GetBits()

uint32_t fl::third_party::GetBits	(	BitStreamInfo *	bsi,
		int32_t	nBits )

Definition at line 134 of file bitstream.hpp.

{
    uint32_t data, lowBits;
 
    nBits &= 0x1f;                          /* nBits mod 32 to avoid unpredictable results like >> by negative amount */
    data = bsi->iCache >> (31 - nBits);       /* unsigned >> so zero-extend */
    data >>= 1;                             /* do as >> 31, >> 1 so that nBits = 0 works okay (returns 0) */
    bsi->iCache <<= nBits;                    /* left-justify cache */
    bsi->cachedBits -= nBits;             /* how many bits have we drawn from the cache so far */
 
    /* if we cross an int boundary, refill the cache */
    if (bsi->cachedBits < 0) {
        lowBits = -bsi->cachedBits;
        RefillBitstreamCache(bsi);
        data |= bsi->iCache >> (32 - lowBits);        /* get the low-order bits */
 
        bsi->cachedBits -= lowBits;           /* how many bits have we drawn from the cache so far */
        bsi->iCache <<= lowBits;          /* left-justify cache */
    }
 
    return data;
}

References FL_NOEXCEPT, and RefillBitstreamCache().

Referenced by UnpackScaleFactors(), UnpackSFMPEG1(), UnpackSFMPEG2(), and UnpackSideInfo().

Here is the call graph for this function:

Here is the caller graph for this function: