set minimal data len in example

Reviewed-on: #1

CHANGELOG.md

@@ -6,9 +6,54 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
-## [unreleased]
+# [unreleased]
 
-## [v0.1.0] 16.08.2022
+## Changed
+
+- `serde` support is now optional and behind the `serde` feature
+- `PusTcSecondaryHeaderT` trait renamed to `GenericPusTcSecondaryHeader`
+- `PusTmSecondaryHeaderT` trait renamed to `GenericPusTmSecondaryHeader`
+- `SpHeader`: Former `tc` and `tm` methods now named `tc_unseg` and `tm_unseg`.
+  Former `new` method now called `new_from_single_fields`
+
+## Added
+
+- `serde` `Serialize` and `Deserialize` added to all types
+- Added `const` constructors for `PacketId`, `PacketSeqCtrl` and
+  `SpHeader`
+- Added `PartialEq` and `Eq` `derive`s to `CdsShortTimeProvider`
+
+# [v0.3.1] 03.12.2022
+
+- Small fix for faulty docs.rs build
+
+# [v0.3.0] 01.12.2022
+
+## Added
+
+- `EcssEnumerationExt` trait which implements `Debug`, `Copy`, `Clone`,
+  `PartialEq` and `Eq` in addition to `EcssEnumeration`
+
+## Changed
+
+- `EcssEnumeration` trait: Rename `write_to_bytes`
+  to `write_to_be_bytes`
+
+# [v0.2.0] 13.09.2022
+
+## Added
+
+- Basic support for ECSS enumeration types for u8, u16, u32 and u64
+
+## Changed
+
+- Better names for generic error enumerations: `PacketError` renamed to `ByteConversionError`
+- CCSDS module: `ssc` abbreviations fully replaced by better name `seq_count`
+- Time module: `CcsdsTimeProvider::date_time` now has `Option<DateTime<Utc>>` as
+  a returnvalue instead of `DateTime<Utc>`
+- `PusTc` and `PusTm`: `new_from_raw_slice` renamed to simpler `from_bytes`
+
+# [v0.1.0] 16.08.2022
 
 Initial release with CCSDS Space Packet Primary Header implementation and basic PUS TC and TM
 implementations.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "spacepackets"
-version = "0.1.0"
+version = "0.3.1"
 edition = "2021"
 authors = ["Robin Mueller <muellerr@irs.uni-stuttgart.de>"]
 description = "Generic implementations for various CCSDS and ECSS packet standards"
@@ -12,17 +12,18 @@ categories = ["aerospace", "aerospace::space-protocols", "no-std", "hardware-sup
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-zerocopy = "0.6.1"
-crc = "3.0.0"
-delegate = "0.7.0"
+zerocopy = "0.6"
+crc = "3.0"
+delegate = "0.8"
 
 [dependencies.serde]
-version = "1.0.142"
+version = "1.0"
+optional = true
 default-features = false
 features = ["derive"]
 
 [dependencies.chrono]
-version = "0.4.20"
+version = "0.4"
 default-features = false
 
 [dependencies.num-traits]
@@ -30,9 +31,14 @@ version = "0.2"
 default-features = false
 
 [dev-dependencies.postcard]
-version = "1.0.1"
+version = "1.0"
 
 [features]
-default = ["std"]
+default = ["std", "dep:serde"]
 std = ["chrono/std", "chrono/clock", "alloc"]
+serde = ["chrono/serde"]
 alloc = ["postcard/alloc"]
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "doc_cfg"]

README.md

@@ -20,12 +20,9 @@ Currently, this includes the following components:
  
 # Features
 
-`spacepackets` supports various runtime environments and is also suitable
-for suitable for `no_std` environments. It has several features which may be enabled
-for disabled.
+`spacepackets` supports various runtime environments and is also suitable for `no_std` environments.
 
-It also offers support for [`serde`](https://serde.rs/). The Space Paccket, PUS TM and TC
-implementations derive the `serde` `Serialize` and `Deserialize` trait. This allows serializing and
+It also offers optional support for [`serde`](https://serde.rs/). This allows serializing and
 deserializing them with an appropriate `serde` provider like
 [`postcard`](https://github.com/jamesmunns/postcard).
 
@@ -35,3 +32,9 @@ Default features:
  - [`alloc`](https://doc.rust-lang.org/alloc/): Enables features which operate on containers
    like [`alloc::vec::Vec`](https://doc.rust-lang.org/beta/alloc/vec/struct.Vec.html).
    Enabled by the `std` feature.
+ - [`serde`](https://serde.rs/): Adds `serde` support for most types by adding `Serialize` and `Deserialize` `derive`s
+
+# Examples
+
+You can check the [documentation](https://docs.rs/spacepackets) of individual modules for various
+usage examples.

src/ecss.rs

@@ -1,8 +1,10 @@
 //! Common definitions and helpers required to create PUS TMTC packets according to
 //! [ECSS-E-ST-70-41C](https://ecss.nl/standard/ecss-e-st-70-41c-space-engineering-telemetry-and-telecommand-packet-utilization-15-april-2016/)
-use crate::{CcsdsPacket, PacketError};
+use crate::{ByteConversionError, CcsdsPacket, SizeMissmatch};
+use core::fmt::Debug;
 use core::mem::size_of;
 use crc::{Crc, CRC_16_IBM_3740};
+#[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
 pub type CrcType = u16;
@@ -12,7 +14,8 @@ pub const CRC_CCITT_FALSE: Crc<u16> = Crc::<u16>::new(&CRC_16_IBM_3740);
 pub const CCSDS_HEADER_LEN: usize = size_of::<crate::zc::SpHeader>();
 
 /// All PUS versions. Only PUS C is supported by this library.
-#[derive(PartialEq, Eq, Copy, Clone, Serialize, Deserialize, Debug)]
+#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum PusVersion {
     EsaPus = 0,
     PusA = 1,
@@ -34,6 +37,24 @@ impl TryFrom<u8> for PusVersion {
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub enum PacketTypeCodes {
+    Boolean = 1,
+    Enumerated = 2,
+    UnsignedInt = 3,
+    SignedInt = 4,
+    Real = 5,
+    BitString = 6,
+    OctetString = 7,
+    CharString = 8,
+    AbsoluteTime = 9,
+    RelativeTime = 10,
+    Deduced = 11,
+    Packet = 12,
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum PusError {
     VersionNotSupported(PusVersion),
     IncorrectCrc(u16),
@@ -41,7 +62,13 @@ pub enum PusError {
     NoRawData,
     /// CRC16 needs to be calculated first
     CrcCalculationMissing,
-    PacketError(PacketError),
+    ByteConversionError(ByteConversionError),
+}
+
+impl From<ByteConversionError> for PusError {
+    fn from(e: ByteConversionError) -> Self {
+        PusError::ByteConversionError(e)
+    }
 }
 
 pub trait PusPacket: CcsdsPacket {
@@ -135,3 +162,174 @@ macro_rules! sp_header_impls {
 
 pub(crate) use ccsds_impl;
 pub(crate) use sp_header_impls;
+
+/// Generic trait for ECSS enumeration which consist of a PFC field denoting their bit length
+/// and an unsigned value. The trait makes no assumptions about the actual type of the unsigned
+/// value and only requires implementors to implement a function which writes the enumeration into
+/// a raw byte format.
+pub trait EcssEnumeration {
+    /// Packet Format Code, which denotes the number of bits of the enumeration
+    fn pfc(&self) -> u8;
+    fn byte_width(&self) -> usize {
+        (self.pfc() / 8) as usize
+    }
+    fn write_to_be_bytes(&self, buf: &mut [u8]) -> Result<(), ByteConversionError>;
+}
+
+pub trait EcssEnumerationExt: EcssEnumeration + Debug + Copy + Clone + PartialEq + Eq {}
+
+pub trait ToBeBytes {
+    type ByteArray: AsRef<[u8]>;
+    fn to_be_bytes(&self) -> Self::ByteArray;
+}
+
+impl ToBeBytes for u8 {
+    type ByteArray = [u8; 1];
+
+    fn to_be_bytes(&self) -> Self::ByteArray {
+        u8::to_be_bytes(*self)
+    }
+}
+
+impl ToBeBytes for u16 {
+    type ByteArray = [u8; 2];
+
+    fn to_be_bytes(&self) -> Self::ByteArray {
+        u16::to_be_bytes(*self)
+    }
+}
+
+impl ToBeBytes for u32 {
+    type ByteArray = [u8; 4];
+
+    fn to_be_bytes(&self) -> Self::ByteArray {
+        u32::to_be_bytes(*self)
+    }
+}
+
+impl ToBeBytes for u64 {
+    type ByteArray = [u8; 8];
+
+    fn to_be_bytes(&self) -> Self::ByteArray {
+        u64::to_be_bytes(*self)
+    }
+}
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct GenericEcssEnumWrapper<TYPE> {
+    val: TYPE,
+}
+
+impl<TYPE> GenericEcssEnumWrapper<TYPE> {
+    pub const fn ptc() -> PacketTypeCodes {
+        PacketTypeCodes::Enumerated
+    }
+
+    pub fn new(val: TYPE) -> Self {
+        Self { val }
+    }
+}
+
+impl<TYPE: ToBeBytes> EcssEnumeration for GenericEcssEnumWrapper<TYPE> {
+    fn pfc(&self) -> u8 {
+        size_of::<TYPE>() as u8 * 8_u8
+    }
+
+    fn write_to_be_bytes(&self, buf: &mut [u8]) -> Result<(), ByteConversionError> {
+        if buf.len() < self.byte_width() as usize {
+            return Err(ByteConversionError::ToSliceTooSmall(SizeMissmatch {
+                found: buf.len(),
+                expected: self.byte_width() as usize,
+            }));
+        }
+        buf[0..self.byte_width() as usize].copy_from_slice(self.val.to_be_bytes().as_ref());
+        Ok(())
+    }
+}
+
+impl<TYPE: Debug + Copy + Clone + PartialEq + Eq + ToBeBytes> EcssEnumerationExt
+    for GenericEcssEnumWrapper<TYPE>
+{
+}
+
+pub type EcssEnumU8 = GenericEcssEnumWrapper<u8>;
+pub type EcssEnumU16 = GenericEcssEnumWrapper<u16>;
+pub type EcssEnumU32 = GenericEcssEnumWrapper<u32>;
+pub type EcssEnumU64 = GenericEcssEnumWrapper<u64>;
+
+#[cfg(test)]
+mod tests {
+    use crate::ecss::{EcssEnumU16, EcssEnumU32, EcssEnumU8, EcssEnumeration};
+    use crate::ByteConversionError;
+
+    #[test]
+    fn test_enum_u8() {
+        let mut buf = [0, 0, 0];
+        let my_enum = EcssEnumU8::new(1);
+        my_enum
+            .write_to_be_bytes(&mut buf[1..2])
+            .expect("To byte conversion of u8 failed");
+        assert_eq!(buf[1], 1);
+    }
+
+    #[test]
+    fn test_enum_u16() {
+        let mut buf = [0, 0, 0];
+        let my_enum = EcssEnumU16::new(0x1f2f);
+        my_enum
+            .write_to_be_bytes(&mut buf[1..3])
+            .expect("To byte conversion of u8 failed");
+        assert_eq!(buf[1], 0x1f);
+        assert_eq!(buf[2], 0x2f);
+    }
+
+    #[test]
+    fn test_slice_u16_too_small() {
+        let mut buf = [0];
+        let my_enum = EcssEnumU16::new(0x1f2f);
+        let res = my_enum.write_to_be_bytes(&mut buf[0..1]);
+        assert!(res.is_err());
+        let error = res.unwrap_err();
+        match error {
+            ByteConversionError::ToSliceTooSmall(missmatch) => {
+                assert_eq!(missmatch.expected, 2);
+                assert_eq!(missmatch.found, 1);
+            }
+            _ => {
+                panic!("Unexpected error {:?}", error);
+            }
+        }
+    }
+
+    #[test]
+    fn test_enum_u32() {
+        let mut buf = [0, 0, 0, 0, 0];
+        let my_enum = EcssEnumU32::new(0x1f2f3f4f);
+        my_enum
+            .write_to_be_bytes(&mut buf[1..5])
+            .expect("To byte conversion of u8 failed");
+        assert_eq!(buf[1], 0x1f);
+        assert_eq!(buf[2], 0x2f);
+        assert_eq!(buf[3], 0x3f);
+        assert_eq!(buf[4], 0x4f);
+    }
+
+    #[test]
+    fn test_slice_u32_too_small() {
+        let mut buf = [0, 0, 0, 0, 0];
+        let my_enum = EcssEnumU32::new(0x1f2f3f4f);
+        let res = my_enum.write_to_be_bytes(&mut buf[0..3]);
+        assert!(res.is_err());
+        let error = res.unwrap_err();
+        match error {
+            ByteConversionError::ToSliceTooSmall(missmatch) => {
+                assert_eq!(missmatch.expected, 4);
+                assert_eq!(missmatch.found, 3);
+            }
+            _ => {
+                panic!("Unexpected error {:?}", error);
+            }
+        }
+    }
+}

