bitstream tracing support

Originally committed as revision 1698 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/common.h

@@ -786,6 +786,46 @@ static always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
     return code;
 }
 
+//#define TRACE
+
+#ifdef TRACE
+
+static inline void print_bin(int bits, int n){
+    int i;
+    
+    for(i=n-1; i>=0; i--){
+        printf("%d", (bits>>i)&1);
+    }
+    for(i=n; i<24; i++)
+        printf(" ");
+}
+
+static inline int get_bits_trace(GetBitContext *s, int n, char *file, char *func, int line){
+    int r= get_bits(s, n);
+    
+    print_bin(r, n);
+    printf("%5d %2d %3d bit @%5d in %s %s:%d\n", r, n, r, get_bits_count(s)-n, file, func, line);
+    return r;
+}
+static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, char *func, int line){
+    int show= show_bits(s, 24);
+    int pos= get_bits_count(s);
+    int r= get_vlc2(s, table, bits, max_depth);
+    int len= get_bits_count(s) - pos;
+    int bits2= show>>(24-len);
+    
+    print_bin(bits2, len);
+    
+    printf("%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
+    return r;
+}
+
+#define get_bits(s, n)  get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
+#define get_bits1(s)    get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
+#define get_vlc(s, vlc)            get_vlc_trace(s, vlc->table, vlc->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
+#define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
+
+#endif
 
 /* define it to include statistics code (useful only for optimizing
    codec efficiency */