Merge pull request 'small changelog tweak' (#128) from small-changelog-tweak into main

Reviewed-on: #128

.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/checkout@v4
-      - uses: actions-rs/toolchain@v1
+      - uses: dtolnay/rust-toolchain@stable
-        with:
+      - run: cargo check --release
-          profile: minimal
-          toolchain: stable
-      - uses: actions-rs/cargo@v1
-        with:
-          command: check
-          args: --release
 
-  msrv:
+  test:
-    name: Check with MSRV
+    name: Run Tests
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
-      - uses: actions-rs/toolchain@v1
+      - uses: dtolnay/rust-toolchain@stable
-        with:
+      - name: Install nextest
-          toolchain: 1.61.0
+        uses: taiki-e/install-action@nextest
-          override: true
+      - run: cargo nextest run --all-features
-          profile: minimal
+      - run: cargo test --doc
-      - uses: actions-rs/cargo@v1
+
-        with:
+  msrv:
-          command: check
+    name: Check MSRV
-          args: --release
+    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/checkout@v4
-      - uses: actions-rs/toolchain@v1
+      - uses: dtolnay/rust-toolchain@stable
         with:
-          profile: minimal
+          targets: "armv7-unknown-linux-gnueabihf, thumbv7em-none-eabihf"
-          toolchain: stable
+      - run: cargo check --release --target=${{matrix.target}} --no-default-features
-          target: ${{ matrix.target }}
-          override: true
-      - uses: actions-rs/cargo@v1
-        with:
-          use-cross: true
-          command: check
-          args: --release --target=${{ matrix.target }} --no-default-features
 
   fmt:
-    name: Rustfmt
+    name: Check formatting
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
-      - uses: actions-rs/toolchain@v1
+      - uses: dtolnay/rust-toolchain@stable
-        with:
+      - run: cargo fmt --all -- --check
-          profile: minimal
-          toolchain: stable
-          override: true
-      - run: rustup component add rustfmt
-      - uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: --all -- --check
 
-  check-doc:
+  docs:
     name: Check Documentation Build
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
-      - uses: actions-rs/toolchain@v1
+      - uses: dtolnay/rust-toolchain@nightly
-        with:
+      - run: RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc --all-features
-          toolchain: nightly
-          override: true
-          profile: minimal
-      - uses: actions-rs/cargo@v1
-        with:
-          command: doc
-          args: --all-features
 
   clippy:
     name: Clippy
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
-      - uses: actions-rs/toolchain@v1
+      - uses: dtolnay/rust-toolchain@stable
-        with:
+      - run: cargo clippy -- -D warnings
-          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

CHANGELOG.md

@@ -8,6 +8,189 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 # [unreleased]
 
+# [v0.14.0] 2025-05-10
+
+## Changed
+
+- Moved CRC constants/implementations to dedicated `crc` module.
+- `crc::CRC_CCITT_FALSE_NO_TABLE` and `crc::CRC_CCITT_FALSE_BIG_TABLE` variants.
+- Renamed `PusPacket::crc16` to `PusPacket::opt_crc16`.
+
+## Added
+
+- `WritablePusPacket::write_to_bytes_crc_no_table` and `WritablePusPacket::write_to_bytes_no_crc`
+  variants.
+- `PusTmReader::new_crc_no_table` and `PusTcReader::new_crc_no_table` variants.
+- `crc16` methods for PUS TM and PUS TC reader.
+- PUS TM and PUS TC reader now return the reader instance directly instead of a tuple of the reader
+  and the read size. The instance `total_len` method can be used to retrieve the read lenght.
+
+# [v0.13.1] 2025-03-21
+
+- Bugfix due to operator precendence for `PusTcSecondaryHeader::pus_version`, 
+  `PusTcSecondaryHeaderWithoutTimestamp::pus_version`, `CdsTime::from_bytes_with_u16_days` and
+  `CdsTime::from_bytes_with_u24_days`
+
+# [v0.13.0] 2024-11-08
+
+- Bumped MSRV to 1.81.0
+- Bump `zerocopy` to v0.8.0
+- Bump `thiserror` to v2.0.0
+
+## Changed
+
+- Migrated all Error implementations to thiserror, improved some naming and error handling in
+  general
+
+# [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
@@ -401,3 +584,9 @@ The timestamp of `PusTm` is now optional. See Added and Changed section for deta
 
 Initial release with CCSDS Space Packet Primary Header implementation and basic PUS TC and TM
 implementations.
+
+[unreleased]: https://egit.irs.uni-stuttgart.de/rust/spacepackets/compare/v0.14.0...HEAD
+[v0.14.0]: https://egit.irs.uni-stuttgart.de/rust/spacepackets/compare/v0.13.1...v0.14.0
+[v0.13.1]: https://egit.irs.uni-stuttgart.de/rust/spacepackets/compare/v0.13.0...v0.13.1
+[v0.13.0]: https://egit.irs.uni-stuttgart.de/rust/spacepackets/compare/v0.12.0...v0.13.0
+[v0.12.0]: https://egit.irs.uni-stuttgart.de/rust/spacepackets/compare/v0.11.2...v0.12.0

Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "spacepackets"
-version = "0.10.0"
+version = "0.14.0"
 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"
@@ -13,44 +13,30 @@ categories = ["aerospace", "aerospace::space-protocols", "no-std", "hardware-sup
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-crc = "3"
+crc = "3.3"
-delegate = ">=0.8, <0.11"
+delegate = ">=0.8, <=0.13"
+paste = "1"
+zerocopy = { version = "0.8", features = ["derive"] }
+thiserror = { version = "2", default-features = false }
+num_enum = { version = ">0.5, <=0.7", default-features = false }
+num-traits = { version = "0.2", default-features = false }
+serde = { version = "1", optional = true, default-features = false, features = ["derive"] }
 
-[dependencies.zerocopy]
+time = { version = "0.3", default-features = false, optional = true }
-version = "0.7"
+chrono = { version = "0.4", default-features = false, optional = true }
-features = ["derive"]
+defmt = { version = "1", default-features = false, optional = true }
-
-[dependencies.thiserror]
-version = "1"
-optional = true
-
-[dependencies.num_enum]
-version = ">0.5, <=0.7"
-default-features = false
-
-[dependencies.serde]
-version = "1"
-optional = true
-default-features = false
-features = ["derive"]
-
-[dependencies.chrono]
-version = "0.4"
-default-features = false
-
-[dependencies.num-traits]
-version = "0.2"
-default-features = false
-
-[dev-dependencies.postcard]
-version = "1"
 
 [features]
 default = ["std"]
-std = ["chrono/std", "chrono/clock", "alloc", "thiserror"]
+std = ["alloc", "chrono/std", "chrono/clock", "thiserror/std"]
-serde = ["dep:serde", "chrono/serde"]
+serde = ["dep:serde", "chrono?/serde"]
-alloc = ["postcard/alloc", "chrono/alloc"]
+alloc = ["chrono?/alloc", "defmt?/alloc", "serde?/alloc"]
+timelib = ["dep:time"]
+
+[dev-dependencies]
+postcard = { version = "1", features = ["alloc"] }
+chrono = "0.4"
 
 [package.metadata.docs.rs]
 all-features = true
-rustdoc-args = ["--cfg", "doc_cfg", "--generate-link-to-definition"]
+rustdoc-args = ["--generate-link-to-definition"]

FUNDING.yml

@@ -0,0 +1 @@
+github: robamu

README.md

@@ -1,7 +1,6 @@
 [![Crates.io](https://img.shields.io/crates/v/spacepackets)](https://crates.io/crates/spacepackets)
 [![docs.rs](https://img.shields.io/docsrs/spacepackets)](https://docs.rs/spacepackets)
 [![ci](https://github.com/us-irs/spacepackets-rs/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/us-irs/spacepackets-rs/actions/workflows/ci.yml)
-[![coverage](https://shields.io/endpoint?url=https://absatsw.irs.uni-stuttgart.de/projects/spacepackets/coverage-rs/latest/coverage.json)](https://absatsw.irs.uni-stuttgart.de/projects/spacepackets/coverage-rs/latest/index.html)
 
 ECSS and CCSDS Spacepackets
 ======
@@ -29,10 +28,6 @@ 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 +38,10 @@ 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 +60,13 @@ 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') {

docs.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+export RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options"
+cargo +nightly doc --all-features --open

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::TlvLvDataTooLargeError;
+
 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, TlvLvDataTooLargeError> {
         if data.len() > u8::MAX as usize {
-            return Err(TlvLvError::DataTooLarge(data.len()));
+            return Err(TlvLvDataTooLargeError(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, TlvLvDataTooLargeError> {
         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")))]
+    #[inline]
-    pub fn new_from_string(string: &'data String) -> Result<Lv<'data>, TlvLvError> {
+    pub fn new_from_string(string: &'data String) -> Result<Lv<'data>, TlvLvDataTooLargeError> {
         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!(error.0, u8::MAX as usize + 1);
-            assert_eq!(size, u8::MAX as usize + 1);
+        assert_eq!(
-            assert_eq!(
+            error.to_string(),
-                error.to_string(),
+            "data with size 256 larger than allowed 255 bytes"
-                "data with size 256 larger than allowed 255 bytes"
+        );
-            );
-        } else {
-            panic!("invalid exception {:?}", error)
-        }
     }
 
