Merge pull request 'update PusTmZeroCopyWriter' (#61) from update-pus-tm-zero-copy-writer into main

Reviewed-on: #61

CHANGELOG.md

@@ -8,6 +8,43 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 # [unreleased]
 
+# [v0.9.0] 2024-02-07
+
+## Added
+
+- `CcsdsPacket`, `PusPacket` and `GenericPusTmSecondaryHeader` implementation for
+  `PusTmZeroCopyWriter`.
+- Additional length checks for `PusTmZeroCopyWriter`.
+
+## Changed
+
+- `PusTmZeroCopyWriter`: Added additional timestamp length argument for `new` constructor.
+
+## Fixed
+
+- Typo: `PUC_TM_MIN_HEADER_LEN` -> `PUS_TM_MIN_HEADER_LEN`
+
+# [v0.8.1] 2024-02-05
+
+## Fixed
+
+- Added `pub` visibility for `PacketSequenceCtrl::const_new`.
+
+# [v0.8.0] 2024-02-05
+
+## Added
+
+- Added `len_written` and `to_vec` methods to the `TimeWriter` trait.
+
+# [v0.7.0] 2024-02-01
+
+# [v0.7.0-beta.4] 2024-01-23
+
+## Fixed
+
+- `MetadataPduCreator`: The serialization function shifted the closure requested information
+  to the wrong position (first reserved bit) inside the raw content field.
+
 # [v0.7.0-beta.3] 2023-12-06
 
 ## Added

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "spacepackets"
-version = "0.7.0-beta.3"
+version = "0.9.0"
 edition = "2021"
 rust-version = "1.61"
 authors = ["Robin Mueller <muellerr@irs.uni-stuttgart.de>"]
@@ -53,4 +53,4 @@ alloc = ["postcard/alloc", "chrono/alloc"]
 
 [package.metadata.docs.rs]
 all-features = true
-rustdoc-args = ["--cfg", "doc_cfg"]
+rustdoc-args = ["--cfg", "doc_cfg", "--generate-link-to-definition"]

src/cfdp/pdu/metadata.rs

@@ -175,7 +175,7 @@ impl WritablePduPacket for MetadataPduCreator<'_, '_, '_> {
         let mut current_idx = self.pdu_header.write_to_bytes(buf)?;
         buf[current_idx] = FileDirectiveType::MetadataPdu as u8;
         current_idx += 1;
-        buf[current_idx] = ((self.metadata_params.closure_requested as u8) << 7)
+        buf[current_idx] = ((self.metadata_params.closure_requested as u8) << 6)
             | (self.metadata_params.checksum_type as u8);
         current_idx += 1;
         current_idx += write_fss_field(
@@ -364,6 +364,8 @@ pub mod tests {
 
     fn generic_metadata_pdu<'opts>(
         crc_flag: CrcFlag,
+        checksum_type: ChecksumType,
+        closure_requested: bool,
         fss: LargeFileFlag,
         opts: &'opts [Tlv],
     ) -> (
@@ -372,7 +374,7 @@ pub mod tests {
         MetadataPduCreator<'static, 'static, 'opts>,
     ) {
         let pdu_header = PduHeader::new_no_file_data(common_pdu_conf(crc_flag, fss), 0);
-        let metadata_params = MetadataGenericParams::new(false, ChecksumType::Crc32, 0x1010);
+        let metadata_params = MetadataGenericParams::new(closure_requested, checksum_type, 0x1010);
         let src_filename = Lv::new_from_str(SRC_FILENAME).expect("Generating string LV failed");
         let dest_filename =
             Lv::new_from_str(DEST_FILENAME).expect("Generating destination LV failed");
@@ -391,8 +393,13 @@ pub mod tests {
 
     #[test]
     fn test_basic() {
-        let (src_filename, dest_filename, metadata_pdu) =
-            generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Normal, &[]);
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            false,
+            LargeFileFlag::Normal,
+            &[],
+        );
         assert_eq!(
             metadata_pdu.len_written(),
             metadata_pdu.pdu_header().header_len()
@@ -408,6 +415,11 @@ pub mod tests {
         assert_eq!(metadata_pdu.crc_flag(), CrcFlag::NoCrc);
         assert_eq!(metadata_pdu.file_flag(), LargeFileFlag::Normal);
         assert_eq!(metadata_pdu.pdu_type(), PduType::FileDirective);
+        assert!(!metadata_pdu.metadata_params().closure_requested);
+        assert_eq!(
+            metadata_pdu.metadata_params().checksum_type,
+            ChecksumType::Crc32
+        );
         assert_eq!(
             metadata_pdu.file_directive_type(),
             Some(FileDirectiveType::MetadataPdu)
@@ -422,44 +434,103 @@ pub mod tests {
         assert_eq!(metadata_pdu.transaction_seq_num(), TEST_SEQ_NUM.into());
     }
 
