Always call getbit_context structures gbc.

[paraslash.git] / bitstream.h

diff --git a/bitstream.h b/bitstream.h
index d052337c1a1825d29bc700c8a918177220dc4f74..cc56a83c0207c2abc9c6fd25e9e9fd1aa4c5bb7d 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. */
@@ -34,90 +32,39 @@ struct vlc {
        int table_size, table_allocated;
 };
 
-/** Load \a gb into local variables. */
-#define OPEN_READER(name, gb)\
-       int name##_index= (gb)->index;\
-       int name##_cache= 0;\
-
-/** Store local vars in gb. */
-#define CLOSE_READER(name, gb)\
-       (gb)->index= name##_index;\
-
-/**
- * Refill the internal cache from the bitstream.
- */
-#define UPDATE_CACHE(name, gb)\
-       name##_cache= AV_RB32( ((gb)->buffer) \
-               + (name##_index >> 3) ) << (name##_index & 0x07);\
-
-/**
- * Remove the next num bits from the cache.
- *
- * SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER).
- */
-#define SKIP_CACHE(name, gb, num)\
-       name##_cache <<= (num);
-
-/**
- * Increment the internal bit counter.
- *
- * \sa SKIP_CACHE, SKIP_BITS.
- */
-#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)
+static inline uint32_t show_bits(struct getbit_context *gbc, int num)
+{
+       int idx = gbc->index;
+       uint32_t x = AV_RB32(gbc->buffer + (idx >> 3)) << (idx & 7);
+       return x >> (32 - num);
+}
 
-static inline int get_bits_count(struct getbit_context *s)
+static inline int get_bits_count(struct getbit_context *gbc)
 {
-       return s->index;
+       return gbc->index;
 }
 
-/**
- * Read 1-17 bits.
- */
-static inline unsigned int get_bits(struct getbit_context *s, int n)
+static inline void skip_bits(struct getbit_context *gbc, int n)
 {
-       register int tmp;
-       OPEN_READER(re, s)
-       UPDATE_CACHE(re, s)
-       tmp = SHOW_UBITS(re, s, n);
-       SKIP_COUNTER(re, s, n)
-       CLOSE_READER(re, s)
-       return tmp;
+       gbc->index += n;
 }
 
-static inline void skip_bits(struct getbit_context *s, int n)
+static inline unsigned int get_bits(struct getbit_context *gbc, 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)
+       unsigned int ret = show_bits(gbc, n);
+       skip_bits(gbc, n);
+       return ret;
 }
 
-static inline unsigned int get_bits1(struct getbit_context *s)
+static inline unsigned int get_bits1(struct getbit_context *gbc)
 {
-       int idx = s->index;
-       uint8_t result = s->buffer[idx >> 3];
+       int idx = gbc->index;
+       uint8_t result = gbc->buffer[idx >> 3];
 
        result <<= (idx & 0x07);
        result >>= 8 - 1;
        idx++;
-       s->index = idx;
+       gbc->index = idx;
        return result;
 }
 
@@ -130,12 +77,12 @@ static inline unsigned int get_bits1(struct getbit_context *s)
  *
  * \param bit_size The size of the buffer in bytes.
  */
-static inline void init_get_bits(struct getbit_context *s,
+static inline void init_get_bits(struct getbit_context *gbc,
                const uint8_t *buffer, int size)
 {
-       s->buffer = buffer;
-       s->buffer_end = buffer + size;
-       s->index = 0;
+       gbc->buffer = buffer;
+       gbc->buffer_end = buffer + size;
+       gbc->index = 0;
 }
 
 void init_vlc(struct vlc *vlc, int nb_bits, int nb_codes, const void *bits,
@@ -152,33 +99,28 @@ void free_vlc(struct vlc *vlc);
  * \param max_depth The number of times bits bits must be read to completely
  * read the longest vlc code = (max_vlc_length + bits - 1) / bits.
  */
-static inline int get_vlc(struct getbit_context *gb, VLC_TYPE(*table)[2],
+static inline int get_vlc(struct getbit_context *gbc, VLC_TYPE(*table)[2],
                int bits, int max_depth)
 {
        int n, idx, nb_bits, code;
 
-       OPEN_READER(re, gb)
-       UPDATE_CACHE(re, gb)
-       idx = SHOW_UBITS(re, gb, bits);
+       idx = show_bits(gbc, bits);
        code = table[idx][0];
        n = table[idx][1];
        if (max_depth > 1 && n < 0) {
-               SKIP_COUNTER(re, gb, bits)
-               UPDATE_CACHE(re, gb)
+               skip_bits(gbc, bits);
                nb_bits = -n;
-               idx = SHOW_UBITS(re, gb, nb_bits) + code;
+               idx = show_bits(gbc, nb_bits) + code;
                code = table[idx][0];
                n = table[idx][1];
                if (max_depth > 2 && n < 0) {
-                       SKIP_COUNTER(re, gb, nb_bits)
-                       UPDATE_CACHE(re, gb)
+                       skip_bits(gbc, nb_bits);
                        nb_bits = -n;
-                       idx = SHOW_UBITS(re, gb, nb_bits) + code;
+                       idx = show_bits(gbc, nb_bits) + code;
                        code = table[idx][0];
                        n = table[idx][1];
                }
        }
-       SKIP_BITS(re, gb, n)
-       CLOSE_READER(re, gb)
+       skip_bits(gbc, n);
        return code;
 }