     #[test]

src/cfdp/mod.rs

@@ -1,11 +1,8 @@
 //! Low-level CCSDS File Delivery Protocol (CFDP) support according to [CCSDS 727.0-B-5](https://public.ccsds.org/Pubs/727x0b5.pdf).
 use crate::ByteConversionError;
-use core::fmt::{Display, Formatter};
 use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
-#[cfg(feature = "std")]
-use std::error::Error;
 
 pub mod lv;
 pub mod pdu;
@@ -18,6 +15,7 @@ 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 +24,7 @@ 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 +33,7 @@ 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 +42,7 @@ 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 +70,7 @@ 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 +80,7 @@ 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 +89,7 @@ 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 +100,7 @@ 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 +113,7 @@ 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 +123,7 @@ 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 +135,7 @@ 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 +153,7 @@ 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
@@ -165,75 +173,43 @@ impl Default for ChecksumType {
 
 pub const NULL_CHECKSUM_U32: [u8; 4] = [0; 4];
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, thiserror::Error)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[error("data with size {0} larger than allowed {max} bytes", max = u8::MAX)]
+pub struct TlvLvDataTooLargeError(pub usize);
+
+/// First value: Found value. Second value: Expected value if there is one.
+#[derive(Debug, Copy, Clone, PartialEq, Eq, thiserror::Error)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[error("invalid TLV type field, found {found}, expected {expected:?}")]
+pub struct InvalidTlvTypeFieldError {
+    found: u8,
+    expected: Option<u8>,
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq, thiserror::Error)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum TlvLvError {
-    DataTooLarge(usize),
+    #[error("{0}")]
-    ByteConversion(ByteConversionError),
+    DataTooLarge(#[from] TlvLvDataTooLargeError),
-    /// First value: Found value. Second value: Expected value if there is one.
+    #[error("byte conversion error: {0}")]
-    InvalidTlvTypeField {
+    ByteConversion(#[from] ByteConversionError),
-        found: u8,
+    #[error("{0}")]
-        expected: Option<u8>,
+    InvalidTlvTypeField(#[from] InvalidTlvTypeFieldError),
-    },
+    #[error("invalid value length {0}")]
-    /// Logically invalid value length detected. The value length may not exceed 255 bytes.
-    /// Depending on the concrete TLV type, the value length may also be logically invalid.
     InvalidValueLength(usize),
     /// Only applies to filestore requests and responses. Second name was missing where one is
     /// expected.
+    #[error("second name missing for filestore request or response")]
     SecondNameMissing,
     /// Invalid action code for filestore requests or responses.
+    #[error("invalid action code {0}")]
     InvalidFilestoreActionCode(u8),
 }
 
-impl From<ByteConversionError> for TlvLvError {
-    fn from(value: ByteConversionError) -> Self {
-        Self::ByteConversion(value)
-    }
-}
-
-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::ByteConversion(e) => {
-                write!(f, "tlv or lv byte conversion: {}", e)
-            }
-            TlvLvError::InvalidTlvTypeField { found, expected } => {
-                write!(
-                    f,
-                    "invalid TLV type field, found {found}, expected {expected:?}"
-                )
-            }
-            TlvLvError::InvalidValueLength(len) => {
-                write!(f, "invalid value length {len}")
-            }
-            TlvLvError::SecondNameMissing => {
-                write!(f, "second name missing for filestore request or response")
-            }
-            TlvLvError::InvalidFilestoreActionCode(raw) => {
-                write!(f, "invalid filestore action code with raw value {raw}")
-            }
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl Error for TlvLvError {
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        match self {
-            TlvLvError::ByteConversion(e) => Some(e),
-            _ => None,
-        }
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;

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]
@@ -270,7 +297,7 @@ mod tests {
         buf[written - 1] -= 1;
         let crc: u16 = ((buf[written - 2] as u16) << 8) as u16 | buf[written - 1] as u16;
         let error = EofPdu::from_bytes(&buf).unwrap_err();
-        if let PduError::ChecksumError(e) = error {
+        if let PduError::Checksum(e) = error {
             assert_eq!(e, crc);
         } else {
             panic!("expected crc error");
@@ -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>>,
+    common: FdPduBase<'seg_meta>,
-    offset: u64,
     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,
+            common: FdPduBase {
-            segment_metadata,
+                pdu_header,
-            offset,
+                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>();
+        self.common
-        if self.pdu_header.pdu_conf.file_flag == LargeFileFlag::Large {
+            .calc_pdu_datafield_len(self.file_data.len() as u64)
-            len += 4;
+    }
-        }
+
-        if self.segment_metadata.is_some() {
+    pub fn segment_metadata(&self) -> Option<&SegmentMetadata> {
-            len += self.segment_metadata.as_ref().unwrap().written_len()
+        self.common.segment_metadata.as_ref()
-        }
-        len += self.file_data.len();
-        if self.crc_flag() == CrcFlag::WithCrc {
-            len += 2;
-        }
-        len
     }
 
     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,
+            common: FdPduBase {
-            segment_metadata,
+                pdu_header,
-            offset,
+                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() {
+        let mut current_idx = self.common.write_common_fields_to_bytes(buf)?;
-            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..],
-        )?;
         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 [FileDataPduCreatorWithReservedDatafield::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(),
         );
@@ -353,7 +544,7 @@ mod tests {
         buf[written - 1] -= 1;
         let crc: u16 = ((buf[written - 2] as u16) << 8) | buf[written - 1] as u16;
         let error = FileDataPdu::from_bytes(&buf).unwrap_err();
-        if let PduError::ChecksumError(e) = error {
+        if let PduError::Checksum(e) = error {
             assert_eq!(e, crc);
         } else {
             panic!("expected crc error");
@@ -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::Checksum(_) => (),
+            _ => {
+                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

@@ -4,16 +4,18 @@ use crate::cfdp::pdu::{
 use crate::cfdp::tlv::{
     EntityIdTlv, FilestoreResponseTlv, GenericTlv, Tlv, TlvType, TlvTypeField, WritableTlv,
 };
-use crate::cfdp::{ConditionCode, CrcFlag, Direction, PduType, TlvLvError};
+use crate::cfdp::{ConditionCode, CrcFlag, Direction, PduType};
 use crate::ByteConversionError;
 use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
-use super::{CfdpPdu, WritablePduPacket};
+use super::tlv::ReadableTlv;
+use super::{CfdpPdu, InvalidTlvTypeFieldError, 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,
@@ -327,22 +332,26 @@ impl<'buf> FinishedPduReader<'buf> {
                         // last TLV, everything else would break the whole handling of the packet
                         // TLVs.
                         if current_idx != full_len_without_crc {
-                            return Err(PduError::FormatError);
+                            return Err(PduError::Format);
                         }
                     } else {
-                        return Err(TlvLvError::InvalidTlvTypeField {
+                        return Err(PduError::TlvLv(
-                            found: tlv_type.into(),
+                            InvalidTlvTypeFieldError {
-                            expected: Some(TlvType::FilestoreResponse.into()),
+                                found: tlv_type.into(),
-                        }
+                                expected: Some(TlvType::FilestoreResponse.into()),
-                        .into());
+                            }
+                            .into(),
+                        ));
                     }
                 }
                 TlvTypeField::Custom(raw) => {
-                    return Err(TlvLvError::InvalidTlvTypeField {
+                    return Err(PduError::TlvLv(
-                        found: raw,
+                        InvalidTlvTypeFieldError {
-                        expected: None,
+                            found: raw,
-                    }
+                            expected: None,
-                    .into());
+                        }
+                        .into(),
+                    ));
                 }
             }
         }
@@ -559,7 +568,7 @@ mod tests {
         buf[written - 1] -= 1;
         let crc: u16 = ((buf[written - 2] as u16) << 8) as u16 | buf[written - 1] as u16;
         let error = FinishedPduReader::new(&buf).unwrap_err();
-        if let PduError::ChecksumError(e) = error {
+        if let PduError::Checksum(e) = error {
             assert_eq!(e, crc);
         } else {
             panic!("expected crc error");

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 += self.options().len();
-            len += tlv.len_full()
-        }
         if self.crc_flag() == CrcFlag::WithCrc {
             len += 2;
         }
@@ -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() {
+        buf[current_idx..current_idx + self.options.len()].copy_from_slice(self.options);
-            opt.write_to_bytes(&mut buf[current_idx..current_idx + opt.len_full()])?;
+        current_idx += self.options.len();
-            current_idx += opt.len_full();
-        }
         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,
@@ -362,16 +381,16 @@ 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(closure_requested, checksum_type, 0x1010);
@@ -541,9 +560,9 @@ 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();
+        let opts = written.options_iter();
-        for (tlv_written, tlv_read) in opts.iter().zip(read.options_iter().unwrap()) {
+        for (tlv_written, tlv_read) in opts.zip(read.options_iter().unwrap()) {
-            assert_eq!(tlv_written, &tlv_read);
+            assert_eq!(&tlv_written, &tlv_read);
         }
     }
 
@@ -658,14 +677,14 @@ 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 mut tlv_buf: [u8; 64] = [0; 64];
-        let opts_len = tlv1.len_full() + tlv2.len_full();
+        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_vec,
+            &tlv_buf[0..opts_len],
         );
         let mut buf: [u8; 128] = [0; 128];
         let write_res = metadata_pdu.write_to_bytes(&mut buf);
@@ -688,7 +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);
+        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());
@@ -713,7 +780,7 @@ pub mod tests {
             assert_eq!(expected, Some(FileDirectiveType::MetadataPdu));
             assert_eq!(
                 error.to_string(),
-                "invalid directive type value 255, expected Some(MetadataPdu)"
+                "invalid directive type, found 255, expected Some(MetadataPdu)"
             );
         } else {
             panic!("Expected InvalidDirectiveType error, got {:?}", error);
@@ -739,7 +806,7 @@ pub mod tests {
             assert_eq!(expected, FileDirectiveType::MetadataPdu);
             assert_eq!(
                 error.to_string(),
-                "found directive type EofPdu, expected MetadataPdu"
+                "wrong directive type, found EofPdu, expected MetadataPdu"
             );
         } else {
             panic!("Expected InvalidDirectiveType error, got {:?}", error);

src/cfdp/pdu/mod.rs

@@ -1,13 +1,10 @@
 //! CFDP Packet Data Unit (PDU) support.
 use crate::cfdp::*;
+use crate::crc::CRC_CCITT_FALSE;
 use crate::util::{UnsignedByteField, UnsignedByteFieldU8, UnsignedEnum};
 use crate::ByteConversionError;
-use crate::CRC_CCITT_FALSE;
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
-use core::fmt::{Display, Formatter};
-#[cfg(feature = "std")]
-use std::error::Error;
 
