base line cuc impl done

src/time.rs

@@ -7,15 +7,14 @@ use core::fmt::{Display, Formatter};
 #[cfg(not(feature = "std"))]
 use num_traits::float::FloatCore;
 
+use crate::time::cuc::CucError;
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 #[cfg(feature = "std")]
 use std::error::Error;
 #[cfg(feature = "std")]
 use std::time::{SystemTime, SystemTimeError};
 
-use crate::time::cds::LengthOfDaySegment;
-#[cfg(feature = "serde")]
-use serde::{Deserialize, Serialize};
-
 pub const DAYS_CCSDS_TO_UNIX: i32 = -4383;
 pub const SECONDS_PER_DAY: u32 = 86400;
 
@@ -51,36 +50,6 @@ pub fn ccsds_time_code_from_p_field(pfield: u8) -> Result<CcsdsTimeCodes, u8> {
     CcsdsTimeCodes::try_from(raw_bits).map_err(|_| raw_bits)
 }
 
-#[derive(Debug, PartialEq, Eq, Copy, Clone)]
-#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub enum CdsError {
-    /// CCSDS days value exceeds maximum allowed size or is negative
-    InvalidCcsdsDays(i64),
-    /// There are distinct constructors depending on the days field width detected in the preamble
-    /// field. This error will be returned if there is a missmatch.
-    InvalidCtorForDaysOfLenInPreamble(LengthOfDaySegment),
-}
-
-impl Display for CdsError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
-        match self {
-            CdsError::InvalidCcsdsDays(days) => {
-                write!(f, "invalid ccsds days {}", days)
-            }
-            CdsError::InvalidCtorForDaysOfLenInPreamble(length_of_day) => {
-                write!(
-                    f,
-                    "wrong constructor for length of day {:?} detected in preamble",
-                    length_of_day
-                )
-            }
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl Error for CdsError {}
-
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum TimestampError {
@@ -88,13 +57,20 @@ pub enum TimestampError {
     /// value is the found raw value
     InvalidTimeCode(CcsdsTimeCodes, u8),
     ByteConversionError(ByteConversionError),
-    CdsError(CdsError),
+    CdsError(cds::CdsError),
+    CucError(cuc::CucError),
     CustomEpochNotSupported,
 }
 
-impl From<CdsError> for TimestampError {
-    fn from(v: CdsError) -> Self {
-        TimestampError::CdsError(v)
+impl From<cds::CdsError> for TimestampError {
+    fn from(e: cds::CdsError) -> Self {
+        TimestampError::CdsError(e)
+    }
+}
+
+impl From<cuc::CucError> for TimestampError {
+    fn from(e: CucError) -> Self {
+        TimestampError::CucError(e)
     }
 }
 
@@ -133,6 +109,9 @@ impl Display for TimestampError {
             TimestampError::CdsError(e) => {
                 write!(f, "cds error {}", e)
             }
+            TimestampError::CucError(e) => {
+                write!(f, "cuc error {}", e)
+            }
             TimestampError::ByteConversionError(e) => {
                 write!(f, "byte conversion error {}", e)
             }
@@ -149,6 +128,7 @@ impl Error for TimestampError {
         match self {
             TimestampError::ByteConversionError(e) => Some(e),
             TimestampError::CdsError(e) => Some(e),
+            TimestampError::CucError(e) => Some(e),
             _ => None,
         }
     }
@@ -270,6 +250,35 @@ pub mod cds {
         Reserved,
     }
 
+    #[derive(Debug, PartialEq, Eq, Copy, Clone)]
+    #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+    pub enum CdsError {
+        /// CCSDS days value exceeds maximum allowed size or is negative
+        InvalidCcsdsDays(i64),
+        /// There are distinct constructors depending on the days field width detected in the preamble
+        /// field. This error will be returned if there is a missmatch.
+        InvalidCtorForDaysOfLenInPreamble(LengthOfDaySegment),
+    }
+
+    impl Display for CdsError {
+        fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+            match self {
+                CdsError::InvalidCcsdsDays(days) => {
+                    write!(f, "invalid ccsds days {}", days)
+                }
+                CdsError::InvalidCtorForDaysOfLenInPreamble(length_of_day) => {
+                    write!(
+                        f,
+                        "wrong constructor for length of day {:?} detected in preamble",
+                        length_of_day
+                    )
+                }
+            }
+        }
+    }
+
+    #[cfg(feature = "std")]
+    impl Error for CdsError {}
     pub fn length_of_day_segment_from_pfield(pfield: u8) -> LengthOfDaySegment {
         if (pfield >> 2) & 0b1 == 1 {
             return LengthOfDaySegment::Long24Bits;
@@ -816,8 +825,41 @@ pub mod cds {
 }
 
