typedef struct {
int high;
- int bits;
+ int bits; /* Stored negated (i.e. negative "bits" is a positive number of bits left)
+ * in order to eliminate a negate in cache refilling */
const uint8_t *buffer;
const uint8_t *end;
unsigned long code_word;
const uint8_t *buf, int buf_size)
{
c->high = 255;
- c->bits = 8;
+ c->bits = -8;
c->buffer = buf;
c->end = buf + buf_size;
c->code_word = bytestream_get_be16(&c->buffer);
shift = ff_h264_norm_shift[c->high] - 1;
c->high <<= shift;
c->code_word <<= shift;
- c->bits -= shift;
- if(c->bits <= 0 && c->buffer < c->end) {
- c->code_word |= *c->buffer++ << -c->bits;
- c->bits += 8;
+ c->bits += shift;
+ if(c->bits >= 0 && c->buffer < c->end) {
+ c->code_word |= *c->buffer++ << c->bits;
+ c->bits -= 8;
}
return bit;
}
/* normalize */
c->code_word <<= 1;
- if (--c->bits == 0 && c->buffer < c->end) {
- c->bits = 8;
+ if (++c->bits == 0 && c->buffer < c->end) {
+ c->bits = -8;
c->code_word |= *c->buffer++;
}
return bit;