// Detect-It-Easy signature file
// Various parser helpers from vgmstream, modified for DiE.
// Author: Kaens (TG @kaens)
/* beautify ignore:start */

includeScript("read");

/** Read values from an 'old' XMA2 RIFF "XMA2" chunk (XMA2WAVEFORMAT), starting from an offset *after* chunk type+size.
 * Useful as custom X360 headers commonly have it lurking inside.
 * @param Int p  - offset
 * @return [channels, sample rate, loop flag, raw samples, start loop sample, end loop sample]
 */

function xma2_parse_xma2_chunk(p) {
    //ref vgmstream coding_utils.c
    var hkver = X.U8(p), strm = X.U8(p+1), lpst = X.U32(p+4, _BE), lped = X.U32(p+8, _BE),
        lp = X.U8(p+3) > 0 || lped, sr = X.U32(p+0xC, _BE),
        smp = X.U32(p+(hkver == 3 ? 0x14 : 0x1C), _BE),
        ch = 0, ofs = hkver == 3? 0x20 : 0x28;
        for(var i=0; i < strm; i++) ch += X.U8(p+ofs+i*4);
        return [ch, sr, lp, smp, lpst, lped]
}

/** Read values from a 'new' XMA2 RIFF "fmt" chunk (XMA2WAVEFORMATEX), starting from an offset *after* chunk type+size.
 * Useful as custom X360 headers commonly have it lurking inside. Only parses the extra data (before is a normal WAVEFORMATEX).
 * @param Int p - offset
 * @param Int e - endianness
 * @return [loop flag, samples, start loop sample, end loop sample]
 */
function xma2_parse_fmt_chunk_extra(p, e) {
    var smp = X.U32(p+0x18, e), lpst = X.U32(p+0x28, e), lped = X.U32(p+0x2C, e), lp = X.U8(p+0x30) || lped;
    //source bugfix:
    if(lpst+128-512 == 0 && lped+128-512+256 >= smp+128-512) lp = false;
    return [lp, smp, lpst, lped]
}

/* beautify ignore:end */