cabac_functions: Allow more functions to be overridden

Allow more of the cabac functions to be overridden and avoid generating any
code for unwanted refill functions.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/cabac_functions.h

@@ -51,6 +51,7 @@ static const uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS
 static const uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET;
 static const uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET;
 
+#if !defined(get_cabac_bypass) || !defined(get_cabac_terminate)
 static void refill(CABACContext *c){
 #if CABAC_BITS == 16
         c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
@@ -63,7 +64,9 @@ static void refill(CABACContext *c){
 #endif
         c->bytestream += CABAC_BITS / 8;
 }
+#endif
 
+#ifndef get_cabac_terminate
 static inline void renorm_cabac_decoder_once(CABACContext *c){
     int shift= (uint32_t)(c->range - 0x100)>>31;
     c->range<<= shift;
@@ -71,6 +74,7 @@ static inline void renorm_cabac_decoder_once(CABACContext *c){
     if(!(c->low & CABAC_MASK))
         refill(c);
 }
+#endif
 
 #ifndef get_cabac_inline
 static void refill2(CABACContext *c){
@@ -97,7 +101,9 @@ static void refill2(CABACContext *c){
 #endif
         c->bytestream += CABAC_BITS/8;
 }
+#endif
 
+#ifndef get_cabac_inline
 static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
     int s = *state;
     int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
@@ -169,6 +175,7 @@ static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
  *
  * @return the number of bytes read or 0 if no end
  */
+#ifndef get_cabac_terminate
 static int av_unused get_cabac_terminate(CABACContext *c){
     c->range -= 2;
     if(c->low < c->range<<(CABAC_BITS+1)){
@@ -178,11 +185,13 @@ static int av_unused get_cabac_terminate(CABACContext *c){
         return c->bytestream - c->bytestream_start;
     }
 }
+#endif
 
 /**
  * Skip @p n bytes and reset the decoder.
  * @return the address of the first skipped byte or NULL if there's less than @p n bytes left
  */
+#ifndef skip_bytes
 static av_unused const uint8_t* skip_bytes(CABACContext *c, int n) {
     const uint8_t *ptr = c->bytestream;
 
@@ -199,5 +208,6 @@ static av_unused const uint8_t* skip_bytes(CABACContext *c, int n) {
 
     return ptr;
 }
+#endif
 
 #endif /* AVCODEC_CABAC_FUNCTIONS_H */