-    #[test]
-    fn test_serialization() {
-        let (src_filename, dest_filename, metadata_pdu) =
-            generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Normal, &[]);
-        let mut buf: [u8; 64] = [0; 64];
-        let res = metadata_pdu.write_to_bytes(&mut buf);
-        assert!(res.is_ok());
-        let written = res.unwrap();
+    fn check_metadata_raw_fields(
+        metadata_pdu: &MetadataPduCreator,
+        buf: &[u8],
+        written_bytes: usize,
+        checksum_type: ChecksumType,
+        closure_requested: bool,
+        expected_src_filename: &Lv,
+        expected_dest_filename: &Lv,
+    ) {
+        verify_raw_header(metadata_pdu.pdu_header(), buf);
         assert_eq!(
-            written,
+            written_bytes,
             metadata_pdu.pdu_header.header_len()
                 + 1
                 + 1
                 + 4
-                + src_filename.len_full()
-                + dest_filename.len_full()
+                + expected_src_filename.len_full()
+                + expected_dest_filename.len_full()
         );
-        verify_raw_header(metadata_pdu.pdu_header(), &buf);
         assert_eq!(buf[7], FileDirectiveType::MetadataPdu as u8);
-        assert_eq!(buf[8] >> 6, false as u8);
-        assert_eq!(buf[8] & 0b1111, ChecksumType::Crc32 as u8);
+        assert_eq!(buf[8] >> 6, closure_requested as u8);
+        assert_eq!(buf[8] & 0b1111, checksum_type as u8);
         assert_eq!(u32::from_be_bytes(buf[9..13].try_into().unwrap()), 0x1010);
         let mut current_idx = 13;
         let src_name_from_raw =
             Lv::from_bytes(&buf[current_idx..]).expect("Creating source name LV failed");
-        assert_eq!(src_name_from_raw, src_filename);
+        assert_eq!(src_name_from_raw, *expected_src_filename);
         current_idx += src_name_from_raw.len_full();
         let dest_name_from_raw =
             Lv::from_bytes(&buf[current_idx..]).expect("Creating dest name LV failed");
-        assert_eq!(dest_name_from_raw, dest_filename);
+        assert_eq!(dest_name_from_raw, *expected_dest_filename);
         current_idx += dest_name_from_raw.len_full();
         // No options, so no additional data here.
-        assert_eq!(current_idx, written);
+        assert_eq!(current_idx, written_bytes);
+    }
+
+    #[test]
+    fn test_serialization_0() {
+        let checksum_type = ChecksumType::Crc32;
+        let closure_requested = false;
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            checksum_type,
+            closure_requested,
+            LargeFileFlag::Normal,
+            &[],
+        );
+        let mut buf: [u8; 64] = [0; 64];
+        let res = metadata_pdu.write_to_bytes(&mut buf);
+        assert!(res.is_ok());
+        let written = res.unwrap();
+        check_metadata_raw_fields(
+            &metadata_pdu,
+            &buf,
+            written,
+            checksum_type,
+            closure_requested,
+            &src_filename,
+            &dest_filename,
+        );
+    }
+
+    #[test]
+    fn test_serialization_1() {
+        let checksum_type = ChecksumType::Modular;
+        let closure_requested = true;
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            checksum_type,
+            closure_requested,
+            LargeFileFlag::Normal,
+            &[],
+        );
+        let mut buf: [u8; 64] = [0; 64];
+        let res = metadata_pdu.write_to_bytes(&mut buf);
+        assert!(res.is_ok());
+        let written = res.unwrap();
+        check_metadata_raw_fields(
+            &metadata_pdu,
+            &buf,
+            written,
+            checksum_type,
+            closure_requested,
+            &src_filename,
+            &dest_filename,
+        );
     }
 
     #[test]
     fn test_write_to_vec() {
-        let (_, _, metadata_pdu) = generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Normal, &[]);
+        let (_, _, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            false,
+            LargeFileFlag::Normal,
+            &[],
+        );
         let mut buf: [u8; 64] = [0; 64];
         let pdu_vec = metadata_pdu.to_vec().unwrap();
         let written = metadata_pdu.write_to_bytes(&mut buf).unwrap();
@@ -478,7 +549,13 @@ pub mod tests {
 
     #[test]
     fn test_deserialization() {
-        let (_, _, metadata_pdu) = generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Normal, &[]);
+        let (_, _, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            true,
+            LargeFileFlag::Normal,
+            &[],
+        );
         let mut buf: [u8; 64] = [0; 64];
         metadata_pdu.write_to_bytes(&mut buf).unwrap();
         let pdu_read_back = MetadataPduReader::from_bytes(&buf);
@@ -489,8 +566,13 @@ pub mod tests {
 
     #[test]
     fn test_with_crc_flag() {
-        let (src_filename, dest_filename, metadata_pdu) =
-            generic_metadata_pdu(CrcFlag::WithCrc, LargeFileFlag::Normal, &[]);
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::WithCrc,
+            ChecksumType::Crc32,
+            true,
+            LargeFileFlag::Normal,
+            &[],
+        );
         assert_eq!(metadata_pdu.crc_flag(), CrcFlag::WithCrc);
         let mut buf: [u8; 64] = [0; 64];
         let write_res = metadata_pdu.write_to_bytes(&mut buf);
@@ -513,8 +595,13 @@ pub mod tests {
 
     #[test]
     fn test_with_large_file_flag() {
-        let (src_filename, dest_filename, metadata_pdu) =
-            generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Large, &[]);
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            false,
+            LargeFileFlag::Large,
+            &[],
+        );
         let mut buf: [u8; 64] = [0; 64];
         let write_res = metadata_pdu.write_to_bytes(&mut buf);
         assert!(write_res.is_ok());
@@ -573,8 +660,13 @@ pub mod tests {
         let tlv2 = Tlv::new(TlvType::MsgToUser, &msg_to_user).unwrap();
         let tlv_vec = vec![tlv1, tlv2];
         let opts_len = tlv1.len_full() + tlv2.len_full();
-        let (src_filename, dest_filename, metadata_pdu) =
-            generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Normal, &tlv_vec);
+        let (src_filename, dest_filename, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            false,
+            LargeFileFlag::Normal,
+            &tlv_vec,
+        );
         let mut buf: [u8; 128] = [0; 128];
         let write_res = metadata_pdu.write_to_bytes(&mut buf);
         assert!(write_res.is_ok());
@@ -604,7 +696,13 @@ pub mod tests {
 
     #[test]
     fn test_invalid_directive_code() {
-        let (_, _, metadata_pdu) = generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Large, &[]);
+        let (_, _, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            true,
+            LargeFileFlag::Large,
+            &[],
+        );
         let mut metadata_vec = metadata_pdu.to_vec().unwrap();
         metadata_vec[7] = 0xff;
         let metadata_error = MetadataPduReader::from_bytes(&metadata_vec);
@@ -624,7 +722,13 @@ pub mod tests {
 
     #[test]
     fn test_wrong_directive_code() {
-        let (_, _, metadata_pdu) = generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Large, &[]);
+        let (_, _, metadata_pdu) = generic_metadata_pdu(
+            CrcFlag::NoCrc,
+            ChecksumType::Crc32,
+            false,
+            LargeFileFlag::Large,
+            &[],
+        );
         let mut metadata_vec = metadata_pdu.to_vec().unwrap();
         metadata_vec[7] = FileDirectiveType::EofPdu as u8;
         let metadata_error = MetadataPduReader::from_bytes(&metadata_vec);

src/ecss/tm.rs

@@ -21,12 +21,14 @@ use delegate::delegate;
 use crate::time::{TimeWriter, TimestampError};
 pub use legacy_tm::*;
 
+use self::zc::PusTmSecHeaderWithoutTimestamp;
+
 pub trait IsPusTelemetry {}
 
 /// Length without timestamp
-pub const PUC_TM_MIN_SEC_HEADER_LEN: usize = 7;
+pub const PUS_TM_MIN_SEC_HEADER_LEN: usize = 7;
 pub const PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA: usize =
-    CCSDS_HEADER_LEN + PUC_TM_MIN_SEC_HEADER_LEN + size_of::<CrcType>();
+    CCSDS_HEADER_LEN + PUS_TM_MIN_SEC_HEADER_LEN + size_of::<CrcType>();
 
 pub trait GenericPusTmSecondaryHeader {
     fn pus_version(&self) -> PusVersion;
@@ -198,7 +200,7 @@ impl<'slice> TryFrom<zc::PusTmSecHeader<'slice>> for PusTmSecondaryHeader<'slice
 pub mod legacy_tm {
     use crate::ecss::tm::{
         zc, GenericPusTmSecondaryHeader, IsPusTelemetry, PusTmSecondaryHeader,
-        PUC_TM_MIN_SEC_HEADER_LEN, PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA,
+        PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA, PUS_TM_MIN_SEC_HEADER_LEN,
     };
     use crate::ecss::PusVersion;
     use crate::ecss::{
@@ -406,10 +408,10 @@ pub mod legacy_tm {
                 .into());
             }
             let sec_header_zc = zc::PusTmSecHeaderWithoutTimestamp::from_bytes(
-                &slice[current_idx..current_idx + PUC_TM_MIN_SEC_HEADER_LEN],
+                &slice[current_idx..current_idx + PUS_TM_MIN_SEC_HEADER_LEN],
             )
             .ok_or(ByteConversionError::ZeroCopyFromError)?;
-            current_idx += PUC_TM_MIN_SEC_HEADER_LEN;
+            current_idx += PUS_TM_MIN_SEC_HEADER_LEN;
             let zc_sec_header_wrapper = zc::PusTmSecHeader {
                 zc_header: sec_header_zc,
                 timestamp: &slice[current_idx..current_idx + timestamp_len],
@@ -814,10 +816,10 @@ impl<'raw_data> PusTmReader<'raw_data> {
             .into());
         }
         let sec_header_zc = zc::PusTmSecHeaderWithoutTimestamp::from_bytes(
-            &slice[current_idx..current_idx + PUC_TM_MIN_SEC_HEADER_LEN],
+            &slice[current_idx..current_idx + PUS_TM_MIN_SEC_HEADER_LEN],
         )
         .ok_or(ByteConversionError::ZeroCopyFromError)?;
-        current_idx += PUC_TM_MIN_SEC_HEADER_LEN;
+        current_idx += PUS_TM_MIN_SEC_HEADER_LEN;
         let zc_sec_header_wrapper = zc::PusTmSecHeader {
             zc_header: sec_header_zc,
             timestamp: &slice[current_idx..current_idx + timestamp_len],
@@ -912,36 +914,40 @@ impl PartialEq<PusTmReader<'_>> for PusTmCreator<'_> {
 }
 
 /// This is a helper class to update certain fields in a raw PUS telemetry packet directly in place.
-/// This can be more efficient than creating a full [PusTm], modifying the fields and then writing
-/// it back to another buffer.
+/// This can be more efficient than creating a full [PusTmReader], modifying the fields and then
+/// writing it back to another buffer.
 ///
 /// Please note that the [Self::finish] method has to be called for the PUS TM CRC16 to be valid
 /// after changing fields of the TM packet. Furthermore, the constructor of this class will not
-/// do any checks except a length check to ensure that all relevant fields can be updated without
-/// a panic. If a full validity check of the PUS TM packet is required, it is recommended
-/// to construct a full [PusTm] object from the raw bytestream first.
+/// do any checks except basic length checks to ensure that all relevant fields can be updated and
+/// all methods can be called without a panic. If a full validity check of the PUS TM packet is
+/// required, it is recommended to construct a full [PusTmReader] object from the raw bytestream
+/// first.
 pub struct PusTmZeroCopyWriter<'raw> {
     raw_tm: &'raw mut [u8],
+    timestamp_len: usize,
 }
 
 impl<'raw> PusTmZeroCopyWriter<'raw> {
     /// This function will not do any other checks on the raw data other than a length check
-    /// for all internal fields which can be updated. It is the responsibility of the user to ensure
-    /// the raw slice contains a valid telemetry packet. The slice should have the exact length
-    /// of the telemetry packet for this class to work properly.
-    pub fn new(raw_tm: &'raw mut [u8]) -> Option<Self> {
-        if raw_tm.len() < 13 {
+    /// for all internal fields which can be updated.
+    ///
+    /// It is the responsibility of the user to ensure the raw slice contains a valid telemetry
+    /// packet.
+    pub fn new(raw_tm: &'raw mut [u8], timestamp_len: usize) -> Option<Self> {
+        let raw_tm_len = raw_tm.len();
+        if raw_tm_len < CCSDS_HEADER_LEN + PUS_TM_MIN_SEC_HEADER_LEN + timestamp_len {
             return None;
         }
-        Some(Self { raw_tm })
-    }
-
-    pub fn service(&self) -> u8 {
-        self.raw_tm[7]
-    }
-
-    pub fn subservice(&self) -> u8 {
-        self.raw_tm[8]
+        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;
+        }
+        let writer = Self {
+            raw_tm: &mut raw_tm[..sp_header.total_len()],
+            timestamp_len,
+        };
+        Some(writer)
     }
 
     /// Set the sequence count. Returns false and does not update the value if the passed value
@@ -967,6 +973,24 @@ impl<'raw> PusTmZeroCopyWriter<'raw> {
         self.raw_tm[11..13].copy_from_slice(&dest_id.to_be_bytes())
     }
 
+    /// Helper API to generate the space packet header portion of the PUS TM from the raw memory.
+    #[inline]
+    pub fn sp_header(&self) -> crate::zc::SpHeader {
+        // Valid minimum length of packet was checked before.
+        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
+    /// raw memory.
+    #[inline]
+    pub fn sec_header_without_timestamp(&self) -> PusTmSecHeaderWithoutTimestamp {
+        // Valid minimum length of packet was checked before.
+        PusTmSecHeaderWithoutTimestamp::from_bytes(
+            &self.raw_tm[CCSDS_HEADER_LEN..CCSDS_HEADER_LEN + PUS_TM_MIN_SEC_HEADER_LEN],
+        )
+        .unwrap()
+    }
+
     /// Set the sequence count. Returns false and does not update the value if the passed value
     /// exceeds [MAX_SEQ_COUNT].
     pub fn set_seq_count(&mut self, seq_count: u16) -> bool {
@@ -988,6 +1012,85 @@ impl<'raw> PusTmZeroCopyWriter<'raw> {
     }
 }
 
+impl CcsdsPacket for PusTmZeroCopyWriter<'_> {
+    #[inline]
+    fn ccsds_version(&self) -> u8 {
+        self.sp_header().ccsds_version()
+    }
+
+    #[inline]
+    fn packet_id(&self) -> crate::PacketId {
+        self.sp_header().packet_id()
+    }
+
+    #[inline]
+    fn psc(&self) -> crate::PacketSequenceCtrl {
+        self.sp_header().psc()
+    }
+
+    #[inline]
+    fn data_len(&self) -> u16 {
+        self.sp_header().data_len()
+    }
+}
+
+impl PusPacket for PusTmZeroCopyWriter<'_> {
+    #[inline]
+    fn pus_version(&self) -> PusVersion {
+        self.sec_header_without_timestamp().pus_version()
+    }
+
+    #[inline]
+    fn service(&self) -> u8 {
+        self.raw_tm[7]
+    }
+
+    #[inline]
+    fn subservice(&self) -> u8 {
+        self.raw_tm[8]
+    }
+
+    #[inline]
+    fn user_data(&self) -> &[u8] {
+        &self.raw_tm[CCSDS_HEADER_LEN + PUS_TM_MIN_SEC_HEADER_LEN + self.timestamp_len
+            ..self.sp_header().total_len() - 2]
+    }
+
+    #[inline]
+    fn crc16(&self) -> Option<u16> {
+        Some(u16::from_be_bytes(
+            self.raw_tm[self.sp_header().total_len() - 2..self.sp_header().total_len()]
+                .try_into()
+                .unwrap(),
+        ))
+    }
+}
+
+impl GenericPusTmSecondaryHeader for PusTmZeroCopyWriter<'_> {
+    delegate! {
+        to self.sec_header_without_timestamp() {
+            #[inline]
+            fn pus_version(&self) -> PusVersion;
+            #[inline]
+            fn sc_time_ref_status(&self) -> u8;
+            #[inline]
+            fn msg_counter(&self) -> u16;
+            #[inline]
+            fn dest_id(&self) -> u16;
+        }
+    }
+
+    #[inline]
+    fn service(&self) -> u8 {
+        PusPacket::service(self)
+    }
+
+    #[inline]
+    fn subservice(&self) -> u8 {
+        PusPacket::subservice(self)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use alloc::string::ToString;
@@ -1001,11 +1104,18 @@ mod tests {
     #[cfg(feature = "serde")]
     use postcard::{from_bytes, to_allocvec};
 
+    const DUMMY_DATA: &[u8] = &[0, 1, 2];
+
     fn base_ping_reply_full_ctor(timestamp: &[u8]) -> PusTmCreator {
         let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
         let tm_header = PusTmSecondaryHeader::new_simple(17, 2, timestamp);
         PusTmCreator::new_no_source_data(&mut sph, tm_header, true)
     }
+    fn ping_reply_with_data(timestamp: &[u8]) -> PusTmCreator {
+        let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
+        let tm_header = PusTmSecondaryHeader::new_simple(17, 2, timestamp);
+        PusTmCreator::new(&mut sph, tm_header, DUMMY_DATA, true)
+    }
 
     fn base_hk_reply<'a>(timestamp: &'a [u8], src_data: &'a [u8]) -> PusTmCreator<'a> {
         let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
@@ -1294,7 +1404,7 @@ mod tests {
         let tm_size = ping_tm
             .write_to_bytes(&mut buf)
             .expect("writing PUS ping TM failed");
-        let mut writer = PusTmZeroCopyWriter::new(&mut buf[..tm_size])
+        let mut writer = PusTmZeroCopyWriter::new(&mut buf[..tm_size], 7)
             .expect("Creating zero copy writer failed");
         writer.set_destination_id(55);
         writer.set_msg_count(100);
@@ -1302,8 +1412,6 @@ mod tests {
         writer.set_apid(MAX_APID);
         assert!(!writer.set_apid(MAX_APID + 1));
         assert!(!writer.set_apid(MAX_SEQ_COUNT + 1));
-        assert_eq!(writer.service(), 17);
-        assert_eq!(writer.subservice(), 2);
         writer.finish();
         // This performs all necessary checks, including the CRC check.
         let (tm_read_back, tm_size_read_back) =
@@ -1315,6 +1423,53 @@ mod tests {
         assert_eq!(tm_read_back.apid(), MAX_APID);
     }
 
+    #[test]
+    fn test_zero_copy_writer_ccsds_api() {
+        let ping_tm = base_ping_reply_full_ctor(dummy_timestamp());
+        let mut buf: [u8; 64] = [0; 64];
+        let tm_size = ping_tm
+            .write_to_bytes(&mut buf)
+            .expect("writing PUS ping TM failed");
+        let mut writer = PusTmZeroCopyWriter::new(&mut buf[..tm_size], 7)
+            .expect("Creating zero copy writer failed");
+        writer.set_destination_id(55);
+        writer.set_msg_count(100);
+        writer.set_seq_count(MAX_SEQ_COUNT);
+        writer.set_apid(MAX_APID);
+        assert_eq!(PusPacket::service(&writer), 17);
+        assert_eq!(PusPacket::subservice(&writer), 2);
+        assert_eq!(writer.apid(), MAX_APID);
+        assert_eq!(writer.seq_count(), MAX_SEQ_COUNT);
+    }
+
+    #[test]
+    fn test_zero_copy_pus_api() {
+        let ping_tm = ping_reply_with_data(dummy_timestamp());
+        let mut buf: [u8; 64] = [0; 64];
+        let tm_size = ping_tm
+            .write_to_bytes(&mut buf)
+            .expect("writing PUS ping TM failed");
+        let crc16_raw = u16::from_be_bytes(buf[tm_size - 2..tm_size].try_into().unwrap());
+        let mut writer = PusTmZeroCopyWriter::new(&mut buf[..tm_size], 7)
+            .expect("Creating zero copy writer failed");
+        writer.set_destination_id(55);
+        writer.set_msg_count(100);
+        writer.set_seq_count(MAX_SEQ_COUNT);
+        writer.set_apid(MAX_APID);
+        assert_eq!(PusPacket::service(&writer), 17);
+        assert_eq!(PusPacket::subservice(&writer), 2);
+        assert_eq!(writer.dest_id(), 55);
+        assert_eq!(writer.msg_counter(), 100);
+        assert_eq!(writer.sec_header_without_timestamp().dest_id(), 55);
+        assert_eq!(writer.sec_header_without_timestamp().msg_counter(), 100);
+        assert_eq!(writer.user_data(), DUMMY_DATA);
+        // Need to check crc16 before finish, because finish will update the CRC.
+        let crc16 = writer.crc16();
+        assert!(crc16.is_some());
+        assert_eq!(crc16.unwrap(), crc16_raw);
+        writer.finish();
+    }
+
     #[test]
     fn test_sec_header_without_stamp() {
         let sec_header = PusTmSecondaryHeader::new_simple_no_timestamp(17, 1);

