file_data_field_mut()
+            .copy_from_slice(test_str.as_bytes());
+        pdu_unwritten.finish();
+
+        let pdu_reader = FileDataPdu::from_bytes(&write_buf).expect("reading file data PDU failed");
+        assert_eq!(
+            core::str::from_utf8(pdu_reader.file_data()).expect("reading utf8 string failed"),
+            "hello world!"
+        );
+    }
+
+    #[test]
+    fn test_fd_pdu_creator_with_reserved_field_with_crc_without_finish_fails() {
+        let mut common_conf =
+            CommonPduConfig::new_with_byte_fields(TEST_SRC_ID, TEST_DEST_ID, TEST_SEQ_NUM).unwrap();
+        common_conf.crc_flag = true.into();
+        let pdu_header = PduHeader::new_for_file_data_default(common_conf, 0);
+        let test_str = "hello world!";
+        let fd_pdu = FileDataPduCreatorWithReservedDatafield::new_no_seg_metadata(
+            pdu_header,
+            10,
+            test_str.len() as u64,
+        );
+        let mut write_buf: [u8; 64] = [0; 64];
+        let mut pdu_unwritten = fd_pdu
+            .write_to_bytes_partially(&mut write_buf)
+            .expect("partial write failed");
+        pdu_unwritten
+            .file_data_field_mut()
+            .copy_from_slice(test_str.as_bytes());
+
+        let pdu_reader_error = FileDataPdu::from_bytes(&write_buf);
+        assert!(pdu_reader_error.is_err());
+        let error = pdu_reader_error.unwrap_err();
+        match error {
+            PduError::ChecksumError(_) => (),
+            _ => {
+                panic!("unexpected PDU error {}", error)
+            }
+        }
+    }
+
+    #[test]
+    fn test_max_file_seg_calculator_0() {
+        let pdu_header = PduHeader::new_for_file_data_default(CommonPduConfig::default(), 0);
+        assert_eq!(
+            calculate_max_file_seg_len_for_max_packet_len_and_pdu_header(&pdu_header, 64, None),
+            53
+        );
+    }
+
+    #[test]
+    fn test_max_file_seg_calculator_1() {
+        let common_conf = CommonPduConfig {
+            crc_flag: CrcFlag::WithCrc,
+            ..Default::default()
+        };
+        let pdu_header = PduHeader::new_for_file_data_default(common_conf, 0);
+        assert_eq!(
+            calculate_max_file_seg_len_for_max_packet_len_and_pdu_header(&pdu_header, 64, None),
+            51
+        );
+    }
+
+    #[test]
+    fn test_max_file_seg_calculator_2() {
+        let common_conf = CommonPduConfig {
+            file_flag: LargeFileFlag::Large,
+            ..Default::default()
+        };
+        let pdu_header = PduHeader::new_for_file_data_default(common_conf, 0);
+        assert_eq!(
+            calculate_max_file_seg_len_for_max_packet_len_and_pdu_header(&pdu_header, 64, None),
+            49
+        );
+    }
+
+    #[test]
+    fn test_max_file_seg_calculator_saturating_sub() {
+        let common_conf = CommonPduConfig {
+            file_flag: LargeFileFlag::Large,
+            ..Default::default()
+        };
+        let pdu_header = PduHeader::new_for_file_data_default(common_conf, 0);
+        assert_eq!(
+            calculate_max_file_seg_len_for_max_packet_len_and_pdu_header(&pdu_header, 15, None),
+            0
+        );
+        assert_eq!(
+            calculate_max_file_seg_len_for_max_packet_len_and_pdu_header(&pdu_header, 14, None),
+            0
+        );
+    }
 }

src/cfdp/pdu/finished.rs

@@ -10,10 +10,12 @@ use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
+use super::tlv::ReadableTlv;
 use super::{CfdpPdu, WritablePduPacket};
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum DeliveryCode {
     Complete = 0,
@@ -22,6 +24,7 @@ pub enum DeliveryCode {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum FileStatus {
     DiscardDeliberately = 0b00,
@@ -34,6 +37,7 @@ pub enum FileStatus {
 ///
 /// For more information, refer to CFDP chapter 5.2.3.
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct FinishedPduCreator<'fs_responses> {
     pdu_header: PduHeader,
     condition_code: ConditionCode,
@@ -219,6 +223,7 @@ impl<'buf> Iterator for FilestoreResponseIterator<'buf> {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct FinishedPduReader<'buf> {
     pdu_header: PduHeader,
     condition_code: ConditionCode,
@@ -581,7 +586,7 @@ mod tests {
         assert_eq!(finished_pdu_vec.len(), 12);
         assert_eq!(finished_pdu_vec[9], TlvType::EntityId.into());
         assert_eq!(finished_pdu_vec[10], 1);
-        assert_eq!(finished_pdu_vec[11], TEST_DEST_ID.value());
+        assert_eq!(finished_pdu_vec[11], TEST_DEST_ID.value_typed());
         assert_eq!(
             finished_pdu.fault_location().unwrap().entity_id(),
             &TEST_DEST_ID.into()

src/cfdp/pdu/metadata.rs

@@ -1,3 +1,5 @@
+#[cfg(feature = "alloc")]
+use super::tlv::TlvOwned;
 use crate::cfdp::lv::Lv;
 use crate::cfdp::pdu::{
     add_pdu_crc, generic_length_checks_pdu_deserialization, read_fss_field, write_fss_field,
@@ -11,10 +13,12 @@ use alloc::vec::Vec;
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
+use super::tlv::ReadableTlv;
 use super::{CfdpPdu, WritablePduPacket};
 
 #[derive(Default, Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct MetadataGenericParams {
     pub closure_requested: bool,
     pub checksum_type: ChecksumType,
@@ -50,6 +54,15 @@ pub fn build_metadata_opts_from_vec(
     build_metadata_opts_from_slice(buf, tlvs.as_slice())
 }
 
+#[cfg(feature = "alloc")]
+pub fn build_metadata_opts_from_owned_slice(tlvs: &[TlvOwned]) -> Vec<u8> {
+    let mut sum_vec = Vec::new();
+    for tlv in tlvs {
+        sum_vec.extend(tlv.to_vec());
+    }
+    sum_vec
+}
+
 /// Metadata PDU creator abstraction.
 ///
 /// This abstraction exposes a specialized API for creating metadata PDUs as specified in
@@ -60,7 +73,7 @@ pub struct MetadataPduCreator<'src_name, 'dest_name, 'opts> {
     metadata_params: MetadataGenericParams,
     src_file_name: Lv<'src_name>,
     dest_file_name: Lv<'dest_name>,
-    options: &'opts [Tlv<'opts>],
+    options: &'opts [u8],
 }
 
 impl<'src_name, 'dest_name, 'opts> MetadataPduCreator<'src_name, 'dest_name, 'opts> {
@@ -84,7 +97,7 @@ impl<'src_name, 'dest_name, 'opts> MetadataPduCreator<'src_name, 'dest_name, 'op
         metadata_params: MetadataGenericParams,
         src_file_name: Lv<'src_name>,
         dest_file_name: Lv<'dest_name>,
-        options: &'opts [Tlv<'opts>],
+        options: &'opts [u8],
     ) -> Self {
         Self::new(
             pdu_header,
@@ -100,7 +113,7 @@ impl<'src_name, 'dest_name, 'opts> MetadataPduCreator<'src_name, 'dest_name, 'op
         metadata_params: MetadataGenericParams,
         src_file_name: Lv<'src_name>,
         dest_file_name: Lv<'dest_name>,
-        options: &'opts [Tlv<'opts>],
+        options: &'opts [u8],
     ) -> Self {
         pdu_header.pdu_type = PduType::FileDirective;
         pdu_header.pdu_conf.direction = Direction::TowardsReceiver;
@@ -127,10 +140,19 @@ impl<'src_name, 'dest_name, 'opts> MetadataPduCreator<'src_name, 'dest_name, 'op
         self.dest_file_name
     }
 
-    pub fn options(&self) -> &'opts [Tlv<'opts>] {
+    pub fn options(&self) -> &'opts [u8] {
         self.options
     }
 
+    /// Yield an iterator which can be used to loop through all options. Returns [None] if the
+    /// options field is empty.
+    pub fn options_iter(&self) -> OptionsIter<'_> {
+        OptionsIter {
+            opt_buf: self.options,
+            current_idx: 0,
+        }
+    }
+
     fn calc_pdu_datafield_len(&self) -> usize {
         // One directve type octet and one byte of the directive parameter field.
         let mut len = 2;
@@ -141,9 +163,7 @@ impl<'src_name, 'dest_name, 'opts> MetadataPduCreator<'src_name, 'dest_name, 'op
         }
         len += self.src_file_name.len_full();
         len += self.dest_file_name.len_full();
-        for tlv in self.options() {
-            len += tlv.len_full()
-        }
+        len += self.options().len();
         if self.crc_flag() == CrcFlag::WithCrc {
             len += 2;
         }
@@ -175,7 +195,7 @@ impl WritablePduPacket for MetadataPduCreator<'_, '_, '_> {
         let mut current_idx = self.pdu_header.write_to_bytes(buf)?;
         buf[current_idx] = FileDirectiveType::MetadataPdu as u8;
         current_idx += 1;
-        buf[current_idx] = ((self.metadata_params.closure_requested as u8) << 7)
+        buf[current_idx] = ((self.metadata_params.closure_requested as u8) << 6)
             | (self.metadata_params.checksum_type as u8);
         current_idx += 1;
         current_idx += write_fss_field(
@@ -189,10 +209,8 @@ impl WritablePduPacket for MetadataPduCreator<'_, '_, '_> {
         current_idx += self
             .dest_file_name
             .write_to_be_bytes(&mut buf[current_idx..])?;
-        for opt in self.options() {
-            opt.write_to_bytes(&mut buf[current_idx..current_idx + opt.len_full()])?;
-            current_idx += opt.len_full();
-        }
+        buf[current_idx..current_idx + self.options.len()].copy_from_slice(self.options);
+        current_idx += self.options.len();
         if self.crc_flag() == CrcFlag::WithCrc {
             current_idx = add_pdu_crc(buf, current_idx);
         }
@@ -241,6 +259,7 @@ impl<'opts> Iterator for OptionsIter<'opts> {
 /// involved.
 #[derive(Debug)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct MetadataPduReader<'buf> {
     pdu_header: PduHeader,
     metadata_params: MetadataGenericParams,
@@ -352,7 +371,7 @@ pub mod tests {
     };
     use crate::cfdp::pdu::{CfdpPdu, PduError, WritablePduPacket};
     use crate::cfdp::pdu::{FileDirectiveType, PduHeader};
-    use crate::cfdp::tlv::{Tlv, TlvType};
+    use crate::cfdp::tlv::{ReadableTlv, Tlv, TlvOwned, TlvType, WritableTlv};
     use crate::cfdp::{
         ChecksumType, CrcFlag, Direction, LargeFileFlag, PduType, SegmentMetadataFlag,
         SegmentationControl, TransmissionMode,
@@ -362,17 +381,19 @@ pub mod tests {
     const SRC_FILENAME: &str = "hello-world.txt";
     const DEST_FILENAME: &str = "hello-world2.txt";
 
-    fn generic_metadata_pdu<'opts>(
+    fn generic_metadata_pdu(
         crc_flag: CrcFlag,
+        checksum_type: ChecksumType,
+        closure_requested: bool,
         fss: LargeFileFlag,
-        opts: &'opts [Tlv],
+        opts: &[u8],
     ) -> (
         Lv<'static>,
         Lv<'static>,
-        MetadataPduCreator<'static, 'static, 'opts>,
+        MetadataPduCreator<'static, 'static, '_>,
     ) {
         let pdu_header = PduHeader::new_no_file_data(common_pdu_conf(crc_flag, fss), 0);
-        let metadata_params = MetadataGenericParams::new(false, ChecksumType::Crc32, 0x1010);
+        let metadata_params = MetadataGenericParams::new(closure_requested, checksum_type, 0x1010);
         let src_filename = Lv::new_from_str(SRC_FILENAME).expect("Generating string LV failed");
         let dest_filename =
             Lv::new_from_str(DEST_FILENAME).expect("Generating destination LV failed");
@@ -391,8 +412,13 @@ pub mod tests {
 
     #[test]
     fn test_basic() {
-        let (src_filename, dest_filename, metadata_pdu) =
-            generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Normal, &[]);
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            false,
+            LargeFileFlag::Normal,
+            &[],
+        );
         assert_eq!(
             metadata_pdu.len_written(),
             metadata_pdu.pdu_header().header_len()
@@ -408,6 +434,11 @@ pub mod tests {
         assert_eq!(metadata_pdu.crc_flag(), CrcFlag::NoCrc);
         assert_eq!(metadata_pdu.file_flag(), LargeFileFlag::Normal);
         assert_eq!(metadata_pdu.pdu_type(), PduType::FileDirective);
+        assert!(!metadata_pdu.metadata_params().closure_requested);
+        assert_eq!(
+            metadata_pdu.metadata_params().checksum_type,
+            ChecksumType::Crc32
+        );
         assert_eq!(
             metadata_pdu.file_directive_type(),
             Some(FileDirectiveType::MetadataPdu)
@@ -422,44 +453,103 @@ pub mod tests {
         assert_eq!(metadata_pdu.transaction_seq_num(), TEST_SEQ_NUM.into());
     }
 
-    #[test]
-    fn test_serialization() {
-        let (src_filename, dest_filename, metadata_pdu) =
-            generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Normal, &[]);
-        let mut buf: [u8; 64] = [0; 64];
-        let res = metadata_pdu.write_to_bytes(&mut buf);
-        assert!(res.is_ok());
-        let written = res.unwrap();
+    fn check_metadata_raw_fields(
+        metadata_pdu: &MetadataPduCreator,
+        buf: &[u8],
+        written_bytes: usize,
+        checksum_type: ChecksumType,
+        closure_requested: bool,
+        expected_src_filename: &Lv,
+        expected_dest_filename: &Lv,
+    ) {
+        verify_raw_header(metadata_pdu.pdu_header(), buf);
         assert_eq!(
-            written,
+            written_bytes,
             metadata_pdu.pdu_header.header_len()
                 + 1
                 + 1
                 + 4
-                + src_filename.len_full()
-                + dest_filename.len_full()
+                + expected_src_filename.len_full()
+                + expected_dest_filename.len_full()
         );
-        verify_raw_header(metadata_pdu.pdu_header(), &buf);
         assert_eq!(buf[7], FileDirectiveType::MetadataPdu as u8);
-        assert_eq!(buf[8] >> 6, false as u8);
-        assert_eq!(buf[8] & 0b1111, ChecksumType::Crc32 as u8);
+        assert_eq!(buf[8] >> 6, closure_requested as u8);
+        assert_eq!(buf[8] & 0b1111, checksum_type as u8);
         assert_eq!(u32::from_be_bytes(buf[9..13].try_into().unwrap()), 0x1010);
         let mut current_idx = 13;
         let src_name_from_raw =
             Lv::from_bytes(&buf[current_idx..]).expect("Creating source name LV failed");
-        assert_eq!(src_name_from_raw, src_filename);
+        assert_eq!(src_name_from_raw, *expected_src_filename);
         current_idx += src_name_from_raw.len_full();
         let dest_name_from_raw =
             Lv::from_bytes(&buf[current_idx..]).expect("Creating dest name LV failed");
-        assert_eq!(dest_name_from_raw, dest_filename);
+        assert_eq!(dest_name_from_raw, *expected_dest_filename);
         current_idx += dest_name_from_raw.len_full();
         // No options, so no additional data here.
-        assert_eq!(current_idx, written);
+        assert_eq!(current_idx, written_bytes);
+    }
+
+    #[test]
+    fn test_serialization_0() {
+        let checksum_type = ChecksumType::Crc32;
+        let closure_requested = false;
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            checksum_type,
+            closure_requested,
+            LargeFileFlag::Normal,
+            &[],
+        );
+        let mut buf: [u8; 64] = [0; 64];
+        let res = metadata_pdu.write_to_bytes(&mut buf);
+        assert!(res.is_ok());
+        let written = res.unwrap();
+        check_metadata_raw_fields(
+            &metadata_pdu,
+            &buf,
+            written,
+            checksum_type,
+            closure_requested,
+            &src_filename,
+            &dest_filename,
+        );
+    }
+
+    #[test]
+    fn test_serialization_1() {
+        let checksum_type = ChecksumType::Modular;
+        let closure_requested = true;
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            checksum_type,
+            closure_requested,
+            LargeFileFlag::Normal,
+            &[],
+        );
+        let mut buf: [u8; 64] = [0; 64];
+        let res = metadata_pdu.write_to_bytes(&mut buf);
+        assert!(res.is_ok());
+        let written = res.unwrap();
+        check_metadata_raw_fields(
+            &metadata_pdu,
+            &buf,
+            written,
+            checksum_type,
+            closure_requested,
+            &src_filename,
+            &dest_filename,
+        );
     }
 
     #[test]
     fn test_write_to_vec() {
-        let (_, _, metadata_pdu) = generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Normal, &[]);
+        let (_, _, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            false,
+            LargeFileFlag::Normal,
+            &[],
+        );
         let mut buf: [u8; 64] = [0; 64];
         let pdu_vec = metadata_pdu.to_vec().unwrap();
         let written = metadata_pdu.write_to_bytes(&mut buf).unwrap();
@@ -470,15 +560,21 @@ pub mod tests {
         assert_eq!(written.metadata_params(), read.metadata_params());
         assert_eq!(written.src_file_name(), read.src_file_name());
         assert_eq!(written.dest_file_name(), read.dest_file_name());
-        let opts = written.options();
-        for (tlv_written, tlv_read) in opts.iter().zip(read.options_iter().unwrap()) {
-            assert_eq!(tlv_written, &tlv_read);
+        let opts = written.options_iter();
+        for (tlv_written, tlv_read) in opts.zip(read.options_iter().unwrap()) {
+            assert_eq!(&tlv_written, &tlv_read);
         }
     }
 
     #[test]
     fn test_deserialization() {
-        let (_, _, metadata_pdu) = generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Normal, &[]);
+        let (_, _, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            true,
+            LargeFileFlag::Normal,
+            &[],
+        );
         let mut buf: [u8; 64] = [0; 64];
         metadata_pdu.write_to_bytes(&mut buf).unwrap();
         let pdu_read_back = MetadataPduReader::from_bytes(&buf);
@@ -489,8 +585,13 @@ pub mod tests {
 
     #[test]
     fn test_with_crc_flag() {
-        let (src_filename, dest_filename, metadata_pdu) =
-            generic_metadata_pdu(CrcFlag::WithCrc, LargeFileFlag::Normal, &[]);
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::WithCrc,
+            ChecksumType::Crc32,
+            true,
+            LargeFileFlag::Normal,
+            &[],
+        );
         assert_eq!(metadata_pdu.crc_flag(), CrcFlag::WithCrc);
         let mut buf: [u8; 64] = [0; 64];
         let write_res = metadata_pdu.write_to_bytes(&mut buf);
@@ -513,8 +614,13 @@ pub mod tests {
 
     #[test]
     fn test_with_large_file_flag() {
-        let (src_filename, dest_filename, metadata_pdu) =
-            generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Large, &[]);
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            false,
+            LargeFileFlag::Large,
+            &[],
+        );
         let mut buf: [u8; 64] = [0; 64];
         let write_res = metadata_pdu.write_to_bytes(&mut buf);
         assert!(write_res.is_ok());
@@ -571,10 +677,15 @@ pub mod tests {
         let tlv1 = Tlv::new_empty(TlvType::FlowLabel);
         let msg_to_user: [u8; 4] = [1, 2, 3, 4];
         let tlv2 = Tlv::new(TlvType::MsgToUser, &msg_to_user).unwrap();
-        let tlv_vec = vec![tlv1, tlv2];
-        let opts_len = tlv1.len_full() + tlv2.len_full();
-        let (src_filename, dest_filename, metadata_pdu) =
-            generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Normal, &tlv_vec);
+        let mut tlv_buf: [u8; 64] = [0; 64];
+        let opts_len = build_metadata_opts_from_slice(&mut tlv_buf, &[tlv1, tlv2]).unwrap();
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            false,
+            LargeFileFlag::Normal,
+            &tlv_buf[0..opts_len],
+        );
         let mut buf: [u8; 128] = [0; 128];
         let write_res = metadata_pdu.write_to_bytes(&mut buf);
         assert!(write_res.is_ok());
@@ -596,7 +707,55 @@ pub mod tests {
         let opts_iter = opts_iter.unwrap();
         let mut accumulated_len = 0;
         for (idx, opt) in opts_iter.enumerate() {
-            assert_eq!(tlv_vec[idx], opt);
+            if idx == 0 {
+                assert_eq!(tlv1, opt);
+            } else if idx == 1 {
+                assert_eq!(tlv2, opt);
+            }
+            accumulated_len += opt.len_full();
+        }
+        assert_eq!(accumulated_len, pdu_read_back.options().len());
+    }
+    #[test]
+    fn test_with_owned_opts() {
+        let tlv1 = TlvOwned::new_empty(TlvType::FlowLabel);
+        let msg_to_user: [u8; 4] = [1, 2, 3, 4];
+        let tlv2 = TlvOwned::new(TlvType::MsgToUser, &msg_to_user).unwrap();
+        let mut all_tlvs = tlv1.to_vec();
+        all_tlvs.extend(tlv2.to_vec());
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            false,
+            LargeFileFlag::Normal,
+            &all_tlvs,
+        );
+        let mut buf: [u8; 128] = [0; 128];
+        let write_res = metadata_pdu.write_to_bytes(&mut buf);
+        assert!(write_res.is_ok());
+        let written = write_res.unwrap();
+        assert_eq!(
+            written,
+            metadata_pdu.pdu_header.header_len()
+                + 1
+                + 1
+                + 4
+                + src_filename.len_full()
+                + dest_filename.len_full()
+                + all_tlvs.len()
+        );
+        let pdu_read_back = MetadataPduReader::from_bytes(&buf).unwrap();
+        compare_read_pdu_to_written_pdu(&metadata_pdu, &pdu_read_back);
+        let opts_iter = pdu_read_back.options_iter();
+        assert!(opts_iter.is_some());
+        let opts_iter = opts_iter.unwrap();
+        let mut accumulated_len = 0;
+        for (idx, opt) in opts_iter.enumerate() {
+            if idx == 0 {
+                assert_eq!(tlv1, opt);
+            } else if idx == 1 {
+                assert_eq!(tlv2, opt);
+            }
             accumulated_len += opt.len_full();
         }
         assert_eq!(accumulated_len, pdu_read_back.options().len());
@@ -604,7 +763,13 @@ pub mod tests {
 
     #[test]
     fn test_invalid_directive_code() {
-        let (_, _, metadata_pdu) = generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Large, &[]);
+        let (_, _, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            true,
+            LargeFileFlag::Large,
+            &[],
+        );
         let mut metadata_vec = metadata_pdu.to_vec().unwrap();
         metadata_vec[7] = 0xff;
         let metadata_error = MetadataPduReader::from_bytes(&metadata_vec);
@@ -624,7 +789,13 @@ pub mod tests {
 
     #[test]
     fn test_wrong_directive_code() {
-        let (_, _, metadata_pdu) = generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Large, &[]);
+        let (_, _, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            false,
+            LargeFileFlag::Large,
+            &[],
+        );
         let mut metadata_vec = metadata_pdu.to_vec().unwrap();
         metadata_vec[7] = FileDirectiveType::EofPdu as u8;
         let metadata_error = MetadataPduReader::from_bytes(&metadata_vec);

src/cfdp/pdu/mod.rs

@@ -18,6 +18,7 @@ pub mod nak;
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum FileDirectiveType {
     EofPdu = 0x04,
@@ -149,12 +150,14 @@ impl Error for PduError {
 }
 
 impl From<ByteConversionError> for PduError {
+    #[inline]
     fn from(value: ByteConversionError) -> Self {
         Self::ByteConversion(value)
     }
 }
 
 impl From<TlvLvError> for PduError {
+    #[inline]
     fn from(e: TlvLvError) -> Self {
         Self::TlvLvError(e)
     }
@@ -178,33 +181,42 @@ pub trait WritablePduPacket {
 pub trait CfdpPdu {
     fn pdu_header(&self) -> &PduHeader;
 
+    #[inline]
     fn source_id(&self) -> UnsignedByteField {
         self.pdu_header().common_pdu_conf().source_entity_id
     }
 
+    #[inline]
     fn dest_id(&self) -> UnsignedByteField {
         self.pdu_header().common_pdu_conf().dest_entity_id
     }
 
+    #[inline]
     fn transaction_seq_num(&self) -> UnsignedByteField {
         self.pdu_header().common_pdu_conf().transaction_seq_num
     }
 
+    #[inline]
     fn transmission_mode(&self) -> TransmissionMode {
         self.pdu_header().common_pdu_conf().trans_mode
     }
+
+    #[inline]
     fn direction(&self) -> Direction {
         self.pdu_header().common_pdu_conf().direction
     }
 
+    #[inline]
     fn crc_flag(&self) -> CrcFlag {
         self.pdu_header().common_pdu_conf().crc_flag
     }
 
+    #[inline]
     fn file_flag(&self) -> LargeFileFlag {
         self.pdu_header().common_pdu_conf().file_flag
     }
 
+    #[inline]
     fn pdu_type(&self) -> PduType {
         self.pdu_header().pdu_type()
     }
@@ -220,6 +232,7 @@ pub trait CfdpPdu {
 /// same.
 #[derive(Debug, Copy, Clone, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct CommonPduConfig {
     source_entity_id: UnsignedByteField,
     dest_entity_id: UnsignedByteField,
@@ -232,6 +245,7 @@ pub struct CommonPduConfig {
 
 // TODO: Builder pattern might be applicable here..
 impl CommonPduConfig {
+    #[inline]
     pub fn new(
         source_id: impl Into<UnsignedByteField>,
         dest_id: impl Into<UnsignedByteField>,
@@ -263,6 +277,7 @@ impl CommonPduConfig {
         })
     }
 
+    #[inline]
     pub fn new_with_byte_fields(
         source_id: impl Into<UnsignedByteField>,
         dest_id: impl Into<UnsignedByteField>,
@@ -279,10 +294,12 @@ impl CommonPduConfig {
         )
     }
 
+    #[inline]
     pub fn source_id(&self) -> UnsignedByteField {
         self.source_entity_id
     }
 
+    #[inline]
     fn source_dest_id_check(
         source_id: impl Into<UnsignedByteField>,
         dest_id: impl Into<UnsignedByteField>,
@@ -305,6 +322,7 @@ impl CommonPduConfig {
         Ok((source_id, dest_id))
     }
 
+    #[inline]
     pub fn set_source_and_dest_id(
         &mut self,
         source_id: impl Into<UnsignedByteField>,
@@ -316,6 +334,7 @@ impl CommonPduConfig {
         Ok(())
     }
 
+    #[inline]
     pub fn dest_id(&self) -> UnsignedByteField {
         self.dest_entity_id
     }
@@ -324,6 +343,7 @@ impl CommonPduConfig {
 impl Default for CommonPduConfig {
     /// The defaults for the source ID, destination ID and the transaction sequence number is the
     /// [UnsignedByteFieldU8] with an intitial value of 0
+    #[inline]
     fn default() -> Self {
         // The new function can not fail for these input parameters.
         Self::new(
@@ -340,6 +360,7 @@ impl Default for CommonPduConfig {
 }
 
 impl PartialEq for CommonPduConfig {
+    #[inline]
     fn eq(&self, other: &Self) -> bool {
         self.source_entity_id.value() == other.source_entity_id.value()
             && self.dest_entity_id.value() == other.dest_entity_id.value()
@@ -358,6 +379,7 @@ pub const FIXED_HEADER_LEN: usize = 4;
 /// For detailed information, refer to chapter 5.1 of the CFDP standard.
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct PduHeader {
     pdu_type: PduType,
     pdu_conf: CommonPduConfig,
@@ -367,6 +389,7 @@ pub struct PduHeader {
 }
 
 impl PduHeader {
+    #[inline]
     pub fn new_for_file_data(
         pdu_conf: CommonPduConfig,
         pdu_datafield_len: u16,
@@ -382,6 +405,7 @@ impl PduHeader {
         )
     }
 
+    #[inline]
     pub fn new_for_file_data_default(pdu_conf: CommonPduConfig, pdu_datafield_len: u16) -> Self {
         Self::new_generic(
             PduType::FileData,
@@ -391,6 +415,7 @@ impl PduHeader {
             SegmentationControl::NoRecordBoundaryPreservation,
         )
     }
+    #[inline]
     pub fn new_no_file_data(pdu_conf: CommonPduConfig, pdu_datafield_len: u16) -> Self {
         Self::new_generic(
             PduType::FileDirective,
@@ -401,6 +426,7 @@ impl PduHeader {
         )
     }
 
+    #[inline]
     pub fn new_generic(
         pdu_type: PduType,
         pdu_conf: CommonPduConfig,
@@ -418,6 +444,7 @@ impl PduHeader {
     }
 
     /// Returns only the length of the PDU header when written to a raw buffer.
+    #[inline]
     pub fn header_len(&self) -> usize {
         FIXED_HEADER_LEN
             + self.pdu_conf.source_entity_id.size()
@@ -425,12 +452,14 @@ impl PduHeader {
             + self.pdu_conf.dest_entity_id.size()
     }
 
+    #[inline]
     pub fn pdu_datafield_len(&self) -> usize {
         self.pdu_datafield_len.into()
     }
 
     /// Returns the full length of the PDU when written to a raw buffer, which is the header length
     /// plus the PDU datafield length.
+    #[inline]
     pub fn pdu_len(&self) -> usize {
         self.header_len() + self.pdu_datafield_len as usize
     }
@@ -603,10 +632,13 @@ impl PduHeader {
             current_idx,
         ))
     }
+
+    #[inline]
     pub fn pdu_type(&self) -> PduType {
         self.pdu_type
     }
 
+    #[inline]
     pub fn common_pdu_conf(&self) -> &CommonPduConfig {
         &self.pdu_conf
     }
@@ -614,6 +646,8 @@ impl PduHeader {
     pub fn seg_metadata_flag(&self) -> SegmentMetadataFlag {
         self.seg_metadata_flag
     }
+
+    #[inline]
     pub fn seg_ctrl(&self) -> SegmentationControl {
         self.seg_ctrl
     }

src/cfdp/pdu/nak.rs

@@ -12,6 +12,7 @@ use super::{
 /// Helper type to encapsulate both normal file size segment requests and large file size segment
 /// requests.
 #[derive(Debug, PartialEq, Eq, Clone)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum SegmentRequests<'a> {
     U32Pairs(&'a [(u32, u32)]),
     U64Pairs(&'a [(u64, u64)]),
@@ -31,6 +32,7 @@ impl SegmentRequests<'_> {
 /// It exposes a specialized API which simplifies to generate these NAK PDUs with the
 /// format according to CFDP chapter 5.2.6.
 #[derive(Debug, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct NakPduCreator<'seg_reqs> {
     pdu_header: PduHeader,
     start_of_scope: u64,
@@ -353,6 +355,7 @@ impl<T: SegReqFromBytes> SegmentRequestIter<'_, T> {
 ///
 /// The NAK format is expected to be conforming to CFDP chapter 5.2.6.
 #[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct NakPduReader<'seg_reqs> {
     pdu_header: PduHeader,
     start_of_scope: u64,

src/cfdp/tlv/mod.rs

@@ -9,10 +9,14 @@ use crate::ByteConversionError;
 use alloc::vec;
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
+#[cfg(feature = "alloc")]
+pub use alloc_mod::*;
 use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
+use super::TlvLvDataTooLarge;
+
 pub mod msg_to_user;
 
 pub const MIN_TLV_LEN: usize = 2;
@@ -39,6 +43,26 @@ pub trait GenericTlv {
     }
 }
 
+pub trait ReadableTlv {
+    fn value(&self) -> &[u8];
+
+    /// Checks whether the value field is empty.
+    fn is_empty(&self) -> bool {
+        self.value().is_empty()
+    }
+
+    /// Helper method to retrieve the length of the value. Simply calls the [slice::len] method of
+    /// [Self::value]
+    fn len_value(&self) -> usize {
+        self.value().len()
+    }
+
+    /// Returns the full raw length, including the length byte.
+    fn len_full(&self) -> usize {
+        self.len_value() + 2
+    }
+}
+
 pub trait WritableTlv {
     fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError>;
     fn len_written(&self) -> usize;
@@ -52,6 +76,7 @@ pub trait WritableTlv {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum TlvType {
     FilestoreRequest = 0x00,
@@ -64,6 +89,7 @@ pub enum TlvType {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum TlvTypeField {
     Standard(TlvType),
     Custom(u8),
@@ -71,6 +97,7 @@ pub enum TlvTypeField {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum FilestoreActionCode {
     CreateFile = 0b0000,
@@ -118,6 +145,7 @@ impl From<TlvTypeField> for u8 {
 ///    this will be the lifetime of that data reference.
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct Tlv<'data> {
     tlv_type_field: TlvTypeField,
     #[cfg_attr(feature = "serde", serde(borrow))]
@@ -125,14 +153,14 @@ pub struct Tlv<'data> {
 }
 
 impl<'data> Tlv<'data> {
-    pub fn new(tlv_type: TlvType, data: &[u8]) -> Result<Tlv, TlvLvError> {
+    pub fn new(tlv_type: TlvType, data: &[u8]) -> Result<Tlv, TlvLvDataTooLarge> {
         Ok(Tlv {
             tlv_type_field: TlvTypeField::Standard(tlv_type),
             lv: Lv::new(data)?,
         })
     }
 
-    pub fn new_with_custom_type(tlv_type: u8, data: &[u8]) -> Result<Tlv, TlvLvError> {
+    pub fn new_with_custom_type(tlv_type: u8, data: &[u8]) -> Result<Tlv, TlvLvDataTooLarge> {
         Ok(Tlv {
             tlv_type_field: TlvTypeField::Custom(tlv_type),
             lv: Lv::new(data)?,
@@ -147,26 +175,6 @@ impl<'data> Tlv<'data> {
         }
     }
 
-    pub fn value(&self) -> &[u8] {
-        self.lv.value()
-    }
-
-    /// Checks whether the value field is empty.
-    pub fn is_empty(&self) -> bool {
-        self.value().is_empty()
-    }
-
-    /// Helper method to retrieve the length of the value. Simply calls the [slice::len] method of
-    /// [Self::value]
-    pub fn len_value(&self) -> usize {
-        self.value().len()
-    }
-
-    /// Returns the full raw length, including the length byte.
-    pub fn len_full(&self) -> usize {
-        self.len_value() + 2
-    }
-
     /// Creates a TLV give a raw bytestream. Please note that is is not necessary to pass the
     /// bytestream with the exact size of the expected TLV. This function will take care
     /// of parsing the length byte, and the length of the parsed TLV can be retrieved using
@@ -188,6 +196,27 @@ impl<'data> Tlv<'data> {
     pub fn raw_data(&self) -> Option<&[u8]> {
         self.lv.raw_data()
     }
+
+    #[cfg(feature = "alloc")]
+    pub fn to_owned(&self) -> TlvOwned {
+        TlvOwned {
+            tlv_type_field: self.tlv_type_field,
+            data: self.value().to_vec(),
+        }
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl PartialEq<TlvOwned> for Tlv<'_> {
+    fn eq(&self, other: &TlvOwned) -> bool {
+        self.tlv_type_field == other.tlv_type_field && self.value() == other.value()
+    }
+}
+
+impl ReadableTlv for Tlv<'_> {
+    fn value(&self) -> &[u8] {
+        self.lv.value()
+    }
 }
 
 impl WritableTlv for Tlv<'_> {
@@ -208,22 +237,103 @@ impl GenericTlv for Tlv<'_> {
     }
 }
 
-pub(crate) fn verify_tlv_type(raw_type: u8, expected_tlv_type: TlvType) -> Result<(), TlvLvError> {
-    let tlv_type = TlvType::try_from(raw_type).map_err(|_| TlvLvError::InvalidTlvTypeField {
-        found: raw_type,
-        expected: Some(expected_tlv_type.into()),
-    })?;
-    if tlv_type != expected_tlv_type {
-        return Err(TlvLvError::InvalidTlvTypeField {
-            found: tlv_type as u8,
-            expected: Some(expected_tlv_type as u8),
-        });
+#[cfg(feature = "alloc")]
+pub mod alloc_mod {
+    use crate::cfdp::TlvLvDataTooLarge;
+
+    use super::*;
+
+    /// Owned variant of [Tlv] which is consequently [Clone]able and does not have a lifetime
+    /// associated to a data slice.
+    #[derive(Debug, Clone, PartialEq, Eq)]
+    #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+    #[cfg_attr(feature = "defmt", derive(defmt::Format))]
+    pub struct TlvOwned {
+        pub(crate) tlv_type_field: TlvTypeField,
+        pub(crate) data: Vec<u8>,
+    }
+
+    impl TlvOwned {
+        pub fn new(tlv_type: TlvType, data: &[u8]) -> Result<Self, TlvLvDataTooLarge> {
+            if data.len() > u8::MAX as usize {
+                return Err(TlvLvDataTooLarge(data.len()));
+            }
+            Ok(Self {
+                tlv_type_field: TlvTypeField::Standard(tlv_type),
+                data: data.to_vec(),
+            })
+        }
+
+        pub fn new_with_custom_type(tlv_type: u8, data: &[u8]) -> Result<Self, TlvLvDataTooLarge> {
+            if data.len() > u8::MAX as usize {
+                return Err(TlvLvDataTooLarge(data.len()));
+            }
+            Ok(Self {
+                tlv_type_field: TlvTypeField::Custom(tlv_type),
+                data: data.to_vec(),
+            })
+        }
+
+        /// Creates a TLV with an empty value field.
+        pub fn new_empty(tlv_type: TlvType) -> Self {
+            Self {
+                tlv_type_field: TlvTypeField::Standard(tlv_type),
+                data: Vec::new(),
+            }
+        }
+
+        pub fn as_tlv(&self) -> Tlv<'_> {
+            Tlv {
+                tlv_type_field: self.tlv_type_field,
+                // The API should ensure that the data length is never to large, so the unwrap for the
+                // LV creation should never be an issue.
+                lv: Lv::new(&self.data).expect("lv creation failed unexpectedly"),
+            }
+        }
+    }
+
+    impl ReadableTlv for TlvOwned {
+        fn value(&self) -> &[u8] {
+            &self.data
+        }
+    }
+
+    impl WritableTlv for TlvOwned {
+        fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
+            generic_len_check_data_serialization(buf, self.data.len(), MIN_TLV_LEN)?;
+            buf[0] = self.tlv_type_field.into();
+            buf[1] = self.data.len() as u8;
+            buf[2..2 + self.data.len()].copy_from_slice(&self.data);
+            Ok(self.len_written())
+        }
+
+        fn len_written(&self) -> usize {
+            self.data.len() + 2
+        }
+    }
+
+    impl GenericTlv for TlvOwned {
+        fn tlv_type_field(&self) -> TlvTypeField {
+            self.tlv_type_field
+        }
+    }
+
+    impl From<Tlv<'_>> for TlvOwned {
+        fn from(value: Tlv<'_>) -> Self {
+            value.to_owned()
+        }
+    }
+
+    impl PartialEq<Tlv<'_>> for TlvOwned {
+        fn eq(&self, other: &Tlv) -> bool {
+            self.tlv_type_field == other.tlv_type_field && self.data == other.value()
+        }
     }
-    Ok(())
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct EntityIdTlv {
     entity_id: UnsignedByteField,
 }
@@ -233,7 +343,7 @@ impl EntityIdTlv {
         Self { entity_id }
     }
 
-    fn len_check(buf: &[u8]) -> Result<(), ByteConversionError> {
+    fn check_min_len(buf: &[u8]) -> Result<(), ByteConversionError> {
         if buf.len() < 2 {
             return Err(ByteConversionError::ToSliceTooSmall {
                 found: buf.len(),
@@ -256,7 +366,7 @@ impl EntityIdTlv {
     }
 
     pub fn from_bytes(buf: &[u8]) -> Result<Self, TlvLvError> {
-        Self::len_check(buf)?;
+        Self::check_min_len(buf)?;
         verify_tlv_type(buf[0], TlvType::EntityId)?;
         let len = buf[1];
         if len != 1 && len != 2 && len != 4 && len != 8 {
@@ -267,22 +377,31 @@ impl EntityIdTlv {
         Ok(Self { entity_id })
     }
 
-    /// Convert to a generic [Tlv], which also erases the programmatic type information.
+    /// Convert to a generic [Tlv], which also erases the type information.
     pub fn to_tlv(self, buf: &mut [u8]) -> Result<Tlv, ByteConversionError> {
-        Self::len_check(buf)?;
+        Self::check_min_len(buf)?;
         self.entity_id
             .write_to_be_bytes(&mut buf[2..2 + self.entity_id.size()])?;
-        Tlv::new(TlvType::EntityId, &buf[2..2 + self.entity_id.size()]).map_err(|e| match e {
-            TlvLvError::ByteConversion(e) => e,
-            // All other errors are impossible.
-            _ => panic!("unexpected TLV error"),
-        })
+        if buf.len() < self.len_value() {
+            return Err(ByteConversionError::ToSliceTooSmall {
+                found: buf.len(),
+                expected: self.len_value(),
+            });
+        }
+        // We performed all checks necessary to ensure this call never panics.
+        Ok(Tlv::new(TlvType::EntityId, &buf[2..2 + self.entity_id.size()]).unwrap())
+    }
+
+    #[cfg(feature = "alloc")]
+    pub fn to_owned(&self) -> TlvOwned {
+        // Unwrap is okay here, entity ID should never be larger than maximum allowed size.
+        TlvOwned::new(TlvType::EntityId, &self.entity_id.to_vec()).unwrap()
     }
 }
 
 impl WritableTlv for EntityIdTlv {
     fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
-        Self::len_check(buf)?;
+        Self::check_min_len(buf)?;
         buf[0] = TlvType::EntityId as u8;
         buf[1] = self.entity_id.size() as u8;
         Ok(2 + self.entity_id.write_to_be_bytes(&mut buf[2..])?)
@@ -348,6 +467,7 @@ pub fn fs_request_has_second_filename(action_code: FilestoreActionCode) -> bool
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 struct FilestoreTlvBase<'first_name, 'second_name> {
     pub action_code: FilestoreActionCode,
     #[cfg_attr(feature = "serde", serde(borrow))]
@@ -520,6 +640,12 @@ impl<'first_name, 'second_name> FilestoreRequestTlv<'first_name, 'second_name> {
             },
         })
     }
+
+    #[cfg(feature = "alloc")]
+    pub fn to_owned(&self) -> TlvOwned {
+        // The API should ensure the data field is never too large, so unwrapping here is okay.
+        TlvOwned::new(TlvType::FilestoreRequest, &self.to_vec()[2..]).unwrap()
+    }
 }
 
 impl WritableTlv for FilestoreRequestTlv<'_, '_> {
@@ -561,6 +687,7 @@ impl GenericTlv for FilestoreRequestTlv<'_, '_> {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct FilestoreResponseTlv<'first_name, 'second_name, 'fs_msg> {
     #[cfg_attr(feature = "serde", serde(borrow))]
     base: FilestoreTlvBase<'first_name, 'second_name>,
@@ -704,6 +831,12 @@ impl<'first_name, 'second_name, 'fs_msg> FilestoreResponseTlv<'first_name, 'seco
             filestore_message,
         })
     }
+
+    #[cfg(feature = "alloc")]
+    pub fn to_owned(&self) -> TlvOwned {
+        // The API should ensure the data field is never too large, so unwrap is okay here.
+        TlvOwned::new(TlvType::FilestoreResponse, &self.to_vec()[2..]).unwrap()
+    }
 }
 
 impl WritableTlv for FilestoreResponseTlv<'_, '_, '_> {
@@ -745,6 +878,20 @@ impl GenericTlv for FilestoreResponseTlv<'_, '_, '_> {
     }
 }
 
+pub(crate) fn verify_tlv_type(raw_type: u8, expected_tlv_type: TlvType) -> Result<(), TlvLvError> {
+    let tlv_type = TlvType::try_from(raw_type).map_err(|_| TlvLvError::InvalidTlvTypeField {
+        found: raw_type,
+        expected: Some(expected_tlv_type.into()),
+    })?;
+    if tlv_type != expected_tlv_type {
+        return Err(TlvLvError::InvalidTlvTypeField {
+            found: tlv_type as u8,
+            expected: Some(expected_tlv_type as u8),
+        });
+    }
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -932,15 +1079,11 @@ mod tests {
         let tlv_res = Tlv::new(TlvType::MsgToUser, &buf_too_large);
         assert!(tlv_res.is_err());
         let error = tlv_res.unwrap_err();
-        if let TlvLvError::DataTooLarge(size) = error {
-            assert_eq!(size, u8::MAX as usize + 1);
-            assert_eq!(
-                error.to_string(),
-                "data with size 256 larger than allowed 255 bytes"
-            );
-        } else {
-            panic!("unexpected error {:?}", error);
-        }
+        assert_eq!(error.0, u8::MAX as usize + 1);
+        assert_eq!(
+            error.to_string(),
+            "data with size 256 larger than allowed 255 bytes"
+        );
     }
 
     #[test]
@@ -1293,4 +1436,71 @@ mod tests {
         assert_eq!(tlv_as_vec[0], 20);
         assert_eq!(tlv_as_vec[1], 0);
     }
+
+    #[test]
+    fn test_tlv_to_owned() {
+        let entity_id = UbfU8::new(5);
+        let mut buf: [u8; 4] = [0; 4];
+        assert!(entity_id.write_to_be_bytes(&mut buf).is_ok());
+        let tlv_res = Tlv::new(TlvType::EntityId, &buf[0..1]);
+        assert!(tlv_res.is_ok());
+        let tlv_res = tlv_res.unwrap();
+        let tlv_owned = tlv_res.to_owned();
+        assert_eq!(tlv_res, tlv_owned);
+        let tlv_owned_from_conversion: TlvOwned = tlv_res.into();
+        assert_eq!(tlv_owned_from_conversion, tlv_owned);
+        assert_eq!(tlv_owned_from_conversion, tlv_res);
+    }
+
+    #[test]
+    fn test_owned_tlv() {
+        let entity_id = UbfU8::new(5);
+        let mut buf: [u8; 4] = [0; 4];
+        assert!(entity_id.write_to_be_bytes(&mut buf).is_ok());
+        let tlv_res = TlvOwned::new(TlvType::EntityId, &buf[0..1]).expect("creating TLV failed");
+        assert_eq!(
+            tlv_res.tlv_type_field(),
+            TlvTypeField::Standard(TlvType::EntityId)
+        );
+        assert_eq!(tlv_res.len_full(), 3);
+        assert_eq!(tlv_res.value().len(), 1);
+        assert_eq!(tlv_res.len_value(), 1);
+        assert!(!tlv_res.is_empty());
+        assert_eq!(tlv_res.value()[0], 5);
+    }
+
+    #[test]
+    fn test_owned_tlv_empty() {
+        let tlv_res = TlvOwned::new_empty(TlvType::FlowLabel);
+        assert_eq!(
+            tlv_res.tlv_type_field(),
+            TlvTypeField::Standard(TlvType::FlowLabel)
+        );
+        assert_eq!(tlv_res.len_full(), 2);
+        assert_eq!(tlv_res.value().len(), 0);
+        assert_eq!(tlv_res.len_value(), 0);
+        assert!(tlv_res.is_empty());
+    }
+
+    #[test]
+    fn test_owned_tlv_custom_type() {
+        let tlv_res = TlvOwned::new_with_custom_type(32, &[]).unwrap();
+        assert_eq!(tlv_res.tlv_type_field(), TlvTypeField::Custom(32));
+        assert_eq!(tlv_res.len_full(), 2);
+        assert_eq!(tlv_res.value().len(), 0);
+        assert_eq!(tlv_res.len_value(), 0);
+        assert!(tlv_res.is_empty());
+    }
+
+    #[test]
+    fn test_owned_tlv_conversion_to_bytes() {
+        let entity_id = UbfU8::new(5);
+        let mut buf: [u8; 4] = [0; 4];
+        assert!(entity_id.write_to_be_bytes(&mut buf).is_ok());
+        let tlv_res = Tlv::new(TlvType::EntityId, &buf[0..1]);
+        assert!(tlv_res.is_ok());
+        let tlv_res = tlv_res.unwrap();
+        let tlv_owned_from_conversion: TlvOwned = tlv_res.into();
+        assert_eq!(tlv_res.to_vec(), tlv_owned_from_conversion.to_vec());
+    }
 }

src/cfdp/tlv/msg_to_user.rs

@@ -1,6 +1,8 @@
 //! Abstractions for the Message to User CFDP TLV subtype.
-use super::{GenericTlv, Tlv, TlvLvError, TlvType, TlvTypeField, WritableTlv};
-use crate::ByteConversionError;
+#[cfg(feature = "alloc")]
+use super::TlvOwned;
+use super::{GenericTlv, ReadableTlv, Tlv, TlvLvError, TlvType, TlvTypeField, WritableTlv};
+use crate::{cfdp::TlvLvDataTooLarge, ByteConversionError};
 use delegate::delegate;
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
@@ -10,7 +12,7 @@ pub struct MsgToUserTlv<'data> {
 
 impl<'data> MsgToUserTlv<'data> {
     /// Create a new message to user TLV where the type field is set correctly.
-    pub fn new(value: &'data [u8]) -> Result<MsgToUserTlv<'data>, TlvLvError> {
+    pub fn new(value: &'data [u8]) -> Result<MsgToUserTlv<'data>, TlvLvDataTooLarge> {
         Ok(Self {
             tlv: Tlv::new(TlvType::MsgToUser, value)?,
         })
@@ -75,6 +77,21 @@ impl<'data> MsgToUserTlv<'data> {
         }
         Ok(msg_to_user)
     }
+
+    pub fn to_tlv(&self) -> Tlv<'data> {
+        self.tlv
+    }
+
+    #[cfg(feature = "alloc")]
+    pub fn to_owned(&self) -> TlvOwned {
+        self.tlv.to_owned()
+    }
+}
+
+impl<'a> From<MsgToUserTlv<'a>> for Tlv<'a> {
+    fn from(value: MsgToUserTlv<'a>) -> Tlv<'a> {
+        value.to_tlv()
+    }
 }
 
 impl WritableTlv for MsgToUserTlv<'_> {
@@ -139,6 +156,40 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_msg_to_user_type_reduction() {
+        let custom_value: [u8; 4] = [1, 2, 3, 4];
+        let msg_to_user = MsgToUserTlv::new(&custom_value).unwrap();
+        let tlv = msg_to_user.to_tlv();
+        assert_eq!(
+            tlv.tlv_type_field(),
+            TlvTypeField::Standard(TlvType::MsgToUser)
+        );
+
+        assert_eq!(tlv.value(), custom_value);
+    }
+
+    #[test]
+    fn test_msg_to_user_to_tlv() {
+        let custom_value: [u8; 4] = [1, 2, 3, 4];
+        let msg_to_user = MsgToUserTlv::new(&custom_value).unwrap();
+        let tlv: Tlv = msg_to_user.into();
+        assert_eq!(msg_to_user.to_tlv(), tlv);
+    }
+
+    #[test]
+    fn test_msg_to_user_owner_converter() {
+        let custom_value: [u8; 4] = [1, 2, 3, 4];
+        let msg_to_user = MsgToUserTlv::new(&custom_value).unwrap();
+        let tlv = msg_to_user.to_owned();
+        assert_eq!(
+            tlv.tlv_type_field(),
+            TlvTypeField::Standard(TlvType::MsgToUser)
+        );
+
+        assert_eq!(tlv.value(), custom_value);
+    }
+
     #[test]
     fn test_reserved_msg_deserialization() {
         let custom_value: [u8; 3] = [1, 2, 3];

src/ecss/hk.rs

@@ -5,6 +5,7 @@ use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Eq, PartialEq, Copy, Clone, IntoPrimitive, TryFromPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum Subservice {
     // Regular HK

src/ecss/mod.rs

@@ -1,8 +1,8 @@
 //! Common definitions and helpers required to create PUS TMTC packets according to
 //! [ECSS-E-ST-70-41C](https://ecss.nl/standard/ecss-e-st-70-41c-space-engineering-telemetry-and-telecommand-packet-utilization-15-april-2016/)
 //!
-//! You can find the PUS telecommand definitions in the [tc] module and ithe PUS telemetry definitions
-//! inside the [tm] module.
+//! You can find the PUS telecommand types in the [tc] module and the the PUS telemetry
+//! types inside the [tm] module.
 use crate::{ByteConversionError, CcsdsPacket, CRC_CCITT_FALSE};
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
@@ -22,7 +22,6 @@ pub mod tm;
 pub mod verification;
 
 pub type CrcType = u16;
-pub const CCSDS_HEADER_LEN: usize = size_of::<crate::zc::SpHeader>();
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq, IntoPrimitive, TryFromPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
@@ -74,6 +73,7 @@ pub enum PusServiceId {
 /// All PUS versions. Only PUS C is supported by this library.
 #[derive(PartialEq, Eq, Copy, Clone, Debug)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[non_exhaustive]
 pub enum PusVersion {
     EsaPus = 0,
@@ -150,6 +150,7 @@ pub enum PfcReal {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum PusError {
     VersionNotSupported(PusVersion),
     ChecksumFailure(u16),
@@ -205,13 +206,12 @@ pub trait PusPacket: CcsdsPacket {
     fn crc16(&self) -> Option<u16>;
 }
 
-pub(crate) fn crc_from_raw_data(raw_data: &[u8]) -> Result<u16, PusError> {
+pub(crate) fn crc_from_raw_data(raw_data: &[u8]) -> Result<u16, ByteConversionError> {
     if raw_data.len() < 2 {
         return Err(ByteConversionError::FromSliceTooSmall {
             found: raw_data.len(),
             expected: 2,
-        }
-        .into());
+        });
     }
     Ok(u16::from_be_bytes(
         raw_data[raw_data.len() - 2..raw_data.len()]
@@ -226,35 +226,16 @@ pub(crate) fn calc_pus_crc16(bytes: &[u8]) -> u16 {
     digest.finalize()
 }
 
