bitcode_lightyear_patch 0.5.1

bitcode is a bitwise binary serializer
Documentation 
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use crate::word::Word;

#[inline(always)]
pub fn pack_lsb<const BITS: usize>(word: Word) -> Word {
    let mask = Word::from_le_bytes([(1 << BITS) - 1; 8]);

    // TODO: use pext (see https://github.com/SoftbearStudios/bitcode/issues/17)

    // Mask off bits that we don't care about.
    let bytes = (word & mask).to_le_bytes();
    let mut ret1 = 0;
    for (i, &b) in bytes[..4].iter().enumerate() {
        ret1 |= (b as u32) << (i * BITS);
    }
    let mut ret2 = 0;
    for (i, &b) in bytes[4..].iter().enumerate() {
        ret2 |= (b as u32) << (i * BITS);
    }

    // 2 steps + merge is a tiny bit faster.
    ret1 as u64 | (ret2 as u64) << (BITS * 4)
}

#[inline(always)]
pub fn unpack_lsb<const BITS: usize>(word: Word) -> Word {
    // TODO: use pdep (see https://github.com/SoftbearStudios/bitcode/issues/17)

    let mut bytes = [0u8; 8];

    for (i, b) in bytes.iter_mut().enumerate() {
        *b = (word >> (i * BITS) & ((1 << BITS) - 1)) as u8;
    }

    Word::from_le_bytes(bytes)
}