 pub mod cuc {
-    use core::fmt::Debug;
     use super::*;
+    use core::fmt::Debug;
+
+    const MIN_CUC_LEN: usize = 2;
+
+    #[derive(Copy, Clone, PartialEq, Eq, Debug)]
+    #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+    pub enum CucError {
+        InvalidCounterWidth(u8),
+        InvalidFractionWidth(u8),
+        InvalidCounter(u8, u64),
+        InvalidFractions(u8, u64),
+    }
+
+    impl Display for CucError {
+        fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+            match self {
+                CucError::InvalidCounterWidth(w) => {
+                    write!(f, "invalid cuc counter byte width {}", w)
+                }
+                CucError::InvalidFractionWidth(w) => {
+                    write!(f, "invalid cuc fractional part byte width {}", w)
+                }
+                CucError::InvalidCounter(w, c) => {
+                    write!(f, "invalid cuc counter {} for width {}", c, w)
+                }
+                CucError::InvalidFractions(w, c) => {
+                    write!(f, "invalid cuc fractional part {} for width {}", c, w)
+                }
+            }
+        }
+    }
+
+    #[cfg(feature = "std")]
+    impl Error for CucError {}
 
     #[derive(Copy, Clone, PartialEq, Eq, Debug)]
     #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
@@ -833,7 +875,7 @@ pub mod cuc {
     pub struct TimeProviderCcsdsEpoch {
         pfield: u8,
         counter: WidthCounterPair,
-        fractions: Option<WidthCounterPair>
+        fractions: Option<WidthCounterPair>,
     }
 
     #[inline]
@@ -841,53 +883,183 @@ pub mod cuc {
         if ((pfield >> 7) & 0b1) == 1 {
             return 2;
         }
-        return 1
+        1
     }
 
     impl TimeProviderCcsdsEpoch {
         fn build_p_field(counter_width: u8, fractions_width: Option<u8>) -> u8 {
             let mut pfield = (CcsdsTimeCodes::CucCcsdsEpoch as u8) << 4;
-            if counter_width < 1 || counter_width > 4 {
+            if !(1..=4).contains(&counter_width) {
+                // Okay to panic here, this function is private and all input values should
+                // have been sanitized
                 panic!("invalid counter width {} for cuc timestamp", counter_width);
             }
-            pfield |= counter_width << 3;
+            pfield |= (counter_width - 1) << 3;
             if let Some(fractions_width) = fractions_width {
-                if fractions_width < 1 || fractions_width > 3 {
-                    panic!("invalid fractions width {} for cuc timestamp", fractions_width);
+                if !(1..=3).contains(&fractions_width) {
+                    // Okay to panic here, this function is private and all input values should
+                    // have been sanitized
+                    panic!(
+                        "invalid fractions width {} for cuc timestamp",
+                        fractions_width
+                    );
                 }
                 pfield |= fractions_width;
             }
             pfield
         }
 
-
         pub fn len_packed(&self) -> usize {
-            // TODO: Implement
-            todo!()
+            Self::len_packed_from_pfield(self.pfield)
+        }
+
+        #[inline]
+        pub fn len_cntr_from_pfield(pfield: u8) -> u8 {
+            ((pfield >> 2) & 0b11) + 1
+        }
+
+        #[inline]
+        pub fn len_fractions_from_pfield(pfield: u8) -> u8 {
+            pfield & 0b11
+        }
+
+        /// This returns the length of the individual components of the CUC timestamp in addition
+        /// to the total size.
+        ///
+        /// This function will return a tuple where the first value is the byte width of the
+        /// counter, the second value is the byte width of the fractional part, and the third
+        /// components is the total size.
+        pub fn len_components_and_total_from_pfield(pfield: u8) -> (u8, u8, usize) {
+            let base_len: usize = 1;
+            let cntr_len = Self::len_cntr_from_pfield(pfield);
+            let fractions_len = Self::len_fractions_from_pfield(pfield);
+            (
+                cntr_len,
+                fractions_len,
+                base_len + cntr_len as usize + fractions_len as usize,
+            )
+        }
+
+        pub fn len_packed_from_pfield(pfield: u8) -> usize {
+            let mut base_len: usize = 1;
+            base_len += Self::len_cntr_from_pfield(pfield) as usize;
+            base_len += Self::len_fractions_from_pfield(pfield) as usize;
+            base_len
+        }
+
+        /// Verifies the raw width parameter and returns the actual length, which is the raw
+        /// value plus 1.
+        fn verify_counter_width(width: u8) -> Result<(), CucError> {
+            if width == 0 || width > 4 {
+                return Err(CucError::InvalidCounterWidth(width));
+            }
+            Ok(())
+        }
+
+        fn verify_fractions_width(width: u8) -> Result<(), CucError> {
+            if width > 3 {
+                return Err(CucError::InvalidFractionWidth(width));
+            }
+            Ok(())
         }
     }
 
     impl TimeProviderCcsdsEpoch {
         pub fn new_default(counter: u32) -> Self {
-            Self::new(WidthCounterPair(4, counter), None)
+            // These values are definitely valid, so it is okay to unwrap here.
+            Self::new(WidthCounterPair(4, counter), None).unwrap()
+        }
+        pub fn new_u16_counter(counter: u16) -> Self {
+            // These values are definitely valid, so it is okay to unwrap here.
+            Self::new(WidthCounterPair(2, counter as u32), None).unwrap()
         }
 
-        pub fn new(counter: WidthCounterPair, fractions: Option<WidthCounterPair>) -> Self {
-            let fractions_width = match fractions {
-                None => 0,
-                Some(fractions) => fractions.0
-            };
-            Self {
-                pfield: Self::build_p_field(counter.0.into(), fractions_width.into()),
-                counter,
-                fractions
+        pub fn new(
+            counter: WidthCounterPair,
+            fractions: Option<WidthCounterPair>,
+        ) -> Result<Self, CucError> {
+            Self::verify_counter_width(counter.0)?;
+            if counter.1 > 2u32.pow(counter.0 as u32 * 8) - 1 {
+                return Err(CucError::InvalidCounter(counter.0, counter.1 as u64));
             }
+            if let Some(fractions) = fractions {
+                Self::verify_fractions_width(fractions.0)?;
+                if fractions.1 > 2u32.pow((fractions.0 as u32) * 8) - 1 {
+                    return Err(CucError::InvalidFractions(fractions.0, fractions.1 as u64));
+                }
+            }
+            Ok(Self {
+                pfield: Self::build_p_field(counter.0, fractions.map(|v| v.0)),
+                counter,
+                fractions,
+            })
         }
     }
 
     impl TimeReader for TimeProviderCcsdsEpoch {
-        fn from_bytes(_buf: &[u8]) -> Result<Self, TimestampError> where Self: Sized {
-            todo!()
+        fn from_bytes(buf: &[u8]) -> Result<Self, TimestampError>
+        where
+            Self: Sized,
+        {
+            if buf.len() < MIN_CUC_LEN {
+                return Err(TimestampError::ByteConversionError(
+                    ByteConversionError::FromSliceTooSmall(SizeMissmatch {
+                        expected: MIN_CUC_LEN,
+                        found: buf.len(),
+                    }),
+                ));
+            }
+            let (cntr_len, fractions_len, total_len) =
+                Self::len_components_and_total_from_pfield(buf[0]);
+            if buf.len() < total_len {
+                return Err(TimestampError::ByteConversionError(
+                    ByteConversionError::FromSliceTooSmall(SizeMissmatch {
+                        expected: total_len,
+                        found: buf.len(),
+                    }),
+                ));
+            }
+            let mut current_idx = 1;
+            let counter =
+                match cntr_len {
+                    1 => buf[current_idx] as u32,
+                    2 => u16::from_be_bytes(buf[current_idx..current_idx + 2].try_into().unwrap())
+                        as u32,
+                    3 => {
+                        let mut tmp_buf: [u8; 4] = [0; 4];
+                        tmp_buf[1..4].copy_from_slice(&buf[current_idx..current_idx + 3]);
+                        u32::from_be_bytes(tmp_buf) as u32
+                    }
+                    4 => u32::from_be_bytes(buf[current_idx..current_idx + 4].try_into().unwrap())
+                        as u32,
+                    _ => panic!("unreachable match arm"),
+                };
+            current_idx += cntr_len as usize;
+            let mut fractions = None;
+            if fractions_len > 0 {
+                match fractions_len {
+                    1 => fractions = Some(WidthCounterPair(fractions_len, buf[current_idx] as u32)),
+                    2 => {
+                        fractions = Some(WidthCounterPair(
+                            fractions_len,
+                            u16::from_be_bytes(
+                                buf[current_idx..current_idx + 2].try_into().unwrap(),
+                            ) as u32,
+                        ))
+                    }
+                    3 => {
+                        let mut tmp_buf: [u8; 4] = [0; 4];
+                        tmp_buf[1..4].copy_from_slice(&buf[current_idx..current_idx + 3]);
+                        fractions = Some(WidthCounterPair(
+                            fractions_len,
+                            u32::from_be_bytes(tmp_buf) as u32,
+                        ))
+                    }
+                    _ => panic!("unreachable match arm"),
+                }
+            }
+            let provider = Self::new(WidthCounterPair(cntr_len, counter), fractions)?;
+            Ok(provider)
         }
     }
 