-pub(crate) fn crc_procedure(
-    calc_on_serialization: bool,
-    cached_crc16: &Option<u16>,
-    start_idx: usize,
-    curr_idx: usize,
-    slice: &[u8],
-) -> Result<u16, PusError> {
-    let crc16;
-    if calc_on_serialization {
-        crc16 = calc_pus_crc16(&slice[start_idx..curr_idx])
-    } else if cached_crc16.is_none() {
-        return Err(PusError::CrcCalculationMissing);
-    } else {
-        crc16 = cached_crc16.unwrap();
-    }
-    Ok(crc16)
-}
-
 pub(crate) fn user_data_from_raw(
     current_idx: usize,
     total_len: usize,
     slice: &[u8],
-) -> Result<&[u8], PusError> {
+) -> Result<&[u8], ByteConversionError> {
     match current_idx {
         _ if current_idx > total_len - 2 => Err(ByteConversionError::FromSliceTooSmall {
             found: total_len - 2,
             expected: current_idx,
-        }
-        .into()),
+        }),
         _ => Ok(&slice[current_idx..total_len - 2]),
     }
 }
@@ -264,7 +245,7 @@ pub(crate) fn verify_crc16_ccitt_false_from_raw_to_pus_error(
     crc16: u16,
 ) -> Result<(), PusError> {
     verify_crc16_ccitt_false_from_raw(raw_data)
-        .then(|| ())
+        .then_some(())
         .ok_or(PusError::ChecksumFailure(crc16))
 }
 
@@ -280,9 +261,13 @@ pub(crate) fn verify_crc16_ccitt_false_from_raw(raw_data: &[u8]) -> bool {
 macro_rules! ccsds_impl {
     () => {
         delegate!(to self.sp_header {
+            #[inline]
             fn ccsds_version(&self) -> u8;
+            #[inline]
             fn packet_id(&self) -> crate::PacketId;
+            #[inline]
             fn psc(&self) -> crate::PacketSequenceCtrl;
+            #[inline]
             fn data_len(&self) -> u16;
         });
     }
@@ -291,8 +276,11 @@ macro_rules! ccsds_impl {
 macro_rules! sp_header_impls {
     () => {
         delegate!(to self.sp_header {
+            #[inline]
             pub fn set_apid(&mut self, apid: u16) -> bool;
+            #[inline]
             pub fn set_seq_count(&mut self, seq_count: u16) -> bool;
+            #[inline]
             pub fn set_seq_flags(&mut self, seq_flag: SequenceFlags);
         });
     }
@@ -315,15 +303,19 @@ pub trait EcssEnumerationExt: EcssEnumeration + Debug + Copy + Clone + PartialEq
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub struct GenericEcssEnumWrapper<TYPE: Copy> {
+pub struct GenericEcssEnumWrapper<TYPE: Copy + Into<u64>> {
     field: GenericUnsignedByteField<TYPE>,
 }
 
-impl<TYPE: Copy> GenericEcssEnumWrapper<TYPE> {
+impl<TYPE: Copy + Into<u64>> GenericEcssEnumWrapper<TYPE> {
     pub const fn ptc() -> PacketTypeCodes {
         PacketTypeCodes::Enumerated
     }
 
+    pub const fn value_typed(&self) -> TYPE {
+        self.field.value_typed()
+    }
+
     pub fn new(val: TYPE) -> Self {
         Self {
             field: GenericUnsignedByteField::new(val),
@@ -331,7 +323,7 @@ impl<TYPE: Copy> GenericEcssEnumWrapper<TYPE> {
     }
 }
 
-impl<TYPE: Copy + ToBeBytes> UnsignedEnum for GenericEcssEnumWrapper<TYPE> {
+impl<TYPE: Copy + ToBeBytes + Into<u64>> UnsignedEnum for GenericEcssEnumWrapper<TYPE> {
     fn size(&self) -> usize {
         (self.pfc() / 8) as usize
     }
@@ -339,23 +331,51 @@ impl<TYPE: Copy + ToBeBytes> UnsignedEnum for GenericEcssEnumWrapper<TYPE> {
     fn write_to_be_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
         self.field.write_to_be_bytes(buf)
     }
+
+    fn value(&self) -> u64 {
+        self.field.value()
+    }
 }
 
-impl<TYPE: Copy + ToBeBytes> EcssEnumeration for GenericEcssEnumWrapper<TYPE> {
+impl<TYPE: Copy + ToBeBytes + Into<u64>> EcssEnumeration for GenericEcssEnumWrapper<TYPE> {
     fn pfc(&self) -> u8 {
         size_of::<TYPE>() as u8 * 8_u8
     }
 }
 
-impl<TYPE: Debug + Copy + Clone + PartialEq + Eq + ToBeBytes> EcssEnumerationExt
+impl<TYPE: Debug + Copy + Clone + PartialEq + Eq + ToBeBytes + Into<u64>> EcssEnumerationExt
     for GenericEcssEnumWrapper<TYPE>
 {
 }
 
-pub type EcssEnumU8 = GenericEcssEnumWrapper<u8>;
-pub type EcssEnumU16 = GenericEcssEnumWrapper<u16>;
-pub type EcssEnumU32 = GenericEcssEnumWrapper<u32>;
-pub type EcssEnumU64 = GenericEcssEnumWrapper<u64>;
+impl<T: Copy + Into<u64>> From<T> for GenericEcssEnumWrapper<T> {
+    fn from(value: T) -> Self {
+        Self::new(value)
+    }
+}
+
+macro_rules! generic_ecss_enum_typedefs_and_from_impls {
+    ($($ty:ty => $Enum:ident),*) => {
+        $(
+            pub type $Enum = GenericEcssEnumWrapper<$ty>;
+
+            impl From<$Enum> for $ty {
+                fn from(value: $Enum) -> Self {
+                    value.value_typed()
+                }
+            }
+        )*
+    };
+}
+
+// Generates EcssEnum<$TY> type definitions as well as a From<$TY> for EcssEnum<$TY>
+// implementation.
+generic_ecss_enum_typedefs_and_from_impls! {
+    u8 => EcssEnumU8,
+    u16 => EcssEnumU16,
+    u32 => EcssEnumU32,
+    u64 => EcssEnumU64
+}
 
 /// Generic trait for PUS packet abstractions which can written to a raw slice as their raw
 /// byte representation. This is especially useful for generic abstractions which depend only
@@ -396,6 +416,12 @@ mod tests {
             .write_to_be_bytes(&mut buf[1..2])
             .expect("To byte conversion of u8 failed");
         assert_eq!(buf[1], 1);
+        assert_eq!(my_enum.value(), 1);
+        assert_eq!(my_enum.value_typed(), 1);
+        let enum_as_u8: u8 = my_enum.into();
+        assert_eq!(enum_as_u8, 1);
+        let vec = my_enum.to_vec();
+        assert_eq!(vec, buf[1..2]);
     }
 
     #[test]
@@ -409,6 +435,12 @@ mod tests {
         assert_eq!(my_enum.pfc(), 16);
         assert_eq!(buf[1], 0x1f);
         assert_eq!(buf[2], 0x2f);
+        assert_eq!(my_enum.value(), 0x1f2f);
+        assert_eq!(my_enum.value_typed(), 0x1f2f);
+        let enum_as_raw: u16 = my_enum.into();
+        assert_eq!(enum_as_raw, 0x1f2f);
+        let vec = my_enum.to_vec();
+        assert_eq!(vec, buf[1..3]);
     }
 
     #[test]
@@ -440,6 +472,12 @@ mod tests {
         assert_eq!(buf[2], 0x2f);
         assert_eq!(buf[3], 0x3f);
         assert_eq!(buf[4], 0x4f);
+        assert_eq!(my_enum.value(), 0x1f2f3f4f);
+        assert_eq!(my_enum.value_typed(), 0x1f2f3f4f);
+        let enum_as_raw: u32 = my_enum.into();
+        assert_eq!(enum_as_raw, 0x1f2f3f4f);
+        let vec = my_enum.to_vec();
+        assert_eq!(vec, buf[1..5]);
     }
 
     #[test]
@@ -460,6 +498,27 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_enum_u64() {
+        let mut buf = [0; 8];
+        let my_enum = EcssEnumU64::new(0x1f2f3f4f5f);
+        my_enum
+            .write_to_be_bytes(&mut buf)
+            .expect("To byte conversion of u64 failed");
+        assert_eq!(buf[3], 0x1f);
+        assert_eq!(buf[4], 0x2f);
+        assert_eq!(buf[5], 0x3f);
+        assert_eq!(buf[6], 0x4f);
+        assert_eq!(buf[7], 0x5f);
+        assert_eq!(my_enum.value(), 0x1f2f3f4f5f);
+        assert_eq!(my_enum.value_typed(), 0x1f2f3f4f5f);
+        let enum_as_raw: u64 = my_enum.into();
+        assert_eq!(enum_as_raw, 0x1f2f3f4f5f);
+        assert_eq!(u64::from_be_bytes(buf), 0x1f2f3f4f5f);
+        let vec = my_enum.to_vec();
+        assert_eq!(vec, buf);
+    }
+
     #[test]
     fn test_pus_error_display() {
         let unsupport_version = PusError::VersionNotSupported(super::PusVersion::EsaPus);

src/ecss/scheduling.rs

@@ -54,6 +54,7 @@ pub enum SchedStatus {
 }
 
 impl From<bool> for SchedStatus {
+    #[inline]
     fn from(value: bool) -> Self {
         if value {
             SchedStatus::Enabled

src/ecss/tc.rs

@@ -9,9 +9,11 @@
 //! use spacepackets::ecss::tc::{PusTcCreator, PusTcReader, PusTcSecondaryHeader};
 //!
 //! // Create a ping telecommand with no user application data
-//! let mut sph = SpHeader::tc_unseg(0x02, 0x34, 0).unwrap();
-//! let tc_header = PusTcSecondaryHeader::new_simple(17, 1);
-//! let pus_tc = PusTcCreator::new_no_app_data(&mut sph, tc_header, true);
+//! let pus_tc = PusTcCreator::new_no_app_data(
+//!     SpHeader::new_from_apid(0x02),
+//!     PusTcSecondaryHeader::new_simple(17, 1),
+//!     true
+//! );
 //! println!("{:?}", pus_tc);
 //! assert_eq!(pus_tc.service(), 17);
 //! assert_eq!(pus_tc.subservice(), 1);
@@ -48,8 +50,6 @@ use zerocopy::AsBytes;
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
 
-pub use legacy_tc::*;
-
 /// PUS C secondary header length is fixed
 pub const PUC_TC_SECONDARY_HEADER_LEN: usize = size_of::<zc::PusTcSecondaryHeader>();
 pub const PUS_TC_MIN_LEN_WITHOUT_APP_DATA: usize =
@@ -61,6 +61,7 @@ pub trait IsPusTelecommand {}
 
 #[derive(Debug, Eq, PartialEq, Copy, Clone, IntoPrimitive, TryFromPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 enum AckOpts {
     Acceptance = 0b1000,
@@ -112,22 +113,27 @@ pub mod zc {
     }
 
     impl GenericPusTcSecondaryHeader for PusTcSecondaryHeader {
+        #[inline]
         fn pus_version(&self) -> PusVersion {
             PusVersion::try_from(self.version_ack >> 4 & 0b1111).unwrap_or(PusVersion::Invalid)
         }
 
+        #[inline]
         fn ack_flags(&self) -> u8 {
             self.version_ack & 0b1111
         }
 
+        #[inline]
         fn service(&self) -> u8 {
             self.service
         }
 
+        #[inline]
         fn subservice(&self) -> u8 {
             self.subservice
         }
 
+        #[inline]
         fn source_id(&self) -> u16 {
             self.source_id.get()
         }
@@ -146,6 +152,7 @@ pub mod zc {
 
 #[derive(PartialEq, Eq, Copy, Clone, Debug)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct PusTcSecondaryHeader {
     pub service: u8,
     pub subservice: u8,
@@ -155,22 +162,27 @@ pub struct PusTcSecondaryHeader {
 }
 
 impl GenericPusTcSecondaryHeader for PusTcSecondaryHeader {
+    #[inline]
     fn pus_version(&self) -> PusVersion {
         self.version
     }
 
+    #[inline]
     fn ack_flags(&self) -> u8 {
         self.ack
     }
 
+    #[inline]
     fn service(&self) -> u8 {
         self.service
     }
 
+    #[inline]
     fn subservice(&self) -> u8 {
         self.subservice
     }
 
+    #[inline]
     fn source_id(&self) -> u16 {
         self.source_id
     }
@@ -191,6 +203,7 @@ impl TryFrom<zc::PusTcSecondaryHeader> for PusTcSecondaryHeader {
 }
 
 impl PusTcSecondaryHeader {
+    #[inline]
     pub fn new_simple(service: u8, subservice: u8) -> Self {
         PusTcSecondaryHeader {
             service,
@@ -201,6 +214,7 @@ impl PusTcSecondaryHeader {
         }
     }
 
+    #[inline]
     pub fn new(service: u8, subservice: u8, ack: u8, source_id: u16) -> Self {
         PusTcSecondaryHeader {
             service,
@@ -212,333 +226,6 @@ impl PusTcSecondaryHeader {
     }
 }
 
-pub mod legacy_tc {
-    use crate::ecss::tc::{
-        zc, GenericPusTcSecondaryHeader, IsPusTelecommand, PusTcSecondaryHeader, ACK_ALL,
-        PUC_TC_SECONDARY_HEADER_LEN, PUS_TC_MIN_LEN_WITHOUT_APP_DATA,
-    };
-    use crate::ecss::{
-        ccsds_impl, crc_from_raw_data, crc_procedure, sp_header_impls,
-        verify_crc16_ccitt_false_from_raw_to_pus_error, PusError, PusPacket, WritablePusPacket,
-        CCSDS_HEADER_LEN,
-    };
-    use crate::ecss::{user_data_from_raw, PusVersion};
-    use crate::SequenceFlags;
-    use crate::{ByteConversionError, CcsdsPacket, PacketType, SpHeader, CRC_CCITT_FALSE};
-    use core::mem::size_of;
-    use delegate::delegate;
-    use zerocopy::AsBytes;
-
-    #[cfg(feature = "alloc")]
-    use alloc::vec::Vec;
-
-    #[cfg(feature = "serde")]
-    use serde::{Deserialize, Serialize};
-
-    /// This class models the PUS C telecommand packet. It is the primary data structure to generate the
-    /// raw byte representation of a PUS telecommand or to deserialize from one from raw bytes.
-    ///
-    /// This class also derives the [serde::Serialize] and [serde::Deserialize] trait if the
-    /// [serde] feature is used, which allows to send around TC packets in a raw byte format using a
-    /// serde provider like [postcard](https://docs.rs/postcard/latest/postcard/).
-    ///
-    /// There is no spare bytes support yet.
-    ///
-    /// # Lifetimes
-    ///
-    /// * `'raw_data` - If the TC is not constructed from a raw slice, this will be the life time of
-    ///    a buffer where the user provided application data will be serialized into. If it
-    ///    is, this is the lifetime of the raw byte slice it is constructed from.
-    #[derive(Eq, Copy, Clone, Debug)]
-    #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-    pub struct PusTc<'raw_data> {
-        sp_header: SpHeader,
-        pub sec_header: PusTcSecondaryHeader,
-        /// If this is set to false, a manual call to [PusTc::calc_own_crc16] or
-        /// [PusTc::update_packet_fields] is necessary for the serialized or cached CRC16 to be valid.
-        pub calc_crc_on_serialization: bool,
-        #[cfg_attr(feature = "serde", serde(skip))]
-        raw_data: Option<&'raw_data [u8]>,
-        app_data: &'raw_data [u8],
-        crc16: Option<u16>,
-    }
-
-    impl<'raw_data> PusTc<'raw_data> {
-        /// Generates a new struct instance.
-        ///
-        /// # Arguments
-        ///
-        /// * `sp_header` - Space packet header information. The correct packet type will be set
-        ///     automatically
-        /// * `sec_header` - Information contained in the data field header, including the service
-        ///     and subservice type
-        /// * `app_data` - Custom application data
-        /// * `set_ccsds_len` - Can be used to automatically update the CCSDS space packet data length
-        ///     field. If this is not set to true, [PusTc::update_ccsds_data_len] can be called to set
-        ///     the correct value to this field manually
-        #[deprecated(
-            since = "0.7.0",
-            note = "Use specialized PusTcCreator or PusTcReader classes instead"
-        )]
-        pub fn new(
-            sp_header: &mut SpHeader,
-            sec_header: PusTcSecondaryHeader,
-            app_data: Option<&'raw_data [u8]>,
-            set_ccsds_len: bool,
-        ) -> Self {
-            sp_header.set_packet_type(PacketType::Tc);
-            sp_header.set_sec_header_flag();
-            let mut pus_tc = Self {
-                sp_header: *sp_header,
-                raw_data: None,
-                app_data: app_data.unwrap_or(&[]),
-                sec_header,
-                calc_crc_on_serialization: true,
-                crc16: None,
-            };
-            if set_ccsds_len {
-                pus_tc.update_ccsds_data_len();
-            }
-            pus_tc
-        }
-
-        /// Simplified version of the [PusTc::new] function which allows to only specify service and
-        /// subservice instead of the full PUS TC secondary header.
-        #[deprecated(
-            since = "0.7.0",
-            note = "Use specialized PusTcCreator or PusTcReader classes instead"
-        )]
-        pub fn new_simple(
-            sph: &mut SpHeader,
-            service: u8,
-            subservice: u8,
-            app_data: Option<&'raw_data [u8]>,
-            set_ccsds_len: bool,
-        ) -> Self {
-            #[allow(deprecated)]
-            Self::new(
-                sph,
-                PusTcSecondaryHeader::new(service, subservice, ACK_ALL, 0),
-                app_data,
-                set_ccsds_len,
-            )
-        }
-
-        pub fn sp_header(&self) -> &SpHeader {
-            &self.sp_header
-        }
-
-        pub fn set_ack_field(&mut self, ack: u8) -> bool {
-            if ack > 0b1111 {
-                return false;
-            }
-            self.sec_header.ack = ack & 0b1111;
-            true
-        }
-
-        pub fn set_source_id(&mut self, source_id: u16) {
-            self.sec_header.source_id = source_id;
-        }
-
-        sp_header_impls!();
-
-        /// Calculate the CCSDS space packet data length field and sets it
-        /// This is called automatically if the `set_ccsds_len` argument in the [PusTc::new] call was
-        /// used.
-        /// If this was not done or the application data is set or changed after construction,
-        /// this function needs to be called to ensure that the data length field of the CCSDS header
-        /// is set correctly.
-        pub fn update_ccsds_data_len(&mut self) {
-            self.sp_header.data_len =
-                self.len_written() as u16 - size_of::<crate::zc::SpHeader>() as u16 - 1;
-        }
-
-        /// This function should be called before the TC packet is serialized if
-        /// [PusTc::calc_crc_on_serialization] is set to False. It will calculate and cache the CRC16.
-        pub fn calc_own_crc16(&mut self) {
-            let mut digest = CRC_CCITT_FALSE.digest();
-            let sph_zc = crate::zc::SpHeader::from(self.sp_header);
-            digest.update(sph_zc.as_bytes());
-            let pus_tc_header = zc::PusTcSecondaryHeader::try_from(self.sec_header).unwrap();
-            digest.update(pus_tc_header.as_bytes());
-            if !self.app_data.is_empty() {
-                digest.update(self.app_data);
-            }
-            self.crc16 = Some(digest.finalize())
-        }
-
-        /// This helper function calls both [PusTc::update_ccsds_data_len] and [PusTc::calc_own_crc16].
-        pub fn update_packet_fields(&mut self) {
-            self.update_ccsds_data_len();
-            self.calc_own_crc16();
-        }
-
-        #[cfg(feature = "alloc")]
-        #[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
-        pub fn append_to_vec(&self, vec: &mut Vec<u8>) -> Result<usize, PusError> {
-            let sph_zc = crate::zc::SpHeader::from(self.sp_header);
-            let appended_len = PUS_TC_MIN_LEN_WITHOUT_APP_DATA + self.app_data.len();
-            let start_idx = vec.len();
-            let mut ser_len = 0;
-            vec.extend_from_slice(sph_zc.as_bytes());
-            ser_len += sph_zc.as_bytes().len();
-            // The PUS version is hardcoded to PUS C
-            let pus_tc_header = zc::PusTcSecondaryHeader::try_from(self.sec_header).unwrap();
-            vec.extend_from_slice(pus_tc_header.as_bytes());
-            ser_len += pus_tc_header.as_bytes().len();
-            vec.extend_from_slice(self.app_data);
-            ser_len += self.app_data.len();
-            let crc16 = crc_procedure(
-                self.calc_crc_on_serialization,
-                &self.crc16,
-                start_idx,
-                ser_len,
-                &vec[start_idx..ser_len],
-            )?;
-            vec.extend_from_slice(crc16.to_be_bytes().as_slice());
-            Ok(appended_len)
-        }
-
-        /// Create a [PusTc] instance from a raw slice. On success, it returns a tuple containing
-        /// the instance and the found byte length of the packet.
-        #[deprecated(
-            since = "0.7.0",
-            note = "Use specialized PusTcCreator or PusTcReader classes instead"
-        )]
-        pub fn from_bytes(slice: &'raw_data [u8]) -> Result<(Self, usize), PusError> {
-            let raw_data_len = slice.len();
-            if raw_data_len < PUS_TC_MIN_LEN_WITHOUT_APP_DATA {
-                return Err(ByteConversionError::FromSliceTooSmall {
-                    found: raw_data_len,
-                    expected: PUS_TC_MIN_LEN_WITHOUT_APP_DATA,
-                }
-                .into());
-            }
-            let mut current_idx = 0;
-            let (sp_header, _) = SpHeader::from_be_bytes(&slice[0..CCSDS_HEADER_LEN])?;
-            current_idx += CCSDS_HEADER_LEN;
-            let total_len = sp_header.total_len();
-            if raw_data_len < total_len || total_len < PUS_TC_MIN_LEN_WITHOUT_APP_DATA {
-                return Err(ByteConversionError::FromSliceTooSmall {
-                    found: raw_data_len,
-                    expected: total_len,
-                }
-                .into());
-            }
-            let sec_header = zc::PusTcSecondaryHeader::from_bytes(
-                &slice[current_idx..current_idx + PUC_TC_SECONDARY_HEADER_LEN],
-            )
-            .ok_or(ByteConversionError::ZeroCopyFromError)?;
-            current_idx += PUC_TC_SECONDARY_HEADER_LEN;
-            let raw_data = &slice[0..total_len];
-            let pus_tc = Self {
-                sp_header,
-                sec_header: PusTcSecondaryHeader::try_from(sec_header).unwrap(),
-                raw_data: Some(raw_data),
-                app_data: user_data_from_raw(current_idx, total_len, slice)?,
-                calc_crc_on_serialization: false,
-                crc16: Some(crc_from_raw_data(raw_data)?),
-            };
-            verify_crc16_ccitt_false_from_raw_to_pus_error(
-                raw_data,
-                pus_tc.crc16.expect("CRC16 invalid"),
-            )?;
-            Ok((pus_tc, total_len))
-        }
-
-        #[deprecated(since = "0.5.2", note = "use raw_bytes() instead")]
-        pub fn raw(&self) -> Option<&'raw_data [u8]> {
-            self.raw_bytes()
-        }
-
-        /// If [Self] was constructed [Self::from_bytes], this function will return the slice it was
-        /// constructed from. Otherwise, [None] will be returned.
-        pub fn raw_bytes(&self) -> Option<&'raw_data [u8]> {
-            self.raw_data
-        }
-    }
-
-    impl WritablePusPacket for PusTc<'_> {
-        fn len_written(&self) -> usize {
-            PUS_TC_MIN_LEN_WITHOUT_APP_DATA + self.app_data.len()
-        }
-
-        /// Write the raw PUS byte representation to a provided buffer.
-        fn write_to_bytes(&self, slice: &mut [u8]) -> Result<usize, PusError> {
-            let mut curr_idx = 0;
-            let tc_header_len = size_of::<zc::PusTcSecondaryHeader>();
-            let total_size = self.len_written();
-            if total_size > slice.len() {
-                return Err(ByteConversionError::ToSliceTooSmall {
-                    found: slice.len(),
-                    expected: total_size,
-                }
-                .into());
-            }
-            self.sp_header.write_to_be_bytes(slice)?;
-            curr_idx += CCSDS_HEADER_LEN;
-            let sec_header = zc::PusTcSecondaryHeader::try_from(self.sec_header).unwrap();
-            sec_header
-                .write_to_bytes(&mut slice[curr_idx..curr_idx + tc_header_len])
-                .ok_or(ByteConversionError::ZeroCopyToError)?;
-
-            curr_idx += tc_header_len;
-            slice[curr_idx..curr_idx + self.app_data.len()].copy_from_slice(self.app_data);
-            curr_idx += self.app_data.len();
-            let crc16 = crc_procedure(
-                self.calc_crc_on_serialization,
-                &self.crc16,
-                0,
-                curr_idx,
-                slice,
-            )?;
-            slice[curr_idx..curr_idx + 2].copy_from_slice(crc16.to_be_bytes().as_slice());
-            curr_idx += 2;
-            Ok(curr_idx)
-        }
-    }
-
-    impl PartialEq for PusTc<'_> {
-        fn eq(&self, other: &Self) -> bool {
-            self.sp_header == other.sp_header
-                && self.sec_header == other.sec_header
-                && self.app_data == other.app_data
-        }
-    }
-
-    impl CcsdsPacket for PusTc<'_> {
-        ccsds_impl!();
-    }
-
-    impl PusPacket for PusTc<'_> {
-        delegate!(to self.sec_header {
-            fn pus_version(&self) -> PusVersion;
-            fn service(&self) -> u8;
-            fn subservice(&self) -> u8;
-        });
-
-        fn user_data(&self) -> &[u8] {
-            self.app_data
-        }
-
-        fn crc16(&self) -> Option<u16> {
-            self.crc16
-        }
-    }
-
-    impl GenericPusTcSecondaryHeader for PusTc<'_> {
-        delegate!(to self.sec_header {
-            fn pus_version(&self) -> PusVersion;
-            fn service(&self) -> u8;
-            fn subservice(&self) -> u8;
-            fn source_id(&self) -> u16;
-            fn ack_flags(&self) -> u8;
-        });
-    }
-
-    impl IsPusTelecommand for PusTc<'_> {}
-}
-
 /// This class can be used to create PUS C telecommand packet. It is the primary data structure to
 /// generate the raw byte representation of a PUS telecommand.
 ///
@@ -549,35 +236,37 @@ pub mod legacy_tc {
 /// There is no spare bytes support yet.
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub struct PusTcCreator<'raw_data> {
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct PusTcCreator<'app_data> {
     sp_header: SpHeader,
     pub sec_header: PusTcSecondaryHeader,
-    app_data: &'raw_data [u8],
+    app_data: &'app_data [u8],
 }
 
