avcodec/dvbsubdec: Compute scoretab without iterating over pixels multiple times...
[ffmpeg.git] / libavcodec / rangecoder.h
index 47c0362..44af88b 100644 (file)
 #define AVCODEC_RANGECODER_H
 
 #include <stdint.h>
-#include <assert.h>
+
 #include "libavutil/common.h"
+#include "libavutil/avassert.h"
 
-typedef struct RangeCoder{
+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;
+    int overread;
+#define MAX_OVERREAD 2
+} 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){
+    av_assert2(*state);
+    av_assert2(range1 < c->range);
+    av_assert2(range1 > 0);
+    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->bytestream++;
+        c->low   <<= 8;
+        if (c->bytestream < c->bytestream_end) {
+            c->low += c->bytestream[0];
+            c->bytestream++;
+        } else
+            c->overread ++;
     }
 }
 
-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 */