 pub mod ack;
 pub mod eof;
@@ -18,6 +15,7 @@ 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,
@@ -29,135 +27,62 @@ pub enum FileDirectiveType {
     KeepAlivePdu = 0x0c,
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, thiserror::Error)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum PduError {
-    ByteConversion(ByteConversionError),
+    #[error("byte conversion error: {0}")]
-    /// Found version ID invalid, not equal to [CFDP_VERSION_2].
+    ByteConversion(#[from] ByteConversionError),
+    /// Found version ID invalid, not equal to [super::CFDP_VERSION_2].
+    #[error("CFDP version missmatch, found {0}, expected {ver}", ver = super::CFDP_VERSION_2)]
     CfdpVersionMissmatch(u8),
     /// Invalid length for the entity ID detected. Only the values 1, 2, 4 and 8 are supported.
+    #[error("invalid PDU entity ID length {0}, only [1, 2, 4, 8] are allowed")]
     InvalidEntityLen(u8),
     /// Invalid length for the entity ID detected. Only the values 1, 2, 4 and 8 are supported.
+    #[error("invalid transaction ID length {0}")]
     InvalidTransactionSeqNumLen(u8),
+    #[error(
+        "missmatch of PDU source ID length {src_id_len} and destination ID length {dest_id_len}"
+    )]
     SourceDestIdLenMissmatch {
         src_id_len: usize,
         dest_id_len: usize,
     },
     /// Wrong directive type, for example when parsing the directive field for a file directive
     /// PDU.
+    #[error("wrong directive type, found {found:?}, expected {expected:?}")]
     WrongDirectiveType {
         found: FileDirectiveType,
         expected: FileDirectiveType,
     },
     /// The directive type field contained a value not in the range of permitted values. This can
     /// also happen if an invalid value is passed to the ACK PDU constructor.
+    #[error("invalid directive type, found {found:?}, expected {expected:?}")]
     InvalidDirectiveType {
         found: u8,
         expected: Option<FileDirectiveType>,
     },
+    #[error("invalid start or end of scope value for NAK PDU")]
     InvalidStartOrEndOfScopeValue,
     /// Invalid condition code. Contains the raw detected value.
+    #[error("invalid condition code {0}")]
     InvalidConditionCode(u8),
     /// Invalid checksum type which is not part of the checksums listed in the
     /// [SANA Checksum Types registry](https://sanaregistry.org/r/checksum_identifiers/).
+    #[error("invalid checksum type {0}")]
     InvalidChecksumType(u8),
+    #[error("file size {0} too large")]
     FileSizeTooLarge(u64),
     /// If the CRC flag for a PDU is enabled and the checksum check fails. Contains raw 16-bit CRC.
-    ChecksumError(u16),
+    #[error("checksum error for checksum {0}")]
+    Checksum(u16),
     /// Generic error for invalid PDU formats.
-    FormatError,
+    #[error("generic PDU format error")]
+    Format,
     /// Error handling a TLV field.
-    TlvLvError(TlvLvError),
+    #[error("PDU error: {0}")]
-}
+    TlvLv(#[from] TlvLvError),
-
-impl Display for PduError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
-        match self {
-            PduError::InvalidEntityLen(raw_id) => {
-                write!(
-                    f,
-                    "invalid PDU entity ID length {raw_id}, only [1, 2, 4, 8] are allowed"
-                )
-            }
-            PduError::InvalidStartOrEndOfScopeValue => {
-                write!(f, "invalid start or end of scope for NAK PDU")
-            }
-            PduError::InvalidTransactionSeqNumLen(raw_id) => {
-                write!(
-                    f,
-                    "invalid PDUtransaction seq num length {raw_id}, only [1, 2, 4, 8] are allowed"
-                )
-            }
-            PduError::CfdpVersionMissmatch(raw) => {
-                write!(
-                    f,
-                    "cfdp version missmatch, found {raw}, expected {CFDP_VERSION_2}"
-                )
-            }
-            PduError::SourceDestIdLenMissmatch {
-                src_id_len,
-                dest_id_len,
-            } => {
-                write!(
-                    f,
-                    "missmatch of PDU source length {src_id_len} and destination length {dest_id_len}"
-                )
-            }
-            PduError::ByteConversion(e) => {
-                write!(f, "{}", e)
-            }
-            PduError::FileSizeTooLarge(value) => {
-                write!(f, "file size value {value} exceeds allowed 32 bit width")
-            }
-            PduError::WrongDirectiveType { found, expected } => {
-                write!(f, "found directive type {found:?}, expected {expected:?}")
-            }
-            PduError::InvalidConditionCode(raw_code) => {
-                write!(f, "found invalid condition code with raw value {raw_code}")
-            }
-            PduError::InvalidDirectiveType { found, expected } => {
-                write!(
-                    f,
-                    "invalid directive type value {found}, expected {expected:?}"
-                )
-            }
-            PduError::InvalidChecksumType(checksum_type) => {
-                write!(f, "invalid checksum type {checksum_type}")
-            }
-            PduError::ChecksumError(checksum) => {
-                write!(f, "checksum error for CRC {checksum:#04x}")
-            }
-            PduError::TlvLvError(error) => {
-                write!(f, "pdu tlv error: {error}")
-            }
-            PduError::FormatError => {
-                write!(f, "generic PDU format error")
-            }
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl Error for PduError {
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        match self {
-            PduError::ByteConversion(e) => Some(e),
-            PduError::TlvLvError(e) => Some(e),
-            _ => None,
-        }
-    }
-}
-
-impl From<ByteConversionError> for PduError {
-    fn from(value: ByteConversionError) -> Self {
-        Self::ByteConversion(value)
-    }
-}
-
-impl From<TlvLvError> for PduError {
-    fn from(e: TlvLvError) -> Self {
-        Self::TlvLvError(e)
-    }
 }
 
 pub trait WritablePduPacket {
@@ -178,33 +103,42 @@ 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 +154,7 @@ 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 +167,7 @@ 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 +199,7 @@ impl CommonPduConfig {
         })
     }
 
+    #[inline]
     pub fn new_with_byte_fields(
         source_id: impl Into<UnsignedByteField>,
         dest_id: impl Into<UnsignedByteField>,
@@ -279,10 +216,12 @@ 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 +244,7 @@ impl CommonPduConfig {
         Ok((source_id, dest_id))
     }
 
+    #[inline]
     pub fn set_source_and_dest_id(
         &mut self,
         source_id: impl Into<UnsignedByteField>,
@@ -316,6 +256,7 @@ impl CommonPduConfig {
         Ok(())
     }
 
+    #[inline]
     pub fn dest_id(&self) -> UnsignedByteField {
         self.dest_entity_id
     }
@@ -324,6 +265,7 @@ 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 +282,7 @@ 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 +301,7 @@ 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 +311,7 @@ pub struct PduHeader {
 }
 
 impl PduHeader {
+    #[inline]
     pub fn new_for_file_data(
         pdu_conf: CommonPduConfig,
         pdu_datafield_len: u16,
@@ -382,6 +327,7 @@ 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 +337,7 @@ 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 +348,7 @@ impl PduHeader {
         )
     }
 
+    #[inline]
     pub fn new_generic(
         pdu_type: PduType,
         pdu_conf: CommonPduConfig,
@@ -418,6 +366,7 @@ 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 +374,14 @@ 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
     }
@@ -503,7 +454,7 @@ impl PduHeader {
             let mut digest = CRC_CCITT_FALSE.digest();
             digest.update(&buf[..self.pdu_len()]);
             if digest.finalize() != 0 {
-                return Err(PduError::ChecksumError(u16::from_be_bytes(
+                return Err(PduError::Checksum(u16::from_be_bytes(
                     buf[self.pdu_len() - 2..self.pdu_len()].try_into().unwrap(),
                 )));
             }
@@ -603,10 +554,13 @@ 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 +568,8 @@ impl PduHeader {
     pub fn seg_metadata_flag(&self) -> SegmentMetadataFlag {
         self.seg_metadata_flag
     }
+
+    #[inline]
     pub fn seg_ctrl(&self) -> SegmentationControl {
         self.seg_ctrl
     }
@@ -947,7 +903,7 @@ mod tests {
             assert_eq!(raw_version, CFDP_VERSION_2 + 1);
             assert_eq!(
                 error.to_string(),
-                "cfdp version missmatch, found 2, expected 1"
+                "CFDP version missmatch, found 2, expected 1"
             );
         } else {
             panic!("invalid exception: {}", error);
@@ -995,7 +951,7 @@ mod tests {
             assert_eq!(expected, 7);
             assert_eq!(
                 error.to_string(),
-                "source slice with size 6 too small, expected at least 7 bytes"
+                "byte conversion error: source slice with size 6 too small, expected at least 7 bytes"
             );
         }
     }
@@ -1050,7 +1006,7 @@ mod tests {
             assert_eq!(dest_id_len, 2);
             assert_eq!(
                 error.to_string(),
-                "missmatch of PDU source length 1 and destination length 2"
+                "missmatch of PDU source ID length 1 and destination ID length 2"
             );
         }
     }

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,
@@ -59,7 +61,7 @@ impl<'seg_reqs> NakPduCreator<'seg_reqs> {
         start_of_scope: u32,
         end_of_scope: u32,
         segment_requests: &'seg_reqs [(u32, u32)],
-    ) -> Result<NakPduCreator, PduError> {
+    ) -> Result<NakPduCreator<'seg_reqs>, PduError> {
         let mut passed_segment_requests = None;
         if !segment_requests.is_empty() {
             passed_segment_requests = Some(SegmentRequests::U32Pairs(segment_requests));
@@ -77,7 +79,7 @@ impl<'seg_reqs> NakPduCreator<'seg_reqs> {
         start_of_scope: u64,
         end_of_scope: u64,
         segment_requests: &'seg_reqs [(u64, u64)],
-    ) -> Result<NakPduCreator, PduError> {
+    ) -> Result<NakPduCreator<'seg_reqs>, PduError> {
         let mut passed_segment_requests = None;
         if !segment_requests.is_empty() {
             passed_segment_requests = Some(SegmentRequests::U64Pairs(segment_requests));
@@ -95,7 +97,7 @@ impl<'seg_reqs> NakPduCreator<'seg_reqs> {
         start_of_scope: u64,
         end_of_scope: u64,
         segment_requests: Option<SegmentRequests<'seg_reqs>>,
-    ) -> Result<NakPduCreator, PduError> {
+    ) -> Result<NakPduCreator<'seg_reqs>, PduError> {
         // Force correct direction flag.
         pdu_header.pdu_conf.direction = Direction::TowardsSender;
         if let Some(ref segment_requests) = segment_requests {
@@ -267,7 +269,7 @@ impl SegReqFromBytes for u64 {
     }
 }
 
-impl<'a, T> Iterator for SegmentRequestIter<'a, T>
+impl<T> Iterator for SegmentRequestIter<'_, T>
 where
     T: SegReqFromBytes,
 {
@@ -280,8 +282,8 @@ where
     }
 }
 
-impl<'a, 'b> PartialEq<SegmentRequests<'a>> for SegmentRequestIter<'b, u32> {
+impl<'a> PartialEq<SegmentRequests<'a>> for SegmentRequestIter<'_, u32> {
-    fn eq(&self, other: &SegmentRequests) -> bool {
+    fn eq(&self, other: &SegmentRequests<'a>) -> bool {
         match other {
             SegmentRequests::U32Pairs(pairs) => self.compare_pairs(pairs),
             SegmentRequests::U64Pairs(pairs) => {
@@ -294,8 +296,8 @@ impl<'a, 'b> PartialEq<SegmentRequests<'a>> for SegmentRequestIter<'b, u32> {
     }
 }
 