-impl<'raw_data> PusTcCreator<'raw_data> {
+impl<'app_data> PusTcCreator<'app_data> {
     /// Generates a new struct instance.
     ///
     /// # Arguments
     ///
-    /// * `sp_header` - Space packet header information. The correct packet type will be set
-    ///     automatically
+    /// * `sp_header` - Space packet header information. The correct packet type and the secondary
+    ///     header flag are set correctly by the constructor.
     /// * `sec_header` - Information contained in the data field header, including the service
     ///     and subservice type
     /// * `app_data` - Custom application data
     /// * `set_ccsds_len` - Can be used to automatically update the CCSDS space packet data length
-    ///     field. If this is not set to true, [PusTc::update_ccsds_data_len] can be called to set
+    ///     field. If this is not set to true, [Self::update_ccsds_data_len] can be called to set
     ///     the correct value to this field manually
+    #[inline]
     pub fn new(
-        sp_header: &mut SpHeader,
+        mut sp_header: SpHeader,
         sec_header: PusTcSecondaryHeader,
-        app_data: &'raw_data [u8],
+        app_data: &'app_data [u8],
         set_ccsds_len: bool,
     ) -> Self {
         sp_header.set_packet_type(PacketType::Tc);
         sp_header.set_sec_header_flag();
         let mut pus_tc = Self {
-            sp_header: *sp_header,
+            sp_header,
             app_data,
             sec_header,
         };
@@ -587,35 +276,44 @@ impl<'raw_data> PusTcCreator<'raw_data> {
         pus_tc
     }
 
-    /// Simplified version of the [PusTcCreator::new] function which allows to only specify service
+    /// Simplified version of the [Self::new] function which allows to only specify service
     /// and subservice instead of the full PUS TC secondary header.
+    #[inline]
     pub fn new_simple(
-        sph: &mut SpHeader,
+        sph: SpHeader,
         service: u8,
         subservice: u8,
-        app_data: Option<&'raw_data [u8]>,
+        app_data: &'app_data [u8],
         set_ccsds_len: bool,
     ) -> Self {
         Self::new(
             sph,
             PusTcSecondaryHeader::new(service, subservice, ACK_ALL, 0),
-            app_data.unwrap_or(&[]),
+            app_data,
             set_ccsds_len,
         )
     }
 
+    #[inline]
     pub fn new_no_app_data(
-        sp_header: &mut SpHeader,
+        sp_header: SpHeader,
         sec_header: PusTcSecondaryHeader,
         set_ccsds_len: bool,
     ) -> Self {
         Self::new(sp_header, sec_header, &[], set_ccsds_len)
     }
 
+    #[inline]
     pub fn sp_header(&self) -> &SpHeader {
         &self.sp_header
     }
 
+    #[inline]
+    pub fn sp_header_mut(&mut self) -> &mut SpHeader {
+        &mut self.sp_header
+    }
+
+    #[inline]
     pub fn set_ack_field(&mut self, ack: u8) -> bool {
         if ack > 0b1111 {
             return false;
@@ -624,6 +322,7 @@ impl<'raw_data> PusTcCreator<'raw_data> {
         true
     }
 
+    #[inline]
     pub fn set_source_id(&mut self, source_id: u16) {
         self.sec_header.source_id = source_id;
     }
@@ -631,18 +330,18 @@ impl<'raw_data> PusTcCreator<'raw_data> {
     sp_header_impls!();
 
     /// Calculate the CCSDS space packet data length field and sets it
-    /// This is called automatically if the `set_ccsds_len` argument in the [PusTc::new] call was
+    /// This is called automatically if the `set_ccsds_len` argument in the [Self::new] call was
     /// used.
     /// If this was not done or the application data is set or changed after construction,
     /// this function needs to be called to ensure that the data length field of the CCSDS header
     /// is set correctly.
+    #[inline]
     pub fn update_ccsds_data_len(&mut self) {
         self.sp_header.data_len =
             self.len_written() as u16 - size_of::<crate::zc::SpHeader>() as u16 - 1;
     }
 
-    /// This function should be called before the TC packet is serialized if
-    /// [PusTc::calc_crc_on_serialization] is set to False. It will calculate and cache the CRC16.
+    /// This function calculates and returns the CRC16 for the current packet.
     pub fn calc_own_crc16(&self) -> u16 {
         let mut digest = CRC_CCITT_FALSE.digest();
         let sph_zc = crate::zc::SpHeader::from(self.sp_header);
@@ -654,8 +353,7 @@ impl<'raw_data> PusTcCreator<'raw_data> {
     }
 
     #[cfg(feature = "alloc")]
-    #[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
-    pub fn append_to_vec(&self, vec: &mut Vec<u8>) -> Result<usize, PusError> {
+    pub fn append_to_vec(&self, vec: &mut Vec<u8>) -> usize {
         let sph_zc = crate::zc::SpHeader::from(self.sp_header);
         let mut appended_len = PUS_TC_MIN_LEN_WITHOUT_APP_DATA;
         appended_len += self.app_data.len();
@@ -668,11 +366,12 @@ impl<'raw_data> PusTcCreator<'raw_data> {
         let mut digest = CRC_CCITT_FALSE.digest();
         digest.update(&vec[start_idx..start_idx + appended_len - 2]);
         vec.extend_from_slice(&digest.finalize().to_be_bytes());
-        Ok(appended_len)
+        appended_len
     }
 }
 
 impl WritablePusPacket for PusTcCreator<'_> {
+    #[inline]
     fn len_written(&self) -> usize {
         PUS_TC_MIN_LEN_WITHOUT_APP_DATA + self.app_data.len()
     }
@@ -713,15 +412,20 @@ impl CcsdsPacket for PusTcCreator<'_> {
 
 impl PusPacket for PusTcCreator<'_> {
     delegate!(to self.sec_header {
+        #[inline]
         fn pus_version(&self) -> PusVersion;
+        #[inline]
         fn service(&self) -> u8;
+        #[inline]
         fn subservice(&self) -> u8;
     });
 
+    #[inline]
     fn user_data(&self) -> &[u8] {
         self.app_data
     }
 
+    #[inline]
     fn crc16(&self) -> Option<u16> {
         Some(self.calc_own_crc16())
     }
@@ -729,10 +433,15 @@ impl PusPacket for PusTcCreator<'_> {
 
 impl GenericPusTcSecondaryHeader for PusTcCreator<'_> {
     delegate!(to self.sec_header {
+        #[inline]
         fn pus_version(&self) -> PusVersion;
+        #[inline]
         fn service(&self) -> u8;
+        #[inline]
         fn subservice(&self) -> u8;
+        #[inline]
         fn source_id(&self) -> u16;
+        #[inline]
         fn ack_flags(&self) -> u8;
     });
 }
@@ -752,6 +461,7 @@ impl IsPusTelecommand for PusTcCreator<'_> {}
 /// * `'raw_data` - Lifetime of the provided raw slice.
 #[derive(Eq, Copy, Clone, Debug)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct PusTcReader<'raw_data> {
     #[cfg_attr(feature = "serde", serde(skip))]
     raw_data: &'raw_data [u8],
@@ -763,7 +473,8 @@ pub struct PusTcReader<'raw_data> {
 
 impl<'raw_data> PusTcReader<'raw_data> {
     /// Create a [PusTcReader] instance from a raw slice. On success, it returns a tuple containing
-    /// the instance and the found byte length of the packet.
+    /// the instance and the found byte length of the packet. This function also performs a CRC
+    /// check and will return an appropriate [PusError] if the check fails.
     pub fn new(slice: &'raw_data [u8]) -> Result<(Self, usize), PusError> {
         let raw_data_len = slice.len();
         if raw_data_len < PUS_TC_MIN_LEN_WITHOUT_APP_DATA {
@@ -808,24 +519,29 @@ impl<'raw_data> PusTcReader<'raw_data> {
         Ok((pus_tc, total_len))
     }
 
+    #[inline]
     pub fn app_data(&self) -> &[u8] {
         self.user_data()
     }
 
+    #[inline]
     pub fn raw_data(&self) -> &[u8] {
         self.raw_data
     }
 
+    #[inline]
     pub fn len_packed(&self) -> usize {
         self.sp_header.total_len()
     }
 
+    #[inline]
     pub fn sp_header(&self) -> &SpHeader {
         &self.sp_header
     }
 }
 
 impl PartialEq for PusTcReader<'_> {
+    #[inline]
     fn eq(&self, other: &Self) -> bool {
         self.raw_data == other.raw_data
     }
@@ -837,15 +553,20 @@ impl CcsdsPacket for PusTcReader<'_> {
 
 impl PusPacket for PusTcReader<'_> {
     delegate!(to self.sec_header {
+        #[inline]
         fn pus_version(&self) -> PusVersion;
+        #[inline]
         fn service(&self) -> u8;
+        #[inline]
         fn subservice(&self) -> u8;
     });
 
+    #[inline]
     fn user_data(&self) -> &[u8] {
         self.app_data
     }
 
+    #[inline]
     fn crc16(&self) -> Option<u16> {
         Some(self.crc16)
     }
@@ -853,10 +574,15 @@ impl PusPacket for PusTcReader<'_> {
 
 impl GenericPusTcSecondaryHeader for PusTcReader<'_> {
     delegate!(to self.sec_header {
+        #[inline]
         fn pus_version(&self) -> PusVersion;
+        #[inline]
         fn service(&self) -> u8;
+        #[inline]
         fn subservice(&self) -> u8;
+        #[inline]
         fn source_id(&self) -> u16;
+        #[inline]
         fn ack_flags(&self) -> u8;
     });
 }
@@ -894,19 +620,19 @@ mod tests {
     use postcard::{from_bytes, to_allocvec};
 
     fn base_ping_tc_full_ctor() -> PusTcCreator<'static> {
-        let mut sph = SpHeader::tc_unseg(0x02, 0x34, 0).unwrap();
+        let sph = SpHeader::new_for_unseg_tc_checked(0x02, 0x34, 0).unwrap();
         let tc_header = PusTcSecondaryHeader::new_simple(17, 1);
-        PusTcCreator::new_no_app_data(&mut sph, tc_header, true)
+        PusTcCreator::new_no_app_data(sph, tc_header, true)
     }
 
     fn base_ping_tc_simple_ctor() -> PusTcCreator<'static> {
-        let mut sph = SpHeader::tc_unseg(0x02, 0x34, 0).unwrap();
-        PusTcCreator::new_simple(&mut sph, 17, 1, None, true)
+        let sph = SpHeader::new_for_unseg_tc_checked(0x02, 0x34, 0).unwrap();
+        PusTcCreator::new_simple(sph, 17, 1, &[], true)
     }
 
     fn base_ping_tc_simple_ctor_with_app_data(app_data: &'static [u8]) -> PusTcCreator<'static> {
-        let mut sph = SpHeader::tc_unseg(0x02, 0x34, 0).unwrap();
-        PusTcCreator::new_simple(&mut sph, 17, 1, Some(app_data), true)
+        let sph = SpHeader::new_for_unseg_tc_checked(0x02, 0x34, 0).unwrap();
+        PusTcCreator::new_simple(sph, 17, 1, app_data, true)
     }
 
     #[test]
@@ -962,8 +688,8 @@ mod tests {
 
     #[test]
     fn test_update_func() {
-        let mut sph = SpHeader::tc_unseg(0x02, 0x34, 0).unwrap();
-        let mut tc = PusTcCreator::new_simple(&mut sph, 17, 1, None, false);
+        let sph = SpHeader::new_for_unseg_tc_checked(0x02, 0x34, 0).unwrap();
+        let mut tc = PusTcCreator::new_simple(sph, 17, 1, &[], false);
         assert_eq!(tc.data_len(), 0);
         tc.update_ccsds_data_len();
         assert_eq!(tc.data_len(), 6);
@@ -1010,9 +736,7 @@ mod tests {
     fn test_vec_ser_deser() {
         let pus_tc = base_ping_tc_simple_ctor();
         let mut test_vec = Vec::new();
-        let size = pus_tc
-            .append_to_vec(&mut test_vec)
-            .expect("Error writing TC to vector");
+        let size = pus_tc.append_to_vec(&mut test_vec);
         assert_eq!(size, 13);
         verify_test_tc_raw(&test_vec.as_slice());
         verify_crc_no_app_data(&test_vec.as_slice());
@@ -1058,9 +782,7 @@ mod tests {
         let pus_tc = base_ping_tc_simple_ctor_with_app_data(&[1, 2, 3]);
         verify_test_tc(&pus_tc, true, 16);
         let mut test_vec = Vec::new();
-        let size = pus_tc
-            .append_to_vec(&mut test_vec)
-            .expect("Error writing TC to vector");
+        let size = pus_tc.append_to_vec(&mut test_vec);
         assert_eq!(test_vec[11], 1);
         assert_eq!(test_vec[12], 2);
         assert_eq!(test_vec[13], 3);
@@ -1139,7 +861,8 @@ mod tests {
         if !has_user_data {
             assert!(tc.user_data().is_empty());
         }
-        let mut comp_header = SpHeader::tc_unseg(0x02, 0x34, exp_full_len as u16 - 7).unwrap();
+        let mut comp_header =
+            SpHeader::new_for_unseg_tc_checked(0x02, 0x34, exp_full_len as u16 - 7).unwrap();
         comp_header.set_sec_header_flag();
         assert_eq!(*tc.sp_header(), comp_header);
     }
@@ -1150,7 +873,8 @@ mod tests {
             assert!(tc.user_data().is_empty());
         }
         assert_eq!(tc.len_packed(), exp_full_len);
-        let mut comp_header = SpHeader::tc_unseg(0x02, 0x34, exp_full_len as u16 - 7).unwrap();
+        let mut comp_header =
+            SpHeader::new_for_unseg_tc_checked(0x02, 0x34, exp_full_len as u16 - 7).unwrap();
         comp_header.set_sec_header_flag();
         assert_eq!(*tc.sp_header(), comp_header);
     }

src/lib.rs

@@ -22,10 +22,6 @@
 //!
 //! `spacepackets` supports various runtime environments and is also suitable for `no_std` environments.
 //!
-//! It also offers optional support for [`serde`](https://serde.rs/). This allows serializing and
-//! deserializing them with an appropriate `serde` provider like
-//! [`postcard`](https://github.com/jamesmunns/postcard).
-//!
 //! ### Default features
 //!
 //!  - [`std`](https://doc.rust-lang.org/std/): Enables functionality relying on the standard library.
@@ -36,7 +32,11 @@
 //! ### Optional features
 //!
 //!  - [`serde`](https://serde.rs/): Adds `serde` support for most types by adding `Serialize` and
-//!    `Deserialize` `derive`s
+//!    `Deserialize` `derives.
+//!  - [`chrono`](https://crates.io/crates/chrono): Add basic support for the `chrono` time library.
+//!  - [`timelib`](https://crates.io/crates/time): Add basic support for the `time` time library.
+//!  - [`defmt`](https://defmt.ferrous-systems.com/): Add support for the `defmt` by adding the
+//!    [`defmt::Format`](https://defmt.ferrous-systems.com/format) derive on many types.
 //!
 //! ## Module
 //!
@@ -48,20 +48,19 @@
 //!
 //! ```rust
 //! use spacepackets::SpHeader;
-//! let sp_header = SpHeader::tc_unseg(0x42, 12, 1).expect("Error creating CCSDS TC header");
+//! let sp_header = SpHeader::new_for_unseg_tc_checked(0x42, 12, 1).expect("error creating CCSDS TC header");
 //! println!("{:?}", sp_header);
 //! let mut ccsds_buf: [u8; 32] = [0; 32];
 //! sp_header.write_to_be_bytes(&mut ccsds_buf).expect("Writing CCSDS TC header failed");
 //! println!("{:x?}", &ccsds_buf[0..6]);
 //! ```
 #![no_std]
-#![cfg_attr(doc_cfg, feature(doc_cfg))]
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
 #[cfg(feature = "alloc")]
 extern crate alloc;
 #[cfg(any(feature = "std", test))]
 extern crate std;
 
-use crate::ecss::CCSDS_HEADER_LEN;
 use core::{
     fmt::{Debug, Display, Formatter},
     hash::Hash,
@@ -77,13 +76,17 @@ use serde::{Deserialize, Serialize};
 
 pub mod cfdp;
 pub mod ecss;
+pub mod seq_count;
 pub mod time;
+pub mod uslp;
 pub mod util;
 
 mod private {
     pub trait Sealed {}
 }
 
+pub const CCSDS_HEADER_LEN: usize = core::mem::size_of::<crate::zc::SpHeader>();
+
 /// CRC algorithm used by the PUS standard, the CCSDS TC standard and the CFDP standard.
 pub const CRC_CCITT_FALSE: Crc<u16> = Crc::<u16>::new(&CRC_16_IBM_3740);
 
@@ -93,6 +96,7 @@ pub const MAX_SEQ_COUNT: u16 = 2u16.pow(14) - 1;
 /// Generic error type when converting to and from raw byte slices.
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum ByteConversionError {
     /// The passed slice is too small. Returns the passed slice length and expected minimum size
     ToSliceTooSmall {
@@ -142,6 +146,7 @@ impl Error for ByteConversionError {}
 /// CCSDS packet type enumeration.
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum PacketType {
     Tm = 0,
     Tc = 1,
@@ -165,6 +170,7 @@ pub fn packet_type_in_raw_packet_id(packet_id: u16) -> PacketType {
 
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum SequenceFlags {
     ContinuationSegment = 0b00,
     FirstSegment = 0b01,
@@ -192,6 +198,7 @@ impl TryFrom<u8> for SequenceFlags {
 /// of the first two bytes in the CCSDS primary header.
 #[derive(Debug, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct PacketId {
     pub ptype: PacketType,
     pub sec_header_flag: bool,
@@ -199,18 +206,21 @@ pub struct PacketId {
 }
 
 impl PartialEq for PacketId {
+    #[inline]
     fn eq(&self, other: &Self) -> bool {
         self.raw().eq(&other.raw())
     }
 }
 
 impl PartialOrd for PacketId {
+    #[inline]
     fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
         Some(self.cmp(other))
     }
 }
 
 impl Ord for PacketId {
+    #[inline]
     fn cmp(&self, other: &Self) -> core::cmp::Ordering {
         self.raw().cmp(&other.raw())
     }
@@ -224,6 +234,7 @@ impl Hash for PacketId {
 }
 
 impl Default for PacketId {
+    #[inline]
     fn default() -> Self {
         PacketId {
             ptype: PacketType::Tm,
@@ -234,23 +245,34 @@ impl Default for PacketId {
 }
 
 impl PacketId {
-    pub const fn const_tc(sec_header: bool, apid: u16) -> Self {
-        Self::const_new(PacketType::Tc, sec_header, apid)
-    }
-
-    pub const fn const_tm(sec_header: bool, apid: u16) -> Self {
-        Self::const_new(PacketType::Tm, sec_header, apid)
-    }
-
-    pub fn tc(sec_header: bool, apid: u16) -> Option<Self> {
+    /// This constructor will panic if the passed APID exceeds [MAX_APID].
+    /// Use the checked constructor variants to avoid panics.
+    #[inline]
+    pub const fn new_for_tc(sec_header: bool, apid: u16) -> Self {
         Self::new(PacketType::Tc, sec_header, apid)
     }
 
-    pub fn tm(sec_header: bool, apid: u16) -> Option<Self> {
+    /// This constructor will panic if the passed APID exceeds [MAX_APID].
+    /// Use the checked constructor variants to avoid panics.
+    #[inline]
+    pub const fn new_for_tm(sec_header: bool, apid: u16) -> Self {
         Self::new(PacketType::Tm, sec_header, apid)
     }
 
-    pub const fn const_new(ptype: PacketType, sec_header: bool, apid: u16) -> Self {
+    #[inline]
+    pub fn new_for_tc_checked(sec_header: bool, apid: u16) -> Option<Self> {
+        Self::new_checked(PacketType::Tc, sec_header, apid)
+    }
+
+    #[inline]
+    pub fn new_for_tm_checked(sec_header: bool, apid: u16) -> Option<Self> {
+        Self::new_checked(PacketType::Tm, sec_header, apid)
+    }
+
+    /// This constructor will panic if the passed APID exceeds [MAX_APID].
+    /// Use the checked variants to avoid panics.
+    #[inline]
+    pub const fn new(ptype: PacketType, sec_header: bool, apid: u16) -> Self {
         if apid > MAX_APID {
             panic!("APID too large");
         }
@@ -261,16 +283,18 @@ impl PacketId {
         }
     }
 
-    pub fn new(ptype: PacketType, sec_header_flag: bool, apid: u16) -> Option<PacketId> {
+    #[inline]
+    pub fn new_checked(ptype: PacketType, sec_header_flag: bool, apid: u16) -> Option<PacketId> {
         if apid > MAX_APID {
             return None;
         }
-        Some(PacketId::const_new(ptype, sec_header_flag, apid))
+        Some(PacketId::new(ptype, sec_header_flag, apid))
     }
 
     /// Set a new Application Process ID (APID). If the passed number is invalid, the APID will
     /// not be set and false will be returned. The maximum allowed value for the 11-bit field is
     /// 2047
+    #[inline]
     pub fn set_apid(&mut self, apid: u16) -> bool {
         if apid > MAX_APID {
             return false;
@@ -279,6 +303,7 @@ impl PacketId {
         true
     }
 
+    #[inline]
     pub fn apid(&self) -> u16 {
         self.apid
     }
@@ -303,15 +328,17 @@ impl From<u16> for PacketId {
 /// third and the fourth byte in the CCSDS primary header.
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct PacketSequenceCtrl {
     pub seq_flags: SequenceFlags,
     seq_count: u16,
 }
 
 impl PacketSequenceCtrl {
-    /// const variant of [PacketSequenceCtrl::new], but panics if the sequence count exceeds
-    /// [MAX_SEQ_COUNT].
-    const fn const_new(seq_flags: SequenceFlags, seq_count: u16) -> PacketSequenceCtrl {
+    /// This constructor panics if the sequence count exceeds [MAX_SEQ_COUNT].
+    /// Use [Self::new_checked] to avoid panics.
+    #[inline]
+    pub const fn new(seq_flags: SequenceFlags, seq_count: u16) -> PacketSequenceCtrl {
         if seq_count > MAX_SEQ_COUNT {
             panic!("Sequence count too large");
         }
@@ -322,18 +349,22 @@ impl PacketSequenceCtrl {
     }
 
     /// Returns [None] if the passed sequence count exceeds [MAX_SEQ_COUNT].
-    pub fn new(seq_flags: SequenceFlags, seq_count: u16) -> Option<PacketSequenceCtrl> {
+    #[inline]
+    pub fn new_checked(seq_flags: SequenceFlags, seq_count: u16) -> Option<PacketSequenceCtrl> {
         if seq_count > MAX_SEQ_COUNT {
             return None;
         }
-        Some(PacketSequenceCtrl::const_new(seq_flags, seq_count))
+        Some(PacketSequenceCtrl::new(seq_flags, seq_count))
     }
+
+    #[inline]
     pub fn raw(&self) -> u16 {
         ((self.seq_flags as u16) << 14) | self.seq_count
     }
 
     /// Set a new sequence count. If the passed number is invalid, the sequence count will not be
     /// set and false will be returned. The maximum allowed value for the 14-bit field is 16383.
+    #[inline]
     pub fn set_seq_count(&mut self, ssc: u16) -> bool {
         if ssc > MAX_SEQ_COUNT {
             return false;
@@ -342,6 +373,7 @@ impl PacketSequenceCtrl {
         true
     }
 
+    #[inline]
     pub fn seq_count(&self) -> u16 {
         self.seq_count
     }
@@ -383,6 +415,7 @@ pub trait CcsdsPacket {
     /// Retrieve data length field
     fn data_len(&self) -> u16;
     /// Retrieve the total packet size based on the data length field
+    #[inline]
     fn total_len(&self) -> usize {
         usize::from(self.data_len()) + CCSDS_HEADER_LEN + 1
     }
@@ -463,6 +496,7 @@ pub trait CcsdsPrimaryHeader {
 /// * `data_len` - Data length field occupies the fifth and the sixth byte of the raw header
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct SpHeader {
     pub version: u8,
     pub packet_id: PacketId,
@@ -470,9 +504,12 @@ pub struct SpHeader {
     pub data_len: u16,
 }
 
+pub type SpacePacketHeader = SpHeader;
+
 impl Default for SpHeader {
-    /// The default function sets the sequence flag field to [SequenceFlags::Unsegmented]. The data
-    /// length field is set to 1, which denotes an empty space packets.
+    /// The default function sets the sequence flag field to [SequenceFlags::Unsegmented] and the
+    /// data length to 0.
+    #[inline]
     fn default() -> Self {
         SpHeader {
             version: 0,
@@ -481,12 +518,13 @@ impl Default for SpHeader {
                 seq_flags: SequenceFlags::Unsegmented,
                 seq_count: 0,
             },
-            data_len: 1,
+            data_len: 0,
         }
     }
 }
 
 impl SpHeader {
+    #[inline]
     pub const fn new(packet_id: PacketId, psc: PacketSequenceCtrl, data_len: u16) -> Self {
         Self {
             version: 0,
@@ -496,9 +534,43 @@ impl SpHeader {
         }
     }
 
-    /// const variant of the [SpHeader::new_fron_single_fields] function. Panics if the passed
-    /// APID exceeds [MAX_APID] or the passed packet sequence count exceeds [MAX_SEQ_COUNT].
-    const fn const_new_from_single_fields(
+    /// This constructor sets the sequence flag field to [SequenceFlags::Unsegmented] and the data
+    /// length to 0.
+    ///
+    /// This constructor will panic if the APID exceeds [MAX_APID].
+    #[inline]
+    pub const fn new_from_apid(apid: u16) -> Self {
+        SpHeader {
+            version: 0,
+            packet_id: PacketId::new(PacketType::Tm, false, apid),
+            psc: PacketSequenceCtrl {
+                seq_flags: SequenceFlags::Unsegmented,
+                seq_count: 0,
+            },
+            data_len: 0,
+        }
+    }
+
+    /// Checked variant of [Self::new_from_apid].
+    #[inline]
+    pub fn new_from_apid_checked(apid: u16) -> Option<Self> {
+        Some(SpHeader {
+            version: 0,
+            packet_id: PacketId::new_checked(PacketType::Tm, false, apid)?,
+            psc: PacketSequenceCtrl {
+                seq_flags: SequenceFlags::Unsegmented,
+                seq_count: 0,
+            },
+            data_len: 0,
+        })
+    }
+
+    /// This constructor panics if the passed APID exceeds [MAX_APID] or the passed packet sequence
+    /// count exceeds [MAX_SEQ_COUNT].
+    ///
+    /// The checked constructor variants can be used to avoid panics.
+    #[inline]
+    pub const fn new_from_fields(
         ptype: PacketType,
         sec_header: bool,
         apid: u16,
@@ -513,17 +585,20 @@ impl SpHeader {
             panic!("APID is too large");
         }
         Self {
-            psc: PacketSequenceCtrl::const_new(seq_flags, seq_count),
-            packet_id: PacketId::const_new(ptype, sec_header, apid),
+            psc: PacketSequenceCtrl::new(seq_flags, seq_count),
+            packet_id: PacketId::new(ptype, sec_header, apid),
             data_len,
             version: 0,
         }
     }
 
