The mp4 tagger.

[paraslash.git] / bitstream.h

diff --git a/bitstream.h b/bitstream.h
index d13ef4c2bd6946deff17e9104432052b1319b25e..5890d08c89d4033f7fefb9a19be525860a701d77 100644 (file)
--- a/bitstream.h
+++ b/bitstream.h
@@ -9,16 +9,11 @@
 
 /** \file bitstream.h Bitstream structures and inline functions. */
 
-#define AV_RB32(x)  ((((const uint8_t*)(x))[0] << 24) | \
-                     (((const uint8_t*)(x))[1] << 16) | \
-                     (((const uint8_t*)(x))[2] <<  8) | \
-                      ((const uint8_t*)(x))[3])
-
 /** Structure for bistream I/O. */
 struct getbit_context {
-       /* Start of the internal buffer. */
+       /** Start of the internal buffer. */
        const uint8_t *buffer;
-       /* End of the internal buffer. */
+       /** End of the internal buffer. */
        const uint8_t *buffer_end;
        /** Bit counter. */
        int index;
@@ -26,17 +21,24 @@ struct getbit_context {
 
 #define VLC_TYPE int16_t
 
+/** A variable length code table. */
 struct vlc {
+       /** Number of bits of the table. */
        int bits;
-       VLC_TYPE(*table)[2];    ///< code, bits
-       int table_size, table_allocated;
+       /** The code and the bits table. */
+       VLC_TYPE(*table)[2];
+       /** The size of the table. */
+       int table_size;
+       /** Amount of memory allocated so far. */
+       int table_allocated;
 };
 
 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);
+       const uint8_t *p = gbc->buffer + (idx >> 3);
+       uint32_t x = ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
+       return (x << (idx & 7)) >> (32 - num);
 }
 
 static inline int get_bits_count(struct getbit_context *gbc)
@@ -57,7 +59,7 @@ static inline unsigned int get_bits(struct getbit_context *gbc, int n)
 }
 
 /* This is rather hot, we can do better than get_bits(gbc, 1). */
-static inline unsigned int get_bits1(struct getbit_context *gbc)
+static inline unsigned int get_bit(struct getbit_context *gbc)
 {
        int idx = gbc->index++;
        uint8_t tmp = gbc->buffer[idx >> 3], mask = (1 << (7 - (idx & 7)));
@@ -67,11 +69,13 @@ static inline unsigned int get_bits1(struct getbit_context *gbc)
 /**
  * Initialize a getbit_context structure.
  *
- * \param buffer The bitstream buffer. It must be FF_INPUT_BUFFER_PADDING_SIZE
- * 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 gbc The structure to initialize.
+ * \param buffer The bitstream buffer.
+ * \param size The size of the buffer in bytes.
  *
- * \param bit_size The size of the buffer in bytes.
+ * The bitstream buffer must be 4 bytes larger then the actual read bits
+ * because the bitstream reader might read 32 bits at once and could read over
+ * the end.
  */
 static inline void init_get_bits(struct getbit_context *gbc,
                const uint8_t *buffer, int size)
@@ -83,40 +87,6 @@ static inline void init_get_bits(struct getbit_context *gbc,
 
 void init_vlc(struct vlc *vlc, int nb_bits, int nb_codes, const void *bits,
                const void *codes, int codes_size);
-
 void free_vlc(struct vlc *vlc);
-
-/**
- * Parse a vlc code.
- *
- * \param bits The number of bits which will be read at once, must be
- * identical to nb_bits in init_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 *gbc, VLC_TYPE(*table)[2],
-               int bits, int max_depth)
-{
-       int n, idx, nb_bits, code;
-
-       idx = show_bits(gbc, bits);
-       code = table[idx][0];
-       n = table[idx][1];
-       if (max_depth > 1 && n < 0) {
-               skip_bits(gbc, bits);
-               nb_bits = -n;
-               idx = show_bits(gbc, nb_bits) + code;
-               code = table[idx][0];
-               n = table[idx][1];
-               if (max_depth > 2 && n < 0) {
-                       skip_bits(gbc, nb_bits);
-                       nb_bits = -n;
-                       idx = show_bits(gbc, nb_bits) + code;
-                       code = table[idx][0];
-                       n = table[idx][1];
-               }
-       }
-       skip_bits(gbc, n);
-       return code;
-}
+int get_vlc(struct getbit_context *gbc, VLC_TYPE(*table)[2], int bits,
+               int max_depth);