small update for unsigned byte field

.github/workflows/ci.yml

@@ -29,7 +29,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@1.81.0
+      - uses: dtolnay/rust-toolchain@1.68.2
       - run: cargo check --release
 
   cross-check:
@@ -61,7 +61,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
-      - run: RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc --all-features
+      - run: cargo +nightly doc --all-features --config 'build.rustdocflags=["--cfg", "docs_rs"]'
 
   clippy:
     name: Clippy

CHANGELOG.md

@@ -8,52 +8,15 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 # [unreleased]
 
-# [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
+# [v0.12.0] 2024-06-06
 
 ## 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).
+- `Default` impl for `GenericUnsignedByteField<()>` (also called `UnsignedByteFieldEmpty`)
 
 ## Changed
 
-- Minor documentation build updates.
-- Increased delegate version range to v0.13
+- Removed `Into<u64>` type constraint for `GenericUnsignedByteField`
 
 # [v0.11.2] 2024-05-19
 

Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "spacepackets"
-version = "0.13.0"
+version = "0.11.2"
 edition = "2021"
-rust-version = "1.81.0"
+rust-version = "1.68.2"
 authors = ["Robin Mueller <muellerr@irs.uni-stuttgart.de>"]
 description = "Generic implementations for various CCSDS and ECSS packet standards"
 homepage = "https://egit.irs.uni-stuttgart.de/rust/spacepackets"
@@ -14,16 +14,15 @@ categories = ["aerospace", "aerospace::space-protocols", "no-std", "hardware-sup
 
 [dependencies]
 crc = "3"
-delegate = ">=0.8, <=0.13"
-paste = "1"
+delegate = ">=0.8, <0.11"
 
 [dependencies.zerocopy]
-version = "0.8"
+version = "0.7"
 features = ["derive"]
 
 [dependencies.thiserror]
-version = "2"
-default-features = false
+version = "1"
+optional = true
 
 [dependencies.num_enum]
 version = ">0.5, <=0.7"
@@ -53,17 +52,19 @@ default-features = false
 version = "0.3"
 optional = true
 
+[dev-dependencies]
+postcard = "1"
+chrono = "0.4"
+
 [features]
 default = ["std"]
-std = ["alloc", "chrono/std", "chrono/clock", "thiserror/std"]
-serde = ["dep:serde", "chrono?/serde"]
-alloc = ["chrono?/alloc", "defmt?/alloc", "serde?/alloc"]
+std = ["chrono/std", "chrono/clock", "alloc", "thiserror"]
+serde = ["dep:serde", "chrono/serde"]
+alloc = ["postcard/alloc", "chrono/alloc"]
+chrono = ["dep:chrono"]
 timelib = ["dep:time"]
-
-[dev-dependencies]
-postcard = { version = "1", features = ["alloc"] }
-chrono = "0.4"
+defmt = ["dep:defmt"]
 
 [package.metadata.docs.rs]
 all-features = true
-rustdoc-args = ["--generate-link-to-definition"]
+rustdoc-args = ["--cfg", "docs_rs", "--generate-link-to-definition"]

automation/Jenkinsfile

@@ -21,9 +21,7 @@ pipeline {
     }
     stage('Docs') {
         steps {
-          sh """
-            RUSTDOCFLAGS="--cfg docsrs --generate-link-to-definition -Z unstable-options" cargo +nightly doc --all-features
-          """
+          sh 'cargo +nightly doc --all-features'
         }
     }
     stage('Rustfmt') {

docs.sh

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

release-checklist.md

@@ -4,9 +4,7 @@ Checklist for new releases
 # Pre-Release
 
 1. Make sure any new modules are documented sufficiently enough and check docs with
-   `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).
+   `cargo +nightly doc --all-features --config 'build.rustdocflags=["--cfg", "docs_rs"]' --open`.
 2. Bump version specifier in `Cargo.toml`.
 3. Update `CHANGELOG.md`: Convert `unreleased` section into version section with date and add new
    `unreleased` section.

src/cfdp/lv.rs

@@ -1,4 +1,5 @@
 //! 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")]
@@ -6,8 +7,6 @@ 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.
@@ -64,9 +63,9 @@ pub(crate) fn generic_len_check_deserialization(
 
 impl<'data> Lv<'data> {
     #[inline]
-    pub fn new(data: &[u8]) -> Result<Lv, TlvLvDataTooLargeError> {
+    pub fn new(data: &[u8]) -> Result<Lv, TlvLvError> {
         if data.len() > u8::MAX as usize {
-            return Err(TlvLvDataTooLargeError(data.len()));
+            return Err(TlvLvError::DataTooLarge(data.len()));
         }
         Ok(Lv {
             data,
@@ -86,7 +85,7 @@ impl<'data> Lv<'data> {
     /// Helper function to build a string LV. This is especially useful for the file or directory
     /// path LVs
     #[inline]
-    pub fn new_from_str(str_slice: &str) -> Result<Lv, TlvLvDataTooLargeError> {
+    pub fn new_from_str(str_slice: &str) -> Result<Lv, TlvLvError> {
         Self::new(str_slice.as_bytes())
     }
 
@@ -94,7 +93,7 @@ impl<'data> Lv<'data> {
     /// path LVs
     #[cfg(feature = "std")]
     #[inline]
-    pub fn new_from_string(string: &'data String) -> Result<Lv<'data>, TlvLvDataTooLargeError> {
+    pub fn new_from_string(string: &'data String) -> Result<Lv<'data>, TlvLvError> {
         Self::new(string.as_bytes())
     }
 
@@ -178,10 +177,10 @@ impl<'data> Lv<'data> {
 
 #[cfg(test)]
 pub mod tests {
+    use super::*;
     use alloc::string::ToString;
 
-    use super::*;
-
+    use crate::cfdp::TlvLvError;
     use crate::ByteConversionError;
     use std::string::String;
 
@@ -272,11 +271,15 @@ pub mod tests {
         let lv = Lv::new(&data_big);
         assert!(lv.is_err());
         let error = lv.unwrap_err();
-        assert_eq!(error.0, u8::MAX as usize + 1);
-        assert_eq!(
-            error.to_string(),
-            "data with size 256 larger than allowed 255 bytes"
-        );
+        if let TlvLvError::DataTooLarge(size) = error {
+            assert_eq!(size, u8::MAX as usize + 1);
+            assert_eq!(
+                error.to_string(),
+                "data with size 256 larger than allowed 255 bytes"
+            );
+        } else {
+            panic!("invalid exception {:?}", error)
+        }
     }
 