-impl<'a, 'b> PartialEq<SegmentRequests<'a>> for SegmentRequestIter<'b, u64> {
+impl<'a> PartialEq<SegmentRequests<'a>> for SegmentRequestIter<'_, u64> {
-    fn eq(&self, other: &SegmentRequests) -> bool {
+    fn eq(&self, other: &SegmentRequests<'a>) -> bool {
         match other {
             SegmentRequests::U32Pairs(pairs) => {
                 if pairs.is_empty() && self.seq_req_raw.is_empty() {
@@ -308,7 +310,7 @@ impl<'a, 'b> PartialEq<SegmentRequests<'a>> for SegmentRequestIter<'b, u64> {
     }
 }
 
-impl<'a, T> SegmentRequestIter<'a, T>
+impl<T> SegmentRequestIter<'_, T>
 where
     T: SegReqFromBytes + PartialEq,
 {
@@ -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,
@@ -371,11 +374,11 @@ impl CfdpPdu for NakPduReader<'_> {
 }
 
 impl<'seg_reqs> NakPduReader<'seg_reqs> {
-    pub fn new(buf: &'seg_reqs [u8]) -> Result<NakPduReader, PduError> {
+    pub fn new(buf: &'seg_reqs [u8]) -> Result<NakPduReader<'seg_reqs>, PduError> {
         Self::from_bytes(buf)
     }
 
-    pub fn from_bytes(buf: &'seg_reqs [u8]) -> Result<NakPduReader, PduError> {
+    pub fn from_bytes(buf: &'seg_reqs [u8]) -> Result<NakPduReader<'seg_reqs>, PduError> {
         let (pdu_header, mut current_idx) = PduHeader::from_bytes(buf)?;
         let full_len_without_crc = pdu_header.verify_length_and_checksum(buf)?;
         // Minimum length of 9: 1 byte directive field and start and end of scope for normal file
@@ -471,7 +474,7 @@ impl<'seg_reqs> NakPduReader<'seg_reqs> {
     }
 }
 
-impl<'a, 'b> PartialEq<NakPduCreator<'a>> for NakPduReader<'b> {
+impl<'a> PartialEq<NakPduCreator<'a>> for NakPduReader<'_> {
     fn eq(&self, other: &NakPduCreator<'a>) -> bool {
         if self.pdu_header() != other.pdu_header()
             || self.end_of_scope() != other.end_of_scope()
@@ -748,7 +751,7 @@ mod tests {
         if let PduError::InvalidStartOrEndOfScopeValue = error {
             assert_eq!(
                 error.to_string(),
-                "invalid start or end of scope for NAK PDU"
+                "invalid start or end of scope value for NAK PDU"
             );
         } else {
             panic!("unexpected error {error}");
@@ -793,7 +796,7 @@ mod tests {
         nak_vec[nak_pdu.len_written() - 1] -= 1;
         let nak_pdu_deser = NakPduReader::new(&nak_vec);
         assert!(nak_pdu_deser.is_err());
-        if let Err(PduError::ChecksumError(raw)) = nak_pdu_deser {
+        if let Err(PduError::Checksum(raw)) = nak_pdu_deser {
             assert_eq!(
                 raw,
                 u16::from_be_bytes(nak_vec[nak_pdu.len_written() - 2..].try_into().unwrap())

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::{InvalidTlvTypeFieldError, TlvLvDataTooLargeError};
+
 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, TlvLvDataTooLargeError> {
         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, TlvLvDataTooLargeError> {
         Ok(Tlv {
             tlv_type_field: TlvTypeField::Custom(tlv_type),
             lv: Lv::new(data)?,
@@ -147,31 +175,11 @@ 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
     /// [Self::len_full].
-    pub fn from_bytes(buf: &'data [u8]) -> Result<Tlv<'data>, TlvLvError> {
+    pub fn from_bytes(buf: &'data [u8]) -> Result<Tlv<'data>, ByteConversionError> {
         generic_len_check_deserialization(buf, MIN_TLV_LEN)?;
         let mut tlv = Self {
             tlv_type_field: TlvTypeField::from(buf[0]),
@@ -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 +237,95 @@ impl GenericTlv for Tlv<'_> {
     }
 }
 
-pub(crate) fn verify_tlv_type(raw_type: u8, expected_tlv_type: TlvType) -> Result<(), TlvLvError> {
+#[cfg(feature = "alloc")]
-    let tlv_type = TlvType::try_from(raw_type).map_err(|_| TlvLvError::InvalidTlvTypeField {
+pub mod alloc_mod {
-        found: raw_type,
+    use super::*;
-        expected: Some(expected_tlv_type.into()),
+
-    })?;
+    /// Owned variant of [Tlv] which is consequently [Clone]able and does not have a lifetime
-    if tlv_type != expected_tlv_type {
+    /// associated to a data slice.
-        return Err(TlvLvError::InvalidTlvTypeField {
+    #[derive(Debug, Clone, PartialEq, Eq)]
-            found: tlv_type as u8,
+    #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
-            expected: Some(expected_tlv_type as u8),
+    #[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]) -> Self {
+            Self {
+                tlv_type_field: TlvTypeField::Standard(tlv_type),
+                data: data.to_vec(),
+            }
+        }
+
+        pub fn new_with_custom_type(tlv_type: u8, data: &[u8]) -> Self {
+            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,
 }
@@ -272,11 +374,8 @@ impl EntityIdTlv {
         Self::len_check(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 {
+        // Can't fail.
-            TlvLvError::ByteConversion(e) => e,
+        Ok(Tlv::new(TlvType::EntityId, &buf[2..2 + self.entity_id.size()]).unwrap())
-            // All other errors are impossible.
-            _ => panic!("unexpected TLV error"),
-        })
     }
 }
 
@@ -299,24 +398,26 @@ impl GenericTlv for EntityIdTlv {
     }
 }
 
-impl<'data> TryFrom<Tlv<'data>> for EntityIdTlv {
+impl TryFrom<Tlv<'_>> for EntityIdTlv {
     type Error = TlvLvError;
 
-    fn try_from(value: Tlv) -> Result<Self, Self::Error> {
+    fn try_from(value: Tlv) -> Result<Self, TlvLvError> {
         match value.tlv_type_field {
             TlvTypeField::Standard(tlv_type) => {
                 if tlv_type != TlvType::EntityId {
-                    return Err(TlvLvError::InvalidTlvTypeField {
+                    return Err(InvalidTlvTypeFieldError {
                         found: tlv_type as u8,
                         expected: Some(TlvType::EntityId as u8),
-                    });
+                    }
+                    .into());
                 }
             }
             TlvTypeField::Custom(val) => {
-                return Err(TlvLvError::InvalidTlvTypeField {
+                return Err(InvalidTlvTypeFieldError {
                     found: val,
                     expected: Some(TlvType::EntityId as u8),
-                });
+                }
+                .into());
             }
         }
         let len_value = value.value().len();
@@ -348,6 +449,7 @@ 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))]
@@ -561,6 +663,7 @@ 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>,
@@ -745,6 +848,23 @@ impl GenericTlv for FilestoreResponseTlv<'_, '_, '_> {
     }
 }
 
+pub(crate) fn verify_tlv_type(
+    raw_type: u8,
+    expected_tlv_type: TlvType,
+) -> Result<(), InvalidTlvTypeFieldError> {
+    let tlv_type = TlvType::try_from(raw_type).map_err(|_| InvalidTlvTypeFieldError {
+        found: raw_type,
+        expected: Some(expected_tlv_type.into()),
+    })?;
+    if tlv_type != expected_tlv_type {
+        return Err(InvalidTlvTypeFieldError {
+            found: tlv_type as u8,
+            expected: Some(expected_tlv_type as u8),
+        });
+    }
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -932,14 +1052,14 @@ 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 {
+        match error {
-            assert_eq!(size, u8::MAX as usize + 1);
+            TlvLvDataTooLargeError(size) => {
-            assert_eq!(
+                assert_eq!(size, u8::MAX as usize + 1);
-                error.to_string(),
+                assert_eq!(
-                "data with size 256 larger than allowed 255 bytes"
+                    error.to_string(),
-            );
+                    "data with size 256 larger than allowed 255 bytes"
-        } else {
+                );
-            panic!("unexpected error {:?}", error);
+            }
         }
     }
 
@@ -1249,7 +1369,8 @@ mod tests {
         let error = EntityIdTlv::try_from(msg_to_user_tlv);
         assert!(error.is_err());
         let error = error.unwrap_err();
-        if let TlvLvError::InvalidTlvTypeField { found, expected } = error {
+        if let TlvLvError::InvalidTlvTypeField(InvalidTlvTypeFieldError { found, expected }) = error
+        {
             assert_eq!(found, TlvType::MsgToUser as u8);
             assert_eq!(expected, Some(TlvType::EntityId as u8));
             assert_eq!(
@@ -1293,4 +1414,71 @@ 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]);
+        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, &[]);
+        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 +1,11 @@
 //! Abstractions for the Message to User CFDP TLV subtype.
-use super::{GenericTlv, Tlv, TlvLvError, TlvType, TlvTypeField, WritableTlv};
+#[cfg(feature = "alloc")]
-use crate::ByteConversionError;
+use super::TlvOwned;
+use super::{GenericTlv, ReadableTlv, Tlv, TlvLvError, TlvType, TlvTypeField, WritableTlv};
+use crate::{
+    cfdp::{InvalidTlvTypeFieldError, TlvLvDataTooLargeError},
+    ByteConversionError,
+};
 use delegate::delegate;
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
@@ -10,7 +15,7 @@ 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>, TlvLvDataTooLargeError> {
         Ok(Self {
             tlv: Tlv::new(TlvType::MsgToUser, value)?,
         })
@@ -60,21 +65,38 @@ impl<'data> MsgToUserTlv<'data> {
         match msg_to_user.tlv.tlv_type_field() {
             TlvTypeField::Standard(tlv_type) => {
                 if tlv_type != TlvType::MsgToUser {
-                    return Err(TlvLvError::InvalidTlvTypeField {
+                    return Err(InvalidTlvTypeFieldError {
                         found: tlv_type as u8,
                         expected: Some(TlvType::MsgToUser as u8),
-                    });
+                    }
+                    .into());
                 }
             }
             TlvTypeField::Custom(raw) => {
-                return Err(TlvLvError::InvalidTlvTypeField {
+                return Err(InvalidTlvTypeFieldError {
                     found: raw,
                     expected: Some(TlvType::MsgToUser as u8),
-                });
+                }
+                .into());
             }
         }
         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 +161,40 @@ 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];
@@ -154,9 +210,9 @@ mod tests {
     fn test_reserved_msg_deserialization_invalid_type() {
         let trash: [u8; 5] = [TlvType::FlowLabel as u8, 3, 1, 2, 3];
         let error = MsgToUserTlv::from_bytes(&trash).unwrap_err();
-        if let TlvLvError::InvalidTlvTypeField { found, expected } = error {
+        if let TlvLvError::InvalidTlvTypeField(inner) = error {
-            assert_eq!(found, TlvType::FlowLabel as u8);
+            assert_eq!(inner.found, TlvType::FlowLabel as u8);
-            assert_eq!(expected, Some(TlvType::MsgToUser as u8));
+            assert_eq!(inner.expected, Some(TlvType::MsgToUser as u8));
         } else {
             panic!("Wrong error type returned: {:?}", error);
         }

src/crc.rs

@@ -0,0 +1,11 @@
+/// CRC algorithm used by the PUS standard, the CCSDS TC standard and the CFDP standard, using
+/// a [crc::NoTable] as the CRC implementation.
+pub const CRC_CCITT_FALSE_NO_TABLE: crc::Crc<u16, crc::NoTable> =
+    crc::Crc::<u16, crc::NoTable>::new(&crc::CRC_16_IBM_3740);
+/// CRC algorithm used by the PUS standard, the CCSDS TC standard and the CFDP standard, using
+/// [crc::Table<1>] as the CRC implementation.
+pub const CRC_CCITT_FALSE: crc::Crc<u16> = crc::Crc::<u16>::new(&crc::CRC_16_IBM_3740);
+/// CRC algorithm used by the PUS standard, the CCSDS TC standard and the CFDP standard, using
+/// a [crc::Table<16>] large table as the CRC implementation.
+pub const CRC_CCITT_FALSE_BIG_TABLE: crc::Crc<u16, crc::Table<16>> =
+    crc::Crc::<u16, crc::Table<16>>::new(&crc::CRC_16_IBM_3740);

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

@@ -1,18 +1,19 @@
 //! 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
+//! You can find the PUS telecommand types in the [tc] module and the the PUS telemetry
-//! inside the [tm] module.
+//! types inside the [tm] module.
-use crate::{ByteConversionError, CcsdsPacket, CRC_CCITT_FALSE};
+use crate::{
+    crc::{CRC_CCITT_FALSE, CRC_CCITT_FALSE_NO_TABLE},
+    ByteConversionError, CcsdsPacket,
+};
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
-use core::fmt::{Debug, Display, Formatter};
+use core::fmt::Debug;
 use core::mem::size_of;
 use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
-#[cfg(feature = "std")]
-use std::error::Error;
 
 pub mod event;
 pub mod hk;
@@ -22,7 +23,6 @@ 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 +74,7 @@ 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,
@@ -148,49 +149,19 @@ pub enum PfcReal {
     DoubleMilStd = 4,
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, thiserror::Error)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum PusError {
+    #[error("PUS version {0:?} not supported")]
     VersionNotSupported(PusVersion),
+    #[error("checksum verification for crc16 {0:#06x} failed")]
     ChecksumFailure(u16),
     /// CRC16 needs to be calculated first
-    CrcCalculationMissing,
+    //#[error("crc16 was not calculated")]
-    ByteConversion(ByteConversionError),
+    //CrcCalculationMissing,
-}
+    #[error("pus error: {0}")]
-
+    ByteConversion(#[from] ByteConversionError),
-impl Display for PusError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
-        match self {
-            PusError::VersionNotSupported(v) => {
-                write!(f, "PUS version {v:?} not supported")
-            }
-            PusError::ChecksumFailure(crc) => {
-                write!(f, "checksum verification for crc16 {crc:#06x} failed")
-            }
-            PusError::CrcCalculationMissing => {
-                write!(f, "crc16 was not calculated")
-            }
-            PusError::ByteConversion(e) => {
-                write!(f, "pus error: {e}")
-            }
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl Error for PusError {
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        if let PusError::ByteConversion(e) = self {
-            return Some(e);
-        }
-        None
-    }
-}
-
-impl From<ByteConversionError> for PusError {
-    fn from(e: ByteConversionError) -> Self {
-        PusError::ByteConversion(e)
-    }
 }
 
 /// Generic trait to describe common attributes for both PUS Telecommands (TC) and PUS Telemetry
@@ -202,16 +173,15 @@ pub trait PusPacket: CcsdsPacket {
     fn service(&self) -> u8;
     fn subservice(&self) -> u8;
     fn user_data(&self) -> &[u8];
-    fn crc16(&self) -> Option<u16>;
+    fn opt_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()]
@@ -226,45 +196,35 @@ 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]),
     }
 }
 
-pub(crate) fn verify_crc16_ccitt_false_from_raw_to_pus_error(
+pub fn verify_crc16_ccitt_false_from_raw_to_pus_error(
     raw_data: &[u8],
     crc16: u16,
 ) -> Result<(), PusError> {
     verify_crc16_ccitt_false_from_raw(raw_data)
-        .then(|| ())
+        .then_some(())
+        .ok_or(PusError::ChecksumFailure(crc16))
+}
+
+pub fn verify_crc16_ccitt_false_from_raw_to_pus_error_no_table(
+    raw_data: &[u8],
+    crc16: u16,
+) -> Result<(), PusError> {
+    verify_crc16_ccitt_false_from_raw_no_table(raw_data)
+        .then_some(())
         .ok_or(PusError::ChecksumFailure(crc16))
 }
 
@@ -277,12 +237,25 @@ pub(crate) fn verify_crc16_ccitt_false_from_raw(raw_data: &[u8]) -> bool {
     false
 }
 
+pub(crate) fn verify_crc16_ccitt_false_from_raw_no_table(raw_data: &[u8]) -> bool {
+    let mut digest = CRC_CCITT_FALSE_NO_TABLE.digest();
+    digest.update(raw_data);
+    if digest.finalize() == 0 {
+        return true;
+    }
+    false
+}
+
 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 +264,11 @@ 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);
         });
     }
@@ -360,17 +336,68 @@ impl<TYPE: Debug + Copy + Clone + PartialEq + Eq + ToBeBytes + Into<u64>> EcssEn
 {
 }
 
-pub type EcssEnumU8 = GenericEcssEnumWrapper<u8>;
+impl<T: Copy + Into<u64>> From<T> for GenericEcssEnumWrapper<T> {
-pub type EcssEnumU16 = GenericEcssEnumWrapper<u16>;
+    fn from(value: T) -> Self {
-pub type EcssEnumU32 = GenericEcssEnumWrapper<u32>;
+        Self::new(value)
-pub type EcssEnumU64 = GenericEcssEnumWrapper<u64>;
+    }
+}
+
+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
 /// on the serialization of those packets.
 pub trait WritablePusPacket {
     fn len_written(&self) -> usize;
-    fn write_to_bytes(&self, slice: &mut [u8]) -> Result<usize, PusError>;
+
+    /// Writes the packet to the given slice without writing the CRC.
+    ///
+    /// The returned size is the written size WITHOUT the CRC.
+    fn write_to_bytes_no_crc(&self, slice: &mut [u8]) -> Result<usize, PusError>;
+
+    /// First uses [Self::write_to_bytes_no_crc] to write the packet to the given slice and then
+    /// uses the [CRC_CCITT_FALS] to calculate the CRC and write it to the slice.
+    fn write_to_bytes(&self, slice: &mut [u8]) -> Result<usize, PusError> {
+        let mut curr_idx = self.write_to_bytes_no_crc(slice)?;
+        let mut digest = CRC_CCITT_FALSE.digest();
+        digest.update(&slice[0..curr_idx]);
+        slice[curr_idx..curr_idx + 2].copy_from_slice(&digest.finalize().to_be_bytes());
+        curr_idx += 2;
+        Ok(curr_idx)
+    }
+
+    /// First uses [Self::write_to_bytes_no_crc] to write the packet to the given slice and then
+    /// uses the [CRC_CCITT_FALSE_NO_TABLE] to calculate the CRC and write it to the slice.
+    fn write_to_bytes_crc_no_table(&self, slice: &mut [u8]) -> Result<usize, PusError> {
+        let mut curr_idx = self.write_to_bytes_no_crc(slice)?;
+        let mut digest = CRC_CCITT_FALSE_NO_TABLE.digest();
+        digest.update(&slice[0..curr_idx]);
+        slice[curr_idx..curr_idx + 2].copy_from_slice(&digest.finalize().to_be_bytes());
+        curr_idx += 2;
+        Ok(curr_idx)
+    }
+
     #[cfg(feature = "alloc")]
     fn to_vec(&self) -> Result<Vec<u8>, PusError> {
         // This is the correct way to do this. See
@@ -406,6 +433,8 @@ mod tests {
         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]);
     }
@@ -423,6 +452,8 @@ mod tests {
         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]);
     }
@@ -458,6 +489,8 @@ mod tests {
         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]);
     }
@@ -494,6 +527,8 @@ mod tests {
         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);

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/lib.rs

@@ -22,21 +22,21 @@
 //!
 //! `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.
 //!  - [`alloc`](https://doc.rust-lang.org/alloc/): Enables features which operate on containers
-//!     like [`alloc::vec::Vec`](https://doc.rust-lang.org/beta/alloc/vec/struct.Vec.html).
+//!    like [`alloc::vec::Vec`](https://doc.rust-lang.org/beta/alloc/vec/struct.Vec.html).
-//!     Enabled by the `std` feature.
+//!    Enabled by the `std` feature.
 //!
 //! ### 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
 //!
@@ -48,35 +48,30 @@
 //!
 //! ```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, hash::Hash};
-use core::{
-    fmt::{Debug, Display, Formatter},
-    hash::Hash,
-};
-use crc::{Crc, CRC_16_IBM_3740};
 use delegate::delegate;
-
+use zerocopy::{FromBytes, IntoBytes};
-#[cfg(feature = "std")]
-use std::error::Error;
 
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
 pub mod cfdp;
+pub mod crc;
 pub mod ecss;
+pub mod seq_count;
 pub mod time;
 pub mod util;
 