@@ -895,45 +1067,52 @@ pub mod cuc {
         fn write_to_bytes(&self, bytes: &mut [u8]) -> Result<usize, TimestampError> {
             // Cross check the sizes of the counters against byte widths in the ctor
             if bytes.len() < self.len_packed() {
-                return Err(TimestampError::ByteConversionError(ByteConversionError::ToSliceTooSmall(SizeMissmatch {
-                    found: bytes.len(),
-                    expected: self.len_packed()
-                })))
+                return Err(TimestampError::ByteConversionError(
+                    ByteConversionError::ToSliceTooSmall(SizeMissmatch {
+                        found: bytes.len(),
+                        expected: self.len_packed(),
+                    }),
+                ));
             }
             bytes[0] = self.pfield;
             let mut current_idx: usize = 1;
             match self.counter.0 {
                 1 => {
-                    bytes[1] = self.counter.1 as u8;
-                },
+                    bytes[current_idx] = self.counter.1 as u8;
+                }
                 2 => {
-                    bytes[1..3].copy_from_slice(&(self.counter.1 as u16).to_be_bytes());
-                },
+                    bytes[current_idx..current_idx + 2]
+                        .copy_from_slice(&(self.counter.1 as u16).to_be_bytes());
+                }
                 3 => {
-                    bytes[1..4].copy_from_slice(&self.counter.1.to_be_bytes()[1..4]);
-                },
+                    bytes[current_idx..current_idx + 3]
+                        .copy_from_slice(&self.counter.1.to_be_bytes()[1..4]);
+                }
                 4 => {
-                    bytes[1..5].copy_from_slice(&self.counter.1.to_be_bytes());
-                },
+                    bytes[current_idx..current_idx + 4]
+                        .copy_from_slice(&self.counter.1.to_be_bytes());
+                }
                 // Should never happen
-                _ => panic!("invalid counter width value")
+                _ => panic!("invalid counter width value"),
             }
             current_idx += self.counter.0 as usize;
             if let Some(fractions) = self.fractions {
                 match fractions.0 {
                     1 => bytes[current_idx] = fractions.1 as u8,
-                    2 => bytes[current_idx..current_idx + 2].copy_from_slice(&(fractions.1 as u16).to_be_bytes()),
-                    3 => bytes[current_idx..current_idx + 3].copy_from_slice(&fractions.1.to_be_bytes()[1..4]),
+                    2 => bytes[current_idx..current_idx + 2]
+                        .copy_from_slice(&(fractions.1 as u16).to_be_bytes()),
+                    3 => bytes[current_idx..current_idx + 3]
+                        .copy_from_slice(&fractions.1.to_be_bytes()[1..4]),
                     // Should also never happen
-                    _ => panic!("invalid fractions value")
+                    _ => panic!("invalid fractions value"),
                 }
                 current_idx += fractions.0 as usize;
             }
             Ok(current_idx)
         }
     }
-
 }
+
 /// Module to generate the ASCII timecodes specified in
 /// [CCSDS 301.0-B-4](https://public.ccsds.org/Pubs/301x0b4e1.pdf) section 3.5 .
 /// See [chrono::DateTime::format] for a usage example of the generated
@@ -1006,7 +1185,7 @@ pub mod ascii {
 mod tests {
     use super::cds::TimeProvider;
     use super::*;
-    use crate::time::cds::{DaysLen16Bits, DaysLen24Bits, SubmillisPrecision};
+    use crate::time::cds::{DaysLen16Bits, DaysLen24Bits, LengthOfDaySegment, SubmillisPrecision};
     use crate::time::TimestampError::{ByteConversionError, InvalidTimeCode};
     use crate::ByteConversionError::{FromSliceTooSmall, ToSliceTooSmall};
     use alloc::format;
@@ -1163,8 +1342,9 @@ mod tests {
         let faulty_ctor = TimeProvider::<DaysLen16Bits>::from_bytes(&buf);
         assert!(faulty_ctor.is_err());
         let error = faulty_ctor.unwrap_err();
-        if let TimestampError::CdsError(CdsError::InvalidCtorForDaysOfLenInPreamble(len_of_day)) =
-            error
+        if let TimestampError::CdsError(cds::CdsError::InvalidCtorForDaysOfLenInPreamble(
+            len_of_day,
+        )) = error
         {
             assert_eq!(len_of_day, LengthOfDaySegment::Long24Bits);
         } else {