(((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. */
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( ((const uint8_t *)(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)\
- }\
-
-/** This is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER. */
-#define LAST_SKIP_BITS(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)
{
return s->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 *s, int n)
{
- register int tmp;
- OPEN_READER(re, s)
- UPDATE_CACHE(re, s)
- tmp = SHOW_UBITS(re, s, n);
- LAST_SKIP_BITS(re, s, n)
- CLOSE_READER(re, s)
- return tmp;
+ s->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)
- LAST_SKIP_BITS(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)
* 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;
}
{
int n, idx, nb_bits, code;
- OPEN_READER(re, gb)
- UPDATE_CACHE(re, gb)
- idx = SHOW_UBITS(re, gb, bits);
+ idx = show_bits(gb, bits);
code = table[idx][0];
n = table[idx][1];
if (max_depth > 1 && n < 0) {
- LAST_SKIP_BITS(re, gb, bits)
- UPDATE_CACHE(re, gb)
+ skip_bits(gb, bits);
nb_bits = -n;
- idx = SHOW_UBITS(re, gb, nb_bits) + code;
+ idx = show_bits(gb, nb_bits) + code;
code = table[idx][0];
n = table[idx][1];
if (max_depth > 2 && n < 0) {
- LAST_SKIP_BITS(re, gb, nb_bits)
- UPDATE_CACHE(re, gb)
+ skip_bits(gb, nb_bits);
nb_bits = -n;
- idx = SHOW_UBITS(re, gb, nb_bits) + code;
+ idx = show_bits(gb, nb_bits) + code;
code = table[idx][0];
n = table[idx][1];
}
}
- SKIP_BITS(re, gb, n)
- CLOSE_READER(re, gb)
+ skip_bits(gb, n);
return code;
}