src/lib.rs

@@ -14,12 +14,9 @@
 //!
 //! ## Features
 //!
-//! `spacepackets` supports various runtime environments and is also suitable
-//! for suitable for `no_std` environments. It has several features which may be enabled
-//! for disabled.
+//! `spacepackets` supports various runtime environments and is also suitable for `no_std` environments.
 //!
-//! It also offers support for [`serde`](https://serde.rs/). The Space Paccket, PUS TM and TC
-//! implementations derive the `serde` `Serialize` and `Deserialize` trait. This allows serializing and
+//! It also offers optional support for [`serde`](https://serde.rs/). This allows serializing and
 //! deserializing them with an appropriate `serde` provider like
 //! [`postcard`](https://github.com/jamesmunns/postcard).
 //!
@@ -29,29 +26,36 @@
 //!  - [`alloc`](https://doc.rust-lang.org/alloc/): Enables features which operate on containers
 //!     like [`alloc::vec::Vec`](https://doc.rust-lang.org/beta/alloc/vec/struct.Vec.html).
 //!     Enabled by the `std` feature.
+//!  - [`serde`](https://serde.rs/): Adds `serde` support for most types by adding `Serialize` and
+//!    `Deserialize` `derive`s
 //!
 //! ## Module
 //!
 //! This module contains helpers and data structures to generate Space Packets according to the
 //! [CCSDS 133.0-B-2](https://public.ccsds.org/Pubs/133x0b2e1.pdf). This includes the
-//! [SpHeader] class to generate the Space Packet Header component common to all space packets
+//! [SpHeader] class to generate the Space Packet Header component common to all space packets.
 //!
 //! ## Example
 //!
 //! ```rust
 //! use spacepackets::SpHeader;
-//! let sp_header = SpHeader::tc(0x42, 12, 0).expect("Error creating SP header");
+//! let sp_header = SpHeader::tc_unseg(0x42, 12, 1).expect("Error creating CCSDS TC header");
 //! println!("{:?}", sp_header);
+//! let mut ccsds_buf: [u8; 32] = [0; 32];
+//! sp_header.write_to_be_bytes(&mut ccsds_buf).expect("Writing CCSDS TC header failed");
+//! println!("{:x?}", &ccsds_buf[0..6]);
 //! ```
 #![no_std]
+#![cfg_attr(doc_cfg, feature(doc_cfg))]
 #[cfg(feature = "alloc")]
 extern crate alloc;
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", test))]
 extern crate std;
 
 use crate::ecss::CCSDS_HEADER_LEN;
 use delegate::delegate;
 
+#[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
 pub mod ecss;
@@ -59,23 +63,30 @@ pub mod tc;
 pub mod time;
 pub mod tm;
 
+pub const MAX_APID: u16 = 2u16.pow(11) - 1;
+pub const MAX_SEQ_COUNT: u16 = 2u16.pow(14) - 1;
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct SizeMissmatch {
     pub found: usize,
     pub expected: usize,
 }
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
-pub enum PacketError {
-    /// The passed slice is too small. Returns the found and expected minimum size
-    ToBytesSliceTooSmall(SizeMissmatch),
-    /// The provider buffer it soo small. Returns the found and expected minimum size
-    FromBytesSliceTooSmall(SizeMissmatch),
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub enum ByteConversionError {
+    /// The passed slice is too small. Returns the passed slice length and expected minimum size
+    ToSliceTooSmall(SizeMissmatch),
+    /// The provider buffer is too small. Returns the passed slice length and expected minimum size
+    FromSliceTooSmall(SizeMissmatch),
     /// The [zerocopy] library failed to write to bytes
-    ToBytesZeroCopyError,
-    FromBytesZeroCopyError,
+    ZeroCopyToError,
+    ZeroCopyFromError,
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Copy, Clone)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum PacketType {
     Tm = 0,
     Tc = 1,
@@ -97,7 +108,8 @@ pub fn packet_type_in_raw_packet_id(packet_id: u16) -> PacketType {
     PacketType::try_from((packet_id >> 12) as u8 & 0b1).unwrap()
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Copy, Clone)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum SequenceFlags {
     ContinuationSegment = 0b00,
     FirstSegment = 0b01,
@@ -121,28 +133,64 @@ impl TryFrom<u8> for SequenceFlags {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Copy, Clone)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct PacketId {
     pub ptype: PacketType,
     pub sec_header_flag: bool,
     apid: u16,
 }
 
-impl PacketId {
-    pub fn new(ptype: PacketType, sec_header_flag: bool, apid: u16) -> Option<PacketId> {
-        let mut pid = PacketId {
-            ptype,
-            sec_header_flag,
+impl Default for PacketId {
+    fn default() -> Self {
+        PacketId {
+            ptype: PacketType::Tm,
+            sec_header_flag: false,
             apid: 0,
-        };
-        pid.set_apid(apid).then(|| pid)
+        }
+    }
+}
+
+impl PacketId {
+    pub const fn const_tc(sec_header: bool, apid: u16) -> Self {
+        Self::const_new(PacketType::Tc, sec_header, apid)
+    }
+
+    pub const fn const_tm(sec_header: bool, apid: u16) -> Self {
+        Self::const_new(PacketType::Tm, sec_header, apid)
+    }
+
+    pub fn tc(sec_header: bool, apid: u16) -> Option<Self> {
+        Self::new(PacketType::Tc, sec_header, apid)
+    }
+
+    pub fn tm(sec_header: bool, apid: u16) -> Option<Self> {
+        Self::new(PacketType::Tm, sec_header, apid)
+    }
+
+    pub const fn const_new(ptype: PacketType, sec_header: bool, apid: u16) -> Self {
+        if apid > MAX_APID {
+            panic!("APID too large");
+        }
+        PacketId {
+            ptype,
+            sec_header_flag: sec_header,
+            apid,
+        }
+    }
+
+    pub fn new(ptype: PacketType, sec_header_flag: bool, apid: u16) -> Option<PacketId> {
+        if apid > MAX_APID {
+            return None;
+        }
+        Some(PacketId::const_new(ptype, sec_header_flag, apid))
     }
 
     /// Set a new Application Process ID (APID). If the passed number is invalid, the APID will
     /// not be set and false will be returned. The maximum allowed value for the 11-bit field is
     /// 2047
     pub fn set_apid(&mut self, apid: u16) -> bool {
-        if apid > 2u16.pow(11) - 1 {
+        if apid > MAX_APID {
             return false;
         }
         self.apid = apid;
@@ -168,35 +216,48 @@ impl From<u16> for PacketId {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Copy, Clone)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct PacketSequenceCtrl {
     pub seq_flags: SequenceFlags,
     seq_count: u16,
 }
 
 impl PacketSequenceCtrl {
-    pub fn new(seq_flags: SequenceFlags, ssc: u16) -> Option<PacketSequenceCtrl> {
-        let mut psc = 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 {
+        if seq_count > MAX_SEQ_COUNT {
+            panic!("Sequence count too large");
+        }
+        PacketSequenceCtrl {
             seq_flags,
-            seq_count: 0,
-        };
-        psc.set_seq_count(ssc).then(|| psc)
+            seq_count,
+        }
+    }
+
+    /// Returns [None] if the passed sequence count exceeds [MAX_SEQ_COUNT].
+    pub fn new(seq_flags: SequenceFlags, seq_count: u16) -> Option<PacketSequenceCtrl> {
+        if seq_count > MAX_SEQ_COUNT {
+            return None;
+        }
+        Some(PacketSequenceCtrl::const_new(seq_flags, seq_count))
     }
     pub fn raw(&self) -> u16 {
         ((self.seq_flags as u16) << 14) | self.seq_count
     }
 
     /// Set a new sequence count. If the passed number is invalid, the sequence count will not be
-    /// set and false will be returned. The maximum allowed value for the 14-bit field is 16383
+    /// set and false will be returned. The maximum allowed value for the 14-bit field is 16383.
     pub fn set_seq_count(&mut self, ssc: u16) -> bool {
-        if ssc > 2u16.pow(14) - 1 {
+        if ssc > MAX_SEQ_COUNT {
             return false;
         }
         self.seq_count = ssc;
         true
     }
 
-    pub fn ssc(&self) -> u16 {
+    pub fn seq_count(&self) -> u16 {
         self.seq_count
     }
 }
@@ -228,7 +289,7 @@ macro_rules! sph_from_other {
 const SSC_MASK: u16 = 0x3FFF;
 const VERSION_MASK: u16 = 0xE000;
 
-/// Generic trait to access fields of a CCSDS space packet header according to CCSDS 133.0-B-2
+/// Generic trait to access fields of a CCSDS space packet header according to CCSDS 133.0-B-2.
 pub trait CcsdsPacket {
     fn ccsds_version(&self) -> u8;
     fn packet_id(&self) -> PacketId;
@@ -242,7 +303,7 @@ pub trait CcsdsPacket {
     }
 
     /// Retrieve 13 bit Packet Identification field. Can usually be retrieved with a bitwise AND
-    /// of the first 2 bytes with 0x1FFF
+    /// of the first 2 bytes with 0x1FFF.
     #[inline]
     fn packet_id_raw(&self) -> u16 {
         self.packet_id().raw()
@@ -253,8 +314,8 @@ pub trait CcsdsPacket {
         self.psc().raw()
     }
 