@@ -84,64 +79,34 @@ mod private {
     pub trait Sealed {}
 }
 
-/// CRC algorithm used by the PUS standard, the CCSDS TC standard and the CFDP standard.
+pub const CCSDS_HEADER_LEN: usize = core::mem::size_of::<crate::zc::SpHeader>();
-pub const CRC_CCITT_FALSE: Crc<u16> = Crc::<u16>::new(&CRC_16_IBM_3740);
 
 pub const MAX_APID: u16 = 2u16.pow(11) - 1;
 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)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, thiserror::Error)]
 #[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 {
+    #[error("target slice with size {found} is too small, expected size of at least {expected}")]
-        found: usize,
+    ToSliceTooSmall { found: usize, expected: usize },
-        expected: usize,
-    },
     /// The provider buffer is too small. Returns the passed slice length and expected minimum size
-    FromSliceTooSmall {
+    #[error("source slice with size {found} too small, expected at least {expected} bytes")]
-        found: usize,
+    FromSliceTooSmall { found: usize, expected: usize },
-        expected: usize,
-    },
     /// The [zerocopy] library failed to write to bytes
+    #[error("zerocopy serialization error")]
     ZeroCopyToError,
+    /// The [zerocopy] library failed to read from bytes
+    #[error("zerocopy deserialization error")]
     ZeroCopyFromError,
 }
 
-impl Display for ByteConversionError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
-        match self {
-            ByteConversionError::ToSliceTooSmall { found, expected } => {
-                write!(
-                    f,
-                    "target slice with size {} is too small, expected size of at least {}",
-                    found, expected
-                )
-            }
-            ByteConversionError::FromSliceTooSmall { found, expected } => {
-                write!(
-                    f,
-                    "source slice with size {} too small, expected at least {} bytes",
-                    found, expected
-                )
-            }
-            ByteConversionError::ZeroCopyToError => {
-                write!(f, "zerocopy serialization error")
-            }
-            ByteConversionError::ZeroCopyFromError => {
-                write!(f, "zerocopy deserialization error")
-            }
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-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 +130,7 @@ 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 +158,7 @@ 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 +166,21 @@ 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 +194,7 @@ impl Hash for PacketId {
 }
 
 impl Default for PacketId {
+    #[inline]
     fn default() -> Self {
         PacketId {
             ptype: PacketType::Tm,
@@ -234,23 +205,34 @@ impl Default for PacketId {
 }
 
 impl PacketId {
-    pub const fn const_tc(sec_header: bool, apid: u16) -> Self {
+    /// This constructor will panic if the passed APID exceeds [MAX_APID].
-        Self::const_new(PacketType::Tc, sec_header, apid)
+    /// Use the checked constructor variants to avoid panics.
-    }
+    #[inline]
-
+    pub const fn new_for_tc(sec_header: bool, apid: u16) -> Self {
-    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> {
         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 +243,18 @@ 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 +263,7 @@ impl PacketId {
         true
     }
 
+    #[inline]
     pub fn apid(&self) -> u16 {
         self.apid
     }
@@ -303,15 +288,17 @@ 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
+    /// This constructor panics if the sequence count exceeds [MAX_SEQ_COUNT].
-    /// [MAX_SEQ_COUNT].
+    /// Use [Self::new_checked] to avoid panics.
-    pub const fn const_new(seq_flags: SequenceFlags, seq_count: u16) -> PacketSequenceCtrl {
+    #[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 +309,22 @@ 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 +333,7 @@ impl PacketSequenceCtrl {
         true
     }
 
+    #[inline]
     pub fn seq_count(&self) -> u16 {
         self.seq_count
     }
@@ -383,6 +375,7 @@ 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
     }
@@ -456,13 +449,14 @@ pub trait CcsdsPrimaryHeader {
 /// # Arguments
 ///
 /// * `version` - CCSDS version field, occupies the first 3 bits of the raw header. Will generally
-///    be set to 0b000 in all constructors provided by this crate.
+///   be set to 0b000 in all constructors provided by this crate.
 /// * `packet_id` - Packet Identifier, which can also be used as a start marker. Occupies the last
-///    13 bits of the first two bytes of the raw header
+///   13 bits of the first two bytes of the raw header
 /// * `psc` - Packet Sequence Control, occupies the third and fourth byte of the raw header
 /// * `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 +464,12 @@ 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
+    /// The default function sets the sequence flag field to [SequenceFlags::Unsegmented] and the
-    /// length field is set to 1, which denotes an empty space packets.
+    /// data length to 0.
+    #[inline]
     fn default() -> Self {
         SpHeader {
             version: 0,
@@ -481,12 +478,13 @@ 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 +494,43 @@ impl SpHeader {
         }
     }
 
-    /// const variant of the [SpHeader::new_fron_single_fields] function. Panics if the passed
+    /// This constructor sets the sequence flag field to [SequenceFlags::Unsegmented] and the data
-    /// APID exceeds [MAX_APID] or the passed packet sequence count exceeds [MAX_SEQ_COUNT].
+    /// length to 0.
-    const fn const_new_from_single_fields(
+    ///
+    /// 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 +545,20 @@ impl SpHeader {
             panic!("APID is too large");
         }
         Self {
-            psc: PacketSequenceCtrl::const_new(seq_flags, seq_count),
+            psc: PacketSequenceCtrl::new(seq_flags, seq_count),
-            packet_id: PacketId::const_new(ptype, sec_header, apid),
+            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 +569,117 @@ 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> {
+    #[inline]
-        Self::new_from_single_fields(PacketType::Tm, false, apid, seq_flags, seq_count, data_len)
+    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> {
+    #[inline]
-        Self::new_from_single_fields(PacketType::Tc, false, apid, seq_flags, seq_count, data_len)
+    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]
+    /// This is an unchecked constructor which can panic on invalid input.
-    pub fn tm_unseg(apid: u16, seq_count: u16, data_len: u16) -> Option<Self> {
+    #[inline]
-        Self::tm(apid, SequenceFlags::Unsegmented, seq_count, data_len)
+    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]
+    /// This is an unchecked constructor which can panic on invalid input.
-    pub fn tc_unseg(apid: u16, seq_count: u16, data_len: u16) -> Option<Self> {
+    #[inline]
-        Self::tc(apid, SequenceFlags::Unsegmented, seq_count, data_len)
+    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
+    /// Variant of [SpHeader::new_for_tm_checked] which sets the sequence flag field to [SequenceFlags::Unsegmented]
-    delegate!(to self.packet_id {
+    #[inline]
-        /// Returns [false] and fails if the APID exceeds [MAX_APID]
+    pub fn new_for_unseg_tm_checked(apid: u16, seq_count: u16, data_len: u16) -> Option<Self> {
-        pub fn set_apid(&mut self, apid: u16) -> bool;
+        Self::new_for_tm_checked(apid, SequenceFlags::Unsegmented, seq_count, data_len)
-    });
+    }
 
-    delegate!(to self.psc {
+    /// Variant of [SpHeader::new_for_tc_checked] which sets the sequence flag field to [SequenceFlags::Unsegmented]
-        /// Returns [false] and fails if the sequence count exceeds [MAX_SEQ_COUNT]
+    #[inline]
-        pub fn set_seq_count(&mut self, seq_count: u16) -> bool;
+    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;
     }
@@ -598,8 +694,8 @@ impl SpHeader {
                 expected: CCSDS_HEADER_LEN,
             });
         }
-        let zc_header = zc::SpHeader::from_bytes(&buf[0..CCSDS_HEADER_LEN])
+        let zc_header = zc::SpHeader::read_from_bytes(&buf[0..CCSDS_HEADER_LEN])
-            .ok_or(ByteConversionError::ZeroCopyFromError)?;
+            .map_err(|_| ByteConversionError::ZeroCopyFromError)?;
         Ok((Self::from(zc_header), &buf[CCSDS_HEADER_LEN..]))
     }
 
@@ -617,10 +713,19 @@ impl SpHeader {
         }
         let zc_header: zc::SpHeader = zc::SpHeader::from(*self);
         zc_header
-            .to_bytes(&mut buf[0..CCSDS_HEADER_LEN])
+            .write_to(&mut buf[0..CCSDS_HEADER_LEN])
-            .ok_or(ByteConversionError::ZeroCopyToError)?;
+            .map_err(|_| 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 +751,7 @@ impl CcsdsPacket for SpHeader {
 }
 
 impl CcsdsPrimaryHeader for SpHeader {
+    #[inline]
     fn from_composite_fields(
         packet_id: PacketId,
         psc: PacketSequenceCtrl,
@@ -670,9 +776,9 @@ sph_from_other!(SpHeader, crate::zc::SpHeader);
 pub mod zc {
     use crate::{CcsdsPacket, CcsdsPrimaryHeader, PacketId, PacketSequenceCtrl, VERSION_MASK};
     use zerocopy::byteorder::NetworkEndian;
-    use zerocopy::{AsBytes, FromBytes, FromZeroes, Unaligned, U16};
+    use zerocopy::{FromBytes, Immutable, IntoBytes, Unaligned, U16};
 
-    #[derive(FromBytes, FromZeroes, AsBytes, Unaligned, Debug)]
+    #[derive(FromBytes, IntoBytes, Immutable, Unaligned, Debug)]
     #[repr(C)]
     pub struct SpHeader {
         version_packet_id: U16<NetworkEndian>,
@@ -697,14 +803,6 @@ pub mod zc {
                 data_len: U16::from(data_len),
             }
         }
-
-        pub fn from_bytes(slice: &[u8]) -> Option<Self> {
-            SpHeader::read_from(slice)
-        }
-
-        pub fn to_bytes(&self, slice: &mut [u8]) -> Option<()> {
-            self.write_to(slice)
-        }
     }
 
     impl CcsdsPacket for SpHeader {
@@ -713,9 +811,12 @@ 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 +826,12 @@ 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 +855,8 @@ 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::{
@@ -766,14 +871,15 @@ pub(crate) mod tests {
     use postcard::{from_bytes, to_allocvec};
     #[cfg(feature = "serde")]
     use serde::{de::DeserializeOwned, Serialize};
+    use zerocopy::FromBytes;
 
     const CONST_SP: SpHeader = SpHeader::new(
-        PacketId::const_tc(true, 0x36),
+        PacketId::new_for_tc(true, 0x36),
-        PacketSequenceCtrl::const_new(SequenceFlags::ContinuationSegment, 0x88),
+        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 +891,12 @@ 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 +905,32 @@ 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);
+        assert!(packet_id.sec_header_flag);
-        let packet_id_tc = PacketId::tc(true, 0x1ff);
+        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 +971,7 @@ 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 +979,26 @@ 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 +1006,7 @@ 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 +1015,18 @@ 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 +1048,8 @@ 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 +1063,8 @@ 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(),
+            PacketId::new(PacketType::Tc, true, 0x42),
-            PacketSequenceCtrl::new(SequenceFlags::Unsegmented, 0x7).unwrap(),
+            PacketSequenceCtrl::new(SequenceFlags::Unsegmented, 0x7),
             0,
             None,
         );
@@ -971,7 +1081,7 @@ 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 +1099,7 @@ 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 +1107,35 @@ 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);
@@ -1029,10 +1151,10 @@ pub(crate) mod tests {
 