src/lib.rs

@@ -311,7 +311,7 @@ pub struct PacketSequenceCtrl {
 impl PacketSequenceCtrl {
     /// const variant of [PacketSequenceCtrl::new], but panics if the sequence count exceeds
     /// [MAX_SEQ_COUNT].
-    const fn const_new(seq_flags: SequenceFlags, seq_count: u16) -> PacketSequenceCtrl {
+    pub const fn const_new(seq_flags: SequenceFlags, seq_count: u16) -> PacketSequenceCtrl {
         if seq_count > MAX_SEQ_COUNT {
             panic!("Sequence count too large");
         }

src/time/cds.rs

@@ -1201,6 +1201,10 @@ impl TimeWriter for TimeProvider<DaysLen16Bits> {
         }
         Ok(self.len_as_bytes())
     }
+
+    fn len_written(&self) -> usize {
+        self.len_as_bytes()
+    }
 }
 
 impl TimeWriter for TimeProvider<DaysLen24Bits> {
@@ -1221,6 +1225,10 @@ impl TimeWriter for TimeProvider<DaysLen24Bits> {
         }
         Ok(self.len_as_bytes())
     }
+
+    fn len_written(&self) -> usize {
+        self.len_as_bytes()
+    }
 }
 
 impl<DaysLenProvider: ProvidesDaysLength> PartialEq for TimeProvider<DaysLenProvider> {
@@ -2270,4 +2278,22 @@ mod tests {
             assert_eq!(first, second);
         }
     }
+
+    #[test]
+    fn test_stamp_to_vec_u16() {
+        let stamp = TimeProvider::new_with_u16_days(1, 1);
+        let stamp_vec = stamp.to_vec().unwrap();
+        let mut buf: [u8; 7] = [0; 7];
+        stamp.write_to_bytes(&mut buf).unwrap();
+        assert_eq!(stamp_vec, buf);
+    }
+
+    #[test]
+    fn test_stamp_to_vec_u24() {
+        let stamp = TimeProvider::new_with_u24_days(1, 1).unwrap();
+        let stamp_vec = stamp.to_vec().unwrap();
+        let mut buf: [u8; 10] = [0; 10];
+        stamp.write_to_bytes(&mut buf).unwrap();
+        assert_eq!(stamp_vec, buf[..stamp.len_written()]);
+    }
 }

src/time/cuc.rs

@@ -587,6 +587,10 @@ impl TimeWriter for TimeProviderCcsdsEpoch {
         }
         Ok(current_idx)
     }
+
+    fn len_written(&self) -> usize {
+        self.len_as_bytes()
+    }
 }
 
 impl CcsdsTimeProvider for TimeProviderCcsdsEpoch {
@@ -1226,4 +1230,13 @@ mod tests {
             panic!("unexpected error: {}", cuc_error);
         }
     }
+
+    #[test]
+    fn test_stamp_to_vec() {
+        let stamp = TimeProviderCcsdsEpoch::new_u16_counter(100);
+        let stamp_vec = stamp.to_vec().unwrap();
+        let mut buf: [u8; 16] = [0; 16];
+        stamp.write_to_bytes(&mut buf).unwrap();
+        assert_eq!(stamp_vec, buf[..stamp.len_written()]);
+    }
 }

src/time/mod.rs

@@ -189,9 +189,18 @@ pub fn ms_of_day(seconds_since_epoch: f64) -> u32 {
 }
 
 pub trait TimeWriter {
+    fn len_written(&self) -> usize;
+
     /// Generic function to convert write a timestamp into a raw buffer.
     /// Returns the number of written bytes on success.
     fn write_to_bytes(&self, bytes: &mut [u8]) -> Result<usize, TimestampError>;
+
+    #[cfg(feature = "alloc")]
+    fn to_vec(&self) -> Result<alloc::vec::Vec<u8>, TimestampError> {
+        let mut vec = alloc::vec![0; self.len_written()];
+        self.write_to_bytes(&mut vec)?;
+        Ok(vec)
+    }
 }
 
 pub trait TimeReader {