+    /// Retrieve Packet Type (TM: 0, TC: 1).
     #[inline]
-    /// Retrieve Packet Type (TM: 0, TC: 1)
     fn ptype(&self) -> PacketType {
         // This call should never fail because only 0 and 1 can be passed to the try_from call
         self.packet_id().ptype
@@ -271,13 +332,13 @@ pub trait CcsdsPacket {
     }
 
     /// Retrieve the secondary header flag. Returns true if a secondary header is present
-    /// and false if it is not
+    /// and false if it is not.
     #[inline]
     fn sec_header_flag(&self) -> bool {
         self.packet_id().sec_header_flag
     }
 
-    /// Retrieve Application Process ID
+    /// Retrieve Application Process ID.
     #[inline]
     fn apid(&self) -> u16 {
         self.packet_id().apid
@@ -305,65 +366,114 @@ pub trait CcsdsPrimaryHeader {
     ) -> Self;
 }
 
-/// Space Packet Primary Header according to CCSDS 133.0-B-2
+/// Space Packet Primary Header according to CCSDS 133.0-B-2.
 ///
 /// # Arguments
 ///
-/// * `version` - CCSDS version field, occupies the first 3 bits of the raw header
+/// * `version` - CCSDS version field, occupies the first 3 bits of the raw header. Will generally
+///    be set to 0b000 in all constructors provided by this crate.
 /// * `packet_id` - Packet Identifier, which can also be used as a start marker. Occupies the last
 ///    13 bits of the first two bytes of the raw header
 /// * `psc` - Packet Sequence Control, occupies the third and fourth byte of the raw header
 /// * `data_len` - Data length field occupies the fifth and the sixth byte of the raw header
-#[derive(serde::Serialize, serde::Deserialize, Debug, PartialEq, Eq, Copy, Clone)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct SpHeader {
     pub version: u8,
     pub packet_id: PacketId,
     pub psc: PacketSequenceCtrl,
     pub data_len: u16,
 }
+
 impl Default for SpHeader {
+    /// The default function sets the sequence flag field to [SequenceFlags::Unsegmented]. The data
+    /// length field is set to 1, which denotes an empty space packets.
     fn default() -> Self {
         SpHeader {
             version: 0,
-            packet_id: PacketId {
-                ptype: PacketType::Tm,
-                apid: 0,
-                sec_header_flag: false,
-            },
+            packet_id: PacketId::default(),
             psc: PacketSequenceCtrl {
                 seq_flags: SequenceFlags::Unsegmented,
                 seq_count: 0,
             },
-            data_len: 0,
+            data_len: 1,
         }
     }
 }
+
 impl SpHeader {
-    pub fn new(
+    pub const fn new(packet_id: PacketId, psc: PacketSequenceCtrl, data_len: u16) -> Self {
+        Self {
+            version: 0,
+            packet_id,
+            psc,
+            data_len,
+        }
+    }
+
+    /// const variant of the [SpHeader::new_fron_single_fields] function. Panics if the passed
+    /// APID exceeds [MAX_APID] or the passed packet sequence count exceeds [MAX_SEQ_COUNT].
+    const fn const_new_from_single_fields(
         ptype: PacketType,
         sec_header: bool,
         apid: u16,
-        ssc: u16,
+        seq_flags: SequenceFlags,
+        seq_count: u16,
+        data_len: u16,
+    ) -> Self {
+        if seq_count > MAX_SEQ_COUNT {
+            panic!("Sequence count is too large");
+        }
+        if apid > MAX_APID {
+            panic!("APID is too large");
+        }
+        Self {
+            psc: PacketSequenceCtrl::const_new(seq_flags, seq_count),
+            packet_id: PacketId::const_new(ptype, sec_header, apid),
+            data_len,
+            version: 0,
+        }
+    }
+
+    /// Create a new Space Packet Header instance which can be used to create generic
+    /// Space Packets. This will return [None] if the APID or sequence count argument
+    /// exceed [MAX_APID] or [MAX_SEQ_COUNT] respectively. The version field is set to 0b000.
+    pub fn new_from_single_fields(
+        ptype: PacketType,
+        sec_header: bool,
+        apid: u16,
+        seq_flags: SequenceFlags,
+        seq_count: u16,
         data_len: u16,
     ) -> Option<Self> {
-        if ssc > 2u16.pow(14) - 1 || apid > 2u16.pow(11) - 1 {
+        if seq_count > MAX_SEQ_COUNT || apid > MAX_APID {
             return None;
         }
-        let mut header = SpHeader::default();
-        header.packet_id.sec_header_flag = sec_header;
-        header.packet_id.apid = apid;
-        header.packet_id.ptype = ptype;
-        header.psc.seq_count = ssc;
-        header.data_len = data_len;
-        Some(header)
+        Some(SpHeader::const_new_from_single_fields(
+            ptype, sec_header, apid, seq_flags, seq_count, data_len,
+        ))
     }
 
-    pub fn tm(apid: u16, seq_count: u16, data_len: u16) -> Option<Self> {
-        Self::new(PacketType::Tm, false, apid, seq_count, data_len)
+    /// Helper function for telemetry space packet headers. The packet type field will be
+    /// set accordingly. The secondary header flag field is set to false.
+    pub fn tm(apid: u16, seq_flags: SequenceFlags, seq_count: u16, data_len: u16) -> Option<Self> {
+        Self::new_from_single_fields(PacketType::Tm, false, apid, seq_flags, seq_count, data_len)
     }
 
-    pub fn tc(apid: u16, seq_count: u16, data_len: u16) -> Option<Self> {
-        Self::new(PacketType::Tc, false, apid, seq_count, data_len)
+    /// Helper function for telemetry space packet headers. The packet type field will be
+    /// set accordingly. The secondary header flag field is set to false.
+    pub fn tc(apid: u16, seq_flags: SequenceFlags, seq_count: u16, data_len: u16) -> Option<Self> {
+        Self::new_from_single_fields(PacketType::Tc, false, apid, seq_flags, seq_count, data_len)
+    }
+
+    /// Variant of [SpHeader::tm] which sets the sequence flag field to [SequenceFlags::Unsegmented]
+    pub fn tm_unseg(apid: u16, seq_count: u16, data_len: u16) -> Option<Self> {
+        Self::tm(apid, SequenceFlags::Unsegmented, seq_count, data_len)
+    }
+
+    /// Variant of [SpHeader::tc] which sets the sequence flag field to [SequenceFlags::Unsegmented]
+    pub fn tc_unseg(apid: u16, seq_count: u16, data_len: u16) -> Option<Self> {
+        Self::tc(apid, SequenceFlags::Unsegmented, seq_count, data_len)
     }
 
     //noinspection RsTraitImplementation
@@ -391,16 +501,38 @@ impl SpHeader {
         self.packet_id.ptype = packet_type;
     }
 
-    pub fn from_raw_slice(buf: &[u8]) -> Result<Self, PacketError> {
-        if buf.len() < CCSDS_HEADER_LEN + 1 {
-            return Err(PacketError::FromBytesSliceTooSmall(SizeMissmatch {
+    /// Create a struct from a raw slice where the fields have network endianness (big).
+    /// This function will also returns the remaining part of the passed slice starting starting
+    /// past the read CCSDS header.
+    pub fn from_be_bytes(buf: &[u8]) -> Result<(Self, &[u8]), ByteConversionError> {
+        if buf.len() < CCSDS_HEADER_LEN {
+            return Err(ByteConversionError::FromSliceTooSmall(SizeMissmatch {
                 found: buf.len(),
-                expected: CCSDS_HEADER_LEN + 1,
+                expected: CCSDS_HEADER_LEN,
             }));
         }
         let zc_header = zc::SpHeader::from_bytes(&buf[0..CCSDS_HEADER_LEN])
-            .ok_or(PacketError::FromBytesZeroCopyError)?;
-        Ok(Self::from(zc_header))
+            .ok_or(ByteConversionError::ZeroCopyFromError)?;
+        Ok((Self::from(zc_header), &buf[CCSDS_HEADER_LEN..]))
+    }
+
+    /// Write the header to a raw buffer using big endian format. This function returns the
+    /// remaining part of the passed slice starting past the written CCSDS header.
+    pub fn write_to_be_bytes<'a>(
+        &self,
+        buf: &'a mut [u8],
+    ) -> Result<&'a mut [u8], ByteConversionError> {
+        if buf.len() < CCSDS_HEADER_LEN {
+            return Err(ByteConversionError::FromSliceTooSmall(SizeMissmatch {
+                found: buf.len(),
+                expected: CCSDS_HEADER_LEN,
+            }));
+        }
+        let zc_header: zc::SpHeader = zc::SpHeader::from(*self);
+        zc_header
+            .to_bytes(&mut buf[0..CCSDS_HEADER_LEN])
+            .ok_or(ByteConversionError::ZeroCopyToError)?;
+        Ok(&mut buf[CCSDS_HEADER_LEN..])
     }
 }
 
@@ -529,23 +661,75 @@ pub mod zc {
     sph_from_other!(SpHeader, crate::SpHeader);
 }
 
-#[cfg(test)]
+#[cfg(all(test, feature = "std"))]
 mod tests {
-    #[cfg(feature = "std")]
+    #[cfg(feature = "serde")]
     use crate::CcsdsPrimaryHeader;
-    use crate::SpHeader;
     use crate::{
         packet_type_in_raw_packet_id, zc, CcsdsPacket, PacketId, PacketSequenceCtrl, PacketType,
-        SequenceFlags,
     };
+    use crate::{SequenceFlags, SpHeader};
     use alloc::vec;
-    #[cfg(not(feature = "std"))]
-    use num::pow;
-    #[cfg(feature = "std")]
     use num_traits::pow;
-    use postcard::from_bytes;
-    #[cfg(feature = "alloc")]
-    use postcard::to_allocvec;
+    #[cfg(feature = "serde")]
+    use postcard::{from_bytes, to_allocvec};
+
+    const CONST_SP: SpHeader = SpHeader::new(
+        PacketId::const_tc(true, 0x36),
+        PacketSequenceCtrl::const_new(SequenceFlags::ContinuationSegment, 0x88),
+        0x90,
+    );
+
+    const PACKET_ID_TM: PacketId = PacketId::const_tm(true, 0x22);
+
+    #[test]
+    fn verify_const_packet_id() {
+        assert_eq!(PACKET_ID_TM.apid(), 0x22);
+        assert_eq!(PACKET_ID_TM.sec_header_flag, true);
+        assert_eq!(PACKET_ID_TM.ptype, PacketType::Tm);
+        let const_tc_id = PacketId::const_tc(true, 0x23);
+        assert_eq!(const_tc_id.ptype, PacketType::Tc);
+    }
+
+    #[test]
+    fn test_default_packet_id() {
+        let id_default = PacketId::default();
+        assert_eq!(id_default.ptype, PacketType::Tm);
+        assert_eq!(id_default.apid, 0x000);
+        assert_eq!(id_default.sec_header_flag, false);
+    }
+
+    #[test]
+    fn test_packet_id_ctors() {
+        let packet_id = PacketId::new(PacketType::Tc, true, 0x1ff);
+        assert!(packet_id.is_some());
+        let packet_id = packet_id.unwrap();
+        assert_eq!(packet_id.apid(), 0x1ff);
+        assert_eq!(packet_id.ptype, PacketType::Tc);
+        assert_eq!(packet_id.sec_header_flag, true);
+        let packet_id_tc = PacketId::tc(true, 0x1ff);
+        assert!(packet_id_tc.is_some());
+        let packet_id_tc = packet_id_tc.unwrap();
+        assert_eq!(packet_id_tc, packet_id);
+        let packet_id_tm = PacketId::tm(true, 0x2ff);
+        assert!(packet_id_tm.is_some());
+        let packet_id_tm = packet_id_tm.unwrap();
+        assert_eq!(packet_id_tm.sec_header_flag, true);
+        assert_eq!(packet_id_tm.ptype, PacketType::Tm);
+        assert_eq!(packet_id_tm.apid, 0x2ff);
+    }
+
+    #[test]
+    fn verify_const_sp_header() {
+        assert_eq!(CONST_SP.sec_header_flag(), true);
+        assert_eq!(CONST_SP.apid(), 0x36);
+        assert_eq!(
+            CONST_SP.sequence_flags(),
+            SequenceFlags::ContinuationSegment
+        );
+        assert_eq!(CONST_SP.seq_count(), 0x88);
+        assert_eq!(CONST_SP.data_len, 0x90);
+    }
 