     /// Create a new Space Packet Header instance which can be used to create generic
-    /// Space Packets. This will return [None] if the APID or sequence count argument
+    /// Space Packets.
+    ///
+    /// This will return [None] if the APID or sequence count argument
     /// exceed [MAX_APID] or [MAX_SEQ_COUNT] respectively. The version field is set to 0b000.
-    pub fn new_from_single_fields(
+    #[inline]
+    pub fn new_from_fields_checked(
         ptype: PacketType,
         sec_header: bool,
         apid: u16,
@@ -534,56 +609,117 @@ impl SpHeader {
         if seq_count > MAX_SEQ_COUNT || apid > MAX_APID {
             return None;
         }
-        Some(SpHeader::const_new_from_single_fields(
+        Some(SpHeader::new_from_fields(
             ptype, sec_header, apid, seq_flags, seq_count, data_len,
         ))
     }
 
     /// Helper function for telemetry space packet headers. The packet type field will be
     /// set accordingly. The secondary header flag field is set to false.
-    pub fn tm(apid: u16, seq_flags: SequenceFlags, seq_count: u16, data_len: u16) -> Option<Self> {
-        Self::new_from_single_fields(PacketType::Tm, false, apid, seq_flags, seq_count, data_len)
+    #[inline]
+    pub fn new_for_tm_checked(
+        apid: u16,
+        seq_flags: SequenceFlags,
+        seq_count: u16,
+        data_len: u16,
+    ) -> Option<Self> {
+        Self::new_from_fields_checked(PacketType::Tm, false, apid, seq_flags, seq_count, data_len)
     }
 
     /// Helper function for telemetry space packet headers. The packet type field will be
     /// set accordingly. The secondary header flag field is set to false.
-    pub fn tc(apid: u16, seq_flags: SequenceFlags, seq_count: u16, data_len: u16) -> Option<Self> {
-        Self::new_from_single_fields(PacketType::Tc, false, apid, seq_flags, seq_count, data_len)
+    #[inline]
+    pub fn new_for_tc_checked(
+        apid: u16,
+        seq_flags: SequenceFlags,
+        seq_count: u16,
+        data_len: u16,
+    ) -> Option<Self> {
+        Self::new_from_fields_checked(PacketType::Tc, false, apid, seq_flags, seq_count, data_len)
     }
 
-    /// Variant of [SpHeader::tm] which sets the sequence flag field to [SequenceFlags::Unsegmented]
-    pub fn tm_unseg(apid: u16, seq_count: u16, data_len: u16) -> Option<Self> {
-        Self::tm(apid, SequenceFlags::Unsegmented, seq_count, data_len)
+    /// This is an unchecked constructor which can panic on invalid input.
+    #[inline]
+    pub const fn new_for_tm(
+        apid: u16,
+        seq_flags: SequenceFlags,
+        seq_count: u16,
+        data_len: u16,
+    ) -> Self {
+        Self::new_from_fields(PacketType::Tm, false, apid, seq_flags, seq_count, data_len)
     }
 
-    /// Variant of [SpHeader::tc] which sets the sequence flag field to [SequenceFlags::Unsegmented]
-    pub fn tc_unseg(apid: u16, seq_count: u16, data_len: u16) -> Option<Self> {
-        Self::tc(apid, SequenceFlags::Unsegmented, seq_count, data_len)
+    /// This is an unchecked constructor which can panic on invalid input.
+    #[inline]
+    pub const fn new_for_tc(
+        apid: u16,
+        seq_flags: SequenceFlags,
+        seq_count: u16,
+        data_len: u16,
+    ) -> Self {
+        Self::new_from_fields(PacketType::Tc, false, apid, seq_flags, seq_count, data_len)
     }
 
-    //noinspection RsTraitImplementation
-    delegate!(to self.packet_id {
-        /// Returns [false] and fails if the APID exceeds [MAX_APID]
-        pub fn set_apid(&mut self, apid: u16) -> bool;
-    });
+    /// Variant of [SpHeader::new_for_tm_checked] which sets the sequence flag field to [SequenceFlags::Unsegmented]
+    #[inline]
+    pub fn new_for_unseg_tm_checked(apid: u16, seq_count: u16, data_len: u16) -> Option<Self> {
+        Self::new_for_tm_checked(apid, SequenceFlags::Unsegmented, seq_count, data_len)
+    }
 
-    delegate!(to self.psc {
-        /// Returns [false] and fails if the sequence count exceeds [MAX_SEQ_COUNT]
-        pub fn set_seq_count(&mut self, seq_count: u16) -> bool;
-    });
+    /// Variant of [SpHeader::new_for_tc_checked] which sets the sequence flag field to [SequenceFlags::Unsegmented]
+    #[inline]
+    pub fn new_for_unseg_tc_checked(apid: u16, seq_count: u16, data_len: u16) -> Option<Self> {
+        Self::new_for_tc_checked(apid, SequenceFlags::Unsegmented, seq_count, data_len)
+    }
 
+    /// Variant of [SpHeader::new_for_tc] which sets the sequence flag field to [SequenceFlags::Unsegmented].
+    ///
+    /// This is an unchecked constructor which can panic on invalid input.
+    #[inline]
+    pub const fn new_for_unseg_tc(apid: u16, seq_count: u16, data_len: u16) -> Self {
+        Self::new_for_tc(apid, SequenceFlags::Unsegmented, seq_count, data_len)
+    }
+
+    /// Variant of [SpHeader::new_for_tm] which sets the sequence flag field to [SequenceFlags::Unsegmented].
+    ///
+    /// This is an unchecked constructor which can panic on invalid input.
+    #[inline]
+    pub const fn new_for_unseg_tm(apid: u16, seq_count: u16, data_len: u16) -> Self {
+        Self::new_for_tm(apid, SequenceFlags::Unsegmented, seq_count, data_len)
+    }
+
+    delegate! {
+        to self.packet_id {
+            /// Returns [false] and fails if the APID exceeds [MAX_APID]
+            #[inline]
+            pub fn set_apid(&mut self, apid: u16) -> bool;
+        }
+    }
+
+    delegate! {
+        to self.psc {
+            /// Returns [false] and fails if the sequence count exceeds [MAX_SEQ_COUNT]
+            #[inline]
+            pub fn set_seq_count(&mut self, seq_count: u16) -> bool;
+        }
+    }
+
+    #[inline]
     pub fn set_seq_flags(&mut self, seq_flags: SequenceFlags) {
         self.psc.seq_flags = seq_flags;
     }
 
+    #[inline]
     pub fn set_sec_header_flag(&mut self) {
         self.packet_id.sec_header_flag = true;
     }
 
+    #[inline]
     pub fn clear_sec_header_flag(&mut self) {
         self.packet_id.sec_header_flag = false;
     }
 
+    #[inline]
     pub fn set_packet_type(&mut self, packet_type: PacketType) {
         self.packet_id.ptype = packet_type;
     }
@@ -621,6 +757,15 @@ impl SpHeader {
             .ok_or(ByteConversionError::ZeroCopyToError)?;
         Ok(&mut buf[CCSDS_HEADER_LEN..])
     }
+
+    /// Create a vector containing the CCSDS header.
+    #[cfg(feature = "alloc")]
+    pub fn to_vec(&self) -> alloc::vec::Vec<u8> {
+        let mut vec = alloc::vec![0; CCSDS_HEADER_LEN];
+        // This can not fail.
+        self.write_to_be_bytes(&mut vec[..]).unwrap();
+        vec
+    }
 }
 
 impl CcsdsPacket for SpHeader {
@@ -646,6 +791,7 @@ impl CcsdsPacket for SpHeader {
 }
 
 impl CcsdsPrimaryHeader for SpHeader {
+    #[inline]
     fn from_composite_fields(
         packet_id: PacketId,
         psc: PacketSequenceCtrl,
@@ -713,9 +859,12 @@ pub mod zc {
             ((self.version_packet_id.get() >> 13) as u8) & 0b111
         }
 
+        #[inline]
         fn packet_id(&self) -> PacketId {
             PacketId::from(self.packet_id_raw())
         }
+
+        #[inline]
         fn psc(&self) -> PacketSequenceCtrl {
             PacketSequenceCtrl::from(self.psc_raw())
         }
@@ -725,10 +874,12 @@ pub mod zc {
             self.data_len.get()
         }
 
+        #[inline]
         fn packet_id_raw(&self) -> u16 {
             self.version_packet_id.get() & (!VERSION_MASK)
         }
 
+        #[inline]
         fn psc_raw(&self) -> u16 {
             self.psc.get()
         }
@@ -752,6 +903,8 @@ pub mod zc {
 pub(crate) mod tests {
     use std::collections::HashSet;
 
+    #[allow(unused_imports)]
+    use crate::ByteConversionError;
     #[cfg(feature = "serde")]
     use crate::CcsdsPrimaryHeader;
     use crate::{
@@ -768,12 +921,12 @@ pub(crate) mod tests {
     use serde::{de::DeserializeOwned, Serialize};
 
     const CONST_SP: SpHeader = SpHeader::new(
-        PacketId::const_tc(true, 0x36),
-        PacketSequenceCtrl::const_new(SequenceFlags::ContinuationSegment, 0x88),
+        PacketId::new_for_tc(true, 0x36),
+        PacketSequenceCtrl::new(SequenceFlags::ContinuationSegment, 0x88),
         0x90,
     );
 
-    const PACKET_ID_TM: PacketId = PacketId::const_tm(true, 0x22);
+    const PACKET_ID_TM: PacketId = PacketId::new_for_tm(true, 0x22);
 
     #[cfg(feature = "serde")]
     pub(crate) fn generic_serde_test<T: Serialize + DeserializeOwned + PartialEq + Debug>(
@@ -785,11 +938,12 @@ pub(crate) mod tests {
     }
 
     #[test]
+    #[allow(clippy::assertions_on_constants)]
     fn verify_const_packet_id() {
         assert_eq!(PACKET_ID_TM.apid(), 0x22);
         assert!(PACKET_ID_TM.sec_header_flag);
         assert_eq!(PACKET_ID_TM.ptype, PacketType::Tm);
-        let const_tc_id = PacketId::const_tc(true, 0x23);
+        let const_tc_id = PacketId::new_for_tc(true, 0x23);
         assert_eq!(const_tc_id.ptype, PacketType::Tc);
     }
 
@@ -798,32 +952,32 @@ pub(crate) mod tests {
         let id_default = PacketId::default();
         assert_eq!(id_default.ptype, PacketType::Tm);
         assert_eq!(id_default.apid, 0x000);
-        assert_eq!(id_default.sec_header_flag, false);
+        assert!(!id_default.sec_header_flag);
     }
 
     #[test]
     fn test_packet_id_ctors() {
-        let packet_id = PacketId::new(PacketType::Tc, true, 0x1ff);
+        let packet_id = PacketId::new_checked(PacketType::Tc, true, 0x1ff);
         assert!(packet_id.is_some());
         let packet_id = packet_id.unwrap();
         assert_eq!(packet_id.apid(), 0x1ff);
         assert_eq!(packet_id.ptype, PacketType::Tc);
-        assert_eq!(packet_id.sec_header_flag, true);
-        let packet_id_tc = PacketId::tc(true, 0x1ff);
+        assert!(packet_id.sec_header_flag);
+        let packet_id_tc = PacketId::new_for_tc_checked(true, 0x1ff);
         assert!(packet_id_tc.is_some());
         let packet_id_tc = packet_id_tc.unwrap();
         assert_eq!(packet_id_tc, packet_id);
-        let packet_id_tm = PacketId::tm(true, 0x2ff);
+        let packet_id_tm = PacketId::new_for_tm_checked(true, 0x2ff);
         assert!(packet_id_tm.is_some());
         let packet_id_tm = packet_id_tm.unwrap();
-        assert_eq!(packet_id_tm.sec_header_flag, true);
+        assert!(packet_id_tm.sec_header_flag);
         assert_eq!(packet_id_tm.ptype, PacketType::Tm);
         assert_eq!(packet_id_tm.apid, 0x2ff);
     }
 
     #[test]
     fn verify_const_sp_header() {
-        assert_eq!(CONST_SP.sec_header_flag(), true);
+        assert!(CONST_SP.sec_header_flag());
         assert_eq!(CONST_SP.apid(), 0x36);
         assert_eq!(
             CONST_SP.sequence_flags(),
@@ -864,7 +1018,7 @@ pub(crate) mod tests {
     #[test]
     fn test_packet_id() {
         let packet_id =
-            PacketId::new(PacketType::Tm, false, 0x42).expect("Packet ID creation failed");
+            PacketId::new_checked(PacketType::Tm, false, 0x42).expect("Packet ID creation failed");
         assert_eq!(packet_id.raw(), 0x0042);
         let packet_id_from_raw = PacketId::from(packet_id.raw());
         assert_eq!(
@@ -872,26 +1026,26 @@ pub(crate) mod tests {
             PacketType::Tm
         );
         assert_eq!(packet_id_from_raw, packet_id);
-        let packet_id_from_new = PacketId::new(PacketType::Tm, false, 0x42).unwrap();
+        let packet_id_from_new = PacketId::new_checked(PacketType::Tm, false, 0x42).unwrap();
         assert_eq!(packet_id_from_new, packet_id);
     }
 
     #[test]
     fn test_invalid_packet_id() {
-        let packet_id_invalid = PacketId::new(PacketType::Tc, true, 0xFFFF);
+        let packet_id_invalid = PacketId::new_checked(PacketType::Tc, true, 0xFFFF);
         assert!(packet_id_invalid.is_none());
     }
 
     #[test]
     fn test_invalid_apid_setter() {
         let mut packet_id =
-            PacketId::new(PacketType::Tm, false, 0x42).expect("Packet ID creation failed");
+            PacketId::new_checked(PacketType::Tm, false, 0x42).expect("Packet ID creation failed");
         assert!(!packet_id.set_apid(0xffff));
     }
 
     #[test]
     fn test_invalid_seq_count() {
-        let mut psc = PacketSequenceCtrl::new(SequenceFlags::ContinuationSegment, 77)
+        let mut psc = PacketSequenceCtrl::new_checked(SequenceFlags::ContinuationSegment, 77)
             .expect("PSC creation failed");
         assert_eq!(psc.seq_count(), 77);
         assert!(!psc.set_seq_count(0xffff));
@@ -899,7 +1053,7 @@ pub(crate) mod tests {
 
     #[test]
     fn test_packet_seq_ctrl() {
-        let mut psc = PacketSequenceCtrl::new(SequenceFlags::ContinuationSegment, 77)
+        let mut psc = PacketSequenceCtrl::new_checked(SequenceFlags::ContinuationSegment, 77)
             .expect("PSC creation failed");
         assert_eq!(psc.raw(), 77);
         let psc_from_raw = PacketSequenceCtrl::from(psc.raw());
@@ -908,16 +1062,18 @@ pub(crate) mod tests {
         assert!(!psc.set_seq_count(2u16.pow(15)));
         assert_eq!(psc.raw(), 77);
 
-        let psc_invalid = PacketSequenceCtrl::new(SequenceFlags::FirstSegment, 0xFFFF);
+        let psc_invalid = PacketSequenceCtrl::new_checked(SequenceFlags::FirstSegment, 0xFFFF);
         assert!(psc_invalid.is_none());
-        let psc_from_new = PacketSequenceCtrl::new(SequenceFlags::ContinuationSegment, 77).unwrap();
+        let psc_from_new =
+            PacketSequenceCtrl::new_checked(SequenceFlags::ContinuationSegment, 77).unwrap();
         assert_eq!(psc_from_new, psc);
     }
 
     #[test]
     #[cfg(feature = "serde")]
     fn test_serde_sph() {
-        let sp_header = SpHeader::tc_unseg(0x42, 12, 0).expect("Error creating SP header");
+        let sp_header =
+            SpHeader::new_for_unseg_tc_checked(0x42, 12, 0).expect("Error creating SP header");
         assert_eq!(sp_header.ccsds_version(), 0b000);
         assert!(sp_header.is_tc());
         assert!(!sp_header.sec_header_flag());
@@ -939,7 +1095,8 @@ pub(crate) mod tests {
         assert_eq!(sp_header.ccsds_version(), 0b000);
         assert_eq!(sp_header.data_len, 0);
 
-        let sp_header = SpHeader::tm_unseg(0x7, 22, 36).expect("Error creating SP header");
+        let sp_header =
+            SpHeader::new_for_unseg_tm_checked(0x7, 22, 36).expect("Error creating SP header");
         assert_eq!(sp_header.ccsds_version(), 0b000);
         assert!(sp_header.is_tm());
         assert!(!sp_header.sec_header_flag());
@@ -953,8 +1110,8 @@ pub(crate) mod tests {
         assert_eq!(sp_header.ccsds_version(), 0b000);
 
         let from_comp_fields = SpHeader::from_composite_fields(
-            PacketId::new(PacketType::Tc, true, 0x42).unwrap(),
-            PacketSequenceCtrl::new(SequenceFlags::Unsegmented, 0x7).unwrap(),
+            PacketId::new(PacketType::Tc, true, 0x42),
+            PacketSequenceCtrl::new(SequenceFlags::Unsegmented, 0x7),
             0,
             None,
         );
@@ -971,7 +1128,7 @@ pub(crate) mod tests {
 
     #[test]
     fn test_setters() {
-        let sp_header = SpHeader::tc(0x42, SequenceFlags::Unsegmented, 25, 0);
+        let sp_header = SpHeader::new_for_tc_checked(0x42, SequenceFlags::Unsegmented, 25, 0);
         assert!(sp_header.is_some());
         let mut sp_header = sp_header.unwrap();
         sp_header.set_apid(0x12);
@@ -989,7 +1146,7 @@ pub(crate) mod tests {
 
     #[test]
     fn test_tc_ctor() {
-        let sp_header = SpHeader::tc(0x42, SequenceFlags::Unsegmented, 25, 0);
+        let sp_header = SpHeader::new_for_tc_checked(0x42, SequenceFlags::Unsegmented, 25, 0);
         assert!(sp_header.is_some());
         let sp_header = sp_header.unwrap();
         verify_sp_fields(PacketType::Tc, &sp_header);
@@ -997,23 +1154,35 @@ pub(crate) mod tests {
 
     #[test]
     fn test_tc_ctor_unseg() {
-        let sp_header = SpHeader::tc_unseg(0x42, 25, 0);
+        let sp_header = SpHeader::new_for_unseg_tc_checked(0x42, 25, 0);
         assert!(sp_header.is_some());
         let sp_header = sp_header.unwrap();
         verify_sp_fields(PacketType::Tc, &sp_header);
     }
 
+    #[test]
+    fn test_tc_ctor_unseg_const() {
+        let sp_header = SpHeader::new_for_unseg_tc(0x42, 25, 0);
+        verify_sp_fields(PacketType::Tc, &sp_header);
+    }
+
     #[test]
     fn test_tm_ctor() {
-        let sp_header = SpHeader::tm(0x42, SequenceFlags::Unsegmented, 25, 0);
+        let sp_header = SpHeader::new_for_tm_checked(0x42, SequenceFlags::Unsegmented, 25, 0);
         assert!(sp_header.is_some());
         let sp_header = sp_header.unwrap();
         verify_sp_fields(PacketType::Tm, &sp_header);
     }
 
+    #[test]
+    fn test_tm_ctor_const() {
+        let sp_header = SpHeader::new_for_tm(0x42, SequenceFlags::Unsegmented, 25, 0);
+        verify_sp_fields(PacketType::Tm, &sp_header);
+    }
+
     #[test]
     fn test_tm_ctor_unseg() {
-        let sp_header = SpHeader::tm_unseg(0x42, 25, 0);
+        let sp_header = SpHeader::new_for_unseg_tm_checked(0x42, 25, 0);
         assert!(sp_header.is_some());
         let sp_header = sp_header.unwrap();
         verify_sp_fields(PacketType::Tm, &sp_header);
@@ -1031,8 +1200,8 @@ pub(crate) mod tests {
     fn test_zc_sph() {
         use zerocopy::AsBytes;
 
-        let sp_header =
-            SpHeader::tc_unseg(0x7FF, pow(2, 14) - 1, 0).expect("Error creating SP header");
+        let sp_header = SpHeader::new_for_unseg_tc_checked(0x7FF, pow(2, 14) - 1, 0)
+            .expect("Error creating SP header");
         assert_eq!(sp_header.ptype(), PacketType::Tc);
         assert_eq!(sp_header.apid(), 0x7FF);
         assert_eq!(sp_header.data_len(), 0);
@@ -1097,4 +1266,40 @@ pub(crate) mod tests {
         let mut id_set = HashSet::new();
         id_set.insert(PacketId::from(1_u16));
     }
+
+    #[test]
+    fn sp_header_from_apid() {
+        let sp_header = SpHeader::new_from_apid(0x03);
+        assert_eq!(sp_header.apid(), 0x03);
+        assert_eq!(sp_header.data_len(), 0);
+    }
+
+    #[test]
+    fn sp_header_from_apid_checked() {
+        let sp_header = SpHeader::new_from_apid_checked(0x03).unwrap();
+        assert_eq!(sp_header.apid(), 0x03);
+        assert_eq!(sp_header.data_len(), 0);
+    }
+
+    #[cfg(feature = "defmt")]
+    fn is_defmt_format<T: defmt::Format>(_t: T) {}
+
+    #[test]
+    #[cfg(feature = "defmt")]
+    fn test_defmt_format() {
+        is_defmt_format(ByteConversionError::ToSliceTooSmall {
+            found: 1,
+            expected: 2,
+        });
+    }
+
+    #[test]
+    fn test_sp_header_as_vec() {
+        let sp_header = SpHeader::new_for_unseg_tc(0x42, 25, 1);
+        let sp_header_as_vec = sp_header.to_vec();
+        let sp_header_read_back = SpHeader::from_be_bytes(&sp_header_as_vec)
+            .expect("Error reading back SP header")
+            .0;
+        assert_eq!(sp_header, sp_header_read_back);
+    }
 }

src/seq_count.rs

@@ -0,0 +1,250 @@
+use crate::MAX_SEQ_COUNT;
+use core::cell::Cell;
+use paste::paste;
+#[cfg(feature = "std")]
+pub use stdmod::*;
+
+/// Core trait for objects which can provide a sequence count.
+///
+/// The core functions are not mutable on purpose to allow easier usage with
+/// static structs when using the interior mutability pattern. This can be achieved by using
+/// [Cell], [core::cell::RefCell] or atomic types.
+pub trait SequenceCountProvider {
+    type Raw: Into<u64>;
+    const MAX_BIT_WIDTH: usize;
+
+    fn get(&self) -> Self::Raw;
+
+    fn increment(&self);
+
+    fn get_and_increment(&self) -> Self::Raw {
+        let val = self.get();
+        self.increment();
+        val
+    }
+}
+
+#[derive(Clone)]
+pub struct SeqCountProviderSimple<T: Copy> {
+    seq_count: Cell<T>,
+    max_val: T,
+}
+
+macro_rules! impl_for_primitives {
+    ($($ty: ident,)+) => {
+        $(
+            paste! {
+                impl SeqCountProviderSimple<$ty> {
+                    pub fn [<new_custom_max_val_ $ty>](max_val: $ty) -> Self {
+                        Self {
+                            seq_count: Cell::new(0),
+                            max_val,
+                        }
+                    }
+                    pub fn [<new_ $ty>]() -> Self {
+                        Self {
+                            seq_count: Cell::new(0),
+                            max_val: $ty::MAX
+                        }
+                    }
+                }
+
+                impl Default for SeqCountProviderSimple<$ty> {
+                    fn default() -> Self {
+                        Self::[<new_ $ty>]()
+                    }
+                }
+
+                impl SequenceCountProvider for SeqCountProviderSimple<$ty> {
+                    type Raw = $ty;
+                    const MAX_BIT_WIDTH: usize = core::mem::size_of::<Self::Raw>() * 8;
+
+                    fn get(&self) -> Self::Raw {
+                        self.seq_count.get()
+                    }
+
+                    fn increment(&self) {
+                        self.get_and_increment();
+                    }
+
+                    fn get_and_increment(&self) -> Self::Raw {
+                        let curr_count = self.seq_count.get();
+
+                        if curr_count == self.max_val {
+                            self.seq_count.set(0);
+                        } else {
+                            self.seq_count.set(curr_count + 1);
+                        }
+                        curr_count
+                    }
+                }
+            }
+        )+
+    }
+}
+
+impl_for_primitives!(u8, u16, u32, u64,);
+
+/// This is a sequence count provider which wraps around at [MAX_SEQ_COUNT].
+#[derive(Clone)]
+pub struct CcsdsSimpleSeqCountProvider {
+    provider: SeqCountProviderSimple<u16>,
+}
+
+impl Default for CcsdsSimpleSeqCountProvider {
+    fn default() -> Self {
+        Self {
+            provider: SeqCountProviderSimple::new_custom_max_val_u16(MAX_SEQ_COUNT),
+        }
+    }
+}
+
+impl SequenceCountProvider for CcsdsSimpleSeqCountProvider {
+    type Raw = u16;
+    const MAX_BIT_WIDTH: usize = core::mem::size_of::<Self::Raw>() * 8;
+    delegate::delegate! {
+        to self.provider {
+            fn get(&self) -> u16;
+            fn increment(&self);
+            fn get_and_increment(&self) -> u16;
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+pub mod stdmod {
+    use super::*;
+    use std::sync::{Arc, Mutex};
+
+    macro_rules! sync_clonable_seq_counter_impl {
+         ($($ty: ident,)+) => {
+             $(paste! {
+                 /// These sequence counters can be shared between threads and can also be
+                 /// configured to wrap around at specified maximum values. Please note that
+                 /// that the API provided by this class will not panic und [Mutex] lock errors,
+                 /// but it will yield 0 for the getter functions.
+                 #[derive(Clone, Default)]
+                 pub struct [<SeqCountProviderSync $ty:upper>] {
+                     seq_count: Arc<Mutex<$ty>>,
+                     max_val: $ty
+                 }
+
+                 impl [<SeqCountProviderSync $ty:upper>] {
+                     pub fn new() -> Self {
+                        Self::new_with_max_val($ty::MAX)
+                     }
+
+                     pub fn new_with_max_val(max_val: $ty) -> Self {
+                         Self {
+                             seq_count: Arc::default(),
+                             max_val
+                         }
+                     }
+                 }
+                 impl SequenceCountProvider for [<SeqCountProviderSync $ty:upper>] {
+                    type Raw = $ty;
+                    const MAX_BIT_WIDTH: usize = core::mem::size_of::<Self::Raw>() * 8;
+
+                    fn get(&self) -> $ty {
+                        match self.seq_count.lock() {
+                            Ok(counter) => *counter,
+                            Err(_) => 0
+                        }
+                    }
+
+                    fn increment(&self) {
+                        self.get_and_increment();
+                    }
+
+                    fn get_and_increment(&self) -> $ty {
+                        match self.seq_count.lock() {
+                            Ok(mut counter) => {
+                                let val = *counter;
+                                if val == self.max_val {
+                                    *counter = 0;
+                                } else {
+                                    *counter += 1;
+                                }
+                                val
+                            }
+                            Err(_) => 0,
+                        }
+                    }
+                 }
+             })+
+         }
+    }
+    sync_clonable_seq_counter_impl!(u8, u16, u32, u64,);
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::seq_count::{
+        CcsdsSimpleSeqCountProvider, SeqCountProviderSimple, SeqCountProviderSyncU8,
+        SequenceCountProvider,
+    };
+    use crate::MAX_SEQ_COUNT;
+
+    #[test]
+    fn test_u8_counter() {
+        let u8_counter = SeqCountProviderSimple::<u8>::default();
+        assert_eq!(u8_counter.get(), 0);
+        assert_eq!(u8_counter.get_and_increment(), 0);
+        assert_eq!(u8_counter.get_and_increment(), 1);
+        assert_eq!(u8_counter.get(), 2);
+    }
+
+    #[test]
+    fn test_u8_counter_overflow() {
+        let u8_counter = SeqCountProviderSimple::new_u8();
+        for _ in 0..256 {
+            u8_counter.increment();
+        }
+        assert_eq!(u8_counter.get(), 0);
+    }
+
+    #[test]
+    fn test_ccsds_counter() {
+        let ccsds_counter = CcsdsSimpleSeqCountProvider::default();
+        assert_eq!(ccsds_counter.get(), 0);
+        assert_eq!(ccsds_counter.get_and_increment(), 0);
+        assert_eq!(ccsds_counter.get_and_increment(), 1);
+        assert_eq!(ccsds_counter.get(), 2);
+    }
+
+    #[test]
+    fn test_ccsds_counter_overflow() {
+        let ccsds_counter = CcsdsSimpleSeqCountProvider::default();
+        for _ in 0..MAX_SEQ_COUNT + 1 {
+            ccsds_counter.increment();
+        }
+        assert_eq!(ccsds_counter.get(), 0);
+    }
+
+    #[test]
+    fn test_atomic_ref_counters() {
+        let sync_u8_counter = SeqCountProviderSyncU8::new();
+        assert_eq!(sync_u8_counter.get(), 0);
+        assert_eq!(sync_u8_counter.get_and_increment(), 0);
+        assert_eq!(sync_u8_counter.get_and_increment(), 1);
+        assert_eq!(sync_u8_counter.get(), 2);
+    }
+
+    #[test]
+    fn test_atomic_ref_counters_overflow() {
+        let sync_u8_counter = SeqCountProviderSyncU8::new();
+        for _ in 0..u8::MAX as u16 + 1 {
+            sync_u8_counter.increment();
+        }
+        assert_eq!(sync_u8_counter.get(), 0);
+    }
+
+    #[test]
+    fn test_atomic_ref_counters_overflow_custom_max_val() {
+        let sync_u8_counter = SeqCountProviderSyncU8::new_with_max_val(128);
+        for _ in 0..129 {
+            sync_u8_counter.increment();
+        }
+        assert_eq!(sync_u8_counter.get(), 0);
+    }
+}

src/time/ascii.rs

@@ -2,11 +2,8 @@
 //! [CCSDS 301.0-B-4](https://public.ccsds.org/Pubs/301x0b4e1.pdf) section 3.5 .
 //! See [chrono::DateTime::format] for a usage example of the generated
 //! [chrono::format::DelayedFormat] structs.
-#[cfg(feature = "alloc")]
-use chrono::{
-    format::{DelayedFormat, StrftimeItems},
-    DateTime, Utc,
-};
+#[cfg(all(feature = "alloc", feature = "chrono"))]
+pub use alloc_mod_chrono::*;
 