     #[test]
     fn test_zc_sph() {
-        use zerocopy::AsBytes;
+        use zerocopy::IntoBytes;
 
-        let sp_header =
+        let sp_header = SpHeader::new_for_unseg_tc_checked(0x7FF, pow(2, 14) - 1, 0)
-            SpHeader::tc_unseg(0x7FF, pow(2, 14) - 1, 0).expect("Error creating SP header");
+            .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);
@@ -1049,7 +1171,7 @@ pub(crate) mod tests {
         assert_eq!(slice[5], 0x00);
 
         let mut slice = [0; 6];
-        sp_header_zc.write_to(slice.as_mut_slice());
+        sp_header_zc.write_to(slice.as_mut_slice()).unwrap();
         assert_eq!(slice.len(), 6);
         assert_eq!(slice[0], 0x17);
         assert_eq!(slice[1], 0xFF);
@@ -1060,7 +1182,7 @@ pub(crate) mod tests {
 
         let mut test_vec = vec![0_u8; 6];
         let slice = test_vec.as_mut_slice();
-        sp_header_zc.write_to(slice);
+        sp_header_zc.write_to(slice).unwrap();
         let slice = test_vec.as_slice();
         assert_eq!(slice.len(), 6);
         assert_eq!(slice[0], 0x17);
@@ -1070,8 +1192,8 @@ pub(crate) mod tests {
         assert_eq!(slice[4], 0x00);
         assert_eq!(slice[5], 0x00);
 
-        let sp_header = zc::SpHeader::from_bytes(slice);
+        let sp_header = zc::SpHeader::read_from_bytes(slice);
-        assert!(sp_header.is_some());
+        assert!(sp_header.is_ok());
         let sp_header = sp_header.unwrap();
         assert_eq!(sp_header.ccsds_version(), 0b000);
         assert_eq!(sp_header.packet_id_raw(), 0x17FF);
@@ -1097,4 +1219,40 @@ 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")]
+#[cfg(all(feature = "alloc", feature = "chrono"))]
-use chrono::{
+pub use alloc_mod_chrono::*;
-    format::{DelayedFormat, StrftimeItems},
-    DateTime, Utc,
-};
 
 /// 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(all(feature = "alloc", feature = "chrono"))]
-#[cfg(feature = "alloc")]
+pub mod alloc_mod_chrono {
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
+    use super::*;
-pub fn generate_time_code_a(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
+    use chrono::{
-    date.format(FMT_STR_CODE_A_WITH_SIZE.0)
+        format::{DelayedFormat, StrftimeItems},
-}
+        DateTime, Utc,
+    };
 
-/// Generates a time code formatter using the [FMT_STR_CODE_A_TERMINATED_WITH_SIZE] format.
+    /// Generates a time code formatter using the [FMT_STR_CODE_A_WITH_SIZE] format.
-#[cfg(feature = "alloc")]
+    pub fn generate_time_code_a(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
+        date.format(FMT_STR_CODE_A_WITH_SIZE.0)
-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_WITH_SIZE] format.
+    /// Generates a time code formatter using the [FMT_STR_CODE_A_TERMINATED_WITH_SIZE] format.
-#[cfg(feature = "alloc")]
+    pub fn generate_time_code_a_terminated(
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
+        date: &DateTime<Utc>,
-pub fn generate_time_code_b(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
+    ) -> DelayedFormat<StrftimeItems<'static>> {
-    date.format(FMT_STR_CODE_B_WITH_SIZE.0)
+        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.
+    /// Generates a time code formatter using the [FMT_STR_CODE_B_WITH_SIZE] format.
-#[cfg(feature = "alloc")]
+    pub fn generate_time_code_b(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
+        date.format(FMT_STR_CODE_B_WITH_SIZE.0)
-pub fn generate_time_code_b_terminated(
+    }
-    date: &DateTime<Utc>,
+
-) -> DelayedFormat<StrftimeItems<'static>> {
+    /// Generates a time code formatter using the [FMT_STR_CODE_B_TERMINATED_WITH_SIZE] format.
-    date.format(FMT_STR_CODE_B_TERMINATED_WITH_SIZE.0)
+    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() {
+    fn test_ascii_timestamp_a_unterminated_epoch() {
-        let date = Utc::now();
+        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() {
+    fn test_ascii_timestamp_b_unterminated_epoch() {
-        let date = Utc::now();
+        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 == CcsdsTimeCode::CucCcsdsEpoch as u8 => Ok(CcsdsTimeCode::CucCcsdsEpoch),
-            x if x == CcsdsTimeCodes::CucAgencyEpoch as u8 => Ok(CcsdsTimeCodes::CucAgencyEpoch),
+            x if x == CcsdsTimeCode::CucAgencyEpoch as u8 => Ok(CcsdsTimeCode::CucAgencyEpoch),
-            x if x == CcsdsTimeCodes::Cds as u8 => Ok(CcsdsTimeCodes::Cds),
+            x if x == CcsdsTimeCode::Cds as u8 => Ok(CcsdsTimeCode::Cds),
-            x if x == CcsdsTimeCodes::Ccs as u8 => Ok(CcsdsTimeCodes::Ccs),
+            x if x == CcsdsTimeCode::Ccs as u8 => Ok(CcsdsTimeCode::Ccs),
-            x if x == CcsdsTimeCodes::AgencyDefined as u8 => Ok(CcsdsTimeCodes::AgencyDefined),
+            x if x == CcsdsTimeCode::AgencyDefined as u8 => Ok(CcsdsTimeCode::AgencyDefined),
             _ => Err(()),
         }
     }
@@ -55,20 +58,26 @@ 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, thiserror::Error)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[error("date before ccsds epoch: {0:?}")]
+pub struct DateBeforeCcsdsEpochError(UnixTime);
+
 #[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 +99,6 @@ 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 +117,7 @@ impl Error for TimestampError {
         }
     }
 }
+
 impl From<cds::CdsError> for TimestampError {
     fn from(e: cds::CdsError) -> Self {
         TimestampError::Cds(e)
@@ -124,7 +131,6 @@ 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 +138,7 @@ 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 +146,6 @@ 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 +157,7 @@ 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 +166,24 @@ 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())
 }
@@ -203,16 +211,15 @@ pub trait TimeWriter {
     }
 }
 
-pub trait TimeReader {
+pub trait TimeReader: Sized {
-    fn from_bytes(buf: &[u8]) -> Result<Self, TimestampError>
+    fn from_bytes(buf: &[u8]) -> Result<Self, TimestampError>;
-    where
-        Self: Sized;
 }
 
 /// 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;
 
@@ -221,130 +228,203 @@ 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 unix_secs(&self) -> i64;
-    fn subsecond_millis(&self) -> Option<u16>;
+    fn subsec_nanos(&self) -> u32;
-    fn unix_stamp(&self) -> UnixTimestamp {
+
-        if self.subsecond_millis().is_none() {
+    fn subsec_millis(&self) -> u16 {
-            return UnixTimestamp::new_only_seconds(self.unix_seconds());
+        (self.subsec_nanos() / 1_000_000) as u16
-        }
-        UnixTimestamp::const_new(self.unix_seconds(), self.subsecond_millis().unwrap())
     }
 
-    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
+/// This is a commonly used time format and can therefore also be used as a generic format to
-/// subsecond millisecond value of 0 gets converted to [None].
+/// 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 {
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
-    pub unix_seconds: i64,
+pub struct UnixTime {
-    subsecond_millis: Option<u16>,
+    secs: i64,
+    subsec_nanos: u32,
 }
 
-impl UnixTimestamp {
+impl UnixTime {
-    /// Returns none if the subsecond millisecond value is larger than 999. 0 is converted to
+    /// The UNIX epoch time: 1970-01-01T00:00:00+00:00 UTC.
-    /// a [None] value.
+    pub const EPOCH: Self = Self {
-    pub fn new(unix_seconds: i64, subsec_millis: u16) -> Option<Self> {
+        secs: 0,
-        if subsec_millis > 999 {
+        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.
+    /// Returns [None] if the subsecond millisecond value is invalid (larger than fraction of a
-    pub const fn const_new(unix_seconds: i64, subsec_millis: u16) -> Self {
+    /// second)
-        if subsec_millis > 999 {
+    pub fn new_subsec_millis_checked(unix_seconds: i64, subsec_millis: u16) -> Option<Self> {
-            panic!("subsec milliseconds exceeds 999");
+        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,
+            secs: unix_seconds,
-            subsecond_millis,
+            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,
+            secs: unix_seconds,
-            subsecond_millis: None,
+            subsec_nanos: subsecond_millis as u32 * 1_000_000,
         }
     }
 
-    pub fn subsecond_millis(&self) -> Option<u16> {
+    pub fn new_only_secs(unix_seconds: i64) -> Self {
-        self.subsecond_millis
+        Self {
-    }
+            secs: unix_seconds,
-
+            subsec_nanos: 0,
-    #[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))
     }
 
     #[inline]
-    pub fn unix_seconds_f64(&self) -> f64 {
+    pub fn subsec_millis(&self) -> u16 {
-        let mut secs = self.unix_seconds as f64;
+        (self.subsec_nanos / 1_000_000) as u16
-        if let Some(subsec_millis) = self.subsecond_millis {
-            secs += subsec_millis as f64 / 1000.0;
-        }
-        secs
     }
 
-    pub fn as_date_time(&self) -> LocalResult<DateTime<Utc>> {
+    pub fn subsec_nanos(&self) -> u32 {
-        Utc.timestamp_opt(
+        self.subsec_nanos
-            self.unix_seconds,
+    }
-            self.subsecond_millis.unwrap_or(0) as u32 * 10_u32.pow(6),
+
-        )
+    #[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 {
+#[cfg(feature = "chrono")]
-    fn from(value: DateTime<Utc>) -> Self {
+impl From<chrono::DateTime<chrono::Utc>> for UnixTime {
-        Self::const_new(value.timestamp(), value.timestamp_subsec_millis() as u16)
+    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
+        match self.subsec_millis().cmp(&other.subsec_millis()) {
-            .subsecond_millis()
-            .unwrap_or(0)
-            .cmp(&other.subsecond_millis().unwrap_or(0))
-        {
             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
@@ -356,13 +436,36 @@ impl Ord for UnixTimestamp {
     }
 }
 