     #[test]
     fn test_seq_flag_helpers() {
@@ -628,9 +812,9 @@ mod tests {
     }
 
     #[test]
-    #[cfg(feature = "std")]
+    #[cfg(feature = "serde")]
     fn test_serde_sph() {
-        let sp_header = SpHeader::tc(0x42, 12, 0).expect("Error creating SP header");
+        let sp_header = SpHeader::tc_unseg(0x42, 12, 0).expect("Error creating SP header");
         assert_eq!(sp_header.ccsds_version(), 0b000);
         assert!(sp_header.is_tc());
         assert!(!sp_header.sec_header_flag());
@@ -652,7 +836,7 @@ mod tests {
         assert_eq!(sp_header.ccsds_version(), 0b000);
         assert_eq!(sp_header.data_len, 0);
 
-        let sp_header = SpHeader::tm(0x7, 22, 36).expect("Error creating SP header");
+        let sp_header = SpHeader::tm_unseg(0x7, 22, 36).expect("Error creating SP header");
         assert_eq!(sp_header.ccsds_version(), 0b000);
         assert!(sp_header.is_tm());
         assert!(!sp_header.sec_header_flag());
@@ -683,28 +867,69 @@ mod tests {
     }
 
     #[test]
-    fn test_sp_header_setters() {
-        let mut sp_header = SpHeader::tc(0x42, 12, 0).expect("Error creating SP header");
-        assert_eq!(sp_header.apid(), 0x42);
+    fn test_setters() {
+        let sp_header = SpHeader::tc(0x42, SequenceFlags::Unsegmented, 25, 0);
+        assert!(sp_header.is_some());
+        let mut sp_header = sp_header.unwrap();
         sp_header.set_apid(0x12);
         assert_eq!(sp_header.apid(), 0x12);
-
         sp_header.set_sec_header_flag();
         assert!(sp_header.sec_header_flag());
         sp_header.clear_sec_header_flag();
         assert!(!sp_header.sec_header_flag());
-        sp_header.set_seq_count(0x45);
-        assert_eq!(sp_header.seq_count(), 0x45);
         assert_eq!(sp_header.ptype(), PacketType::Tc);
         sp_header.set_packet_type(PacketType::Tm);
         assert_eq!(sp_header.ptype(), PacketType::Tm);
+        sp_header.set_seq_count(0x45);
+        assert_eq!(sp_header.seq_count(), 0x45);
+    }
+
+    #[test]
+    fn test_tc_ctor() {
+        let sp_header = SpHeader::tc(0x42, SequenceFlags::Unsegmented, 25, 0);
+        assert!(sp_header.is_some());
+        let sp_header = sp_header.unwrap();
+        verify_sp_fields(PacketType::Tc, &sp_header);
+    }
+
+    #[test]
+    fn test_tc_ctor_unseg() {
+        let sp_header = SpHeader::tc_unseg(0x42, 25, 0);
+        assert!(sp_header.is_some());
+        let sp_header = sp_header.unwrap();
+        verify_sp_fields(PacketType::Tc, &sp_header);
+    }
+
+    #[test]
+    fn test_tm_ctor() {
+        let sp_header = SpHeader::tm(0x42, SequenceFlags::Unsegmented, 25, 0);
+        assert!(sp_header.is_some());
+        let sp_header = sp_header.unwrap();
+        verify_sp_fields(PacketType::Tm, &sp_header);
+    }
+
+    #[test]
+    fn test_tm_ctor_unseg() {
+        let sp_header = SpHeader::tm_unseg(0x42, 25, 0);
+        assert!(sp_header.is_some());
+        let sp_header = sp_header.unwrap();
+        verify_sp_fields(PacketType::Tm, &sp_header);
+    }
+
+    fn verify_sp_fields(ptype: PacketType, sp_header: &SpHeader) {
+        assert_eq!(sp_header.ptype(), ptype);
+        assert_eq!(sp_header.sequence_flags(), SequenceFlags::Unsegmented);
+        assert_eq!(sp_header.apid(), 0x42);
+        assert_eq!(sp_header.seq_count(), 25);
+        assert_eq!(sp_header.data_len(), 0);
     }
 
     #[test]
     fn test_zc_sph() {
         use zerocopy::AsBytes;
 
-        let sp_header = SpHeader::tc(0x7FF, pow(2, 14) - 1, 0).expect("Error creating SP header");
+        let sp_header =
+            SpHeader::tc_unseg(0x7FF, pow(2, 14) - 1, 0).expect("Error creating SP header");
         assert_eq!(sp_header.ptype(), PacketType::Tc);
         assert_eq!(sp_header.apid(), 0x7FF);
         assert_eq!(sp_header.data_len(), 0);

src/tc.rs

@@ -9,7 +9,7 @@
 //! use spacepackets::ecss::PusPacket;
 //!
 //! // Create a ping telecommand with no user application data
-//! let mut sph = SpHeader::tc(0x02, 0x34, 0).unwrap();
+//! let mut sph = SpHeader::tc_unseg(0x02, 0x34, 0).unwrap();
 //! let tc_header = PusTcSecondaryHeader::new_simple(17, 1);
 //! let pus_tc = PusTc::new(&mut sph, tc_header, None, true);
 //! println!("{:?}", pus_tc);
@@ -20,13 +20,13 @@
 //! // Serialize TC into a raw buffer
 //! let mut test_buf: [u8; 32] = [0; 32];
 //! let size = pus_tc
-//!     .write_to(test_buf.as_mut_slice())
+//!     .write_to_bytes(test_buf.as_mut_slice())
 //!     .expect("Error writing TC to buffer");
 //! assert_eq!(size, 13);
 //! println!("{:?}", &test_buf[0..size]);
 //!
 //! // Deserialize from the raw byte representation
-//! let pus_tc_deserialized = PusTc::new_from_raw_slice(&test_buf).expect("Deserialization failed");
+//! let pus_tc_deserialized = PusTc::from_bytes(&test_buf).expect("Deserialization failed");
 //! assert_eq!(pus_tc.service(), 17);
 //! assert_eq!(pus_tc.subservice(), 1);
 //! assert_eq!(pus_tc.apid(), 0x02);
@@ -36,9 +36,12 @@ use crate::ecss::{
     verify_crc16_from_raw, CrcType, PusError, PusPacket, PusVersion, CRC_CCITT_FALSE,
 };
 use crate::SpHeader;
-use crate::{CcsdsPacket, PacketError, PacketType, SequenceFlags, SizeMissmatch, CCSDS_HEADER_LEN};
+use crate::{
+    ByteConversionError, CcsdsPacket, PacketType, SequenceFlags, SizeMissmatch, CCSDS_HEADER_LEN,
+};
 use core::mem::size_of;
 use delegate::delegate;
+#[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 use zerocopy::AsBytes;
 
@@ -64,7 +67,7 @@ pub const ACK_ALL: u8 = AckOpts::Acceptance as u8
     | AckOpts::Progress as u8
     | AckOpts::Completion as u8;
 
-pub trait PusTcSecondaryHeaderT {
+pub trait GenericPusTcSecondaryHeader {
     fn pus_version(&self) -> PusVersion;
     fn ack_flags(&self) -> u8;
     fn service(&self) -> u8;
@@ -74,7 +77,7 @@ pub trait PusTcSecondaryHeaderT {
 
 pub mod zc {
     use crate::ecss::{PusError, PusVersion};
-    use crate::tc::PusTcSecondaryHeaderT;
+    use crate::tc::GenericPusTcSecondaryHeader;
     use zerocopy::{AsBytes, FromBytes, NetworkEndian, Unaligned, U16};
 
     #[derive(FromBytes, AsBytes, Unaligned)]
@@ -101,7 +104,7 @@ pub mod zc {
         }
     }
 
-    impl PusTcSecondaryHeaderT for PusTcSecondaryHeader {
+    impl GenericPusTcSecondaryHeader for PusTcSecondaryHeader {
         fn pus_version(&self) -> PusVersion {
             PusVersion::try_from(self.version_ack >> 4 & 0b1111).unwrap_or(PusVersion::Invalid)
         }
@@ -124,7 +127,7 @@ pub mod zc {
     }
 
     impl PusTcSecondaryHeader {
-        pub fn to_bytes(&self, slice: &mut [u8]) -> Option<()> {
+        pub fn write_to_bytes(&self, slice: &mut [u8]) -> Option<()> {
             self.write_to(slice)
         }
 
@@ -134,7 +137,8 @@ pub mod zc {
     }
 }
 
-#[derive(PartialEq, Eq, Copy, Clone, Serialize, Deserialize, Debug)]
+#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct PusTcSecondaryHeader {
     pub service: u8,
     pub subservice: u8,
@@ -143,7 +147,7 @@ pub struct PusTcSecondaryHeader {
     pub version: PusVersion,
 }
 
-impl PusTcSecondaryHeaderT for PusTcSecondaryHeader {
+impl GenericPusTcSecondaryHeader for PusTcSecondaryHeader {
     fn pus_version(&self) -> PusVersion {
         self.version
     }
@@ -209,14 +213,15 @@ impl PusTcSecondaryHeader {
 /// [postcard](https://docs.rs/postcard/latest/postcard/).
 ///
 /// There is no spare bytes support yet.
-#[derive(PartialEq, Eq, Copy, Clone, Serialize, Deserialize, Debug)]
+#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct PusTc<'slice> {
     sp_header: SpHeader,
     pub sec_header: PusTcSecondaryHeader,
     /// If this is set to false, a manual call to [PusTc::calc_own_crc16] or
     /// [PusTc::update_packet_fields] is necessary for the serialized or cached CRC16 to be valid.
     pub calc_crc_on_serialization: bool,
-    #[serde(skip)]
+    #[cfg_attr(feature = "serde", serde(skip))]
     raw_data: Option<&'slice [u8]>,
     app_data: Option<&'slice [u8]>,
     crc16: Option<u16>,
@@ -258,7 +263,7 @@ impl<'slice> PusTc<'slice> {
     }
 