     #[test]

src/cfdp/mod.rs

@@ -1,8 +1,11 @@
 //! 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;
@@ -113,7 +116,7 @@ pub enum ConditionCode {
     FileSizeError = 0b0110,
     NakLimitReached = 0b0111,
     InactivityDetected = 0b1000,
-    CheckLimitReached = 0b1010,
+    CheckLimitReached = 0b1001,
     UnsupportedChecksumType = 0b1011,
     /// Not an actual fault condition for which fault handler overrides can be specified
     SuspendRequestReceived = 0b1110,
@@ -173,43 +176,76 @@ impl Default for ChecksumType {
 
 pub const NULL_CHECKSUM_U32: [u8; 4] = [0; 4];
 
-#[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)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum TlvLvError {
-    #[error("{0}")]
-    DataTooLarge(#[from] TlvLvDataTooLargeError),
-    #[error("byte conversion error: {0}")]
-    ByteConversion(#[from] ByteConversionError),
-    #[error("{0}")]
-    InvalidTlvTypeField(#[from] InvalidTlvTypeFieldError),
-    #[error("invalid value length {0}")]
+    DataTooLarge(usize),
+    ByteConversion(ByteConversionError),
+    /// First value: Found value. Second value: Expected value if there is one.
+    InvalidTlvTypeField {
+        found: u8,
+        expected: Option<u8>,
+    },
+    /// 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/eof.rs

@@ -25,36 +25,20 @@ pub struct EofPdu {
 }
 
 impl EofPdu {
-    pub fn new(
-        mut pdu_header: PduHeader,
-        condition_code: ConditionCode,
-        file_checksum: u32,
-        file_size: u64,
-        fault_location: Option<EntityIdTlv>,
-    ) -> Self {
+    pub fn new_no_error(mut pdu_header: PduHeader, file_checksum: u32, file_size: u64) -> Self {
         // Force correct direction flag.
         pdu_header.pdu_conf.direction = Direction::TowardsReceiver;
         let mut eof_pdu = Self {
             pdu_header,
-            condition_code,
+            condition_code: ConditionCode::NoError,
             file_checksum,
             file_size,
-            fault_location,
+            fault_location: None,
         };
         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
     }
@@ -164,7 +148,7 @@ impl WritablePduPacket for EofPdu {
             &mut buf[current_idx..],
         )?;
         if let Some(fault_location) = self.fault_location {
-            current_idx += fault_location.write_to_bytes(&mut buf[current_idx..])?;
+            current_idx += fault_location.write_to_bytes(buf)?;
         }
         if self.crc_flag() == CrcFlag::WithCrc {
             current_idx = add_pdu_crc(buf, current_idx);
@@ -187,23 +171,13 @@ 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_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,
-    ) {
+    fn verify_state(&eof_pdu: &EofPdu, file_flag: LargeFileFlag) {
         assert_eq!(eof_pdu.file_checksum(), 0x01020304);
         assert_eq!(eof_pdu.file_size(), 12);
-        assert_eq!(eof_pdu.condition_code(), cond_code);
+        assert_eq!(eof_pdu.condition_code(), ConditionCode::NoError);
 
-        assert_eq!(eof_pdu.crc_flag(), crc_flag);
+        assert_eq!(eof_pdu.crc_flag(), CrcFlag::NoCrc);
         assert_eq!(eof_pdu.file_flag(), file_flag);
         assert_eq!(eof_pdu.pdu_type(), PduType::FileDirective);
         assert_eq!(
@@ -223,7 +197,7 @@ 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_no_error_no_crc(&eof_pdu, LargeFileFlag::Normal);
+        verify_state(&eof_pdu, LargeFileFlag::Normal);
     }
 
     #[test]
@@ -297,7 +271,7 @@ 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::Checksum(e) = error {
+        if let PduError::ChecksumError(e) = error {
             assert_eq!(e, crc);
         } else {
             panic!("expected crc error");
@@ -309,7 +283,7 @@ 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_no_error_no_crc(&eof_pdu, LargeFileFlag::Large);
+        verify_state(&eof_pdu, LargeFileFlag::Large);
         assert_eq!(eof_pdu.len_written(), pdu_header.header_len() + 2 + 8 + 4);
     }
 
@@ -321,48 +295,4 @@ 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

@@ -92,67 +92,16 @@ 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))]
-    common: FdPduBase<'seg_meta>,
+    segment_metadata: Option<SegmentMetadata<'seg_meta>>,
+    offset: u64,
     file_data: &'file_data [u8],
 }
 
@@ -185,34 +134,42 @@ impl<'seg_meta, 'file_data> FileDataPdu<'seg_meta, 'file_data> {
             pdu_header.seg_metadata_flag = SegmentMetadataFlag::Present;
         }
         let mut pdu = Self {
-            common: FdPduBase {
-                pdu_header,
-                segment_metadata,
-                offset,
-            },
+            pdu_header,
+            segment_metadata,
+            offset,
             file_data,
         };
-        pdu.common.pdu_header.pdu_datafield_len = pdu.calc_pdu_datafield_len() as u16;
+        pdu.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() as u64)
-    }
-
-    pub fn segment_metadata(&self) -> Option<&SegmentMetadata> {
-        self.common.segment_metadata.as_ref()
+        let mut len = core::mem::size_of::<u32>();
+        if self.pdu_header.pdu_conf.file_flag == LargeFileFlag::Large {
+            len += 4;
+        }
+        if self.segment_metadata.is_some() {
+            len += self.segment_metadata.as_ref().unwrap().written_len()
+        }
+        len += self.file_data.len();
+        if self.crc_flag() == CrcFlag::WithCrc {
+            len += 2;
+        }
+        len
     }
 
     pub fn offset(&self) -> u64 {
-        self.common.offset
+        self.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)?;
@@ -233,18 +190,16 @@ impl<'seg_meta, 'file_data> FileDataPdu<'seg_meta, 'file_data> {
             .into());
         }
         Ok(Self {
-            common: FdPduBase {
-                pdu_header,
-                segment_metadata,
-                offset,
-            },
+            pdu_header,
+            segment_metadata,
+            offset,
             file_data: &buf[current_idx..full_len_without_crc],
         })
     }
 }
 impl CfdpPdu for FileDataPdu<'_, '_> {
     fn pdu_header(&self) -> &PduHeader {
-        &self.common.pdu_header
+        &self.pdu_header
     }
 
     fn file_directive_type(&self) -> Option<FileDirectiveType> {
@@ -261,8 +216,19 @@ impl WritablePduPacket for FileDataPdu<'_, '_> {
             }
             .into());
         }
-
-        let mut current_idx = self.common.write_common_fields_to_bytes(buf)?;
+        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..],
+        )?;
         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 {
@@ -272,167 +238,10 @@ impl WritablePduPacket for FileDataPdu<'_, '_> {
     }
 
     fn len_written(&self) -> usize {
-        self.common.pdu_header.header_len() + self.calc_pdu_datafield_len()
+        self.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::*;
@@ -454,7 +263,7 @@ 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);
@@ -481,11 +290,11 @@ 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(),
         );
@@ -544,7 +353,7 @@ 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::Checksum(e) = error {
+        if let PduError::ChecksumError(e) = error {
             assert_eq!(e, crc);
         } else {
             panic!("expected crc error");
@@ -571,7 +380,7 @@ 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>()
@@ -581,7 +390,7 @@ 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
@@ -673,142 +482,4 @@ 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