-fn get_new_stamp_after_addition(
+/// Difference between two UNIX timestamps. The [Duration] type can not contain negative durations,
-    current_stamp: &UnixTimestamp,
+/// so the sign information is supplied separately.
-    duration: Duration,
+#[derive(Clone, Copy, PartialEq, Eq)]
-) -> UnixTimestamp {
+pub struct StampDiff {
-    let mut new_subsec_millis =
+    pub positive_duration: bool,
-        current_stamp.subsecond_millis().unwrap_or(0) + duration.subsec_millis() as u16;
+    pub duration_absolute: Duration,
-    let mut new_unix_seconds = current_stamp.unix_seconds;
+}
+
+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
@@ -374,8 +477,8 @@ fn get_new_stamp_after_addition(
                 .expect("new unix seconds would exceed i64::MAX");
         }
     };
-    if new_subsec_millis >= 1000 {
+    if new_subsec_nanos >= 1_000_000_000 {
-        new_subsec_millis -= 1000;
+        new_subsec_nanos -= 1_000_000_000;
         increment_seconds(1);
     }
     increment_seconds(
@@ -384,7 +487,7 @@ 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:
@@ -392,7 +495,7 @@ 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);
     }
@@ -403,7 +506,7 @@ 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 {
@@ -411,8 +514,8 @@ impl Add<Duration> for UnixTimestamp {
     }
 }
 
-impl Add<Duration> for &UnixTimestamp {
+impl Add<Duration> for &UnixTime {
-    type Output = UnixTimestamp;
+    type Output = UnixTime;
 
     fn add(self, duration: Duration) -> Self::Output {
         get_new_stamp_after_addition(self, duration)
@@ -423,10 +526,15 @@ 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);
@@ -434,6 +542,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(miri, ignore)]
     fn test_get_current_time() {
         let sec_floats = seconds_since_epoch();
         assert!(sec_floats > 0.0);
@@ -448,6 +557,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(miri, ignore)]
     fn test_ccsds_epoch() {
         let now = SystemTime::now()
             .duration_since(SystemTime::UNIX_EPOCH)
@@ -462,29 +572,29 @@ mod tests {
 
     #[test]
     fn basic_unix_stamp_test() {
-        let stamp = UnixTimestamp::new_only_seconds(-200);
+        let stamp = UnixTime::new_only_secs(-200);
-        assert_eq!(stamp.unix_seconds, -200);
+        assert_eq!(stamp.secs, -200);
-        assert!(stamp.subsecond_millis().is_none());
+        assert_eq!(stamp.subsec_millis(), 0);
-        let stamp = UnixTimestamp::new_only_seconds(250);
+        let stamp = UnixTime::new_only_secs(250);
-        assert_eq!(stamp.unix_seconds, 250);
+        assert_eq!(stamp.secs, 250);
-        assert!(stamp.subsecond_millis().is_none());
+        assert_eq!(stamp.subsec_millis(), 0);
     }
 
     #[test]
     fn basic_float_unix_stamp_test() {
-        let stamp = UnixTimestamp::new(500, 600).unwrap();
+        let stamp = UnixTime::new_subsec_millis_checked(500, 600).unwrap();
-        assert!(stamp.subsecond_millis.is_some());
+        assert_eq!(stamp.secs, 500);
-        assert_eq!(stamp.unix_seconds, 500);
+        let subsec_millis = stamp.subsec_millis();
-        let subsec_millis = stamp.subsecond_millis().unwrap();
         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 stamp0 = UnixTime::new_only_secs(5);
-        let stamp1 = UnixTimestamp::new(5, 500).unwrap();
+        let stamp1 = UnixTime::new_subsec_millis_checked(5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(6);
+        let stamp2 = UnixTime::new_only_secs(6);
         assert!(stamp1 > stamp0);
         assert!(stamp2 > stamp0);
         assert!(stamp2 > stamp1);
@@ -492,9 +602,9 @@ mod tests {
 
     #[test]
     fn test_ord_smaller() {
-        let stamp0 = UnixTimestamp::new_only_seconds(5);
+        let stamp0 = UnixTime::new_only_secs(5);
-        let stamp1 = UnixTimestamp::new(5, 500).unwrap();
+        let stamp1 = UnixTime::new_subsec_millis_checked(5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(6);
+        let stamp2 = UnixTime::new_only_secs(6);
         assert!(stamp0 < stamp1);
         assert!(stamp0 < stamp2);
         assert!(stamp1 < stamp2);
@@ -502,9 +612,9 @@ mod tests {
 
     #[test]
     fn test_ord_larger_neg_numbers() {
-        let stamp0 = UnixTimestamp::new_only_seconds(-5);
+        let stamp0 = UnixTime::new_only_secs(-5);
-        let stamp1 = UnixTimestamp::new(-5, 500).unwrap();
+        let stamp1 = UnixTime::new_subsec_millis_checked(-5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(-6);
+        let stamp2 = UnixTime::new_only_secs(-6);
         assert!(stamp0 > stamp1);
         assert!(stamp0 > stamp2);
         assert!(stamp1 > stamp2);
@@ -514,9 +624,9 @@ mod tests {
 
     #[test]
     fn test_ord_smaller_neg_numbers() {
-        let stamp0 = UnixTimestamp::new_only_seconds(-5);
+        let stamp0 = UnixTime::new_only_secs(-5);
-        let stamp1 = UnixTimestamp::new(-5, 500).unwrap();
+        let stamp1 = UnixTime::new_subsec_millis_checked(-5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(-6);
+        let stamp2 = UnixTime::new_only_secs(-6);
         assert!(stamp2 < stamp1);
         assert!(stamp2 < stamp0);
         assert!(stamp1 < stamp0);
@@ -524,10 +634,11 @@ mod tests {
         assert!(stamp2 <= stamp1);
     }
 
+    #[allow(clippy::nonminimal_bool)]
     #[test]
     fn test_eq() {
-        let stamp0 = UnixTimestamp::new(5, 0).unwrap();
+        let stamp0 = UnixTime::new(5, 0);
-        let stamp1 = UnixTimestamp::new_only_seconds(5);
+        let stamp1 = UnixTime::new_only_secs(5);
         assert_eq!(stamp0, stamp1);
         assert!(stamp0 <= stamp1);
         assert!(stamp0 >= stamp1);
@@ -537,28 +648,27 @@ 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_eq!(stamp0.as_secs(), 6);
-        assert!(stamp0.subsecond_millis().is_none());
+        assert_eq!(stamp0.subsec_millis(), 0);
         let stamp1 = stamp0 + Duration::from_millis(500);
-        assert_eq!(stamp1.unix_seconds, 6);
+        assert_eq!(stamp1.secs, 6);
-        assert!(stamp1.subsecond_millis().is_some());
+        assert_eq!(stamp1.subsec_millis(), 500);
-        assert_eq!(stamp1.subsecond_millis().unwrap(), 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_eq!(stamp1.secs, 23);
-        assert!(stamp1.subsecond_millis().is_none());
+        assert_eq!(stamp1.subsec_millis(), 0);
     }
 
     #[test]
     fn test_as_dt() {
-        let stamp = UnixTimestamp::new_only_seconds(0);
+        let stamp = UnixTime::new_only_secs(0);
-        let dt = stamp.as_date_time().unwrap();
+        let dt = stamp.chrono_date_time().unwrap();
         assert_eq!(dt.year(), 1970);
         assert_eq!(dt.month(), 1);
         assert_eq!(dt.day(), 1);
@@ -568,21 +678,57 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(miri, ignore)]
     fn test_from_now() {
-        let stamp_now = UnixTimestamp::from_now().unwrap();
+        let stamp_now = UnixTime::now().unwrap();
-        let dt_now = stamp_now.as_date_time().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_eq!(stamp0.secs, 2);
-        assert!(stamp0.subsecond_millis().is_none());
+        assert_eq!(stamp0.subsec_millis(), 0);
         stamp0 += Duration::from_millis(1100);
-        assert_eq!(stamp0.unix_seconds, 3);
+        assert_eq!(stamp0.secs, 3);
-        assert_eq!(stamp0.subsecond_millis().unwrap(), 100);
+        assert_eq!(stamp0.subsec_millis(), 100);
     }
 
     #[test]
@@ -591,4 +737,26 @@ 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/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)
     }
@@ -104,6 +118,7 @@ pub enum UnsignedByteFieldError {
 }
 
 impl From<ByteConversionError> for UnsignedByteFieldError {
+    #[inline]
     fn from(value: ByteConversionError) -> Self {
         Self::ByteConversionError(value)
     }
@@ -131,20 +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 }
     }
 
+    #[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 {
@@ -177,10 +196,12 @@ impl UnsignedByteField {
 }
 
 impl UnsignedEnum for UnsignedByteField {
+    #[inline]
     fn size(&self) -> usize {
         self.width
     }
 
+    #[inline]
     fn value(&self) -> u64 {
         self.value_const()
     }
@@ -220,6 +241,7 @@ impl UnsignedEnum for UnsignedByteField {
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct GenericUnsignedByteField<TYPE: Copy + Into<u64>> {
     value: TYPE,
 }
@@ -235,6 +257,7 @@ impl<TYPE: Copy + Into<u64>> GenericUnsignedByteField<TYPE> {
 }
 
 impl<TYPE: Copy + ToBeBytes + Into<u64>> UnsignedEnum for GenericUnsignedByteField<TYPE> {
+    #[inline]
     fn size(&self) -> usize {
         self.value.written_len()
     }
@@ -250,6 +273,7 @@ impl<TYPE: Copy + ToBeBytes + Into<u64>> UnsignedEnum for GenericUnsignedByteFie
         Ok(self.value.written_len())
     }
 
+    #[inline]
     fn value(&self) -> u64 {
         self.value_typed().into()
     }
@@ -275,6 +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 {
@@ -287,6 +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)
     }
@@ -295,6 +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 {
@@ -307,6 +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)
     }
@@ -315,6 +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 {
@@ -327,6 +356,7 @@ impl TryFrom<UnsignedByteField> for UnsignedByteFieldU32 {
 }
 
 impl From<UnsignedByteFieldU64> for UnsignedByteField {
+    #[inline]
     fn from(value: UnsignedByteFieldU64) -> Self {
         Self::new(8, value.value)
     }
@@ -335,6 +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 {