* Range coder
* Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
*/
/**
- * @file rangecoder.h
+ * @file
* Range coder.
*/
-typedef struct RangeCoder{
+#ifndef AVCODEC_RANGECODER_H
+#define AVCODEC_RANGECODER_H
+
+#include <stdint.h>
+#include <assert.h>
+
+#include "libavutil/common.h"
+
+typedef struct RangeCoder {
int low;
int range;
int outstanding_count;
int outstanding_byte;
uint8_t zero_state[256];
- uint8_t one_state[256];
+ uint8_t one_state[256];
uint8_t *bytestream_start;
uint8_t *bytestream;
uint8_t *bytestream_end;
-}RangeCoder;
+} RangeCoder;
void ff_init_range_encoder(RangeCoder *c, uint8_t *buf, int buf_size);
void ff_init_range_decoder(RangeCoder *c, const uint8_t *buf, int buf_size);
int ff_rac_terminate(RangeCoder *c);
void ff_build_rac_states(RangeCoder *c, int factor, int max_p);
-static inline void renorm_encoder(RangeCoder *c){
- //FIXME optimize
- while(c->range < 0x100){
- if(c->outstanding_byte < 0){
- c->outstanding_byte= c->low>>8;
- }else if(c->low <= 0xFF00){
+static inline void renorm_encoder(RangeCoder *c)
+{
+ // FIXME: optimize
+ while (c->range < 0x100) {
+ if (c->outstanding_byte < 0) {
+ c->outstanding_byte = c->low >> 8;
+ } else if (c->low <= 0xFF00) {
*c->bytestream++ = c->outstanding_byte;
- for(;c->outstanding_count; c->outstanding_count--)
+ for (; c->outstanding_count; c->outstanding_count--)
*c->bytestream++ = 0xFF;
- c->outstanding_byte= c->low>>8;
- }else if(c->low >= 0x10000){
+ c->outstanding_byte = c->low >> 8;
+ } else if (c->low >= 0x10000) {
*c->bytestream++ = c->outstanding_byte + 1;
- for(;c->outstanding_count; c->outstanding_count--)
+ for (; c->outstanding_count; c->outstanding_count--)
*c->bytestream++ = 0x00;
- c->outstanding_byte= (c->low>>8) & 0xFF;
- }else{
+ c->outstanding_byte = (c->low >> 8) & 0xFF;
+ } else {
c->outstanding_count++;
}
- c->low = (c->low & 0xFF)<<8;
+ c->low = (c->low & 0xFF) << 8;
c->range <<= 8;
}
}
-static inline int get_rac_count(RangeCoder *c){
- int x= c->bytestream - c->bytestream_start + c->outstanding_count;
- if(c->outstanding_byte >= 0)
+static inline int get_rac_count(RangeCoder *c)
+{
+ int x = c->bytestream - c->bytestream_start + c->outstanding_count;
+ if (c->outstanding_byte >= 0)
x++;
- return 8*x - av_log2(c->range);
+ return 8 * x - av_log2(c->range);
}
-static inline void put_rac(RangeCoder *c, uint8_t * const state, int bit){
- int range1= (c->range * (*state)) >> 8;
+static inline void put_rac(RangeCoder *c, uint8_t *const state, int bit)
+{
+ int range1 = (c->range * (*state)) >> 8;
assert(*state);
assert(range1 < c->range);
assert(range1 > 0);
- if(!bit){
+ if (!bit) {
c->range -= range1;
- *state= c->zero_state[*state];
- }else{
- c->low += c->range - range1;
+ *state = c->zero_state[*state];
+ } else {
+ c->low += c->range - range1;
c->range = range1;
- *state= c->one_state[*state];
+ *state = c->one_state[*state];
}
renorm_encoder(c);
}
-static inline void refill(RangeCoder *c){
- if(c->range < 0x100){
+static inline void refill(RangeCoder *c)
+{
+ if (c->range < 0x100) {
c->range <<= 8;
- c->low <<= 8;
- if(c->bytestream < c->bytestream_end)
- c->low+= c->bytestream[0];
+ c->low <<= 8;
+ if (c->bytestream < c->bytestream_end)
+ c->low += c->bytestream[0];
c->bytestream++;
}
}
-static inline int get_rac(RangeCoder *c, uint8_t * const state){
- int range1= (c->range * (*state)) >> 8;
- int av_unused one_mask;
+static inline int get_rac(RangeCoder *c, uint8_t *const state)
+{
+ int range1 = (c->range * (*state)) >> 8;
c->range -= range1;
-#if 1
- if(c->low < c->range){
- *state= c->zero_state[*state];
+ if (c->low < c->range) {
+ *state = c->zero_state[*state];
refill(c);
return 0;
- }else{
- c->low -= c->range;
- *state= c->one_state[*state];
+ } else {
+ c->low -= c->range;
+ *state = c->one_state[*state];
c->range = range1;
refill(c);
return 1;
}
-#else
- one_mask= (c->range - c->low-1)>>31;
-
- c->low -= c->range & one_mask;
- c->range += (range1 - c->range) & one_mask;
-
- *state= c->zero_state[(*state) + (256&one_mask)];
-
- refill(c);
-
- return one_mask&1;
-#endif
}
+#endif /* AVCODEC_RANGECODER_H */
projects / ffmpeg / blobdiff