     /// Simplified version of the [PusTc::new] function which allows to only specify service and
-    /// subservice instead of the full PUS TC secondary header
+    /// subservice instead of the full PUS TC secondary header.
     pub fn new_simple(
         sph: &mut SpHeader,
         service: u8,
@@ -301,7 +306,7 @@ impl<'slice> PusTc<'slice> {
     /// used.
     /// If this was not done or the application data is set or changed after construction,
     /// this function needs to be called to ensure that the data length field of the CCSDS header
-    /// is set correctly
+    /// is set correctly.
     pub fn update_ccsds_data_len(&mut self) {
         self.sp_header.data_len =
             self.len_packed() as u16 - size_of::<crate::zc::SpHeader>() as u16 - 1;
@@ -321,35 +326,30 @@ impl<'slice> PusTc<'slice> {
         self.crc16 = Some(digest.finalize())
     }
 
-    /// This helper function calls both [PusTc.update_ccsds_data_len] and [PusTc.calc_own_crc16]
+    /// This helper function calls both [PusTc.update_ccsds_data_len] and [PusTc.calc_own_crc16].
     pub fn update_packet_fields(&mut self) {
         self.update_ccsds_data_len();
         self.calc_own_crc16();
     }
 
     /// Write the raw PUS byte representation to a provided buffer.
-    pub fn write_to(&self, slice: &mut [u8]) -> Result<usize, PusError> {
+    pub fn write_to_bytes(&self, slice: &mut [u8]) -> Result<usize, PusError> {
         let mut curr_idx = 0;
-        let sph_zc = crate::zc::SpHeader::from(self.sp_header);
         let tc_header_len = size_of::<zc::PusTcSecondaryHeader>();
         let total_size = self.len_packed();
         if total_size > slice.len() {
-            return Err(PusError::PacketError(PacketError::ToBytesSliceTooSmall(
-                SizeMissmatch {
-                    found: slice.len(),
-                    expected: total_size,
-                },
-            )));
+            return Err(ByteConversionError::ToSliceTooSmall(SizeMissmatch {
+                found: slice.len(),
+                expected: total_size,
+            })
+            .into());
         }
-        sph_zc
-            .to_bytes(&mut slice[curr_idx..curr_idx + CCSDS_HEADER_LEN])
-            .ok_or(PusError::PacketError(PacketError::ToBytesZeroCopyError))?;
-
+        self.sp_header.write_to_be_bytes(slice)?;
         curr_idx += CCSDS_HEADER_LEN;
         let sec_header = zc::PusTcSecondaryHeader::try_from(self.sec_header).unwrap();
         sec_header
-            .to_bytes(&mut slice[curr_idx..curr_idx + tc_header_len])
-            .ok_or(PusError::PacketError(PacketError::ToBytesZeroCopyError))?;
+            .write_to_bytes(&mut slice[curr_idx..curr_idx + tc_header_len])
+            .ok_or(ByteConversionError::ZeroCopyToError)?;
 
         curr_idx += tc_header_len;
         if let Some(app_data) = self.app_data {
@@ -369,6 +369,7 @@ impl<'slice> PusTc<'slice> {
     }
 
     #[cfg(feature = "alloc")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
     pub fn append_to_vec(&self, vec: &mut Vec<u8>) -> Result<usize, PusError> {
         let sph_zc = crate::zc::SpHeader::from(self.sp_header);
         let mut appended_len = PUS_TC_MIN_LEN_WITHOUT_APP_DATA;
@@ -399,29 +400,27 @@ impl<'slice> PusTc<'slice> {
     }
 
     /// Create a [PusTc] instance from a raw slice. On success, it returns a tuple containing
-    /// the instance and the found byte length of the packet
-    pub fn new_from_raw_slice(slice: &'slice [u8]) -> Result<(Self, usize), PusError> {
+    /// the instance and the found byte length of the packet.
+    pub fn from_bytes(slice: &'slice [u8]) -> Result<(Self, usize), PusError> {
         let raw_data_len = slice.len();
         if raw_data_len < PUS_TC_MIN_LEN_WITHOUT_APP_DATA {
             return Err(PusError::RawDataTooShort(raw_data_len));
         }
         let mut current_idx = 0;
-        let sph =
-            crate::zc::SpHeader::from_bytes(&slice[current_idx..current_idx + CCSDS_HEADER_LEN])
-                .ok_or(PusError::PacketError(PacketError::FromBytesZeroCopyError))?;
+        let (sp_header, _) = SpHeader::from_be_bytes(&slice[0..CCSDS_HEADER_LEN])?;
         current_idx += CCSDS_HEADER_LEN;
-        let total_len = sph.total_len();
+        let total_len = sp_header.total_len();
         if raw_data_len < total_len || total_len < PUS_TC_MIN_LEN_WITHOUT_APP_DATA {
             return Err(PusError::RawDataTooShort(raw_data_len));
         }
-        let sec_header = crate::tc::zc::PusTcSecondaryHeader::from_bytes(
+        let sec_header = zc::PusTcSecondaryHeader::from_bytes(
             &slice[current_idx..current_idx + PUC_TC_SECONDARY_HEADER_LEN],
         )
-        .ok_or(PusError::PacketError(PacketError::FromBytesZeroCopyError))?;
+        .ok_or(ByteConversionError::ZeroCopyFromError)?;
         current_idx += PUC_TC_SECONDARY_HEADER_LEN;
         let raw_data = &slice[0..total_len];
         let pus_tc = PusTc {
-            sp_header: SpHeader::from(sph),
+            sp_header,
             sec_header: PusTcSecondaryHeader::try_from(sec_header).unwrap(),
             raw_data: Some(raw_data),
             app_data: user_data_from_raw(current_idx, total_len, raw_data_len, slice)?,
@@ -431,6 +430,10 @@ impl<'slice> PusTc<'slice> {
         verify_crc16_from_raw(raw_data, pus_tc.crc16.expect("CRC16 invalid"))?;
         Ok((pus_tc, total_len))
     }
+
+    pub fn raw(&self) -> Option<&'slice [u8]> {
+        self.raw_data
+    }
 }
 
 //noinspection RsTraitImplementation
@@ -456,7 +459,7 @@ impl PusPacket for PusTc<'_> {
 }
 
 //noinspection RsTraitImplementation
-impl PusTcSecondaryHeaderT for PusTc<'_> {
+impl GenericPusTcSecondaryHeader for PusTc<'_> {
     delegate!(to self.sec_header {
         fn pus_version(&self) -> PusVersion;
         fn service(&self) -> u8;
@@ -466,29 +469,29 @@ impl PusTcSecondaryHeaderT for PusTc<'_> {
     });
 }
 
-#[cfg(test)]
+#[cfg(all(test, feature = "std"))]
 mod tests {
     use crate::ecss::PusVersion::PusC;
     use crate::ecss::{PusError, PusPacket};
     use crate::tc::ACK_ALL;
-    use crate::tc::{PusTc, PusTcSecondaryHeader, PusTcSecondaryHeaderT};
+    use crate::tc::{GenericPusTcSecondaryHeader, PusTc, PusTcSecondaryHeader};
+    use crate::{ByteConversionError, SpHeader};
     use crate::{CcsdsPacket, SequenceFlags};
-    use crate::{PacketError, SpHeader};
     use alloc::vec::Vec;
 
     fn base_ping_tc_full_ctor() -> PusTc<'static> {
-        let mut sph = SpHeader::tc(0x02, 0x34, 0).unwrap();
+        let mut sph = SpHeader::tc_unseg(0x02, 0x34, 0).unwrap();
         let tc_header = PusTcSecondaryHeader::new_simple(17, 1);
         PusTc::new(&mut sph, tc_header, None, true)
     }
 
     fn base_ping_tc_simple_ctor() -> PusTc<'static> {
-        let mut sph = SpHeader::tc(0x02, 0x34, 0).unwrap();
+        let mut sph = SpHeader::tc_unseg(0x02, 0x34, 0).unwrap();
         PusTc::new_simple(&mut sph, 17, 1, None, true)
     }
 
     fn base_ping_tc_simple_ctor_with_app_data(app_data: &'static [u8]) -> PusTc<'static> {
-        let mut sph = SpHeader::tc(0x02, 0x34, 0).unwrap();
+        let mut sph = SpHeader::tc_unseg(0x02, 0x34, 0).unwrap();
         PusTc::new_simple(&mut sph, 17, 1, Some(app_data), true)
     }
 
@@ -504,7 +507,7 @@ mod tests {
         let pus_tc = base_ping_tc_simple_ctor();
         let mut test_buf: [u8; 32] = [0; 32];
         let size = pus_tc
-            .write_to(test_buf.as_mut_slice())
+            .write_to_bytes(test_buf.as_mut_slice())
             .expect("Error writing TC to buffer");
         assert_eq!(size, 13);
     }
@@ -514,11 +517,11 @@ mod tests {
         let pus_tc = base_ping_tc_simple_ctor();
         let mut test_buf: [u8; 32] = [0; 32];
         let size = pus_tc
-            .write_to(test_buf.as_mut_slice())
+            .write_to_bytes(test_buf.as_mut_slice())
             .expect("Error writing TC to buffer");
         assert_eq!(size, 13);
-        let (tc_from_raw, size) = PusTc::new_from_raw_slice(&test_buf)
-            .expect("Creating PUS TC struct from raw buffer failed");
+        let (tc_from_raw, size) =
+            PusTc::from_bytes(&test_buf).expect("Creating PUS TC struct from raw buffer failed");
         assert_eq!(size, 13);
         verify_test_tc(&tc_from_raw, false, 13);
         assert!(tc_from_raw.user_data().is_none());
@@ -528,7 +531,7 @@ mod tests {
 
     #[test]
     fn test_update_func() {
-        let mut sph = SpHeader::tc(0x02, 0x34, 0).unwrap();
+        let mut sph = SpHeader::tc_unseg(0x02, 0x34, 0).unwrap();
         let mut tc = PusTc::new_simple(&mut sph, 17, 1, None, false);
         tc.calc_crc_on_serialization = false;
         assert_eq!(tc.data_len(), 0);
@@ -540,11 +543,11 @@ mod tests {
         let pus_tc = base_ping_tc_simple_ctor_with_app_data(&[1, 2, 3]);
         let mut test_buf: [u8; 32] = [0; 32];
         let size = pus_tc
-            .write_to(test_buf.as_mut_slice())
+            .write_to_bytes(test_buf.as_mut_slice())
             .expect("Error writing TC to buffer");
         assert_eq!(size, 16);
-        let (tc_from_raw, size) = PusTc::new_from_raw_slice(&test_buf)
-            .expect("Creating PUS TC struct from raw buffer failed");
+        let (tc_from_raw, size) =
+            PusTc::from_bytes(&test_buf).expect("Creating PUS TC struct from raw buffer failed");
         assert_eq!(size, 16);
         verify_test_tc(&tc_from_raw, true, 16);
         let user_data = tc_from_raw.user_data().unwrap();
@@ -554,7 +557,6 @@ mod tests {
     }
 
     #[test]
-    #[cfg(feature = "alloc")]
     fn test_vec_ser_deser() {
         let pus_tc = base_ping_tc_simple_ctor();
         let mut test_vec = Vec::new();
@@ -571,10 +573,10 @@ mod tests {
         let pus_tc = base_ping_tc_simple_ctor();
         let mut test_buf: [u8; 32] = [0; 32];
         pus_tc
-            .write_to(test_buf.as_mut_slice())
+            .write_to_bytes(test_buf.as_mut_slice())
             .expect("Error writing TC to buffer");
         test_buf[12] = 0;
-        let res = PusTc::new_from_raw_slice(&test_buf);
+        let res = PusTc::from_bytes(&test_buf);
         assert!(res.is_err());
         let err = res.unwrap_err();
         assert!(matches!(err, PusError::IncorrectCrc { .. }));
@@ -587,7 +589,7 @@ mod tests {
         let mut test_buf: [u8; 32] = [0; 32];
         pus_tc.calc_own_crc16();
         pus_tc
-            .write_to(test_buf.as_mut_slice())
+            .write_to_bytes(test_buf.as_mut_slice())
             .expect("Error writing TC to buffer");
         verify_test_tc_raw(&test_buf);
         verify_crc_no_app_data(&test_buf);
@@ -598,7 +600,7 @@ mod tests {
         let mut pus_tc = base_ping_tc_simple_ctor();
         pus_tc.calc_crc_on_serialization = false;
         let mut test_buf: [u8; 32] = [0; 32];
-        let res = pus_tc.write_to(test_buf.as_mut_slice());
+        let res = pus_tc.write_to_bytes(test_buf.as_mut_slice());
         assert!(res.is_err());
         let err = res.unwrap_err();
         assert!(matches!(err, PusError::CrcCalculationMissing { .. }));
@@ -619,15 +621,15 @@ mod tests {
     }
 
     #[test]
-    fn test_write_buf_too_msall() {
+    fn test_write_buf_too_small() {
         let pus_tc = base_ping_tc_simple_ctor();
         let mut test_buf = [0; 12];
-        let res = pus_tc.write_to(test_buf.as_mut_slice());
+        let res = pus_tc.write_to_bytes(test_buf.as_mut_slice());
         assert!(res.is_err());
         let err = res.unwrap_err();
         match err {
-            PusError::PacketError(err) => match err {
-                PacketError::ToBytesSliceTooSmall(missmatch) => {
+            PusError::ByteConversionError(err) => match err {
+                ByteConversionError::ToSliceTooSmall(missmatch) => {
                     assert_eq!(missmatch.expected, pus_tc.len_packed());
                     assert_eq!(missmatch.found, 12);
                 }
@@ -643,7 +645,7 @@ mod tests {
         verify_test_tc(&pus_tc, true, 16);
         let mut test_buf: [u8; 32] = [0; 32];
         let size = pus_tc
-            .write_to(test_buf.as_mut_slice())
+            .write_to_bytes(test_buf.as_mut_slice())
             .expect("Error writing TC to buffer");
         assert_eq!(test_buf[11], 1);
         assert_eq!(test_buf[12], 2);
@@ -667,7 +669,7 @@ mod tests {
         assert_eq!(pus_tc.sequence_flags(), SequenceFlags::Unsegmented);
         pus_tc.calc_own_crc16();
         pus_tc
-            .write_to(test_buf.as_mut_slice())
+            .write_to_bytes(test_buf.as_mut_slice())
             .expect("Error writing TC to buffer");
         assert_eq!(test_buf[0], 0x1f);
         assert_eq!(test_buf[1], 0xff);
@@ -692,7 +694,7 @@ mod tests {
         assert_eq!(tc.apid(), 0x02);
         assert_eq!(tc.ack_flags(), ACK_ALL);
         assert_eq!(tc.len_packed(), exp_full_len);
-        let mut comp_header = SpHeader::tc(0x02, 0x34, exp_full_len as u16 - 7).unwrap();
+        let mut comp_header = SpHeader::tc_unseg(0x02, 0x34, exp_full_len as u16 - 7).unwrap();
         comp_header.set_sec_header_flag();
         assert_eq!(tc.sp_header, comp_header);
     }

src/time.rs

@@ -1,6 +1,6 @@
 //! CCSDS Time Code Formats according to [CCSDS 301.0-B-4](https://public.ccsds.org/Pubs/301x0b4e1.pdf)
-use crate::{PacketError, SizeMissmatch};
-use chrono::{DateTime, TimeZone, Utc};
+use crate::{ByteConversionError, SizeMissmatch};
+use chrono::{DateTime, LocalResult, TimeZone, Utc};
 
 #[allow(unused_imports)]
 #[cfg(not(feature = "std"))]
@@ -10,11 +10,15 @@ use crate::time::CcsdsTimeCodes::Cds;
 #[cfg(feature = "std")]
 use std::time::{SystemTime, SystemTimeError};
 
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
 pub const CDS_SHORT_LEN: usize = 7;
 pub const DAYS_CCSDS_TO_UNIX: i32 = -4383;
 pub const SECONDS_PER_DAY: u32 = 86400;
 
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum CcsdsTimeCodes {
     None = 0,
     CucCcsdsEpoch = 0b001,
@@ -23,6 +27,8 @@ pub enum CcsdsTimeCodes {
     Ccs = 0b101,
 }
 
+const CDS_SHORT_P_FIELD: u8 = (Cds as u8) << 4;
+
 impl TryFrom<u8> for CcsdsTimeCodes {
     type Error = ();
 
@@ -38,15 +44,17 @@ impl TryFrom<u8> for CcsdsTimeCodes {
     }
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum TimestampError {
     /// Contains tuple where first value is the expected time code and the second
     /// value is the found raw value
     InvalidTimeCode(CcsdsTimeCodes, u8),
-    OtherPacketError(PacketError),
+    OtherPacketError(ByteConversionError),
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 pub fn seconds_since_epoch() -> f64 {
     SystemTime::now()
         .duration_since(SystemTime::UNIX_EPOCH)
@@ -71,7 +79,7 @@ pub const fn ccsds_to_unix_days(ccsds_days: i32) -> i32 {
 }
 
 pub trait TimeWriter {
-    fn write_to_bytes(&self, bytes: &mut [u8]) -> Result<(), PacketError>;
+    fn write_to_bytes(&self, bytes: &mut [u8]) -> Result<(), TimestampError>;
 }
 
 pub trait TimeReader {
@@ -80,7 +88,7 @@ pub trait TimeReader {
         Self: Sized;
 }
 
-/// Trait for generic CCSDS time providers
+/// Trait for generic CCSDS time providers.
 pub trait CcsdsTimeProvider {
     fn len_as_bytes(&self) -> usize;
 
@@ -91,26 +99,38 @@ pub trait CcsdsTimeProvider {
     fn p_field(&self) -> (usize, [u8; 2]);
     fn ccdsd_time_code(&self) -> CcsdsTimeCodes;
     fn unix_seconds(&self) -> i64;
-    fn date_time(&self) -> DateTime<Utc>;
+    fn date_time(&self) -> Option<DateTime<Utc>>;
 }
 
-#[derive(Debug, Copy, Clone)]
+/// This object is the abstraction for the CCSDS Day Segmented Time Code (CDS).
+///
+/// It has the capability to generate and read timestamps as specified in the CCSDS 301.0-B-4
+/// section 3.3
+///
+/// # Example
+///
+/// ```
+/// use spacepackets::time::{CdsShortTimeProvider, TimeWriter};
+/// use spacepackets::time::CcsdsTimeCodes::Cds;
+/// let timestamp_now = CdsShortTimeProvider::from_now().unwrap();
+/// let mut raw_stamp = [0; 7];
+/// timestamp_now.write_to_bytes(&mut raw_stamp).unwrap();
+/// assert_eq!((raw_stamp[0] >> 4) & 0b111, Cds as u8);
+/// ```
+#[derive(Debug, Copy, Clone, Default, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct CdsShortTimeProvider {
-    pfield: u8,
     ccsds_days: u16,
     ms_of_day: u32,
     unix_seconds: i64,
-    date_time: Option<DateTime<Utc>>,
 }
 
 impl CdsShortTimeProvider {
     pub fn new(ccsds_days: u16, ms_of_day: u32) -> Self {
         let provider = Self {
-            pfield: (CcsdsTimeCodes::Cds as u8) << 4,
             ccsds_days,
             ms_of_day,
             unix_seconds: 0,
-            date_time: None,
         };
         let unix_days_seconds =
             ccsds_to_unix_days(ccsds_days as i32) as i64 * SECONDS_PER_DAY as i64;
@@ -118,6 +138,7 @@ impl CdsShortTimeProvider {
     }
 
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     pub fn from_now() -> Result<Self, SystemTimeError> {
         let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH)?;
         let epoch = now.as_secs();
@@ -125,23 +146,33 @@ impl CdsShortTimeProvider {
         let unix_days_seconds = epoch - secs_of_day;
         let ms_of_day = secs_of_day * 1000 + now.subsec_millis() as u64;
         let provider = Self {
-            pfield: (CcsdsTimeCodes::Cds as u8) << 4,
             ccsds_days: unix_to_ccsds_days((unix_days_seconds / SECONDS_PER_DAY as u64) as i32)
                 as u16,
             ms_of_day: ms_of_day as u32,
             unix_seconds: 0,
-            date_time: None,
         };
         Ok(provider.setup(unix_days_seconds as i64, ms_of_day))
     }
 
+    #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
+    pub fn update_from_now(&mut self) -> Result<(), SystemTimeError> {
+        let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH)?;
+        let epoch = now.as_secs();
+        let secs_of_day = epoch % SECONDS_PER_DAY as u64;
+        let unix_days_seconds = epoch - secs_of_day;
+        let ms_of_day = secs_of_day * 1000 + now.subsec_millis() as u64;
+        self.setup(unix_days_seconds as i64, ms_of_day);
+        Ok(())
+    }
+
     fn setup(mut self, unix_days_seconds: i64, ms_of_day: u64) -> Self {
         self.calc_unix_seconds(unix_days_seconds, ms_of_day);
-        self.calc_date_time((ms_of_day % 1000) as u32);
         self
     }
 
     #[cfg(feature = "std")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
     pub fn ms_of_day_using_sysclock() -> u32 {
         Self::ms_of_day(seconds_since_epoch())
     }
@@ -164,10 +195,13 @@ impl CdsShortTimeProvider {
         }
     }
 
-    fn calc_date_time(&mut self, ms_since_last_second: u32) {
+    fn calc_date_time(&self, ms_since_last_second: u32) -> Option<DateTime<Utc>> {
         assert!(ms_since_last_second < 1000, "Invalid MS since last second");
         let ns_since_last_sec = ms_since_last_second * 1e6 as u32;
-        self.date_time = Some(Utc.timestamp(self.unix_seconds, ns_since_last_sec));
+        if let LocalResult::Single(val) = Utc.timestamp_opt(self.unix_seconds, ns_since_last_sec) {
+            return Some(val);
+        }
+        None
     }
 }
 
@@ -177,31 +211,33 @@ impl CcsdsTimeProvider for CdsShortTimeProvider {
     }
 
     fn p_field(&self) -> (usize, [u8; 2]) {
-        (1, [self.pfield, 0])
+        (1, [CDS_SHORT_P_FIELD, 0])
     }
 
     fn ccdsd_time_code(&self) -> CcsdsTimeCodes {
-        CcsdsTimeCodes::Cds
+        Cds
     }
 
     fn unix_seconds(&self) -> i64 {
         self.unix_seconds
     }
 
-    fn date_time(&self) -> DateTime<Utc> {
-        self.date_time.expect("Invalid date time")
+    fn date_time(&self) -> Option<DateTime<Utc>> {
+        self.calc_date_time((self.ms_of_day % 1000) as u32)
     }
 }
 
 impl TimeWriter for CdsShortTimeProvider {
-    fn write_to_bytes(&self, buf: &mut [u8]) -> Result<(), PacketError> {
+    fn write_to_bytes(&self, buf: &mut [u8]) -> Result<(), TimestampError> {
         if buf.len() < self.len_as_bytes() {
-            return Err(PacketError::ToBytesSliceTooSmall(SizeMissmatch {
-                expected: self.len_as_bytes(),
-                found: buf.len(),
-            }));
+            return Err(TimestampError::OtherPacketError(
+                ByteConversionError::ToSliceTooSmall(SizeMissmatch {
+                    expected: self.len_as_bytes(),
+                    found: buf.len(),
+                }),
+            ));
         }
-        buf[0] = self.pfield;
+        buf[0] = CDS_SHORT_P_FIELD;
         buf[1..3].copy_from_slice(self.ccsds_days.to_be_bytes().as_slice());
         buf[3..7].copy_from_slice(self.ms_of_day.to_be_bytes().as_slice());
         Ok(())
@@ -212,7 +248,7 @@ impl TimeReader for CdsShortTimeProvider {
     fn from_bytes(buf: &[u8]) -> Result<Self, TimestampError> {
         if buf.len() < CDS_SHORT_LEN {
             return Err(TimestampError::OtherPacketError(
-                PacketError::FromBytesSliceTooSmall(SizeMissmatch {
+                ByteConversionError::FromSliceTooSmall(SizeMissmatch {
                     expected: CDS_SHORT_LEN,
                     found: buf.len(),
                 }),
@@ -222,19 +258,9 @@ impl TimeReader for CdsShortTimeProvider {
         match CcsdsTimeCodes::try_from(pfield >> 4 & 0b111) {
             Ok(cds_type) => match cds_type {
                 Cds => (),
-                _ => {
-                    return Err(TimestampError::InvalidTimeCode(
-                        CcsdsTimeCodes::Cds,
-                        cds_type as u8,
-                    ))
-                }
+                _ => return Err(TimestampError::InvalidTimeCode(Cds, cds_type as u8)),
             },
-            _ => {
-                return Err(TimestampError::InvalidTimeCode(
-                    CcsdsTimeCodes::Cds,
-                    pfield >> 4 & 0b111,
-                ))
-            }
+            _ => return Err(TimestampError::InvalidTimeCode(Cds, pfield >> 4 & 0b111)),
         };
         let ccsds_days: u16 = u16::from_be_bytes(buf[1..3].try_into().unwrap());
         let ms_of_day: u32 = u32::from_be_bytes(buf[3..7].try_into().unwrap());
@@ -242,13 +268,15 @@ impl TimeReader for CdsShortTimeProvider {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, feature = "std"))]
 mod tests {
     use super::*;
     use crate::time::TimestampError::{InvalidTimeCode, OtherPacketError};
-    use crate::PacketError::{FromBytesSliceTooSmall, ToBytesSliceTooSmall};
+    use crate::ByteConversionError::{FromSliceTooSmall, ToSliceTooSmall};
     use alloc::format;
     use chrono::{Datelike, Timelike};
+    #[cfg(feature = "serde")]
+    use postcard::{from_bytes, to_allocvec};
 
     #[test]
     fn test_creation() {
@@ -256,7 +284,6 @@ mod tests {
         assert_eq!(ccsds_to_unix_days(0), DAYS_CCSDS_TO_UNIX);
     }
 
-    #[cfg(feature = "std")]
     #[test]
     fn test_get_current_time() {
         let sec_floats = seconds_since_epoch();
@@ -270,12 +297,9 @@ mod tests {
             time_stamper.unix_seconds(),
             (DAYS_CCSDS_TO_UNIX * SECONDS_PER_DAY as i32) as i64
         );
-        assert_eq!(time_stamper.ccdsd_time_code(), CcsdsTimeCodes::Cds);
-        assert_eq!(
-            time_stamper.p_field(),
-            (1, [(CcsdsTimeCodes::Cds as u8) << 4, 0])
-        );
-        let date_time = time_stamper.date_time();
+        assert_eq!(time_stamper.ccdsd_time_code(), Cds);
+        assert_eq!(time_stamper.p_field(), (1, [(Cds as u8) << 4, 0]));
+        let date_time = time_stamper.date_time().unwrap();
         assert_eq!(date_time.year(), 1958);
         assert_eq!(date_time.month(), 1);
         assert_eq!(date_time.day(), 1);
@@ -288,7 +312,7 @@ mod tests {
     fn test_time_stamp_unix_epoch() {
         let time_stamper = CdsShortTimeProvider::new((-DAYS_CCSDS_TO_UNIX) as u16, 0);
         assert_eq!(time_stamper.unix_seconds(), 0);
-        let date_time = time_stamper.date_time();
+        let date_time = time_stamper.date_time().unwrap();
         assert_eq!(date_time.year(), 1970);
         assert_eq!(date_time.month(), 1);
         assert_eq!(date_time.day(), 1);
@@ -334,7 +358,7 @@ mod tests {
             let res = time_stamper.write_to_bytes(&mut buf[0..i]);
             assert!(res.is_err());
             match res.unwrap_err() {
-                ToBytesSliceTooSmall(missmatch) => {
+                OtherPacketError(ToSliceTooSmall(missmatch)) => {
                     assert_eq!(missmatch.found, i);
                     assert_eq!(missmatch.expected, 7);
                 }
@@ -357,7 +381,7 @@ mod tests {
                     panic!("Unexpected error");
                 }
                 OtherPacketError(e) => match e {
-                    FromBytesSliceTooSmall(missmatch) => {
+                    FromSliceTooSmall(missmatch) => {
                         assert_eq!(missmatch.found, i);
                         assert_eq!(missmatch.expected, 7);
                     }
@@ -379,7 +403,7 @@ mod tests {
         let err = res.unwrap_err();
         match err {
             InvalidTimeCode(code, raw) => {
-                assert_eq!(code, CcsdsTimeCodes::Cds);
+                assert_eq!(code, Cds);
                 assert_eq!(raw, 0);
             }
             OtherPacketError(_) => {}
@@ -407,12 +431,11 @@ mod tests {
         assert_eq!(read_stamp.ms_of_day, u32::MAX - 1);
     }
 
-    #[cfg(feature = "std")]
     #[test]
     fn test_time_now() {
         let timestamp_now = CdsShortTimeProvider::from_now().unwrap();
         let compare_stamp = Utc::now();
-        let dt = timestamp_now.date_time();
+        let dt = timestamp_now.date_time().unwrap();
         if compare_stamp.year() > dt.year() {
             assert_eq!(compare_stamp.year() - dt.year(), 1);
         } else {
@@ -433,7 +456,17 @@ mod tests {
         generic_dt_property_equality_check(dt.minute(), compare_stamp.minute(), 0, 59);
     }
 
-    #[cfg(feature = "std")]
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serialization() {
+        let stamp_now = CdsShortTimeProvider::from_now().expect("Error retrieving time");
+        let val = to_allocvec(&stamp_now).expect("Serializing timestamp failed");
+        assert!(val.len() > 0);
+        let stamp_deser: CdsShortTimeProvider =
+            from_bytes(&val).expect("Stamp deserialization failed");
+        assert_eq!(stamp_deser, stamp_now);
+    }
+
     fn generic_dt_property_equality_check(first: u32, second: u32, start: u32, end: u32) {
         if second < first {
             assert_eq!(second, start);

src/tm.rs

@@ -5,9 +5,11 @@ use crate::ecss::{
     verify_crc16_from_raw, CrcType, PusError, PusPacket, PusVersion, CRC_CCITT_FALSE,
 };
 use crate::{
-    CcsdsPacket, PacketError, PacketType, SequenceFlags, SizeMissmatch, SpHeader, CCSDS_HEADER_LEN,
+    ByteConversionError, CcsdsPacket, PacketType, SequenceFlags, SizeMissmatch, SpHeader,
+    CCSDS_HEADER_LEN,
 };
 use core::mem::size_of;
+#[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 use zerocopy::AsBytes;
 
@@ -20,7 +22,7 @@ pub const PUC_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>();
 
-pub trait PusTmSecondaryHeaderT {
+pub trait GenericPusTmSecondaryHeader {
     fn pus_version(&self) -> PusVersion;
     fn sc_time_ref_status(&self) -> u8;
     fn service(&self) -> u8;
@@ -30,6 +32,7 @@ pub trait PusTmSecondaryHeaderT {
 }
 
 pub mod zc {
+    use super::GenericPusTmSecondaryHeader;
     use crate::ecss::{PusError, PusVersion};
     use zerocopy::{AsBytes, FromBytes, NetworkEndian, Unaligned, U16};
 
@@ -66,7 +69,7 @@ pub mod zc {
     }
 
     impl PusTmSecHeaderWithoutTimestamp {
-        pub fn to_bytes(&self, slice: &mut [u8]) -> Option<()> {
+        pub fn write_to_bytes(&self, slice: &mut [u8]) -> Option<()> {
             self.write_to(slice)
         }
 
@@ -75,7 +78,7 @@ pub mod zc {
         }
     }
 
-    impl super::PusTmSecondaryHeaderT for PusTmSecHeaderWithoutTimestamp {
+    impl GenericPusTmSecondaryHeader for PusTmSecHeaderWithoutTimestamp {
         fn pus_version(&self) -> PusVersion {
             PusVersion::try_from(self.pus_version_and_sc_time_ref_status >> 4 & 0b1111)
                 .unwrap_or(PusVersion::Invalid)
@@ -103,7 +106,8 @@ pub mod zc {
     }
 }
 
-#[derive(PartialEq, Eq, Serialize, Deserialize, Copy, Clone, Debug)]
+#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct PusTmSecondaryHeader<'slice> {
     pus_version: PusVersion,
     pub sc_time_ref_status: u8,
@@ -146,7 +150,7 @@ impl<'slice> PusTmSecondaryHeader<'slice> {
     }
 }
 
