heterob 0.4.0

Library for conversion between bytes/bits and heterogeneous lists (tuples)
Documentation 
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#[cfg(test)]
use heterob::{
    bit_numbering::Lsb,
    endianness::{Be, BeBytesTryInto, Le, LeBytesTryInto, TryFromLeBytes},
    Bool, Seq, P1, P2, P4, U16, U8,
};

#[test]
fn array_from_slice() {
    let data = ['a'; 5].as_slice();
    let Seq { head: result, .. }: Seq<[char; 3], _> = data.try_into().unwrap();
    let sample: &[char] = data[..3].try_into().unwrap();
    assert_eq!(sample, result);
}

#[test]
fn array_from_slice_with_offset() {
    let data = [1, 2, 3, 4, 5].as_slice();

    // Explicit offset array
    let Seq {
        head: (_, result), ..
    }: Seq<([u8; 3], [u8; 2]), _> = P2(data).try_into().unwrap();
    assert_eq!([4, 5], result);

    // Using slice .get() method
    let Seq { head, .. }: Seq<[u8; 2], _> = data.get(3..).unwrap_or_default().try_into().unwrap();
    assert_eq!([4, 5], head);
}

#[test]
fn integer_from_slice() {
    let data = [0x00, 0x11, 0x22, 0x33, 0x44, 0x55].as_slice();
    // We can't use TryInto trait directly like this
    // let Seq {
    //     head: Le(result), ..
    // }: Seq<Le<u32>, _> = data.try_into().unwrap();
    // But we can use LeBytesTryInto trait:
    let Seq { head: result, tail }: Seq<u32, _> = data.le_bytes_try_into().unwrap();
    assert_eq!(0x33221100, result);

    let Seq { head: result, .. } = tail.be_bytes_try_into().unwrap();
    assert_eq!(0x4455u16, result);
}

#[test]
fn single_integer_as_partable_from_slice() {
    let data = [0x00, 0x11, 0x22, 0x33, 0x44, 0x55].as_slice();
    let Seq {
        head: Le((result,)),
        tail,
    } = P1(data).try_into().unwrap();
    assert_eq!(0x33221100u32, result);

    let Seq {
        head: Be((result,)),
        ..
    }: Seq<Be<(u16,)>, _> = P1(tail).try_into().unwrap();
    assert_eq!(0x4455, result);
}

#[test]
fn integers_array_from_slice() {
    let data = [0x00, 0x11, 0x22, 0x33, 0x44, 0x55].as_slice();
    let Seq { head: result, .. }: Seq<[u16; 2], _> =
        // For array to array conversion we should use explicit array length
        TryFromLeBytes::<4>::try_from_le_bytes(data).unwrap();
    assert_eq!([0x1100, 0x3322], result);

    // Or we can use 2 step conversion
    let Seq { head, .. } = data.le_bytes_try_into().unwrap();
    let Le(result): Le<[u16; 2]> = From::<[u8; 4]>::from(head);
    assert_eq!([0x1100, 0x3322], result);
}

#[test]
fn bitfields_with_implemented_from_uint() {
    // enum has From<bool> imlementation, so it can be wrapped as Bool<Fear>
    #[derive(Debug, Clone, PartialEq, Eq)]
    enum Fear {
        Freeze,
        Run,
    }
    impl From<bool> for Fear {
        fn from(b: bool) -> Self {
            if b {
                Self::Run
            } else {
                Self::Freeze
            }
        }
    }

    // enum has From<u8> implementation, so it can be wrapped as U8<Num>
    #[derive(Debug, Clone, PartialEq, Eq)]
    enum Num {
        One,
        Two,
        Three,
        Four,
    }
    impl From<u8> for Num {
        fn from(byte: u8) -> Self {
            match byte {
                0b00 => Self::One,
                0b01 => Self::Two,
                0b10 => Self::Three,
                0b11 => Self::Four,
                _ => unreachable!(),
            }
        }
    }

    // Instead of using From::<u8>::from(field) we use just U8(field) wrapper
    let Lsb((Bool(fear), U8(num), just_bool, just_u8)) = P4::<u8, 1, 2, 1, 4>(0b0101_0101).into();
    assert_eq!(
        (Fear::Run, Num::Three, false, 0b0101u8),
        (fear, num, just_bool, just_u8)
    );
}

#[test]
fn types_with_implemented_from_uint() {
    let Le((
        just_byte,
        // from_byte is u32, u32 has From<u8> trait
        U8(from_byte),
        just_word,
        // from_word is u64, u64 has From<u16> trait
        U16(from_word),
    )) = P4([0x00, 0x11, 0x22, 0x33, 0x44, 0x55]).into();
    assert_eq!(
        (0x00u8, 0x11u32, 0x3322u16, 0x5544u64),
        (just_byte, from_byte, just_word, from_word)
    );
}