@@ -4,14 +4,13 @@ use crate::cfdp::pdu::{
 use crate::cfdp::tlv::{
     EntityIdTlv, FilestoreResponseTlv, GenericTlv, Tlv, TlvType, TlvTypeField, WritableTlv,
 };
-use crate::cfdp::{ConditionCode, CrcFlag, Direction, PduType};
+use crate::cfdp::{ConditionCode, CrcFlag, Direction, PduType, TlvLvError};
 use crate::ByteConversionError;
 use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
-use super::tlv::ReadableTlv;
-use super::{CfdpPdu, InvalidTlvTypeFieldError, WritablePduPacket};
+use super::{CfdpPdu, WritablePduPacket};
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
@@ -332,26 +331,22 @@ 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::Format);
+                            return Err(PduError::FormatError);
                         }
                     } else {
-                        return Err(PduError::TlvLv(
-                            InvalidTlvTypeFieldError {
-                                found: tlv_type.into(),
-                                expected: Some(TlvType::FilestoreResponse.into()),
-                            }
-                            .into(),
-                        ));
+                        return Err(TlvLvError::InvalidTlvTypeField {
+                            found: tlv_type.into(),
+                            expected: Some(TlvType::FilestoreResponse.into()),
+                        }
+                        .into());
                     }
                 }
                 TlvTypeField::Custom(raw) => {
-                    return Err(PduError::TlvLv(
-                        InvalidTlvTypeFieldError {
-                            found: raw,
-                            expected: None,
-                        }
-                        .into(),
-                    ));
+                    return Err(TlvLvError::InvalidTlvTypeField {
+                        found: raw,
+                        expected: None,
+                    }
+                    .into());
                 }
             }
         }
@@ -568,7 +563,7 @@ 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::Checksum(e) = error {
+        if let PduError::ChecksumError(e) = error {
             assert_eq!(e, crc);
         } else {
             panic!("expected crc error");

src/cfdp/pdu/metadata.rs

@@ -1,5 +1,3 @@
-#[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,
@@ -13,7 +11,6 @@ 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)]
@@ -54,15 +51,6 @@ 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
@@ -73,7 +61,7 @@ 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 [u8],
+    options: &'opts [Tlv<'opts>],
 }
 
 impl<'src_name, 'dest_name, 'opts> MetadataPduCreator<'src_name, 'dest_name, 'opts> {
@@ -97,7 +85,7 @@ 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 [u8],
+        options: &'opts [Tlv<'opts>],
     ) -> Self {
         Self::new(
             pdu_header,
@@ -113,7 +101,7 @@ 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 [u8],
+        options: &'opts [Tlv<'opts>],
     ) -> Self {
         pdu_header.pdu_type = PduType::FileDirective;
         pdu_header.pdu_conf.direction = Direction::TowardsReceiver;
@@ -140,19 +128,10 @@ impl<'src_name, 'dest_name, 'opts> MetadataPduCreator<'src_name, 'dest_name, 'op
         self.dest_file_name
     }
 
-    pub fn options(&self) -> &'opts [u8] {
+    pub fn options(&self) -> &'opts [Tlv<'opts>] {
         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;
@@ -163,7 +142,9 @@ 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();
-        len += self.options().len();
+        for tlv in self.options() {
+            len += tlv.len_full()
+        }
         if self.crc_flag() == CrcFlag::WithCrc {
             len += 2;
         }
@@ -209,8 +190,10 @@ impl WritablePduPacket for MetadataPduCreator<'_, '_, '_> {
         current_idx += self
             .dest_file_name
             .write_to_be_bytes(&mut buf[current_idx..])?;
-        buf[current_idx..current_idx + self.options.len()].copy_from_slice(self.options);
-        current_idx += self.options.len();
+        for opt in self.options() {
+            opt.write_to_bytes(&mut buf[current_idx..current_idx + opt.len_full()])?;
+            current_idx += opt.len_full();
+        }
         if self.crc_flag() == CrcFlag::WithCrc {
             current_idx = add_pdu_crc(buf, current_idx);
         }
@@ -371,7 +354,7 @@ pub mod tests {
     };
     use crate::cfdp::pdu::{CfdpPdu, PduError, WritablePduPacket};
     use crate::cfdp::pdu::{FileDirectiveType, PduHeader};
-    use crate::cfdp::tlv::{ReadableTlv, Tlv, TlvOwned, TlvType, WritableTlv};
+    use crate::cfdp::tlv::{Tlv, TlvType};
     use crate::cfdp::{
         ChecksumType, CrcFlag, Direction, LargeFileFlag, PduType, SegmentMetadataFlag,
         SegmentationControl, TransmissionMode,
@@ -381,16 +364,16 @@ pub mod tests {
     const SRC_FILENAME: &str = "hello-world.txt";
     const DEST_FILENAME: &str = "hello-world2.txt";
 
-    fn generic_metadata_pdu(
+    fn generic_metadata_pdu<'opts>(
         crc_flag: CrcFlag,
         checksum_type: ChecksumType,
         closure_requested: bool,
         fss: LargeFileFlag,
-        opts: &[u8],
+        opts: &'opts [Tlv],
     ) -> (
         Lv<'static>,
         Lv<'static>,
-        MetadataPduCreator<'static, 'static, '_>,
+        MetadataPduCreator<'static, 'static, 'opts>,
     ) {
         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);
@@ -560,9 +543,9 @@ 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_iter();
-        for (tlv_written, tlv_read) in opts.zip(read.options_iter().unwrap()) {
-            assert_eq!(&tlv_written, &tlv_read);
+        let opts = written.options();
+        for (tlv_written, tlv_read) in opts.iter().zip(read.options_iter().unwrap()) {
+            assert_eq!(tlv_written, &tlv_read);
         }
     }
 
