sfbinpack 0.6.2

Library to read Stockfish Binpacks
Documentation 
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#[derive(Debug)]
pub struct BitReader {
    read_bits_left: usize,
    read_offset: usize,
}

impl BitReader {
    pub fn new() -> Self {
        Self {
            read_bits_left: 8,
            read_offset: 0,
        }
    }

    pub fn extract_bits_le8(&mut self, movetext: &[u8], count: usize) -> u8 {
        if count == 0 {
            return 0;
        }

        if self.read_bits_left == 0 {
            self.read_offset += 1;
            self.read_bits_left = 8;
        }

        let byte = movetext[self.read_offset] << (8 - self.read_bits_left);

        let mut bits = byte >> (8 - count);

        if count > self.read_bits_left {
            let spill_count = count - self.read_bits_left;

            bits |= movetext[self.read_offset + 1] >> (8 - spill_count);

            self.read_bits_left += 8;
            self.read_offset += 1;
        }

        self.read_bits_left -= count;
        bits
    }

    pub fn extract_vle16(&mut self, movetext: &[u8], block_size: usize) -> u16 {
        let mask = (1 << block_size) - 1;
        let mut v = 0u16;
        let mut offset = 0;

        loop {
            let block = self.extract_bits_le8(movetext, block_size + 1) as u16;
            v |= (block & mask) << offset;
            if (block >> block_size) == 0 {
                break;
            }
            offset += block_size;
        }

        v
    }

    pub fn num_read_bytes(&self) -> usize {
        self.read_offset + (self.read_bits_left != 8) as usize
    }
}