-impl PusTmSecondaryHeaderT for PusTmSecondaryHeader<'_> {
+impl GenericPusTmSecondaryHeader for PusTmSecondaryHeader<'_> {
     fn pus_version(&self) -> PusVersion {
         self.pus_version
     }
@@ -197,14 +201,15 @@ impl<'slice> TryFrom<zc::PusTmSecHeader<'slice>> for PusTmSecondaryHeader<'slice
 /// [postcard](https://docs.rs/postcard/latest/postcard/).
 ///
 /// There is no spare bytes support yet.
-#[derive(PartialEq, Eq, Serialize, Deserialize, Debug, Copy, Clone)]
+#[derive(PartialEq, Eq, Debug, Copy, Clone)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct PusTm<'slice> {
     pub sp_header: SpHeader,
     pub sec_header: PusTmSecondaryHeader<'slice>,
     /// If this is set to false, a manual call to [PusTm::calc_own_crc16] or
     /// [PusTm::update_packet_fields] is necessary for the serialized or cached CRC16 to be valid.
     pub calc_crc_on_serialization: bool,
-    #[serde(skip)]
+    #[cfg_attr(feature = "serde", serde(skip))]
     raw_data: Option<&'slice [u8]>,
     source_data: Option<&'slice [u8]>,
     crc16: Option<u16>,
@@ -258,6 +263,10 @@ impl<'slice> PusTm<'slice> {
         self.sec_header.time_stamp
     }
 
+    pub fn source_data(&self) -> Option<&'slice [u8]> {
+        self.source_data
+    }
+
     pub fn set_dest_id(&mut self, dest_id: u16) {
         self.sec_header.dest_id = dest_id;
     }
@@ -304,28 +313,24 @@ impl<'slice> PusTm<'slice> {
     }
 
     /// Write the raw PUS byte representation to a provided buffer.
-    pub fn write_to(&self, slice: &mut [u8]) -> Result<usize, PusError> {
+    pub fn write_to_bytes(&self, slice: &mut [u8]) -> Result<usize, PusError> {
         let mut curr_idx = 0;
-        let sph_zc = crate::zc::SpHeader::from(self.sp_header);
         let total_size = self.len_packed();
         if total_size > slice.len() {
-            return Err(PusError::PacketError(PacketError::ToBytesSliceTooSmall(
-                SizeMissmatch {
-                    found: slice.len(),
-                    expected: total_size,
-                },
-            )));
+            return Err(ByteConversionError::ToSliceTooSmall(SizeMissmatch {
+                found: slice.len(),
+                expected: total_size,
+            })
+            .into());
         }
-        sph_zc
-            .to_bytes(&mut slice[curr_idx..curr_idx + CCSDS_HEADER_LEN])
-            .ok_or(PusError::PacketError(PacketError::ToBytesZeroCopyError))?;
-
+        self.sp_header
+            .write_to_be_bytes(&mut slice[0..CCSDS_HEADER_LEN])?;
         curr_idx += CCSDS_HEADER_LEN;
         let sec_header_len = size_of::<zc::PusTmSecHeaderWithoutTimestamp>();
         let sec_header = zc::PusTmSecHeaderWithoutTimestamp::try_from(self.sec_header).unwrap();
         sec_header
-            .to_bytes(&mut slice[curr_idx..curr_idx + sec_header_len])
-            .ok_or(PusError::PacketError(PacketError::ToBytesZeroCopyError))?;
+            .write_to_bytes(&mut slice[curr_idx..curr_idx + sec_header_len])
+            .ok_or(ByteConversionError::ZeroCopyToError)?;
         curr_idx += sec_header_len;
         let timestamp_len = self.sec_header.time_stamp.len();
         slice[curr_idx..curr_idx + timestamp_len].copy_from_slice(self.sec_header.time_stamp);
@@ -348,6 +353,7 @@ impl<'slice> PusTm<'slice> {
 
     /// Append the raw PUS byte representation to a provided [alloc::vec::Vec]
     #[cfg(feature = "alloc")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
     pub fn append_to_vec(&self, vec: &mut Vec<u8>) -> Result<usize, PusError> {
         let sph_zc = crate::zc::SpHeader::from(self.sp_header);
         let mut appended_len =
@@ -383,7 +389,7 @@ impl<'slice> PusTm<'slice> {
     /// Create a [PusTm] instance from a raw slice. On success, it returns a tuple containing
     /// the instance and the found byte length of the packet. The timestamp length needs to be
     /// known beforehand.
-    pub fn new_from_raw_slice(
+    pub fn from_bytes(
         slice: &'slice [u8],
         timestamp_len: usize,
     ) -> Result<(Self, usize), PusError> {
@@ -392,18 +398,16 @@ impl<'slice> PusTm<'slice> {
             return Err(PusError::RawDataTooShort(raw_data_len));
         }
         let mut current_idx = 0;
-        let sph =
-            crate::zc::SpHeader::from_bytes(&slice[current_idx..current_idx + CCSDS_HEADER_LEN])
-                .ok_or(PusError::PacketError(PacketError::FromBytesZeroCopyError))?;
+        let (sp_header, _) = SpHeader::from_be_bytes(&slice[0..CCSDS_HEADER_LEN])?;
         current_idx += 6;
-        let total_len = sph.total_len();
+        let total_len = sp_header.total_len();
         if raw_data_len < total_len || total_len < PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA {
             return Err(PusError::RawDataTooShort(raw_data_len));
         }
         let sec_header_zc = zc::PusTmSecHeaderWithoutTimestamp::from_bytes(
             &slice[current_idx..current_idx + PUC_TM_MIN_SEC_HEADER_LEN],
         )
-        .ok_or(PusError::PacketError(PacketError::FromBytesZeroCopyError))?;
+        .ok_or(ByteConversionError::ZeroCopyFromError)?;
         current_idx += PUC_TM_MIN_SEC_HEADER_LEN;
         let zc_sec_header_wrapper = zc::PusTmSecHeader {
             zc_header: sec_header_zc,
@@ -412,7 +416,7 @@ impl<'slice> PusTm<'slice> {
         current_idx += timestamp_len;
         let raw_data = &slice[0..total_len];
         let pus_tm = PusTm {
-            sp_header: SpHeader::from(sph),
+            sp_header,
             sec_header: PusTmSecondaryHeader::try_from(zc_sec_header_wrapper).unwrap(),
             raw_data: Some(&slice[0..total_len]),
             source_data: user_data_from_raw(current_idx, total_len, raw_data_len, slice)?,
@@ -447,7 +451,7 @@ impl PusPacket for PusTm<'_> {
 }
 
 //noinspection RsTraitImplementation
-impl PusTmSecondaryHeaderT for PusTm<'_> {
+impl GenericPusTmSecondaryHeader for PusTm<'_> {
     delegate!(to self.sec_header {
         fn pus_version(&self) -> PusVersion;
         fn service(&self) -> u8;
@@ -465,13 +469,13 @@ mod tests {
     use crate::SpHeader;
 
     fn base_ping_reply_full_ctor(time_stamp: &[u8]) -> PusTm {
-        let mut sph = SpHeader::tm(0x123, 0x234, 0).unwrap();
+        let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
         let tc_header = PusTmSecondaryHeader::new_simple(17, 2, &time_stamp);
         PusTm::new(&mut sph, tc_header, None, true)
     }
 
     fn base_hk_reply<'a>(time_stamp: &'a [u8], src_data: &'a [u8]) -> PusTm<'a> {
-        let mut sph = SpHeader::tm(0x123, 0x234, 0).unwrap();
+        let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
         let tc_header = PusTmSecondaryHeader::new_simple(3, 5, &time_stamp);
         PusTm::new(&mut sph, tc_header, Some(src_data), true)
     }
@@ -492,7 +496,9 @@ mod tests {
         let time_stamp = dummy_time_stamp();
         let pus_tm = base_ping_reply_full_ctor(&time_stamp);
         let mut buf: [u8; 32] = [0; 32];
-        let ser_len = pus_tm.write_to(&mut buf).expect("Serialization failed");
+        let ser_len = pus_tm
+            .write_to_bytes(&mut buf)
+            .expect("Serialization failed");
         assert_eq!(ser_len, 22);
         verify_raw_ping_reply(&buf);
     }
@@ -502,7 +508,9 @@ mod tests {
         let src_data = [1, 2, 3];
         let hk_reply = base_hk_reply(dummy_time_stamp(), &src_data);
         let mut buf: [u8; 32] = [0; 32];
-        let ser_len = hk_reply.write_to(&mut buf).expect("Serialization failed");
+        let ser_len = hk_reply
+            .write_to_bytes(&mut buf)
+            .expect("Serialization failed");
         assert_eq!(ser_len, 25);
         assert_eq!(buf[20], 1);
         assert_eq!(buf[21], 2);
@@ -528,29 +536,30 @@ mod tests {
         let time_stamp = dummy_time_stamp();
         let pus_tm = base_ping_reply_full_ctor(&time_stamp);
         let mut buf: [u8; 32] = [0; 32];
-        let ser_len = pus_tm.write_to(&mut buf).expect("Serialization failed");
+        let ser_len = pus_tm
+            .write_to_bytes(&mut buf)
+            .expect("Serialization failed");
         assert_eq!(ser_len, 22);
-        let (tm_deserialized, size) =
-            PusTm::new_from_raw_slice(&buf, 7).expect("Deserialization failed");
+        let (tm_deserialized, size) = PusTm::from_bytes(&buf, 7).expect("Deserialization failed");
         assert_eq!(ser_len, size);
         verify_ping_reply(&tm_deserialized, false, 22, dummy_time_stamp());
     }
 
     #[test]
     fn test_manual_field_update() {
-        let mut sph = SpHeader::tm(0x123, 0x234, 0).unwrap();
+        let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
         let tc_header = PusTmSecondaryHeader::new_simple(17, 2, dummy_time_stamp());
         let mut tm = PusTm::new(&mut sph, tc_header, None, false);
         tm.calc_crc_on_serialization = false;
         assert_eq!(tm.data_len(), 0x00);
         let mut buf: [u8; 32] = [0; 32];
-        let res = tm.write_to(&mut buf);
+        let res = tm.write_to_bytes(&mut buf);
         assert!(res.is_err());
         assert!(matches!(res.unwrap_err(), PusError::CrcCalculationMissing));
         tm.update_ccsds_data_len();
         assert_eq!(tm.data_len(), 15);
         tm.calc_own_crc16();
-        let res = tm.write_to(&mut buf);
+        let res = tm.write_to_bytes(&mut buf);
         assert!(res.is_ok());
         tm.sp_header.data_len = 0;
         tm.update_packet_fields();
@@ -562,13 +571,13 @@ mod tests {
         let time_stamp = dummy_time_stamp();
         let pus_tm = base_ping_reply_full_ctor(&time_stamp);
         let mut buf: [u8; 16] = [0; 16];
-        let res = pus_tm.write_to(&mut buf);
+        let res = pus_tm.write_to_bytes(&mut buf);
         assert!(res.is_err());
         let error = res.unwrap_err();
-        assert!(matches!(error, PusError::PacketError { .. }));
+        assert!(matches!(error, PusError::ByteConversionError { .. }));
         match error {
-            PusError::PacketError(err) => match err {
-                PacketError::ToBytesSliceTooSmall(size_missmatch) => {
+            PusError::ByteConversionError(err) => match err {
+                ByteConversionError::ToSliceTooSmall(size_missmatch) => {
                     assert_eq!(size_missmatch.expected, 22);
                     assert_eq!(size_missmatch.found, 16);
                 }