 /// Tuple of format string and formatted size for time code A.
 ///
@@ -34,36 +31,37 @@ pub const FMT_STR_CODE_B_WITH_SIZE: (&str, usize) = ("%Y-%jT%T%.3f", 21);
 /// Three digits are used for the decimal fraction and a terminator is added at the end.
 pub const FMT_STR_CODE_B_TERMINATED_WITH_SIZE: (&str, usize) = ("%Y-%jT%T%.3fZ", 22);
 
-/// Generates a time code formatter using the [FMT_STR_CODE_A_WITH_SIZE] format.
-#[cfg(feature = "alloc")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
-pub fn generate_time_code_a(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
-    date.format(FMT_STR_CODE_A_WITH_SIZE.0)
-}
+#[cfg(all(feature = "alloc", feature = "chrono"))]
+pub mod alloc_mod_chrono {
+    use super::*;
+    use chrono::{
+        format::{DelayedFormat, StrftimeItems},
+        DateTime, Utc,
+    };
 
-/// Generates a time code formatter using the [FMT_STR_CODE_A_TERMINATED_WITH_SIZE] format.
-#[cfg(feature = "alloc")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
-pub fn generate_time_code_a_terminated(
-    date: &DateTime<Utc>,
-) -> DelayedFormat<StrftimeItems<'static>> {
-    date.format(FMT_STR_CODE_A_TERMINATED_WITH_SIZE.0)
-}
+    /// Generates a time code formatter using the [FMT_STR_CODE_A_WITH_SIZE] format.
+    pub fn generate_time_code_a(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
+        date.format(FMT_STR_CODE_A_WITH_SIZE.0)
+    }
 
-/// Generates a time code formatter using the [FMT_STR_CODE_B_WITH_SIZE] format.
-#[cfg(feature = "alloc")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
-pub fn generate_time_code_b(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
-    date.format(FMT_STR_CODE_B_WITH_SIZE.0)
-}
+    /// Generates a time code formatter using the [FMT_STR_CODE_A_TERMINATED_WITH_SIZE] format.
+    pub fn generate_time_code_a_terminated(
+        date: &DateTime<Utc>,
+    ) -> DelayedFormat<StrftimeItems<'static>> {
+        date.format(FMT_STR_CODE_A_TERMINATED_WITH_SIZE.0)
+    }
 
-/// Generates a time code formatter using the [FMT_STR_CODE_B_TERMINATED_WITH_SIZE] format.
-#[cfg(feature = "alloc")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
-pub fn generate_time_code_b_terminated(
-    date: &DateTime<Utc>,
-) -> DelayedFormat<StrftimeItems<'static>> {
-    date.format(FMT_STR_CODE_B_TERMINATED_WITH_SIZE.0)
+    /// Generates a time code formatter using the [FMT_STR_CODE_B_WITH_SIZE] format.
+    pub fn generate_time_code_b(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
+        date.format(FMT_STR_CODE_B_WITH_SIZE.0)
+    }
+
+    /// Generates a time code formatter using the [FMT_STR_CODE_B_TERMINATED_WITH_SIZE] format.
+    pub fn generate_time_code_b_terminated(
+        date: &DateTime<Utc>,
+    ) -> DelayedFormat<StrftimeItems<'static>> {
+        date.format(FMT_STR_CODE_B_TERMINATED_WITH_SIZE.0)
+    }
 }
 
 #[cfg(test)]
@@ -73,25 +71,54 @@ mod tests {
     use std::format;
 
     #[test]
-    fn test_ascii_timestamp_a_unterminated() {
-        let date = Utc::now();
+    fn test_ascii_timestamp_a_unterminated_epoch() {
+        let date = chrono::DateTime::UNIX_EPOCH;
         let stamp_formatter = generate_time_code_a(&date);
         let stamp = format!("{}", stamp_formatter);
-        let t_sep = stamp.find("T");
+        let t_sep = stamp.find('T');
         assert!(t_sep.is_some());
         assert_eq!(t_sep.unwrap(), 10);
         assert_eq!(stamp.len(), FMT_STR_CODE_A_WITH_SIZE.1);
     }
 
     #[test]
-    fn test_ascii_timestamp_a_terminated() {
+    #[cfg_attr(miri, ignore)]
+    fn test_ascii_timestamp_a_unterminated_now() {
+        let date = Utc::now();
+        let stamp_formatter = generate_time_code_a(&date);
+        let stamp = format!("{}", stamp_formatter);
+        let t_sep = stamp.find('T');
+        assert!(t_sep.is_some());
+        assert_eq!(t_sep.unwrap(), 10);
+        assert_eq!(stamp.len(), FMT_STR_CODE_A_WITH_SIZE.1);
+    }
+
+    #[test]
+    fn test_ascii_timestamp_a_terminated_epoch() {
+        let date = chrono::DateTime::UNIX_EPOCH;
+        let stamp_formatter = generate_time_code_a_terminated(&date);
+        let stamp = format!("{}", stamp_formatter);
+        let t_sep = stamp.find('T');
+        assert!(t_sep.is_some());
+        assert_eq!(t_sep.unwrap(), 10);
+        let z_terminator = stamp.find('Z');
+        assert!(z_terminator.is_some());
+        assert_eq!(
+            z_terminator.unwrap(),
+            FMT_STR_CODE_A_TERMINATED_WITH_SIZE.1 - 1
+        );
+        assert_eq!(stamp.len(), FMT_STR_CODE_A_TERMINATED_WITH_SIZE.1);
+    }
+    #[test]
+    #[cfg_attr(miri, ignore)]
+    fn test_ascii_timestamp_a_terminated_now() {
         let date = Utc::now();
         let stamp_formatter = generate_time_code_a_terminated(&date);
         let stamp = format!("{}", stamp_formatter);
-        let t_sep = stamp.find("T");
+        let t_sep = stamp.find('T');
         assert!(t_sep.is_some());
         assert_eq!(t_sep.unwrap(), 10);
-        let z_terminator = stamp.find("Z");
+        let z_terminator = stamp.find('Z');
         assert!(z_terminator.is_some());
         assert_eq!(
             z_terminator.unwrap(),
@@ -101,25 +128,55 @@ mod tests {
     }
 
     #[test]
-    fn test_ascii_timestamp_b_unterminated() {
-        let date = Utc::now();
+    fn test_ascii_timestamp_b_unterminated_epoch() {
+        let date = chrono::DateTime::UNIX_EPOCH;
         let stamp_formatter = generate_time_code_b(&date);
         let stamp = format!("{}", stamp_formatter);
-        let t_sep = stamp.find("T");
+        let t_sep = stamp.find('T');
         assert!(t_sep.is_some());
         assert_eq!(t_sep.unwrap(), 8);
         assert_eq!(stamp.len(), FMT_STR_CODE_B_WITH_SIZE.1);
     }
 
     #[test]
-    fn test_ascii_timestamp_b_terminated() {
+    #[cfg_attr(miri, ignore)]
+    fn test_ascii_timestamp_b_unterminated_now() {
+        let date = Utc::now();
+        let stamp_formatter = generate_time_code_b(&date);
+        let stamp = format!("{}", stamp_formatter);
+        let t_sep = stamp.find('T');
+        assert!(t_sep.is_some());
+        assert_eq!(t_sep.unwrap(), 8);
+        assert_eq!(stamp.len(), FMT_STR_CODE_B_WITH_SIZE.1);
+    }
+
+    #[test]
+    fn test_ascii_timestamp_b_terminated_epoch() {
+        let date = chrono::DateTime::UNIX_EPOCH;
+        let stamp_formatter = generate_time_code_b_terminated(&date);
+        let stamp = format!("{}", stamp_formatter);
+        let t_sep = stamp.find('T');
+        assert!(t_sep.is_some());
+        assert_eq!(t_sep.unwrap(), 8);
+        let z_terminator = stamp.find('Z');
+        assert!(z_terminator.is_some());
+        assert_eq!(
+            z_terminator.unwrap(),
+            FMT_STR_CODE_B_TERMINATED_WITH_SIZE.1 - 1
+        );
+        assert_eq!(stamp.len(), FMT_STR_CODE_B_TERMINATED_WITH_SIZE.1);
+    }
+
+    #[test]
+    #[cfg_attr(miri, ignore)]
+    fn test_ascii_timestamp_b_terminated_now() {
         let date = Utc::now();
         let stamp_formatter = generate_time_code_b_terminated(&date);
         let stamp = format!("{}", stamp_formatter);
-        let t_sep = stamp.find("T");
+        let t_sep = stamp.find('T');
         assert!(t_sep.is_some());
         assert_eq!(t_sep.unwrap(), 8);
-        let z_terminator = stamp.find("Z");
+        let z_terminator = stamp.find('Z');
         assert!(z_terminator.is_some());
         assert_eq!(
             z_terminator.unwrap(),

src/time/mod.rs

@@ -1,11 +1,11 @@
 //! CCSDS Time Code Formats according to [CCSDS 301.0-B-4](https://public.ccsds.org/Pubs/301x0b4e1.pdf)
 use crate::ByteConversionError;
-use chrono::{DateTime, LocalResult, TimeZone, Utc};
+#[cfg(feature = "chrono")]
+use chrono::{TimeZone, Utc};
 use core::cmp::Ordering;
 use core::fmt::{Display, Formatter};
-use core::ops::{Add, AddAssign};
+use core::ops::{Add, AddAssign, Sub};
 use core::time::Duration;
-use core::u8;
 
 #[allow(unused_imports)]
 #[cfg(not(feature = "std"))]
@@ -13,6 +13,7 @@ use num_traits::float::FloatCore;
 
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
+
 #[cfg(feature = "std")]
 use std::error::Error;
 #[cfg(feature = "std")]
@@ -27,10 +28,12 @@ pub mod cuc;
 pub const DAYS_CCSDS_TO_UNIX: i32 = -4383;
 pub const SECONDS_PER_DAY: u32 = 86400;
 pub const MS_PER_DAY: u32 = SECONDS_PER_DAY * 1000;
+pub const NANOS_PER_SECOND: u32 = 1_000_000_000;
 
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub enum CcsdsTimeCodes {
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum CcsdsTimeCode {
     CucCcsdsEpoch = 0b001,
     CucAgencyEpoch = 0b010,
     Cds = 0b100,
@@ -38,16 +41,16 @@ pub enum CcsdsTimeCodes {
     AgencyDefined = 0b110,
 }
 
-impl TryFrom<u8> for CcsdsTimeCodes {
+impl TryFrom<u8> for CcsdsTimeCode {
     type Error = ();
 
     fn try_from(value: u8) -> Result<Self, Self::Error> {
         match value {
-            x if x == CcsdsTimeCodes::CucCcsdsEpoch as u8 => Ok(CcsdsTimeCodes::CucCcsdsEpoch),
-            x if x == CcsdsTimeCodes::CucAgencyEpoch as u8 => Ok(CcsdsTimeCodes::CucAgencyEpoch),
-            x if x == CcsdsTimeCodes::Cds as u8 => Ok(CcsdsTimeCodes::Cds),
-            x if x == CcsdsTimeCodes::Ccs as u8 => Ok(CcsdsTimeCodes::Ccs),
-            x if x == CcsdsTimeCodes::AgencyDefined as u8 => Ok(CcsdsTimeCodes::AgencyDefined),
+            x if x == CcsdsTimeCode::CucCcsdsEpoch as u8 => Ok(CcsdsTimeCode::CucCcsdsEpoch),
+            x if x == CcsdsTimeCode::CucAgencyEpoch as u8 => Ok(CcsdsTimeCode::CucAgencyEpoch),
+            x if x == CcsdsTimeCode::Cds as u8 => Ok(CcsdsTimeCode::Cds),
+            x if x == CcsdsTimeCode::Ccs as u8 => Ok(CcsdsTimeCode::Ccs),
+            x if x == CcsdsTimeCode::AgencyDefined as u8 => Ok(CcsdsTimeCode::AgencyDefined),
             _ => Err(()),
         }
     }
@@ -55,20 +58,34 @@ impl TryFrom<u8> for CcsdsTimeCodes {
 
 /// Retrieve the CCSDS time code from the p-field. If no valid time code identifier is found, the
 /// value of the raw time code identification field is returned.
-pub fn ccsds_time_code_from_p_field(pfield: u8) -> Result<CcsdsTimeCodes, u8> {
+pub fn ccsds_time_code_from_p_field(pfield: u8) -> Result<CcsdsTimeCode, u8> {
     let raw_bits = (pfield >> 4) & 0b111;
-    CcsdsTimeCodes::try_from(raw_bits).map_err(|_| raw_bits)
+    CcsdsTimeCode::try_from(raw_bits).map_err(|_| raw_bits)
 }
 
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct DateBeforeCcsdsEpochError(UnixTime);
+
+impl Display for DateBeforeCcsdsEpochError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+        write!(f, "date before ccsds epoch: {:?}", self.0)
+    }
+}
+
+#[cfg(feature = "std")]
+impl Error for DateBeforeCcsdsEpochError {}
+
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[non_exhaustive]
 pub enum TimestampError {
-    InvalidTimeCode { expected: CcsdsTimeCodes, found: u8 },
+    InvalidTimeCode { expected: CcsdsTimeCode, found: u8 },
     ByteConversion(ByteConversionError),
     Cds(cds::CdsError),
     Cuc(cuc::CucError),
-    DateBeforeCcsdsEpoch(DateTime<Utc>),
     CustomEpochNotSupported,
 }
 
@@ -90,9 +107,6 @@ impl Display for TimestampError {
             TimestampError::ByteConversion(e) => {
                 write!(f, "time stamp: {e}")
             }
-            TimestampError::DateBeforeCcsdsEpoch(e) => {
-                write!(f, "datetime with date before ccsds epoch: {e}")
-            }
             TimestampError::CustomEpochNotSupported => {
                 write!(f, "custom epochs are not supported")
             }
@@ -111,6 +125,7 @@ impl Error for TimestampError {
         }
     }
 }
+
 impl From<cds::CdsError> for TimestampError {
     fn from(e: cds::CdsError) -> Self {
         TimestampError::Cds(e)
@@ -124,7 +139,6 @@ impl From<cuc::CucError> for TimestampError {
 }
 
 #[cfg(feature = "std")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 pub mod std_mod {
     use crate::time::TimestampError;
     use std::time::SystemTimeError;
@@ -132,7 +146,7 @@ pub mod std_mod {
 
     #[derive(Debug, Clone, Error)]
     pub enum StdTimestampError {
-        #[error("system time error: {0}")]
+        #[error("system time error: {0:?}")]
         SystemTime(#[from] SystemTimeError),
         #[error("timestamp error: {0}")]
         Timestamp(#[from] TimestampError),
@@ -140,7 +154,6 @@ pub mod std_mod {
 }
 
 #[cfg(feature = "std")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 pub fn seconds_since_epoch() -> f64 {
     SystemTime::now()
         .duration_since(SystemTime::UNIX_EPOCH)
@@ -152,6 +165,7 @@ pub fn seconds_since_epoch() -> f64 {
 ///
 ///  - CCSDS epoch: 1958-01-01T00:00:00+00:00
 ///  - UNIX Epoch: 1970-01-01T00:00:00+00:00
+#[inline]
 pub const fn unix_to_ccsds_days(unix_days: i64) -> i64 {
     unix_days - DAYS_CCSDS_TO_UNIX as i64
 }
@@ -160,22 +174,24 @@ pub const fn unix_to_ccsds_days(unix_days: i64) -> i64 {
 ///
 ///  - CCSDS epoch: 1958-01-01T00:00:00+00:00
 ///  - UNIX Epoch: 1970-01-01T00:00:00+00:00
+#[inline]
 pub const fn ccsds_to_unix_days(ccsds_days: i64) -> i64 {
     ccsds_days + DAYS_CCSDS_TO_UNIX as i64
 }
 
 /// Similar to [unix_to_ccsds_days] but converts the epoch instead, which is the number of elpased
 /// seconds since the CCSDS and UNIX epoch times.
+#[inline]
 pub const fn unix_epoch_to_ccsds_epoch(unix_epoch: i64) -> i64 {
     unix_epoch - (DAYS_CCSDS_TO_UNIX as i64 * SECONDS_PER_DAY as i64)
 }
 
+#[inline]
 pub const fn ccsds_epoch_to_unix_epoch(ccsds_epoch: i64) -> i64 {
     ccsds_epoch + (DAYS_CCSDS_TO_UNIX as i64 * SECONDS_PER_DAY as i64)
 }
 
 #[cfg(feature = "std")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 pub fn ms_of_day_using_sysclock() -> u32 {
     ms_of_day(seconds_since_epoch())
 }
@@ -189,21 +205,29 @@ pub fn ms_of_day(seconds_since_epoch: f64) -> u32 {
 }
 
 pub trait TimeWriter {
+    fn len_written(&self) -> usize;
+
     /// Generic function to convert write a timestamp into a raw buffer.
     /// Returns the number of written bytes on success.
     fn write_to_bytes(&self, bytes: &mut [u8]) -> Result<usize, TimestampError>;
+
+    #[cfg(feature = "alloc")]
+    fn to_vec(&self) -> Result<alloc::vec::Vec<u8>, TimestampError> {
+        let mut vec = alloc::vec![0; self.len_written()];
+        self.write_to_bytes(&mut vec)?;
+        Ok(vec)
+    }
 }
 
-pub trait TimeReader {
-    fn from_bytes(buf: &[u8]) -> Result<Self, TimestampError>
-    where
-        Self: Sized;
+pub trait TimeReader: Sized {
+    fn from_bytes(buf: &[u8]) -> Result<Self, TimestampError>;
 }
 
 /// Trait for generic CCSDS time providers.
 ///
-/// The UNIX helper methods and the [Self::date_time] method are not strictly necessary but extremely
+/// The UNIX helper methods and the helper method are not strictly necessary but extremely
 /// practical because they are a very common and simple exchange format for time information.
+/// Therefore, it was decided to keep them in this trait as well.
 pub trait CcsdsTimeProvider {
     fn len_as_bytes(&self) -> usize;
 
@@ -212,130 +236,203 @@ pub trait CcsdsTimeProvider {
     /// entry denotes the length of the pfield and the second entry is the value of the pfield
     /// in big endian format.
     fn p_field(&self) -> (usize, [u8; 2]);
-    fn ccdsd_time_code(&self) -> CcsdsTimeCodes;
+    fn ccdsd_time_code(&self) -> CcsdsTimeCode;
 
-    fn unix_seconds(&self) -> i64;
-    fn subsecond_millis(&self) -> Option<u16>;
-    fn unix_stamp(&self) -> UnixTimestamp {
-        if self.subsecond_millis().is_none() {
-            return UnixTimestamp::new_only_seconds(self.unix_seconds());
-        }
-        UnixTimestamp::const_new(self.unix_seconds(), self.subsecond_millis().unwrap())
+    fn unix_secs(&self) -> i64;
+    fn subsec_nanos(&self) -> u32;
+
+    fn subsec_millis(&self) -> u16 {
+        (self.subsec_nanos() / 1_000_000) as u16
     }
 
-    fn date_time(&self) -> Option<DateTime<Utc>>;
+    fn unix_time(&self) -> UnixTime {
+        UnixTime::new(self.unix_secs(), self.subsec_nanos())
+    }
+
+    #[cfg(feature = "chrono")]
+    fn chrono_date_time(&self) -> chrono::LocalResult<chrono::DateTime<chrono::Utc>> {
+        chrono::Utc.timestamp_opt(self.unix_secs(), self.subsec_nanos())
+    }
+
+    #[cfg(feature = "timelib")]
+    fn timelib_date_time(&self) -> Result<time::OffsetDateTime, time::error::ComponentRange> {
+        Ok(time::OffsetDateTime::from_unix_timestamp(self.unix_secs())?
+            + time::Duration::nanoseconds(self.subsec_nanos().into()))
+    }
 }
 
-/// UNIX timestamp: Elapsed seconds since 1970-01-01T00:00:00+00:00.
+/// UNIX time: Elapsed non-leap seconds since 1970-01-01T00:00:00+00:00 UTC.
 ///
-/// Also can optionally include subsecond millisecond for greater accuracy. Please note that a
-/// subsecond millisecond value of 0 gets converted to [None].
+/// This is a commonly used time format and can therefore also be used as a generic format to
+/// convert other CCSDS time formats to and from. The subsecond precision is in nanoseconds
+/// similarly to other common time formats and libraries.
 #[derive(Default, Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub struct UnixTimestamp {
-    pub unix_seconds: i64,
-    subsecond_millis: Option<u16>,
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct UnixTime {
+    secs: i64,
+    subsec_nanos: u32,
 }
 
-impl UnixTimestamp {
-    /// Returns none if the subsecond millisecond value is larger than 999. 0 is converted to
-    /// a [None] value.
-    pub fn new(unix_seconds: i64, subsec_millis: u16) -> Option<Self> {
-        if subsec_millis > 999 {
+impl UnixTime {
+    /// The UNIX epoch time: 1970-01-01T00:00:00+00:00 UTC.
+    pub const EPOCH: Self = Self {
+        secs: 0,
+        subsec_nanos: 0,
+    };
+
+    /// The minimum possible `UnixTime`.
+    pub const MIN: Self = Self {
+        secs: i64::MIN,
+        subsec_nanos: 0,
+    };
+
+    /// The maximum possible `UnixTime`.
+    pub const MAX: Self = Self {
+        secs: i64::MAX,
+        subsec_nanos: NANOS_PER_SECOND - 1,
+    };
+
+    /// Returns [None] if the subsecond nanosecond value is invalid (larger than fraction of a
+    /// second)
+    pub fn new_checked(unix_seconds: i64, subsec_nanos: u32) -> Option<Self> {
+        if subsec_nanos >= NANOS_PER_SECOND {
             return None;
         }
-        Some(Self::const_new(unix_seconds, subsec_millis))
+        Some(Self::new(unix_seconds, subsec_nanos))
     }
 
-    /// Like [Self::new] but const. Panics if the subsecond value is larger than 999.
-    pub const fn const_new(unix_seconds: i64, subsec_millis: u16) -> Self {
-        if subsec_millis > 999 {
-            panic!("subsec milliseconds exceeds 999");
+    /// Returns [None] if the subsecond millisecond value is invalid (larger than fraction of a
+    /// second)
+    pub fn new_subsec_millis_checked(unix_seconds: i64, subsec_millis: u16) -> Option<Self> {
+        if subsec_millis >= 1000 {
+            return None;
+        }
+        Self::new_checked(unix_seconds, subsec_millis as u32 * 1_000_000)
+    }
+
+    /// This function will panic if the subsecond value is larger than the fraction of a second.
+    /// Use [Self::new_checked] if you want to handle this case without a panic.
+    pub const fn new(unix_seconds: i64, subsecond_nanos: u32) -> Self {
+        if subsecond_nanos >= NANOS_PER_SECOND {
+            panic!("invalid subsecond nanos value");
         }
-        let subsecond_millis = if subsec_millis == 0 {
-            None
-        } else {
-            Some(subsec_millis)
-        };
         Self {
-            unix_seconds,
-            subsecond_millis,
+            secs: unix_seconds,
+            subsec_nanos: subsecond_nanos,
         }
     }
 
-    pub fn new_only_seconds(unix_seconds: i64) -> Self {
+    /// This function will panic if the subsecond value is larger than the fraction of a second.
+    /// Use [Self::new_subsec_millis_checked] if you want to handle this case without a panic.
+    pub const fn new_subsec_millis(unix_seconds: i64, subsecond_millis: u16) -> Self {
+        if subsecond_millis >= 1000 {
+            panic!("invalid subsecond millisecond value");
+        }
         Self {
-            unix_seconds,
-            subsecond_millis: None,
+            secs: unix_seconds,
+            subsec_nanos: subsecond_millis as u32 * 1_000_000,
         }
     }
 
-    pub fn subsecond_millis(&self) -> Option<u16> {
-        self.subsecond_millis
-    }
-
-    #[cfg(feature = "std")]
-    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
-    pub fn from_now() -> Result<Self, SystemTimeError> {
-        let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH)?;
-        let epoch = now.as_secs();
-        Ok(Self::const_new(epoch as i64, now.subsec_millis() as u16))
+    pub fn new_only_secs(unix_seconds: i64) -> Self {
+        Self {
+            secs: unix_seconds,
+            subsec_nanos: 0,
+        }
     }
 
     #[inline]
-    pub fn unix_seconds_f64(&self) -> f64 {
-        let mut secs = self.unix_seconds as f64;
-        if let Some(subsec_millis) = self.subsecond_millis {
-            secs += subsec_millis as f64 / 1000.0;
-        }
-        secs
+    pub fn subsec_millis(&self) -> u16 {
+        (self.subsec_nanos / 1_000_000) as u16
     }
 