@@ -677,14 +660,14 @@ 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 mut tlv_buf: [u8; 64] = [0; 64];
-        let opts_len = build_metadata_opts_from_slice(&mut tlv_buf, &[tlv1, tlv2]).unwrap();
+        let tlv_vec = vec![tlv1, tlv2];
+        let opts_len = tlv1.len_full() + tlv2.len_full();
         let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
             CrcFlag::NoCrc,
             ChecksumType::Crc32,
             false,
             LargeFileFlag::Normal,
-            &tlv_buf[0..opts_len],
+            &tlv_vec,
         );
         let mut buf: [u8; 128] = [0; 128];
         let write_res = metadata_pdu.write_to_bytes(&mut buf);
@@ -707,55 +690,7 @@ pub mod tests {
         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());
-    }
-    #[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);
-            }
+            assert_eq!(tlv_vec[idx], opt);
             accumulated_len += opt.len_full();
         }
         assert_eq!(accumulated_len, pdu_read_back.options().len());
@@ -780,7 +715,7 @@ pub mod tests {
             assert_eq!(expected, Some(FileDirectiveType::MetadataPdu));
             assert_eq!(
                 error.to_string(),
-                "invalid directive type, found 255, expected Some(MetadataPdu)"
+                "invalid directive type value 255, expected Some(MetadataPdu)"
             );
         } else {
             panic!("Expected InvalidDirectiveType error, got {:?}", error);
@@ -806,7 +741,7 @@ pub mod tests {
             assert_eq!(expected, FileDirectiveType::MetadataPdu);
             assert_eq!(
                 error.to_string(),
-                "wrong directive type, found EofPdu, expected MetadataPdu"
+                "found directive type EofPdu, expected MetadataPdu"
             );
         } else {
             panic!("Expected InvalidDirectiveType error, got {:?}", error);

src/cfdp/pdu/mod.rs

@@ -5,6 +5,9 @@ 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;
@@ -27,62 +30,137 @@ pub enum FileDirectiveType {
     KeepAlivePdu = 0x0c,
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq, thiserror::Error)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum PduError {
-    #[error("byte conversion error: {0}")]
-    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)]
+    ByteConversion(ByteConversionError),
+    /// Found version ID invalid, not equal to [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.
-    #[error("checksum error for checksum {0}")]
-    Checksum(u16),
+    ChecksumError(u16),
     /// Generic error for invalid PDU formats.
-    #[error("generic PDU format error")]
-    Format,
+    FormatError,
     /// Error handling a TLV field.
-    #[error("PDU error: {0}")]
-    TlvLv(#[from] TlvLvError),
+    TlvLvError(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 {
+    #[inline]
+    fn from(value: ByteConversionError) -> Self {
+        Self::ByteConversion(value)
+    }
+}
+
+impl From<TlvLvError> for PduError {
+    #[inline]
+    fn from(e: TlvLvError) -> Self {
+        Self::TlvLvError(e)
+    }
 }
 
 pub trait WritablePduPacket {
@@ -454,7 +532,7 @@ impl PduHeader {
             let mut digest = CRC_CCITT_FALSE.digest();
             digest.update(&buf[..self.pdu_len()]);
             if digest.finalize() != 0 {
-                return Err(PduError::Checksum(u16::from_be_bytes(
+                return Err(PduError::ChecksumError(u16::from_be_bytes(
                     buf[self.pdu_len() - 2..self.pdu_len()].try_into().unwrap(),
                 )));
             }
@@ -903,7 +981,7 @@ 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);
@@ -951,7 +1029,7 @@ mod tests {
             assert_eq!(expected, 7);
             assert_eq!(
                 error.to_string(),
-                "byte conversion error: source slice with size 6 too small, expected at least 7 bytes"
+                "source slice with size 6 too small, expected at least 7 bytes"
             );
         }
     }
@@ -1006,7 +1084,7 @@ mod tests {
             assert_eq!(dest_id_len, 2);
             assert_eq!(
                 error.to_string(),
-                "missmatch of PDU source ID length 1 and destination ID length 2"
+                "missmatch of PDU source length 1 and destination length 2"
             );
         }
     }

src/cfdp/pdu/nak.rs

@@ -751,7 +751,7 @@ mod tests {
         if let PduError::InvalidStartOrEndOfScopeValue = error {
             assert_eq!(
                 error.to_string(),
-                "invalid start or end of scope value for NAK PDU"
+                "invalid start or end of scope for NAK PDU"
             );
         } else {
             panic!("unexpected error {error}");
@@ -796,7 +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::Checksum(raw)) = nak_pdu_deser {
+        if let Err(PduError::ChecksumError(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

@@ -9,14 +9,10 @@ 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;
@@ -43,26 +39,6 @@ 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;
@@ -153,14 +129,14 @@ pub struct Tlv<'data> {
 }
 
 impl<'data> Tlv<'data> {
-    pub fn new(tlv_type: TlvType, data: &[u8]) -> Result<Tlv, TlvLvDataTooLargeError> {
+    pub fn new(tlv_type: TlvType, data: &[u8]) -> Result<Tlv, TlvLvError> {
         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, TlvLvDataTooLargeError> {
+    pub fn new_with_custom_type(tlv_type: u8, data: &[u8]) -> Result<Tlv, TlvLvError> {
         Ok(Tlv {
             tlv_type_field: TlvTypeField::Custom(tlv_type),
             lv: Lv::new(data)?,
@@ -175,11 +151,31 @@ 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>, ByteConversionError> {
+    pub fn from_bytes(buf: &'data [u8]) -> Result<Tlv<'data>, TlvLvError> {
         generic_len_check_deserialization(buf, MIN_TLV_LEN)?;
         let mut tlv = Self {
             tlv_type_field: TlvTypeField::from(buf[0]),
@@ -196,27 +192,6 @@ 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<'_> {
@@ -237,90 +212,18 @@ impl GenericTlv for Tlv<'_> {
     }
 }
 
-#[cfg(feature = "alloc")]
-pub mod alloc_mod {
-    use super::*;
-
-    /// Owned variant of [Tlv] which is consequently [Clone]able and does not have a lifetime
-    /// associated to a data slice.
-    #[derive(Debug, Clone, PartialEq, Eq)]
-    #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
-    #[cfg_attr(feature = "defmt", derive(defmt::Format))]
-    pub struct TlvOwned {
-        pub(crate) tlv_type_field: TlvTypeField,
-        pub(crate) data: Vec<u8>,
-    }
-
-    impl TlvOwned {
-        pub fn new(tlv_type: TlvType, data: &[u8]) -> 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()
-        }
+pub(crate) fn verify_tlv_type(raw_type: u8, expected_tlv_type: TlvType) -> Result<(), TlvLvError> {
+    let tlv_type = TlvType::try_from(raw_type).map_err(|_| TlvLvError::InvalidTlvTypeField {
+        found: raw_type,
+        expected: Some(expected_tlv_type.into()),
+    })?;
+    if tlv_type != expected_tlv_type {
+        return Err(TlvLvError::InvalidTlvTypeField {
+            found: tlv_type as u8,
+            expected: Some(expected_tlv_type as u8),
+        });
     }
+    Ok(())
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
@@ -374,8 +277,11 @@ impl EntityIdTlv {
         Self::len_check(buf)?;
         self.entity_id
             .write_to_be_bytes(&mut buf[2..2 + self.entity_id.size()])?;
-        // Can't fail.
-        Ok(Tlv::new(TlvType::EntityId, &buf[2..2 + self.entity_id.size()]).unwrap())
+        Tlv::new(TlvType::EntityId, &buf[2..2 + self.entity_id.size()]).map_err(|e| match e {
+            TlvLvError::ByteConversion(e) => e,
+            // All other errors are impossible.
+            _ => panic!("unexpected TLV error"),
+        })
     }
 }
 
@@ -401,23 +307,21 @@ impl GenericTlv for EntityIdTlv {
 impl<'data> TryFrom<Tlv<'data>> for EntityIdTlv {
     type Error = TlvLvError;
 
-    fn try_from(value: Tlv) -> Result<Self, TlvLvError> {
+    fn try_from(value: Tlv) -> Result<Self, Self::Error> {
         match value.tlv_type_field {
             TlvTypeField::Standard(tlv_type) => {
                 if tlv_type != TlvType::EntityId {
-                    return Err(InvalidTlvTypeFieldError {
+                    return Err(TlvLvError::InvalidTlvTypeField {
                         found: tlv_type as u8,
                         expected: Some(TlvType::EntityId as u8),
-                    }
-                    .into());
+                    });
                 }
             }
             TlvTypeField::Custom(val) => {
-                return Err(InvalidTlvTypeFieldError {
+                return Err(TlvLvError::InvalidTlvTypeField {
                     found: val,
                     expected: Some(TlvType::EntityId as u8),
-                }
-                .into());
+                });
             }
         }
         let len_value = value.value().len();
@@ -848,23 +752,6 @@ 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::*;
@@ -1052,14 +939,14 @@ mod tests {
         let tlv_res = Tlv::new(TlvType::MsgToUser, &buf_too_large);
         assert!(tlv_res.is_err());
         let error = tlv_res.unwrap_err();
-        match error {
-            TlvLvDataTooLargeError(size) => {
-                assert_eq!(size, u8::MAX as usize + 1);
-                assert_eq!(
-                    error.to_string(),
-                    "data with size 256 larger than allowed 255 bytes"
-                );
-            }
+        if let TlvLvError::DataTooLarge(size) = error {
+            assert_eq!(size, u8::MAX as usize + 1);
+            assert_eq!(
+                error.to_string(),
+                "data with size 256 larger than allowed 255 bytes"
+            );
+        } else {
+            panic!("unexpected error {:?}", error);
         }
     }
 
@@ -1369,8 +1256,7 @@ mod tests {
         let error = EntityIdTlv::try_from(msg_to_user_tlv);
         assert!(error.is_err());
         let error = error.unwrap_err();
-        if let TlvLvError::InvalidTlvTypeField(InvalidTlvTypeFieldError { found, expected }) = error
-        {
+        if let TlvLvError::InvalidTlvTypeField { found, expected } = error {
             assert_eq!(found, TlvType::MsgToUser as u8);
             assert_eq!(expected, Some(TlvType::EntityId as u8));
             assert_eq!(
@@ -1414,71 +1300,4 @@ 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

@@ -1,11 +1,6 @@
 //! Abstractions for the Message to User CFDP TLV subtype.
-#[cfg(feature = "alloc")]
-use super::TlvOwned;
-use super::{GenericTlv, ReadableTlv, Tlv, TlvLvError, TlvType, TlvTypeField, WritableTlv};
-use crate::{
-    cfdp::{InvalidTlvTypeFieldError, TlvLvDataTooLargeError},
-    ByteConversionError,
-};
+use super::{GenericTlv, Tlv, TlvLvError, TlvType, TlvTypeField, WritableTlv};
+use crate::ByteConversionError;
 use delegate::delegate;
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
@@ -15,7 +10,7 @@ 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>, TlvLvDataTooLargeError> {
+    pub fn new(value: &'data [u8]) -> Result<MsgToUserTlv<'data>, TlvLvError> {
         Ok(Self {
             tlv: Tlv::new(TlvType::MsgToUser, value)?,
         })
@@ -65,38 +60,21 @@ impl<'data> MsgToUserTlv<'data> {
         match msg_to_user.tlv.tlv_type_field() {
             TlvTypeField::Standard(tlv_type) => {
                 if tlv_type != TlvType::MsgToUser {
-                    return Err(InvalidTlvTypeFieldError {
+                    return Err(TlvLvError::InvalidTlvTypeField {
                         found: tlv_type as u8,
                         expected: Some(TlvType::MsgToUser as u8),
-                    }
-                    .into());
+                    });
                 }
             }
             TlvTypeField::Custom(raw) => {
-                return Err(InvalidTlvTypeFieldError {
+                return Err(TlvLvError::InvalidTlvTypeField {
                     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<'_> {
@@ -161,40 +139,6 @@ 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];
@@ -210,9 +154,9 @@ 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(inner) = error {
-            assert_eq!(inner.found, TlvType::FlowLabel as u8);
-            assert_eq!(inner.expected, Some(TlvType::MsgToUser as u8));
+        if let TlvLvError::InvalidTlvTypeField { found, expected } = error {
+            assert_eq!(found, TlvType::FlowLabel as u8);
+            assert_eq!(expected, Some(TlvType::MsgToUser as u8));
         } else {
             panic!("Wrong error type returned: {:?}", error);
         }

src/ecss/mod.rs

@@ -6,11 +6,13 @@
 use crate::{ByteConversionError, CcsdsPacket, CRC_CCITT_FALSE};
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
-use core::fmt::Debug;
+use core::fmt::{Debug, Display, Formatter};
 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;
@@ -146,19 +148,50 @@ pub enum PfcReal {
     DoubleMilStd = 4,
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq, thiserror::Error)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[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
-    //#[error("crc16 was not calculated")]
-    //CrcCalculationMissing,
-    #[error("pus error: {0}")]
-    ByteConversion(#[from] ByteConversionError),
+    CrcCalculationMissing,
+    ByteConversion(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

src/ecss/tc.rs

@@ -45,7 +45,7 @@ use delegate::delegate;
 use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
-use zerocopy::{FromBytes, IntoBytes};
+use zerocopy::AsBytes;
 
