open code NEG_USR32

[paraslash.git] / bitstream.h

diff --git a/bitstream.h b/bitstream.h
index f54ae62bc6b132c26c15312e117e69508557bb6c..6765ed8c4a16f698781c0d8f523920a80ae4d1c5 100644 (file)
--- a/bitstream.h
+++ b/bitstream.h
@@ -14,8 +14,6 @@
                      (((const uint8_t*)(x))[2] <<  8) | \
                       ((const uint8_t*)(x))[3])
 
-#define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s)))
-
 /** Structure for bistream I/O. */
 struct getbit_context {
        /* Start of the internal buffer. */
@@ -47,7 +45,7 @@ struct vlc {
  * Refill the internal cache from the bitstream.
  */
 #define UPDATE_CACHE(name, gb)\
-       name##_cache= AV_RB32( ((const uint8_t *)(gb)->buffer) \
+       name##_cache= AV_RB32( ((gb)->buffer) \
                + (name##_index >> 3) ) << (name##_index & 0x07);\
 
 /**
@@ -61,25 +59,14 @@ struct vlc {
 /**
  * Increment the internal bit counter.
  *
- * \sa SKIP_CACHE, SKIP_BITS.
+ * \sa SKIP_CACHE.
  */
 #define SKIP_COUNTER(name, gb, num)\
        name##_index += (num);\
 
-/**
- * Skip over the next num bits.
- *
- * This is equivalent to SKIP_CACHE; SKIP_COUNTER.
- */
-#define SKIP_BITS(name, gb, num)\
-       {\
-               SKIP_CACHE(name, gb, num)\
-               SKIP_COUNTER(name, gb, num)\
-       }\
-
 /** Return the next num bits. */
-#define SHOW_UBITS(name, gb, num)\
-       NEG_USR32(name##_cache, num)
+#define SHOW_UBITS(name, gb, num) \
+       (((uint32_t)(name##_cache)) >> (32 - (num)))
 
 static inline int get_bits_count(struct getbit_context *s)
 {
@@ -102,11 +89,7 @@ static inline unsigned int get_bits(struct getbit_context *s, int n)
 
 static inline void skip_bits(struct getbit_context *s, int n)
 {
-       /* gcc seems to optimize this to s->index+=n for the ALT_READER :)) */
-       OPEN_READER(re, s)
-       UPDATE_CACHE(re, s)
-       SKIP_COUNTER(re, s, n)
-       CLOSE_READER(re, s)
+       s->index += n;
 }
 
 static inline unsigned int get_bits1(struct getbit_context *s)
@@ -128,18 +111,13 @@ static inline unsigned int get_bits1(struct getbit_context *s)
  * bytes larger then the actual read bits * because some optimized bitstream
  * readers read 32 or 64 bit at once and could read over the end.
  *
- * \param bit_size The size of the buffer in bits.
+ * \param bit_size The size of the buffer in bytes.
  */
 static inline void init_get_bits(struct getbit_context *s,
-               const uint8_t *buffer, int bit_size)
+               const uint8_t *buffer, int size)
 {
-       int buffer_size = (bit_size + 7) >> 3;
-       if (buffer_size < 0 || bit_size < 0) {
-               buffer_size = bit_size = 0;
-               buffer = NULL;
-       }
        s->buffer = buffer;
-       s->buffer_end = buffer + buffer_size;
+       s->buffer_end = buffer + size;
        s->index = 0;
 }
 
@@ -183,7 +161,8 @@ static inline int get_vlc(struct getbit_context *gb, VLC_TYPE(*table)[2],
                        n = table[idx][1];
                }
        }
-       SKIP_BITS(re, gb, n)
+       SKIP_CACHE(re, gb, n)
+       SKIP_COUNTER(re, gb, n)
        CLOSE_READER(re, gb)
        return code;
 }