-    pub fn as_date_time(&self) -> LocalResult<DateTime<Utc>> {
-        Utc.timestamp_opt(
-            self.unix_seconds,
-            self.subsecond_millis.unwrap_or(0) as u32 * 10_u32.pow(6),
-        )
+    pub fn subsec_nanos(&self) -> u32 {
+        self.subsec_nanos
+    }
+
+    #[cfg(feature = "std")]
+    pub fn now() -> Result<Self, SystemTimeError> {
+        let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH)?;
+        let epoch = now.as_secs();
+        Ok(Self::new(epoch as i64, now.subsec_nanos()))
+    }
+
+    #[inline]
+    pub fn unix_secs_f64(&self) -> f64 {
+        self.secs as f64 + (self.subsec_nanos as f64 / 1_000_000_000.0)
+    }
+
+    pub fn as_secs(&self) -> i64 {
+        self.secs
+    }
+
+    #[cfg(feature = "chrono")]
+    pub fn chrono_date_time(&self) -> chrono::LocalResult<chrono::DateTime<chrono::Utc>> {
+        Utc.timestamp_opt(self.secs, self.subsec_nanos)
+    }
+
+    #[cfg(feature = "timelib")]
+    pub fn timelib_date_time(&self) -> Result<time::OffsetDateTime, time::error::ComponentRange> {
+        Ok(time::OffsetDateTime::from_unix_timestamp(self.as_secs())?
+            + time::Duration::nanoseconds(self.subsec_nanos().into()))
+    }
+
+    // Calculate the difference in milliseconds between two UnixTimestamps
+    pub fn diff_in_millis(&self, other: &UnixTime) -> Option<i64> {
+        let seconds_difference = self.secs.checked_sub(other.secs)?;
+        // Convert seconds difference to milliseconds
+        let milliseconds_difference = seconds_difference.checked_mul(1000)?;
+
+        // Calculate the difference in subsecond milliseconds directly
+        let subsecond_difference_nanos = self.subsec_nanos as i64 - other.subsec_nanos as i64;
+
+        // Combine the differences
+        Some(milliseconds_difference + (subsecond_difference_nanos / 1_000_000))
     }
 }
 
-impl From<DateTime<Utc>> for UnixTimestamp {
-    fn from(value: DateTime<Utc>) -> Self {
-        Self::const_new(value.timestamp(), value.timestamp_subsec_millis() as u16)
+#[cfg(feature = "chrono")]
+impl From<chrono::DateTime<chrono::Utc>> for UnixTime {
+    fn from(value: chrono::DateTime<chrono::Utc>) -> Self {
+        Self::new(value.timestamp(), value.timestamp_subsec_nanos())
     }
 }
 
-impl PartialOrd for UnixTimestamp {
+#[cfg(feature = "timelib")]
+impl From<time::OffsetDateTime> for UnixTime {
+    fn from(value: time::OffsetDateTime) -> Self {
+        Self::new(value.unix_timestamp(), value.nanosecond())
+    }
+}
+
+impl PartialOrd for UnixTime {
     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
         Some(self.cmp(other))
     }
 }
 
-impl Ord for UnixTimestamp {
+impl Ord for UnixTime {
     fn cmp(&self, other: &Self) -> Ordering {
         if self == other {
             return Ordering::Equal;
         }
-        match self.unix_seconds.cmp(&other.unix_seconds) {
+        match self.secs.cmp(&other.secs) {
             Ordering::Less => return Ordering::Less,
             Ordering::Greater => return Ordering::Greater,
             _ => (),
         }
 
-        match self
-            .subsecond_millis()
-            .unwrap_or(0)
-            .cmp(&other.subsecond_millis().unwrap_or(0))
-        {
+        match self.subsec_millis().cmp(&other.subsec_millis()) {
             Ordering::Less => {
-                return if self.unix_seconds < 0 {
+                return if self.secs < 0 {
                     Ordering::Greater
                 } else {
                     Ordering::Less
                 }
             }
             Ordering::Greater => {
-                return if self.unix_seconds < 0 {
+                return if self.secs < 0 {
                     Ordering::Less
                 } else {
                     Ordering::Greater
@@ -347,13 +444,36 @@ impl Ord for UnixTimestamp {
     }
 }
 
-fn get_new_stamp_after_addition(
-    current_stamp: &UnixTimestamp,
-    duration: Duration,
-) -> UnixTimestamp {
-    let mut new_subsec_millis =
-        current_stamp.subsecond_millis().unwrap_or(0) + duration.subsec_millis() as u16;
-    let mut new_unix_seconds = current_stamp.unix_seconds;
+/// Difference between two UNIX timestamps. The [Duration] type can not contain negative durations,
+/// so the sign information is supplied separately.
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct StampDiff {
+    pub positive_duration: bool,
+    pub duration_absolute: Duration,
+}
+
+impl Sub for UnixTime {
+    type Output = Option<StampDiff>;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        let difference = self.diff_in_millis(&rhs)?;
+        Some(if difference < 0 {
+            StampDiff {
+                positive_duration: false,
+                duration_absolute: Duration::from_millis(-difference as u64),
+            }
+        } else {
+            StampDiff {
+                positive_duration: true,
+                duration_absolute: Duration::from_millis(difference as u64),
+            }
+        })
+    }
+}
+
+fn get_new_stamp_after_addition(current_stamp: &UnixTime, duration: Duration) -> UnixTime {
+    let mut new_subsec_nanos = current_stamp.subsec_nanos() + duration.subsec_nanos();
+    let mut new_unix_seconds = current_stamp.secs;
     let mut increment_seconds = |value: u32| {
         if new_unix_seconds < 0 {
             new_unix_seconds = new_unix_seconds
@@ -365,8 +485,8 @@ fn get_new_stamp_after_addition(
                 .expect("new unix seconds would exceed i64::MAX");
         }
     };
-    if new_subsec_millis >= 1000 {
-        new_subsec_millis -= 1000;
+    if new_subsec_nanos >= 1_000_000_000 {
+        new_subsec_nanos -= 1_000_000_000;
         increment_seconds(1);
     }
     increment_seconds(
@@ -375,7 +495,7 @@ fn get_new_stamp_after_addition(
             .try_into()
             .expect("duration seconds exceeds u32::MAX"),
     );
-    UnixTimestamp::const_new(new_unix_seconds, new_subsec_millis)
+    UnixTime::new(new_unix_seconds, new_subsec_nanos)
 }
 
 /// Please note that this operation will panic on the following conditions:
@@ -383,7 +503,7 @@ fn get_new_stamp_after_addition(
 /// - Unix seconds after subtraction for stamps before the unix epoch exceeds [i64::MIN].
 /// - Unix seconds after addition  exceeds [i64::MAX].
 /// - Seconds from duration to add exceeds [u32::MAX].
-impl AddAssign<Duration> for UnixTimestamp {
+impl AddAssign<Duration> for UnixTime {
     fn add_assign(&mut self, duration: Duration) {
         *self = get_new_stamp_after_addition(self, duration);
     }
@@ -394,7 +514,7 @@ impl AddAssign<Duration> for UnixTimestamp {
 /// - Unix seconds after subtraction for stamps before the unix epoch exceeds [i64::MIN].
 /// - Unix seconds after addition  exceeds [i64::MAX].
 /// - Unix seconds exceeds [u32::MAX].
-impl Add<Duration> for UnixTimestamp {
+impl Add<Duration> for UnixTime {
     type Output = Self;
 
     fn add(self, duration: Duration) -> Self::Output {
@@ -402,8 +522,8 @@ impl Add<Duration> for UnixTimestamp {
     }
 }
 
-impl Add<Duration> for &UnixTimestamp {
-    type Output = UnixTimestamp;
+impl Add<Duration> for &UnixTime {
+    type Output = UnixTime;
 
     fn add(self, duration: Duration) -> Self::Output {
         get_new_stamp_after_addition(self, duration)
@@ -414,10 +534,15 @@ impl Add<Duration> for &UnixTimestamp {
 mod tests {
     use alloc::string::ToString;
     use chrono::{Datelike, Timelike};
-    use std::format;
+    use std::{format, println};
 
     use super::{cuc::CucError, *};
 
+    #[allow(dead_code)]
+    const UNIX_STAMP_CONST: UnixTime = UnixTime::new(5, 999_999_999);
+    #[allow(dead_code)]
+    const UNIX_STAMP_CONST_2: UnixTime = UnixTime::new_subsec_millis(5, 999);
+
     #[test]
     fn test_days_conversion() {
         assert_eq!(unix_to_ccsds_days(DAYS_CCSDS_TO_UNIX.into()), 0);
@@ -425,6 +550,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(miri, ignore)]
     fn test_get_current_time() {
         let sec_floats = seconds_since_epoch();
         assert!(sec_floats > 0.0);
@@ -439,6 +565,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(miri, ignore)]
     fn test_ccsds_epoch() {
         let now = SystemTime::now()
             .duration_since(SystemTime::UNIX_EPOCH)
@@ -453,29 +580,29 @@ mod tests {
 
     #[test]
     fn basic_unix_stamp_test() {
-        let stamp = UnixTimestamp::new_only_seconds(-200);
-        assert_eq!(stamp.unix_seconds, -200);
-        assert!(stamp.subsecond_millis().is_none());
-        let stamp = UnixTimestamp::new_only_seconds(250);
-        assert_eq!(stamp.unix_seconds, 250);
-        assert!(stamp.subsecond_millis().is_none());
+        let stamp = UnixTime::new_only_secs(-200);
+        assert_eq!(stamp.secs, -200);
+        assert_eq!(stamp.subsec_millis(), 0);
+        let stamp = UnixTime::new_only_secs(250);
+        assert_eq!(stamp.secs, 250);
+        assert_eq!(stamp.subsec_millis(), 0);
     }
 
     #[test]
     fn basic_float_unix_stamp_test() {
-        let stamp = UnixTimestamp::new(500, 600).unwrap();
-        assert!(stamp.subsecond_millis.is_some());
-        assert_eq!(stamp.unix_seconds, 500);
-        let subsec_millis = stamp.subsecond_millis().unwrap();
+        let stamp = UnixTime::new_subsec_millis_checked(500, 600).unwrap();
+        assert_eq!(stamp.secs, 500);
+        let subsec_millis = stamp.subsec_millis();
         assert_eq!(subsec_millis, 600);
-        assert!((500.6 - stamp.unix_seconds_f64()).abs() < 0.0001);
+        println!("{:?}", (500.6 - stamp.unix_secs_f64()).to_string());
+        assert!((500.6 - stamp.unix_secs_f64()).abs() < 0.0001);
     }
 
     #[test]
     fn test_ord_larger() {
-        let stamp0 = UnixTimestamp::new_only_seconds(5);
-        let stamp1 = UnixTimestamp::new(5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(6);
+        let stamp0 = UnixTime::new_only_secs(5);
+        let stamp1 = UnixTime::new_subsec_millis_checked(5, 500).unwrap();
+        let stamp2 = UnixTime::new_only_secs(6);
         assert!(stamp1 > stamp0);
         assert!(stamp2 > stamp0);
         assert!(stamp2 > stamp1);
@@ -483,9 +610,9 @@ mod tests {
 
     #[test]
     fn test_ord_smaller() {
-        let stamp0 = UnixTimestamp::new_only_seconds(5);
-        let stamp1 = UnixTimestamp::new(5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(6);
+        let stamp0 = UnixTime::new_only_secs(5);
+        let stamp1 = UnixTime::new_subsec_millis_checked(5, 500).unwrap();
+        let stamp2 = UnixTime::new_only_secs(6);
         assert!(stamp0 < stamp1);
         assert!(stamp0 < stamp2);
         assert!(stamp1 < stamp2);
@@ -493,9 +620,9 @@ mod tests {
 
     #[test]
     fn test_ord_larger_neg_numbers() {
-        let stamp0 = UnixTimestamp::new_only_seconds(-5);
-        let stamp1 = UnixTimestamp::new(-5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(-6);
+        let stamp0 = UnixTime::new_only_secs(-5);
+        let stamp1 = UnixTime::new_subsec_millis_checked(-5, 500).unwrap();
+        let stamp2 = UnixTime::new_only_secs(-6);
         assert!(stamp0 > stamp1);
         assert!(stamp0 > stamp2);
         assert!(stamp1 > stamp2);
@@ -505,9 +632,9 @@ mod tests {
 
     #[test]
     fn test_ord_smaller_neg_numbers() {
-        let stamp0 = UnixTimestamp::new_only_seconds(-5);
-        let stamp1 = UnixTimestamp::new(-5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(-6);
+        let stamp0 = UnixTime::new_only_secs(-5);
+        let stamp1 = UnixTime::new_subsec_millis_checked(-5, 500).unwrap();
+        let stamp2 = UnixTime::new_only_secs(-6);
         assert!(stamp2 < stamp1);
         assert!(stamp2 < stamp0);
         assert!(stamp1 < stamp0);
@@ -515,10 +642,11 @@ mod tests {
         assert!(stamp2 <= stamp1);
     }
 
+    #[allow(clippy::nonminimal_bool)]
     #[test]
     fn test_eq() {
-        let stamp0 = UnixTimestamp::new(5, 0).unwrap();
-        let stamp1 = UnixTimestamp::new_only_seconds(5);
+        let stamp0 = UnixTime::new(5, 0);
+        let stamp1 = UnixTime::new_only_secs(5);
         assert_eq!(stamp0, stamp1);
         assert!(stamp0 <= stamp1);
         assert!(stamp0 >= stamp1);
@@ -528,28 +656,27 @@ mod tests {
 
     #[test]
     fn test_addition() {
-        let mut stamp0 = UnixTimestamp::new_only_seconds(1);
+        let mut stamp0 = UnixTime::new_only_secs(1);
         stamp0 += Duration::from_secs(5);
-        assert_eq!(stamp0.unix_seconds, 6);
-        assert!(stamp0.subsecond_millis().is_none());
+        assert_eq!(stamp0.as_secs(), 6);
+        assert_eq!(stamp0.subsec_millis(), 0);
         let stamp1 = stamp0 + Duration::from_millis(500);
-        assert_eq!(stamp1.unix_seconds, 6);
-        assert!(stamp1.subsecond_millis().is_some());
-        assert_eq!(stamp1.subsecond_millis().unwrap(), 500);
+        assert_eq!(stamp1.secs, 6);
+        assert_eq!(stamp1.subsec_millis(), 500);
     }
 
     #[test]
     fn test_addition_on_ref() {
-        let stamp0 = &UnixTimestamp::new(20, 500).unwrap();
+        let stamp0 = &UnixTime::new_subsec_millis_checked(20, 500).unwrap();
         let stamp1 = stamp0 + Duration::from_millis(2500);
-        assert_eq!(stamp1.unix_seconds, 23);
-        assert!(stamp1.subsecond_millis().is_none());
+        assert_eq!(stamp1.secs, 23);
+        assert_eq!(stamp1.subsec_millis(), 0);
     }
 
     #[test]
     fn test_as_dt() {
-        let stamp = UnixTimestamp::new_only_seconds(0);
-        let dt = stamp.as_date_time().unwrap();
+        let stamp = UnixTime::new_only_secs(0);
+        let dt = stamp.chrono_date_time().unwrap();
         assert_eq!(dt.year(), 1970);
         assert_eq!(dt.month(), 1);
         assert_eq!(dt.day(), 1);
@@ -559,21 +686,57 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(miri, ignore)]
     fn test_from_now() {
-        let stamp_now = UnixTimestamp::from_now().unwrap();
-        let dt_now = stamp_now.as_date_time().unwrap();
+        let stamp_now = UnixTime::now().unwrap();
+        let dt_now = stamp_now.chrono_date_time().unwrap();
         assert!(dt_now.year() >= 2020);
     }
 
+    #[test]
+    fn test_stamp_diff_positive_0() {
+        let stamp_later = UnixTime::new(2, 0);
+        let StampDiff {
+            positive_duration,
+            duration_absolute,
+        } = (stamp_later - UnixTime::new(1, 0)).expect("stamp diff error");
+        assert!(positive_duration);
+        assert_eq!(duration_absolute, Duration::from_secs(1));
+    }
+
+    #[test]
+    fn test_stamp_diff_positive_1() {
+        let stamp_later = UnixTime::new(3, 800 * 1_000_000);
+        let stamp_earlier = UnixTime::new_subsec_millis_checked(1, 900).unwrap();
+        let StampDiff {
+            positive_duration,
+            duration_absolute,
+        } = (stamp_later - stamp_earlier).expect("stamp diff error");
+        assert!(positive_duration);
+        assert_eq!(duration_absolute, Duration::from_millis(1900));
+    }
+
+    #[test]
+    fn test_stamp_diff_negative() {
+        let stamp_later = UnixTime::new_subsec_millis_checked(3, 800).unwrap();
+        let stamp_earlier = UnixTime::new_subsec_millis_checked(1, 900).unwrap();
+        let StampDiff {
+            positive_duration,
+            duration_absolute,
+        } = (stamp_earlier - stamp_later).expect("stamp diff error");
+        assert!(!positive_duration);
+        assert_eq!(duration_absolute, Duration::from_millis(1900));
+    }
+
     #[test]
     fn test_addition_spillover() {
-        let mut stamp0 = UnixTimestamp::new(1, 900).unwrap();
+        let mut stamp0 = UnixTime::new_subsec_millis_checked(1, 900).unwrap();
         stamp0 += Duration::from_millis(100);
-        assert_eq!(stamp0.unix_seconds, 2);
-        assert!(stamp0.subsecond_millis().is_none());
+        assert_eq!(stamp0.secs, 2);
+        assert_eq!(stamp0.subsec_millis(), 0);
         stamp0 += Duration::from_millis(1100);
-        assert_eq!(stamp0.unix_seconds, 3);
-        assert_eq!(stamp0.subsecond_millis().unwrap(), 100);
+        assert_eq!(stamp0.secs, 3);
+        assert_eq!(stamp0.subsec_millis(), 100);
     }
 
     #[test]
@@ -582,4 +745,26 @@ mod tests {
         let stamp_error = TimestampError::from(cuc_error);
         assert_eq!(stamp_error.to_string(), format!("cuc error: {cuc_error}"));
     }
+
+    #[test]
+    #[cfg(feature = "timelib")]
+    fn test_unix_stamp_as_timelib_datetime() {
+        let stamp_epoch = UnixTime::EPOCH;
+        let timelib_dt = stamp_epoch.timelib_date_time().unwrap();
+        assert_eq!(timelib_dt.year(), 1970);
+        assert_eq!(timelib_dt.month(), time::Month::January);
+        assert_eq!(timelib_dt.day(), 1);
+        assert_eq!(timelib_dt.hour(), 0);
+        assert_eq!(timelib_dt.minute(), 0);
+        assert_eq!(timelib_dt.second(), 0);
+    }
+
+    #[test]
+    #[cfg(feature = "timelib")]
+    fn test_unix_stamp_from_timelib_datetime() {
+        let timelib_dt = time::OffsetDateTime::UNIX_EPOCH;
+        let unix_time = UnixTime::from(timelib_dt);
+        let timelib_converted_back = unix_time.timelib_date_time().unwrap();
+        assert_eq!(timelib_dt, timelib_converted_back);
+    }
 }

src/uslp/mod.rs

@@ -0,0 +1,685 @@
+/// # Support of the CCSDS Unified Space Data Link Protocol (USLP)
+use crate::{ByteConversionError, CRC_CCITT_FALSE};
+
+/// Only this version is supported by the library
+pub const USLP_VERSION_NUMBER: u8 = 0b1100;
+
+/// Identifies the association of the data contained in the transfer frame.
+#[derive(
+    Debug, Copy, Clone, PartialEq, Eq, num_enum::TryFromPrimitive, num_enum::IntoPrimitive,
+)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[repr(u8)]
+pub enum SourceOrDestField {
+    /// SCID refers to the source of the transfer frame.
+    Source = 0,
+    /// SCID refers to the destination of the transfer frame.
+    Dest = 1,
+}
+
+#[derive(
+    Debug, Copy, Clone, PartialEq, Eq, num_enum::TryFromPrimitive, num_enum::IntoPrimitive,
+)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[repr(u8)]
+pub enum BypassSequenceControlFlag {
+    /// Acceptance of this frame on the receiving end is subject to normal frame acceptance
+    /// checks of FARM.
+    SequenceControlledQoS = 0,
+    /// Frame Acceptance Checks of FARM by the receiving end shall be bypassed.
+    ExpeditedQoS = 1,
+}
+
+#[derive(
+    Debug, Copy, Clone, PartialEq, Eq, num_enum::TryFromPrimitive, num_enum::IntoPrimitive,
+)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[repr(u8)]
+pub enum ProtocolControlCommandFlag {
+    TfdfContainsUserData = 0,
+    TfdfContainsProtocolInfo = 1,
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum UslpError {
+    ByteConversion(ByteConversionError),
+    HeaderIsTruncated,
+    InvalidProtocolId(u8),
+    InvalidConstructionRule(u8),
+    InvalidVersionNumber(u8),
+    InvalidVcid(u8),
+    InvalidMapId(u8),
+    ChecksumFailure(u16),
+}
+
+impl From<ByteConversionError> for UslpError {
+    fn from(value: ByteConversionError) -> Self {
+        Self::ByteConversion(value)
+    }
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct InvalidValueForLen {
+    value: u64,
+    len: u8,
+}
+
+#[derive(Debug, Copy, Clone, Eq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct PrimaryHeader {
+    pub spacecraft_id: u16,
+    pub source_or_dest_field: SourceOrDestField,
+    pub vc_id: u8,
+    pub map_id: u8,
+    frame_len_field: u16,
+    pub sequence_control_flag: BypassSequenceControlFlag,
+    pub protocol_control_command_flag: ProtocolControlCommandFlag,
+    pub ocf_flag: bool,
+    vc_frame_count_len: u8,
+    vc_frame_count: u64,
+}
+
+impl PrimaryHeader {
+    pub fn new(
+        spacecraft_id: u16,
+        source_or_dest_field: SourceOrDestField,
+        vc_id: u8,
+        map_id: u8,
+        frame_len: u16,
+    ) -> Result<Self, UslpError> {
+        if vc_id > 0b111111 {
+            return Err(UslpError::InvalidVcid(vc_id));
+        }
+        if map_id > 0b1111 {
+            return Err(UslpError::InvalidMapId(map_id));
+        }
+        Ok(Self {
+            spacecraft_id,
+            source_or_dest_field,
+            vc_id,
+            map_id,
+            frame_len_field: frame_len.saturating_sub(1),
+            sequence_control_flag: BypassSequenceControlFlag::SequenceControlledQoS,
+            protocol_control_command_flag: ProtocolControlCommandFlag::TfdfContainsUserData,
+            ocf_flag: false,
+            vc_frame_count_len: 0,
+            vc_frame_count: 0,
+        })
+    }
+
+    pub fn set_vc_frame_count(
+        &mut self,
+        count_len: u8,
+        count: u64,
+    ) -> Result<(), InvalidValueForLen> {
+        if count > 2_u64.pow(count_len as u32 * 8) - 1 {
+            return Err(InvalidValueForLen {
+                value: count,
+                len: count_len,
+            });
+        }
+        self.vc_frame_count_len = count_len;
+        self.vc_frame_count = count;
+        Ok(())
+    }
+
+    #[inline(always)]
+    pub fn vc_frame_count(&self) -> u64 {
+        self.vc_frame_count
+    }
+
+    #[inline(always)]
+    pub fn vc_frame_count_len(&self) -> u8 {
+        self.vc_frame_count_len
+    }
+
+    pub fn from_bytes(buf: &[u8]) -> Result<Self, UslpError> {
+        if buf.len() < 4 {
+            return Err(ByteConversionError::FromSliceTooSmall {
+                found: buf.len(),
+                expected: 4,
+            }
+            .into());
+        }
+        // Can only deal with regular frames for now.
+        if (buf[3] & 0b1) == 1 {
+            return Err(UslpError::HeaderIsTruncated);
+        }
+        // We could check this above, but this is a better error for the case where the user
+        // tries to read a truncated frame.
+        if buf.len() < 7 {
+            return Err(ByteConversionError::FromSliceTooSmall {
+                found: buf.len(),
+                expected: 7,
+            }
+            .into());
+        }
+        let version_number = (buf[0] >> 4) & 0b1111;
+        if version_number != USLP_VERSION_NUMBER {
+            return Err(UslpError::InvalidVersionNumber(version_number));
+        }
+        let source_or_dest_field = match (buf[2] >> 3) & 1 {
+            0 => SourceOrDestField::Source,
+            1 => SourceOrDestField::Dest,
+            _ => unreachable!(),
+        };
+        let vc_frame_count_len = buf[6] & 0b111;
+        if buf.len() < 7 + vc_frame_count_len as usize {
+            return Err(ByteConversionError::FromSliceTooSmall {
+                found: buf.len(),
+                expected: 7 + vc_frame_count_len as usize,
+            }
+            .into());
+        }
+        let vc_frame_count = match vc_frame_count_len {
+            1 => buf[7] as u64,
+            2 => u16::from_be_bytes(buf[7..9].try_into().unwrap()) as u64,
+            4 => u32::from_be_bytes(buf[7..11].try_into().unwrap()) as u64,
+            len => {
+                let mut vcf_count = 0u64;
+                let mut end = len;
+                for byte in buf[7..7 + len as usize].iter() {
+                    vcf_count |= (*byte as u64) << ((end - 1) * 8);
+                    end -= 1;
+                }
+                vcf_count
+            }
+        };
+        Ok(Self {
+            spacecraft_id: (((buf[0] as u16) & 0b1111) << 12)
+                | ((buf[1] as u16) << 4)
+                | ((buf[2] as u16) >> 4) & 0b1111,
+            source_or_dest_field,
+            vc_id: ((buf[2] & 0b111) << 3) | (buf[3] >> 5) & 0b111,
+            map_id: (buf[3] >> 1) & 0b1111,
+            frame_len_field: ((buf[4] as u16) << 8) | buf[5] as u16,
+            sequence_control_flag: ((buf[6] >> 7) & 0b1).try_into().unwrap(),
+            protocol_control_command_flag: ((buf[6] >> 6) & 0b1).try_into().unwrap(),
+            ocf_flag: ((buf[6] >> 3) & 0b1) != 0,
+            vc_frame_count_len,
+            vc_frame_count,
+        })
+    }
+
+    pub fn write_to_be_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
+        if buf.len() < self.len_header() {
+            return Err(ByteConversionError::ToSliceTooSmall {
+                found: buf.len(),
+                expected: self.len_header(),
+            });
+        }
+        buf[0] = (USLP_VERSION_NUMBER << 4) | ((self.spacecraft_id >> 12) as u8) & 0b1111;
+        buf[1] = (self.spacecraft_id >> 4) as u8;
+        buf[2] = (((self.spacecraft_id & 0b1111) as u8) << 4)
+            | ((self.source_or_dest_field as u8) << 3)
+            | (self.vc_id >> 3) & 0b111;
+        buf[3] = ((self.vc_id & 0b111) << 5) | (self.map_id << 1);
+        buf[4..6].copy_from_slice(&self.frame_len_field.to_be_bytes());
+        buf[6] = ((self.sequence_control_flag as u8) << 7)
+            | ((self.protocol_control_command_flag as u8) << 6)
+            | ((self.ocf_flag as u8) << 3)
+            | self.vc_frame_count_len;
+        let mut packet_idx = 7;
+        for idx in (0..self.vc_frame_count_len).rev() {
+            buf[packet_idx] = ((self.vc_frame_count >> (idx * 8)) & 0xff) as u8;
+            packet_idx += 1;
+        }
+        Ok(self.len_header())
+    }
+
+    #[inline(always)]
+    pub fn set_frame_len(&mut self, frame_len: usize) {
+        // 4.1.2.7.2
+        // The field contains a length count C that equals one fewer than the total octets
+        // in the transfer frame.
+        self.frame_len_field = frame_len.saturating_sub(1) as u16;
+    }
+
+    #[inline(always)]
+    pub fn len_header(&self) -> usize {
+        7 + self.vc_frame_count_len as usize
+    }
+
+    #[inline(always)]
+    pub fn len_frame(&self) -> usize {
+        // 4.1.2.7.2
+        // The field contains a length count C that equals one fewer than the total octets
+        // in the transfer frame.
+        self.frame_len_field as usize + 1
+    }
+}
+
+/// Custom implementation which skips the check whether the VC frame count length field is equal.
+/// Only the actual VC count value is compared.
+impl PartialEq for PrimaryHeader {
+    fn eq(&self, other: &Self) -> bool {
+        self.spacecraft_id == other.spacecraft_id
+            && self.source_or_dest_field == other.source_or_dest_field
+            && self.vc_id == other.vc_id
+            && self.map_id == other.map_id
+            && self.frame_len_field == other.frame_len_field
+            && self.sequence_control_flag == other.sequence_control_flag
+            && self.protocol_control_command_flag == other.protocol_control_command_flag
+            && self.ocf_flag == other.ocf_flag
+            && self.vc_frame_count == other.vc_frame_count
+    }
+}
+
+#[derive(
+    Debug, Copy, Clone, PartialEq, Eq, num_enum::TryFromPrimitive, num_enum::IntoPrimitive,
+)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[repr(u8)]
+#[non_exhaustive]
+pub enum UslpProtocolId {
+    SpacePacketsOrEncapsulation = 0b00000,
+    /// COP-1 control commands within the TFDZ.
+    Cop1ControlCommands = 0b00001,
+    /// COP-P control commands within the TFDZ.
+    CopPControlCommands = 0b00010,
+    /// SDLS control commands within the TFDZ.
+    Sdls = 0b00011,
+    UserDefinedOctetStream = 0b00100,
+    /// Proximity-1 Supervisory Protocol Data Units (SPDUs) within the TFDZ.
+    Spdu = 0b00111,
+    /// Entire fixed-length TFDZ contains idle data.
+    Idle = 0b11111,
+}
+
+#[derive(
+    Debug, Copy, Clone, PartialEq, Eq, num_enum::TryFromPrimitive, num_enum::IntoPrimitive,
+)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[repr(u8)]
+pub enum ConstructionRule {
+    /// Indicated fixed-length TFDZ whose contents are CCSDS packets concatenated together, which
+    /// span transfer frame boundaries. The First Header Pointer (FHP) is required for packet
+    /// extraction.
+    PacketSpanningMultipleFrames = 0b000,
+    StartOfMapaSduOrVcaSdu = 0b001,
+    ContinuingPortionOfMapaSdu = 0b010,
+    OctetStream = 0b011,
+    StartingSegment = 0b100,
+    ContinuingSegment = 0b101,
+    LastSegment = 0b110,
+    NoSegmentation = 0b111,
+}
+
+impl ConstructionRule {
+    pub const fn applicable_to_fixed_len_tfdz(&self) -> bool {
+        match self {
+            ConstructionRule::PacketSpanningMultipleFrames => true,
+            ConstructionRule::StartOfMapaSduOrVcaSdu => true,
+            ConstructionRule::ContinuingPortionOfMapaSdu => true,
+            ConstructionRule::OctetStream => false,
+            ConstructionRule::StartingSegment => false,
+            ConstructionRule::ContinuingSegment => false,
+            ConstructionRule::LastSegment => false,
+            ConstructionRule::NoSegmentation => false,
+        }
+    }
+}
+
+pub struct TransferFrameDataFieldHeader {
+    /// Construction rule for the TFDZ.
+    construction_rule: ConstructionRule,
+    uslp_protocol_id: UslpProtocolId,
+    /// First header or last valid octet pointer. Only present if the constuction rule indicated
+    /// a fixed-length TFDZ.
+    fhp_or_lvo: Option<u16>,
+}
+
+impl TransferFrameDataFieldHeader {
+    pub fn len_header(&self) -> usize {
+        if self.construction_rule.applicable_to_fixed_len_tfdz() {
+            3
+        } else {
+            1
+        }
+    }
+
+    pub fn construction_rule(&self) -> ConstructionRule {
+        self.construction_rule
+    }
+
+    pub fn uslp_protocol_id(&self) -> UslpProtocolId {
+        self.uslp_protocol_id
+    }
+
+    pub fn fhp_or_lvo(&self) -> Option<u16> {
+        self.fhp_or_lvo
+    }
+
+    pub fn from_bytes(buf: &[u8]) -> Result<Self, UslpError> {
+        if buf.is_empty() {
+            return Err(ByteConversionError::FromSliceTooSmall {
+                found: 0,
+                expected: 1,
+            }
+            .into());
+        }
+        let construction_rule = ConstructionRule::try_from((buf[0] >> 5) & 0b111)
+            .map_err(|e| UslpError::InvalidConstructionRule(e.number))?;
+        let mut fhp_or_lvo = None;
+        if construction_rule.applicable_to_fixed_len_tfdz() {
+            if buf.len() < 3 {
+                return Err(ByteConversionError::FromSliceTooSmall {
+                    found: buf.len(),
+                    expected: 3,
+                }
+                .into());
+            }
+            fhp_or_lvo = Some(u16::from_be_bytes(buf[1..3].try_into().unwrap()));
+        }
+        Ok(Self {
+            construction_rule,
+            uslp_protocol_id: UslpProtocolId::try_from(buf[0] & 0b11111)
+                .map_err(|e| UslpError::InvalidProtocolId(e.number))?,
+            fhp_or_lvo,
+        })
+    }
+}
+
+/// Simple USLP transfer frame reader.
+///
+/// Currently, only insert zone lengths of 0 are supported.
+pub struct TransferFrameReader<'buf> {
+    primary_header: PrimaryHeader,
+    data_field_header: TransferFrameDataFieldHeader,
+    data: &'buf [u8],
+    operational_control_field: Option<u32>,
+}
+
+impl<'buf> TransferFrameReader<'buf> {
+    /// This function assumes an insert zone length of 0.
+    pub fn from_bytes(
+        buf: &'buf [u8],
+        has_fecf: bool,
+    ) -> Result<TransferFrameReader<'buf>, UslpError> {
+        let primary_header = PrimaryHeader::from_bytes(buf)?;
+        if primary_header.len_frame() > buf.len() {
+            return Err(ByteConversionError::FromSliceTooSmall {
+                expected: primary_header.len_frame(),
+                found: buf.len(),
+            }
+            .into());
+        }
+        let data_field_header =
+            TransferFrameDataFieldHeader::from_bytes(&buf[primary_header.len_header()..])?;
+        let data_idx = primary_header.len_header() + data_field_header.len_header();
+        let frame_len = primary_header.len_frame();
+        let mut operational_control_field = None;
+        let mut data_len = frame_len - data_idx;
+        if has_fecf {
+            data_len -= 2;
+        }
+        if primary_header.ocf_flag {
+            data_len -= 4;
+            operational_control_field = Some(u32::from_be_bytes(
+                buf[data_idx + data_len..data_idx + data_len + 4]
+                    .try_into()
+                    .unwrap(),
+            ));
+        }
+        let data_end = data_idx + data_len;
+        let mut digest = CRC_CCITT_FALSE.digest();
+        digest.update(&buf[0..frame_len]);
+        if digest.finalize() != 0 {
+            return Err(UslpError::ChecksumFailure(u16::from_be_bytes(
+                buf[frame_len - 2..frame_len].try_into().unwrap(),
+            )));
+        }
+        Ok(Self {
+            primary_header,
+            data_field_header,
+            data: buf[data_idx..data_end].try_into().unwrap(),
+            operational_control_field,
+        })
+    }
+
+    pub fn len_frame(&self) -> usize {
+        self.primary_header.len_frame()
+    }
+
+    pub fn primary_header(&self) -> &PrimaryHeader {
+        &self.primary_header
+    }
+
+    pub fn data_field_header(&self) -> &TransferFrameDataFieldHeader {
+        &self.data_field_header
+    }
+
+    pub fn data(&self) -> &'buf [u8] {
+        self.data
+    }
+
+    pub fn operational_control_field(&self) -> &Option<u32> {
+        &self.operational_control_field
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::println;
+
+    use super::*;
+
+    fn common_basic_check(buf: &[u8]) {
+        assert_eq!(buf[0] >> 4, USLP_VERSION_NUMBER);
+        // First four bits SCID.
+        assert_eq!(buf[0] & 0b1111, 0b1010);
+        // Next eight bits SCID.
+        assert_eq!(buf[1], 0b01011100);
+        // Last four bits SCID.
+        assert_eq!(buf[2] >> 4, 0b0011);
+        assert_eq!((buf[2] >> 3) & 0b1, SourceOrDestField::Dest as u8);
+        // First three bits VCID.
+        assert_eq!(buf[2] & 0b111, 0b110);
+        // Last three bits VCID.
+        assert_eq!(buf[3] >> 5, 0b101);
+        // MAP ID
+        assert_eq!((buf[3] >> 1) & 0b1111, 0b1010);
+        // End of primary header flag
+        assert_eq!(buf[3] & 0b1, 0);
+        assert_eq!(u16::from_be_bytes(buf[4..6].try_into().unwrap()), 0x2345);
+    }
+    #[test]
+    fn test_basic_0() {
+        let mut buf: [u8; 8] = [0; 8];
+        // Should be all zeros after writing.
+        buf[6] = 0xff;
+        let primary_header = PrimaryHeader::new(
+            0b10100101_11000011,
+            SourceOrDestField::Dest,
+            0b110101,
+            0b1010,
+            0x2345,
+        )
+        .unwrap();
+        // Virtual channel count 0.
+        assert_eq!(primary_header.write_to_be_bytes(&mut buf).unwrap(), 7);
+        common_basic_check(&buf);
+        // Bypass / Sequence Control Flag.
+        assert_eq!(
+            (buf[6] >> 7) & 0b1,
+            BypassSequenceControlFlag::SequenceControlledQoS as u8
+        );
+        // Protocol Control Command Flag.
+        assert_eq!(
+            (buf[6] >> 6) & 0b1,
+            ProtocolControlCommandFlag::TfdfContainsUserData as u8
+        );
+        // OCF flag.
+        assert_eq!((buf[6] >> 3) & 0b1, false as u8);
+        // VCF count length.
+        assert_eq!(buf[6] & 0b111, 0);
+    }
+
+    #[test]
+    fn test_basic_1() {
+        let mut buf: [u8; 16] = [0; 16];
+        // Should be all zeros after writing.
+        buf[6] = 0xff;
+        let mut primary_header = PrimaryHeader::new(
+            0b10100101_11000011,
+            SourceOrDestField::Dest,
+            0b110101,
+            0b1010,
+            0x2345,
+        )
+        .unwrap();
+        primary_header.sequence_control_flag = BypassSequenceControlFlag::ExpeditedQoS;
+        primary_header.protocol_control_command_flag =
+            ProtocolControlCommandFlag::TfdfContainsProtocolInfo;
+        primary_header.ocf_flag = true;
+        primary_header.set_vc_frame_count(4, 0x12345678).unwrap();
+        // Virtual channel count 4.
+        assert_eq!(primary_header.write_to_be_bytes(&mut buf).unwrap(), 11);
+        common_basic_check(&buf);
+        // Bypass / Sequence Control Flag.
+        assert_eq!(
+            (buf[6] >> 7) & 0b1,
+            BypassSequenceControlFlag::ExpeditedQoS as u8
+        );
+        // Protocol Control Command Flag.
+        assert_eq!(
+            (buf[6] >> 6) & 0b1,
+            ProtocolControlCommandFlag::TfdfContainsProtocolInfo as u8
+        );
+        // OCF flag.
+        assert_eq!((buf[6] >> 3) & 0b1, true as u8);
+        // VCF count length.
+        assert_eq!(buf[6] & 0b111, 4);
+        assert_eq!(
+            u32::from_be_bytes(buf[7..11].try_into().unwrap()),
+            0x12345678
+        );
+    }
+
+    #[test]
+    fn test_reading_0() {
+        let mut buf: [u8; 8] = [0; 8];
+        let primary_header = PrimaryHeader::new(
+            0b10100101_11000011,
+            SourceOrDestField::Dest,
+            0b110101,
+            0b1010,
+            0x2345,
+        )
+        .unwrap();
+        assert_eq!(primary_header.write_to_be_bytes(&mut buf).unwrap(), 7);
+        let parsed_header = PrimaryHeader::from_bytes(&buf).unwrap();
+        assert_eq!(parsed_header, primary_header);
+    }
+
+    #[test]
+    fn test_reading_1() {
+        let mut buf: [u8; 16] = [0; 16];
+        let mut primary_header = PrimaryHeader::new(
+            0b10100101_11000011,
+            SourceOrDestField::Dest,
+            0b110101,
+            0b1010,
+            0x2345,
+        )
+        .unwrap();
+        primary_header.sequence_control_flag = BypassSequenceControlFlag::ExpeditedQoS;
+        primary_header.protocol_control_command_flag =
+            ProtocolControlCommandFlag::TfdfContainsProtocolInfo;
+        primary_header.ocf_flag = true;
+        primary_header.set_vc_frame_count(4, 0x12345678).unwrap();
+        assert_eq!(primary_header.write_to_be_bytes(&mut buf).unwrap(), 11);
+        let parsed_header = PrimaryHeader::from_bytes(&buf).unwrap();
+        assert_eq!(parsed_header, primary_header);
+    }
+
+    #[test]
+    fn test_invalid_vcid() {
+        let error = PrimaryHeader::new(
+            0b10100101_11000011,
+            SourceOrDestField::Dest,
+            0b1101011,
+            0b1010,
+            0x2345,
+        );
+        assert!(error.is_err());
+        let error = error.unwrap_err();
+        matches!(error, UslpError::InvalidVcid(0b1101011));
+    }
+
+    #[test]
+    fn test_invalid_mapid() {
+        let error = PrimaryHeader::new(
+            0b10100101_11000011,
+            SourceOrDestField::Dest,
+            0b110101,
+            0b10101,
+            0x2345,
+        );
+        assert!(error.is_err());
+        let error = error.unwrap_err();
+        matches!(error, UslpError::InvalidMapId(0b10101));
+    }
+
+    #[test]
+    fn test_invalid_vc_count() {
+        let mut primary_header = PrimaryHeader::new(
+            0b10100101_11000011,
+            SourceOrDestField::Dest,
+            0b110101,
+            0b1010,
+            0x2345,
+        )
+        .unwrap();
+        matches!(
+            primary_header.set_vc_frame_count(0, 1).unwrap_err(),
+            InvalidValueForLen { value: 1, len: 0 }
+        );
+        matches!(
+            primary_header.set_vc_frame_count(1, 256).unwrap_err(),
+            InvalidValueForLen { value: 256, len: 1 }
+        );
+    }
+
+    #[test]
+    fn test_frame_parser() {
+        let mut buf: [u8; 32] = [0; 32];
+        // Build a variable frame manually.
+        let mut primary_header =
+            PrimaryHeader::new(0x01, SourceOrDestField::Dest, 0b110101, 0b1010, 0).unwrap();
+        let header_len = primary_header.len_header();
+        buf[header_len] = ((ConstructionRule::NoSegmentation as u8) << 5)
+            | (UslpProtocolId::UserDefinedOctetStream as u8) & 0b11111;
+        buf[header_len + 1] = 0x42;
+        // 1 byte TFDH, 1 byte data, 2 bytes CRC.
+        primary_header.set_frame_len(header_len + 4);
+        primary_header.write_to_be_bytes(&mut buf).unwrap();
+        // Calculate and write CRC16.
+        let mut digest = CRC_CCITT_FALSE.digest();
+        digest.update(&buf[0..header_len + 2]);
+        buf[header_len + 2..header_len + 4].copy_from_slice(&digest.finalize().to_be_bytes());
+        println!("Buffer: {:x?}", buf);
+        // Now parse the frame.
+        let frame = TransferFrameReader::from_bytes(&buf, true).unwrap();
+        assert_eq!(frame.data().len(), 1);
+        assert_eq!(frame.data()[0], 0x42);
+        assert_eq!(
+            frame.data_field_header().uslp_protocol_id,
+            UslpProtocolId::UserDefinedOctetStream
+        );
+        assert_eq!(
+            frame.data_field_header().construction_rule,
+            ConstructionRule::NoSegmentation
+        );
+        assert!(frame.data_field_header().fhp_or_lvo().is_none());
+        assert_eq!(frame.len_frame(), 11);
+    }
+}

src/util.rs

@@ -15,10 +15,12 @@ pub trait ToBeBytes {
 impl ToBeBytes for () {
     type ByteArray = [u8; 0];
 
+    #[inline]
     fn written_len(&self) -> usize {
         0
     }
 
+    #[inline]
     fn to_be_bytes(&self) -> Self::ByteArray {
         []
     }
@@ -27,9 +29,12 @@ impl ToBeBytes for () {
 impl ToBeBytes for u8 {
     type ByteArray = [u8; 1];
 
+    #[inline]
     fn written_len(&self) -> usize {
         1
     }
+
+    #[inline]
     fn to_be_bytes(&self) -> Self::ByteArray {
         u8::to_be_bytes(*self)
     }
@@ -38,9 +43,12 @@ impl ToBeBytes for u8 {
 impl ToBeBytes for u16 {
     type ByteArray = [u8; 2];
 
+    #[inline]
     fn written_len(&self) -> usize {
         2
     }
+
+    #[inline]
     fn to_be_bytes(&self) -> Self::ByteArray {
         u16::to_be_bytes(*self)
     }
@@ -49,9 +57,12 @@ impl ToBeBytes for u16 {
 impl ToBeBytes for u32 {
     type ByteArray = [u8; 4];
 
+    #[inline]
     fn written_len(&self) -> usize {
         4
     }
+
+    #[inline]
     fn to_be_bytes(&self) -> Self::ByteArray {
         u32::to_be_bytes(*self)
     }
@@ -60,9 +71,12 @@ impl ToBeBytes for u32 {
 impl ToBeBytes for u64 {
     type ByteArray = [u8; 8];
 
+    #[inline]
     fn written_len(&self) -> usize {
         8
     }
+
+    #[inline]
     fn to_be_bytes(&self) -> Self::ByteArray {
         u64::to_be_bytes(*self)
     }
@@ -73,6 +87,15 @@ pub trait UnsignedEnum {
     fn size(&self) -> usize;
     /// Write the unsigned enumeration to a raw buffer. Returns the written size on success.
     fn write_to_be_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError>;
+
+    fn value(&self) -> u64;
+
+    #[cfg(feature = "alloc")]
+    fn to_vec(&self) -> alloc::vec::Vec<u8> {
+        let mut buf = alloc::vec![0; self.size()];
+        self.write_to_be_bytes(&mut buf).unwrap();
+        buf
+    }
 }
 
 pub trait UnsignedEnumExt: UnsignedEnum + Debug + Copy + Clone + PartialEq + Eq {}
@@ -95,6 +118,7 @@ pub enum UnsignedByteFieldError {
 }
 
 impl From<ByteConversionError> for UnsignedByteFieldError {
+    #[inline]
     fn from(value: ByteConversionError) -> Self {
         Self::ByteConversionError(value)
     }
@@ -122,20 +146,24 @@ impl Error for UnsignedByteFieldError {}
 /// Type erased variant.
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct UnsignedByteField {
     width: usize,
     value: u64,
 }
 
 impl UnsignedByteField {
+    #[inline]
     pub const fn new(width: usize, value: u64) -> Self {
         Self { width, value }
     }
 
-    pub fn value(&self) -> u64 {
+    #[inline]
+    pub const fn value_const(&self) -> u64 {
         self.value
     }
 
+    #[inline]
     pub fn new_from_be_bytes(width: usize, buf: &[u8]) -> Result<Self, UnsignedByteFieldError> {
         if width > buf.len() {
             return Err(ByteConversionError::FromSliceTooSmall {
@@ -168,10 +196,16 @@ impl UnsignedByteField {
 }
 
 impl UnsignedEnum for UnsignedByteField {
+    #[inline]
     fn size(&self) -> usize {
         self.width
     }
 
+    #[inline]
+    fn value(&self) -> u64 {
+        self.value_const()
+    }
+
     fn write_to_be_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
         if buf.len() < self.size() {
             return Err(ByteConversionError::ToSliceTooSmall {
@@ -207,21 +241,23 @@ impl UnsignedEnum for UnsignedByteField {
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub struct GenericUnsignedByteField<TYPE: Copy> {
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct GenericUnsignedByteField<TYPE: Copy + Into<u64>> {
     value: TYPE,
 }
 
-impl<TYPE: Copy> GenericUnsignedByteField<TYPE> {
+impl<TYPE: Copy + Into<u64>> GenericUnsignedByteField<TYPE> {
     pub const fn new(val: TYPE) -> Self {
         Self { value: val }
     }
 
-    pub const fn value(&self) -> TYPE {
+    pub const fn value_typed(&self) -> TYPE {
         self.value
     }
 }
 
-impl<TYPE: Copy + ToBeBytes> UnsignedEnum for GenericUnsignedByteField<TYPE> {
+impl<TYPE: Copy + ToBeBytes + Into<u64>> UnsignedEnum for GenericUnsignedByteField<TYPE> {
+    #[inline]
     fn size(&self) -> usize {
         self.value.written_len()
     }
@@ -233,9 +269,14 @@ impl<TYPE: Copy + ToBeBytes> UnsignedEnum for GenericUnsignedByteField<TYPE> {
                 expected: self.size(),
             });
         }
-        buf[0..self.size()].copy_from_slice(self.value.to_be_bytes().as_ref());
+        buf[..self.size()].copy_from_slice(self.value.to_be_bytes().as_ref());
         Ok(self.value.written_len())
     }
+
+    #[inline]
+    fn value(&self) -> u64 {
+        self.value_typed().into()
+    }
 }
 
 pub type UnsignedByteFieldEmpty = GenericUnsignedByteField<()>;
@@ -258,6 +299,7 @@ impl From<UnsignedByteFieldU8> for UnsignedByteField {
 impl TryFrom<UnsignedByteField> for UnsignedByteFieldU8 {
     type Error = UnsignedByteFieldError;
 
+    #[inline]
     fn try_from(value: UnsignedByteField) -> Result<Self, Self::Error> {
         if value.width != 1 {
             return Err(UnsignedByteFieldError::InvalidWidth {
@@ -270,6 +312,7 @@ impl TryFrom<UnsignedByteField> for UnsignedByteFieldU8 {
 }
 
 impl From<UnsignedByteFieldU16> for UnsignedByteField {
+    #[inline]
     fn from(value: UnsignedByteFieldU16) -> Self {
         Self::new(2, value.value as u64)
     }
@@ -278,6 +321,7 @@ impl From<UnsignedByteFieldU16> for UnsignedByteField {
 impl TryFrom<UnsignedByteField> for UnsignedByteFieldU16 {
     type Error = UnsignedByteFieldError;
 
+    #[inline]
     fn try_from(value: UnsignedByteField) -> Result<Self, Self::Error> {
         if value.width != 2 {
             return Err(UnsignedByteFieldError::InvalidWidth {
@@ -290,6 +334,7 @@ impl TryFrom<UnsignedByteField> for UnsignedByteFieldU16 {
 }
 
 impl From<UnsignedByteFieldU32> for UnsignedByteField {
+    #[inline]
     fn from(value: UnsignedByteFieldU32) -> Self {
         Self::new(4, value.value as u64)
     }
@@ -298,6 +343,7 @@ impl From<UnsignedByteFieldU32> for UnsignedByteField {
 impl TryFrom<UnsignedByteField> for UnsignedByteFieldU32 {
     type Error = UnsignedByteFieldError;
 
+    #[inline]
     fn try_from(value: UnsignedByteField) -> Result<Self, Self::Error> {
         if value.width != 4 {
             return Err(UnsignedByteFieldError::InvalidWidth {
@@ -310,6 +356,7 @@ impl TryFrom<UnsignedByteField> for UnsignedByteFieldU32 {
 }
 
 impl From<UnsignedByteFieldU64> for UnsignedByteField {
+    #[inline]
     fn from(value: UnsignedByteFieldU64) -> Self {
         Self::new(8, value.value)
     }
@@ -318,6 +365,7 @@ impl From<UnsignedByteFieldU64> for UnsignedByteField {
 impl TryFrom<UnsignedByteField> for UnsignedByteFieldU64 {
     type Error = UnsignedByteFieldError;
 
+    #[inline]
     fn try_from(value: UnsignedByteField) -> Result<Self, Self::Error> {
         if value.width != 8 {
             return Err(UnsignedByteFieldError::InvalidWidth {
@@ -351,6 +399,8 @@ pub mod tests {
         for val in buf.iter().skip(1) {
             assert_eq!(*val, 0);
         }
+        assert_eq!(u8.value_typed(), 5);
+        assert_eq!(u8.value(), 5);
     }
 
     #[test]
@@ -367,6 +417,8 @@ pub mod tests {
         for val in buf.iter().skip(2) {
             assert_eq!(*val, 0);
         }
+        assert_eq!(u16.value_typed(), 3823);
+        assert_eq!(u16.value(), 3823);
     }
 
     #[test]
@@ -383,6 +435,8 @@ pub mod tests {
         (4..8).for_each(|i| {
             assert_eq!(buf[i], 0);
         });
+        assert_eq!(u32.value_typed(), 80932);
+        assert_eq!(u32.value(), 80932);
     }
 
     #[test]
@@ -396,6 +450,8 @@ pub mod tests {
         assert_eq!(len, 8);
         let raw_val = u64::from_be_bytes(buf[0..8].try_into().unwrap());
         assert_eq!(raw_val, 5999999);
+        assert_eq!(u64.value_typed(), 5999999);
+        assert_eq!(u64.value(), 5999999);
     }
 
     #[test]
@@ -534,9 +590,9 @@ pub mod tests {
         u8.write_to_be_bytes(&mut buf)
             .expect("writing to raw buffer failed");
         assert_eq!(buf[0], 5);
-        for i in 1..8 {
+        (1..8).for_each(|i| {
             assert_eq!(buf[i], 0);
-        }
+        });
     }
 
     #[test]
@@ -562,9 +618,9 @@ pub mod tests {
             .expect("writing to raw buffer failed");
         let raw_val = u32::from_be_bytes(buf[0..4].try_into().unwrap());
         assert_eq!(raw_val, 80932);
-        for i in 4..8 {
+        (4..8).for_each(|i| {
             assert_eq!(buf[i], 0);
-        }
+        });
     }
 
     #[test]