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
@@ -86,9 +86,9 @@ pub trait GenericPusTcSecondaryHeader {
 pub mod zc {
     use crate::ecss::tc::GenericPusTcSecondaryHeader;
     use crate::ecss::{PusError, PusVersion};
-    use zerocopy::{FromBytes, Immutable, IntoBytes, NetworkEndian, Unaligned, U16};
+    use zerocopy::{AsBytes, FromBytes, FromZeroes, NetworkEndian, Unaligned, U16};
 
-    #[derive(FromBytes, IntoBytes, Immutable, Unaligned)]
+    #[derive(FromZeroes, FromBytes, AsBytes, Unaligned)]
     #[repr(C)]
     pub struct PusTcSecondaryHeader {
         version_ack: u8,
@@ -138,6 +138,16 @@ pub mod zc {
             self.source_id.get()
         }
     }
+
+    impl PusTcSecondaryHeader {
+        pub fn write_to_bytes(&self, slice: &mut [u8]) -> Option<()> {
+            self.write_to(slice)
+        }
+
+        pub fn from_bytes(slice: &[u8]) -> Option<Self> {
+            Self::read_from(slice)
+        }
+    }
 }
 
 #[derive(PartialEq, Eq, Copy, Clone, Debug)]
@@ -382,8 +392,8 @@ impl WritablePusPacket for PusTcCreator<'_> {
         curr_idx += CCSDS_HEADER_LEN;
         let sec_header = zc::PusTcSecondaryHeader::try_from(self.sec_header).unwrap();
         sec_header
-            .write_to(&mut slice[curr_idx..curr_idx + tc_header_len])
-            .map_err(|_| ByteConversionError::ZeroCopyToError)?;
+            .write_to_bytes(&mut slice[curr_idx..curr_idx + tc_header_len])
+            .ok_or(ByteConversionError::ZeroCopyToError)?;
 
         curr_idx += tc_header_len;
         slice[curr_idx..curr_idx + self.app_data.len()].copy_from_slice(self.app_data);
@@ -492,10 +502,10 @@ impl<'raw_data> PusTcReader<'raw_data> {
             }
             .into());
         }
-        let sec_header = zc::PusTcSecondaryHeader::read_from_bytes(
+        let sec_header = zc::PusTcSecondaryHeader::from_bytes(
             &slice[current_idx..current_idx + PUC_TC_SECONDARY_HEADER_LEN],
         )
-        .map_err(|_| ByteConversionError::ZeroCopyFromError)?;
+        .ok_or(ByteConversionError::ZeroCopyFromError)?;
         current_idx += PUC_TC_SECONDARY_HEADER_LEN;
         let raw_data = &slice[0..total_len];
         let pus_tc = Self {

src/ecss/tm.rs

@@ -54,7 +54,7 @@ use crate::{
 use core::mem::size_of;
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
-use zerocopy::{FromBytes, IntoBytes};
+use zerocopy::AsBytes;
 
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
@@ -83,9 +83,9 @@ pub trait GenericPusTmSecondaryHeader {
 pub mod zc {
     use super::GenericPusTmSecondaryHeader;
     use crate::ecss::{PusError, PusVersion};
-    use zerocopy::{FromBytes, Immutable, IntoBytes, NetworkEndian, Unaligned, U16};
+    use zerocopy::{AsBytes, FromBytes, FromZeroes, NetworkEndian, Unaligned, U16};
 
-    #[derive(FromBytes, IntoBytes, Immutable, Unaligned)]
+    #[derive(FromBytes, FromZeroes, AsBytes, Unaligned)]
     #[repr(C)]
     pub struct PusTmSecHeaderWithoutTimestamp {
         pus_version_and_sc_time_ref_status: u8,
@@ -117,6 +117,16 @@ pub mod zc {
         }
     }
 
+    impl PusTmSecHeaderWithoutTimestamp {
+        pub fn write_to_bytes(&self, slice: &mut [u8]) -> Option<()> {
+            self.write_to(slice)
+        }
+
+        pub fn from_bytes(slice: &[u8]) -> Option<Self> {
+            Self::read_from(slice)
+        }
+    }
+
     impl GenericPusTmSecondaryHeader for PusTmSecHeaderWithoutTimestamp {
         #[inline]
         fn pus_version(&self) -> PusVersion {
@@ -403,8 +413,8 @@ impl<'time, 'src_data> PusTmCreator<'time, 'src_data> {
         let sec_header_len = size_of::<zc::PusTmSecHeaderWithoutTimestamp>();
         let sec_header = zc::PusTmSecHeaderWithoutTimestamp::try_from(self.sec_header).unwrap();
         sec_header
-            .write_to(&mut slice[curr_idx..curr_idx + sec_header_len])
-            .map_err(|_| ByteConversionError::ZeroCopyToError)?;
+            .write_to_bytes(&mut slice[curr_idx..curr_idx + sec_header_len])
+            .ok_or(ByteConversionError::ZeroCopyToError)?;
         curr_idx += sec_header_len;
         slice[curr_idx..curr_idx + self.sec_header.timestamp.len()]
             .copy_from_slice(self.sec_header.timestamp);
@@ -561,10 +571,10 @@ impl<'raw_data> PusTmReader<'raw_data> {
             }
             .into());
         }
-        let sec_header_zc = zc::PusTmSecHeaderWithoutTimestamp::read_from_bytes(
+        let sec_header_zc = zc::PusTmSecHeaderWithoutTimestamp::from_bytes(
             &slice[current_idx..current_idx + PUS_TM_MIN_SEC_HEADER_LEN],
         )
-        .map_err(|_| ByteConversionError::ZeroCopyFromError)?;
+        .ok_or(ByteConversionError::ZeroCopyFromError)?;
         current_idx += PUS_TM_MIN_SEC_HEADER_LEN;
         let zc_sec_header_wrapper = zc::PusTmSecHeader {
             zc_header: sec_header_zc,
@@ -700,7 +710,7 @@ impl<'raw> PusTmZeroCopyWriter<'raw> {
         if raw_tm_len < CCSDS_HEADER_LEN + PUS_TM_MIN_SEC_HEADER_LEN + timestamp_len {
             return None;
         }
-        let sp_header = crate::zc::SpHeader::read_from_bytes(&raw_tm[0..CCSDS_HEADER_LEN]).unwrap();
+        let sp_header = crate::zc::SpHeader::from_bytes(&raw_tm[0..CCSDS_HEADER_LEN]).unwrap();
         if raw_tm_len < sp_header.total_len() {
             return None;
         }
@@ -741,7 +751,7 @@ impl<'raw> PusTmZeroCopyWriter<'raw> {
     #[inline]
     pub fn sp_header(&self) -> crate::zc::SpHeader {
         // Valid minimum length of packet was checked before.
-        crate::zc::SpHeader::read_from_bytes(&self.raw_tm[0..CCSDS_HEADER_LEN]).unwrap()
+        crate::zc::SpHeader::from_bytes(&self.raw_tm[0..CCSDS_HEADER_LEN]).unwrap()
     }
 
