weakauras-codec-lib-compress 0.1.1

Provides a routine for decompressing data compressed by a Lua library called LibCompress.
Documentation 
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// Based on code from LibCompress
// https://www.curseforge.com/wow/addons/libcompress
// Copyright 2008-2018 jjsheets, Galmok
// Copyright 2020-2025 Velithris
// SPDX-License-Identifier: GPL-2.0-only

use crate::{bitfield::Bitfield, error::DecompressionError};

pub(crate) fn get_code(bitfield: &mut Bitfield) -> Result<Option<(u32, u8)>, DecompressionError> {
    if bitfield.get_len() >= 2 {
        for i in 0..=bitfield.get_len() - 2 {
            let b1 = bitfield.get_data() & (1 << i);
            let b2 = bitfield.get_data() & (1 << (i + 1));
            if b1 != 0 && b2 != 0 {
                return if i <= 32 {
                    let code = bitfield.extract_bits(i) as u32;
                    bitfield.discard_bits(2);
                    Ok(Some((code, i)))
                } else {
                    Err(DecompressionError::InvalidData)
                };
            }
        }
    }
    Ok(None)
}

pub(crate) fn unescape_code(code: u32, code_len: u8) -> (u32, u8) {
    let mut unescaped_code: u32 = 0;
    let mut i: u8 = 0;
    let mut l: u8 = 0;
    while i < code_len {
        if (code & (1 << (i as i32))) != 0 {
            unescaped_code |= 1 << (l as u32);
            i += 1;
        }
        i += 1;
        l += 1;
    }
    (unescaped_code, l)
}