Function init_get_bits

libavcodec/get_bits.h:517–534

* Initialize GetBitContext. * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes * larger than the actual read bits because some optimized bitstream * readers read 32 or 64 bit at once and could read over the end * @param bit_size the size of the buffer in bits * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow. */

 * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
 */
static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
                                int bit_size)
{
    int ret = 0;

    if (bit_size >= INT_MAX - FFMAX(7, AV_INPUT_BUFFER_PADDING_SIZE*8) || bit_size < 0 || !buffer) {
        bit_size    = 0;
        buffer      = NULL;
        ret         = AVERROR_INVALIDDATA;
    }

    s->buffer             = buffer;
    s->size_in_bits       = bit_size;
    s->size_in_bits_plus8 = bit_size + 8;
    s->index              = 0;

    return ret;
}

/**
 * Initialize GetBitContext.