     /// Helper API to generate the portion of the secondary header without a timestamp from the
@@ -749,7 +759,7 @@ impl<'raw> PusTmZeroCopyWriter<'raw> {
     #[inline]
     pub fn sec_header_without_timestamp(&self) -> PusTmSecHeaderWithoutTimestamp {
         // Valid minimum length of packet was checked before.
-        PusTmSecHeaderWithoutTimestamp::read_from_bytes(
+        PusTmSecHeaderWithoutTimestamp::from_bytes(
             &self.raw_tm[CCSDS_HEADER_LEN..CCSDS_HEADER_LEN + PUS_TM_MIN_SEC_HEADER_LEN],
         )
         .unwrap()

src/lib.rs

@@ -55,23 +55,27 @@
 //! println!("{:x?}", &ccsds_buf[0..6]);
 //! ```
 #![no_std]
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docs_rs, feature(doc_auto_cfg))]
 #[cfg(feature = "alloc")]
 extern crate alloc;
 #[cfg(any(feature = "std", test))]
 extern crate std;
 
-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 ecss;
-pub mod seq_count;
 pub mod time;
 pub mod util;
 
@@ -88,24 +92,55 @@ 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, thiserror::Error)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum ByteConversionError {
     /// The passed slice is too small. Returns the passed slice length and expected minimum size
-    #[error("target slice with size {found} is too small, expected size of at least {expected}")]
-    ToSliceTooSmall { found: usize, expected: usize },
+    ToSliceTooSmall {
+        found: usize,
+        expected: usize,
+    },
     /// The provider buffer is too small. Returns the passed slice length and expected minimum size
-    #[error("source slice with size {found} too small, expected at least {expected} bytes")]
-    FromSliceTooSmall { found: usize, expected: usize },
+    FromSliceTooSmall {
+        found: 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))]
@@ -697,8 +732,8 @@ impl SpHeader {
                 expected: CCSDS_HEADER_LEN,
             });
         }
-        let zc_header = zc::SpHeader::read_from_bytes(&buf[0..CCSDS_HEADER_LEN])
-            .map_err(|_| ByteConversionError::ZeroCopyFromError)?;
+        let zc_header = zc::SpHeader::from_bytes(&buf[0..CCSDS_HEADER_LEN])
+            .ok_or(ByteConversionError::ZeroCopyFromError)?;
         Ok((Self::from(zc_header), &buf[CCSDS_HEADER_LEN..]))
     }
 
@@ -716,8 +751,8 @@ impl SpHeader {
         }
         let zc_header: zc::SpHeader = zc::SpHeader::from(*self);
         zc_header
-            .write_to(&mut buf[0..CCSDS_HEADER_LEN])
-            .map_err(|_| ByteConversionError::ZeroCopyToError)?;
+            .to_bytes(&mut buf[0..CCSDS_HEADER_LEN])
+            .ok_or(ByteConversionError::ZeroCopyToError)?;
         Ok(&mut buf[CCSDS_HEADER_LEN..])
     }
 
@@ -779,9 +814,9 @@ sph_from_other!(SpHeader, crate::zc::SpHeader);
 pub mod zc {
     use crate::{CcsdsPacket, CcsdsPrimaryHeader, PacketId, PacketSequenceCtrl, VERSION_MASK};
     use zerocopy::byteorder::NetworkEndian;
-    use zerocopy::{FromBytes, Immutable, IntoBytes, Unaligned, U16};
+    use zerocopy::{AsBytes, FromBytes, FromZeroes, Unaligned, U16};
 
-    #[derive(FromBytes, IntoBytes, Immutable, Unaligned, Debug)]
+    #[derive(FromBytes, FromZeroes, AsBytes, Unaligned, Debug)]
     #[repr(C)]
     pub struct SpHeader {
         version_packet_id: U16<NetworkEndian>,
@@ -806,6 +841,14 @@ 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 {
@@ -874,7 +917,6 @@ 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::new_for_tc(true, 0x36),
@@ -1154,7 +1196,7 @@ pub(crate) mod tests {
 
     #[test]
     fn test_zc_sph() {
-        use zerocopy::IntoBytes;
+        use zerocopy::AsBytes;
 
         let sp_header = SpHeader::new_for_unseg_tc_checked(0x7FF, pow(2, 14) - 1, 0)
             .expect("Error creating SP header");
@@ -1174,7 +1216,7 @@ pub(crate) mod tests {
         assert_eq!(slice[5], 0x00);
 
         let mut slice = [0; 6];
-        sp_header_zc.write_to(slice.as_mut_slice()).unwrap();
+        sp_header_zc.write_to(slice.as_mut_slice());
         assert_eq!(slice.len(), 6);
         assert_eq!(slice[0], 0x17);
         assert_eq!(slice[1], 0xFF);
@@ -1185,7 +1227,7 @@ 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).unwrap();
+        sp_header_zc.write_to(slice);
         let slice = test_vec.as_slice();
         assert_eq!(slice.len(), 6);
         assert_eq!(slice[0], 0x17);
@@ -1195,8 +1237,8 @@ pub(crate) mod tests {
         assert_eq!(slice[4], 0x00);
         assert_eq!(slice[5], 0x00);
 
-        let sp_header = zc::SpHeader::read_from_bytes(slice);
-        assert!(sp_header.is_ok());
+        let sp_header = zc::SpHeader::from_bytes(slice);
+        assert!(sp_header.is_some());
         let sp_header = sp_header.unwrap();
         assert_eq!(sp_header.ccsds_version(), 0b000);
         assert_eq!(sp_header.packet_id_raw(), 0x17FF);

src/seq_count.rs

@@ -1,250 +0,0 @@
-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/cds.rs

@@ -7,13 +7,17 @@
 use crate::private::Sealed;
 use crate::ByteConversionError;
 use core::cmp::Ordering;
-use core::fmt::Debug;
+use core::fmt::{Debug, Display, Formatter};
 use core::ops::{Add, AddAssign};
 use core::time::Duration;
 
+use delegate::delegate;
+
 #[cfg(feature = "std")]
 use super::StdTimestampError;
 #[cfg(feature = "std")]
+use std::error::Error;
+#[cfg(feature = "std")]
 use std::time::{SystemTime, SystemTimeError};
 
 #[cfg(feature = "chrono")]
@@ -89,19 +93,49 @@ pub enum SubmillisPrecision {
     Reserved = 0b11,
 }
 
-#[derive(Debug, PartialEq, Eq, Copy, Clone, thiserror::Error)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum CdsError {
     /// CCSDS days value exceeds maximum allowed size or is negative
-    #[error("invalid ccsds days {0}")]
     InvalidCcsdsDays(i64),
     /// There are distinct constructors depending on the days field width detected in the preamble
     /// field. This error will be returned if there is a missmatch.
-    #[error("wrong constructor for length of day {0:?} detected in preamble")]
     InvalidCtorForDaysOfLenInPreamble(LengthOfDaySegment),
-    #[error("date before CCSDS epoch: {0}")]
-    DateBeforeCcsdsEpoch(#[from] DateBeforeCcsdsEpochError),
+    DateBeforeCcsdsEpoch(DateBeforeCcsdsEpochError),
+}
+
+impl Display for CdsError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+        match self {
+            CdsError::InvalidCcsdsDays(days) => {
+                write!(f, "invalid ccsds days {days}")
+            }
+            CdsError::InvalidCtorForDaysOfLenInPreamble(length_of_day) => {
+                write!(
+                    f,
+                    "wrong constructor for length of day {length_of_day:?} detected in preamble",
+                )
+            }
+            CdsError::DateBeforeCcsdsEpoch(e) => write!(f, "date before CCSDS epoch: {e}"),
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl Error for CdsError {
+    fn source(&self) -> Option<&(dyn Error + 'static)> {
+        match self {
+            CdsError::DateBeforeCcsdsEpoch(e) => Some(e),
+            _ => None,
+        }
+    }
+}
+
+impl From<DateBeforeCcsdsEpochError> for CdsError {
+    fn from(value: DateBeforeCcsdsEpochError) -> Self {
+        Self::DateBeforeCcsdsEpoch(value)
+    }
 }
 
 pub fn length_of_day_segment_from_pfield(pfield: u8) -> LengthOfDaySegment {
@@ -266,23 +300,20 @@ impl CdsConverter for ConversionFromUnix {
         self.unix_days_seconds
     }
 }
-
 /// Helper struct which generates fields for the CDS time provider from a datetime.
-#[cfg(feature = "chrono")]
 struct ConversionFromChronoDatetime {
     unix_conversion: ConversionFromUnix,
     submillis_prec: SubmillisPrecision,
     submillis: u32,
 }
 
-#[cfg(feature = "chrono")]
 impl CdsCommon for ConversionFromChronoDatetime {
     #[inline]
     fn submillis_precision(&self) -> SubmillisPrecision {
         self.submillis_prec
     }
 
-    delegate::delegate! {
+    delegate! {
         to self.unix_conversion {
             #[inline]
             fn ms_of_day(&self) -> u32;
@@ -297,9 +328,8 @@ impl CdsCommon for ConversionFromChronoDatetime {
     }
 }
 
-#[cfg(feature = "chrono")]
 impl CdsConverter for ConversionFromChronoDatetime {
-    delegate::delegate! {to self.unix_conversion {
+    delegate! {to self.unix_conversion {
         #[inline]
         fn unix_days_seconds(&self) -> i64;
     }}
@@ -336,6 +366,7 @@ impl ConversionFromChronoDatetime {
         Self::new_generic(dt, SubmillisPrecision::Picoseconds)
     }
 
+    #[cfg(feature = "chrono")]
     fn new_generic(
         dt: &chrono::DateTime<chrono::Utc>,
         prec: SubmillisPrecision,
@@ -417,7 +448,7 @@ impl CdsCommon for ConversionFromNow {
     fn submillis_precision(&self) -> SubmillisPrecision {
         self.submillis_prec
     }
-    delegate::delegate! {
+    delegate! {
         to self.unix_conversion {
             fn ms_of_day(&self) -> u32;
             fn ccsds_days_as_u32(&self) -> u32;
@@ -431,7 +462,7 @@ impl CdsCommon for ConversionFromNow {
 
 #[cfg(feature = "std")]
 impl CdsConverter for ConversionFromNow {
-    delegate::delegate! {to self.unix_conversion { fn unix_days_seconds(&self) -> i64; }}
+    delegate! {to self.unix_conversion { fn unix_days_seconds(&self) -> i64; }}
 }
 
 #[cfg(feature = "alloc")]

src/time/cuc.rs

@@ -9,6 +9,7 @@ use serde::{Deserialize, Serialize};
 use core::fmt::{Debug, Display, Formatter};
 use core::ops::{Add, AddAssign};
 use core::time::Duration;
+use core::u64;
 
 use crate::ByteConversionError;
 

src/time/mod.rs

@@ -6,6 +6,7 @@ use core::cmp::Ordering;
 use core::fmt::{Display, Formatter};
 use core::ops::{Add, AddAssign, Sub};
 use core::time::Duration;
+use core::u8;
 
 #[allow(unused_imports)]
 #[cfg(not(feature = "std"))]
@@ -63,12 +64,20 @@ pub fn ccsds_time_code_from_p_field(pfield: u8) -> Result<CcsdsTimeCode, u8> {
     CcsdsTimeCode::try_from(raw_bits).map_err(|_| raw_bits)
 }
 
-#[derive(Debug, PartialEq, Eq, Copy, Clone, thiserror::Error)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
-#[error("date before ccsds epoch: {0:?}")]
 pub struct DateBeforeCcsdsEpochError(UnixTime);
 
+impl Display for DateBeforeCcsdsEpochError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+        write!(f, "date before ccsds epoch: {:?}", self.0)
+    }
+}
+
+#[cfg(feature = "std")]
+impl Error for DateBeforeCcsdsEpochError {}
+
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]

src/util.rs

@@ -242,7 +242,7 @@ 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>> {
+pub struct GenericUnsignedByteField<TYPE: Copy> {
     value: TYPE,
 }
 
@@ -290,6 +290,14 @@ pub type UbfU16 = UnsignedByteFieldU16;
 pub type UbfU32 = UnsignedByteFieldU32;
 pub type UbfU64 = UnsignedByteFieldU64;
 
+impl Default for GenericUnsignedByteField<()> {
+    fn default() -> Self {
+        Self {
+            value: Default::default(),
+        }
+    }
+}
+
 impl From<UnsignedByteFieldU8> for UnsignedByteField {
     fn from(value: UnsignedByteFieldU8) -> Self {
         Self::new(1, value.value as u64)