lavc/get_bits: add a compat wrapper for the cached bitstream reader

Use that instead of the merged version.

libavcodec/get_bits.h

@@ -1,6 +1,5 @@
 /*
  * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
- * Copyright (c) 2016 Alexandra Hájková
  *
  * This file is part of FFmpeg.
  *
@@ -58,12 +57,55 @@
 #define CACHED_BITSTREAM_READER 0
 #endif
 
-typedef struct GetBitContext {
-    const uint8_t *buffer, *buffer_end;
 #if CACHED_BITSTREAM_READER
-    uint64_t cache;
-    unsigned bits_left;
+
+// we always want the LE implementation, to provide get_bits_le()
+#define BITSTREAM_LE
+
+#ifndef BITSTREAM_READER_LE
+# define BITSTREAM_BE
+# define BITSTREAM_DEFAULT_BE
 #endif
+
+#include "bitstream.h"
+
+#undef BITSTREAM_LE
+#undef BITSTREAM_BE
+#undef BITSTREAM_DEFAULT_BE
+
+typedef BitstreamContext GetBitContext;
+
+#define get_bits_count      bits_tell
+#define get_bits_left       bits_left
+#define skip_bits_long      bits_skip
+#define skip_bits           bits_skip
+#define get_bits            bits_read_nz
+#define get_bitsz           bits_read
+#define get_bits_long       bits_read
+#define get_bits1           bits_read_bit
+#define get_bits64          bits_read_64
+#define get_xbits           bits_read_xbits
+#define get_sbits           bits_read_signed
+#define get_sbits_long      bits_read_signed
+#define show_bits           bits_peek
+#define show_bits_long      bits_peek
+#define init_get_bits       bits_init
+#define init_get_bits8      bits_init8
+#define align_get_bits      bits_align
+#define get_vlc2            bits_read_vlc
+
+#define init_get_bits8_le(s, buffer, byte_size) bits_init8_le((BitstreamContextLE*)s, buffer, byte_size)
+#define get_bits_le(s, n)                       bits_read_le((BitstreamContextLE*)s, n)
+
+#define show_bits1(s)       bits_peek(s, 1)
+#define skip_bits1(s)       bits_skip(s, 1)
+
+#define skip_1stop_8data_bits bits_skip_1stop_8data
+
+#else   // CACHED_BITSTREAM_READER
+
+typedef struct GetBitContext {
+    const uint8_t *buffer, *buffer_end;
     int index;
     int size_in_bits;
     int size_in_bits_plus8;
@@ -120,16 +162,12 @@ static inline unsigned int show_bits(GetBitContext *s, int n);
  * For examples see get_bits, show_bits, skip_bits, get_vlc.
  */
 
-#if CACHED_BITSTREAM_READER
-#   define MIN_CACHE_BITS 64
-#elif defined LONG_BITSTREAM_READER
+#if defined LONG_BITSTREAM_READER
 #   define MIN_CACHE_BITS 32
 #else
 #   define MIN_CACHE_BITS 25
 #endif
 
-#if !CACHED_BITSTREAM_READER
-
 #define OPEN_READER_NOSIZE(name, gb)            \
     unsigned int name ## _index = (gb)->index;  \
     unsigned int av_unused name ## _cache
@@ -214,73 +252,12 @@ static inline unsigned int show_bits(GetBitContext *s, int n);
 
 #define GET_CACHE(name, gb) ((uint32_t) name ## _cache)
 
-#endif
 
 static inline int get_bits_count(const GetBitContext *s)
 {
-#if CACHED_BITSTREAM_READER
-    return s->index - s->bits_left;
-#else
     return s->index;
-#endif
-}
-
-#if CACHED_BITSTREAM_READER
-static inline void refill_32(GetBitContext *s, int is_le)
-{
-#if !UNCHECKED_BITSTREAM_READER
-    if (s->index >> 3 >= s->buffer_end - s->buffer)
-        return;
-#endif
-
-    if (is_le)
-        s->cache = (uint64_t)AV_RL32(s->buffer + (s->index >> 3)) << s->bits_left | s->cache;
-    else
-        s->cache = s->cache | (uint64_t)AV_RB32(s->buffer + (s->index >> 3)) << (32 - s->bits_left);
-    s->index     += 32;
-    s->bits_left += 32;
-}
-
-static inline void refill_64(GetBitContext *s, int is_le)
-{
-#if !UNCHECKED_BITSTREAM_READER
-    if (s->index >> 3 >= s->buffer_end - s->buffer)
-        return;
-#endif
-
-    if (is_le)
-        s->cache = AV_RL64(s->buffer + (s->index >> 3));
-    else
-        s->cache = AV_RB64(s->buffer + (s->index >> 3));
-    s->index += 64;
-    s->bits_left = 64;
 }
 
-static inline uint64_t get_val(GetBitContext *s, unsigned n, int is_le)
-{
-    uint64_t ret;
-    av_assert2(n>0 && n<=63);
-    if (is_le) {
-        ret = s->cache & ((UINT64_C(1) << n) - 1);
-        s->cache >>= n;
-    } else {
-        ret = s->cache >> (64 - n);
-        s->cache <<= n;
-    }
-    s->bits_left -= n;
-    return ret;
-}
-
-static inline unsigned show_val(const GetBitContext *s, unsigned n)
-{
-#ifdef BITSTREAM_READER_LE
-    return s->cache & ((UINT64_C(1) << n) - 1);
-#else
-    return s->cache >> (64 - n);
-#endif
-}
-#endif
-
 /**
  * Skips the specified number of bits.
  * @param n the number of bits to skip,
@@ -290,28 +267,12 @@ static inline unsigned show_val(const GetBitContext *s, unsigned n)
  */
 static inline void skip_bits_long(GetBitContext *s, int n)
 {
-#if CACHED_BITSTREAM_READER
-    skip_bits(s, n);
-#else
 #if UNCHECKED_BITSTREAM_READER
     s->index += n;
 #else
     s->index += av_clip(n, -s->index, s->size_in_bits_plus8 - s->index);
 #endif
-#endif
-}
-
-#if CACHED_BITSTREAM_READER
-static inline void skip_remaining(GetBitContext *s, unsigned n)
-{
-#ifdef BITSTREAM_READER_LE
-    s->cache >>= n;
-#else
-    s->cache <<= n;
-#endif
-    s->bits_left -= n;
 }
-#endif
 
 /**
  * Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
@@ -320,13 +281,6 @@ static inline void skip_remaining(GetBitContext *s, unsigned n)
  */
 static inline int get_xbits(GetBitContext *s, int n)
 {
-#if CACHED_BITSTREAM_READER
-    int32_t cache = show_bits(s, 32);
-    int sign = ~cache >> 31;
-    skip_remaining(s, n);
-
-    return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign;
-#else
     register int sign;
     register int32_t cache;
     OPEN_READER(re, s);
@@ -337,10 +291,8 @@ static inline int get_xbits(GetBitContext *s, int n)
     LAST_SKIP_BITS(re, s, n);
     CLOSE_READER(re, s);
     return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
-#endif
 }
 
-#if !CACHED_BITSTREAM_READER
 static inline int get_xbits_le(GetBitContext *s, int n)
 {
     register int sign;
@@ -354,22 +306,16 @@ static inline int get_xbits_le(GetBitContext *s, int n)
     CLOSE_READER(re, s);
     return (zero_extend(sign ^ cache, n) ^ sign) - sign;
 }
-#endif
 
 static inline int get_sbits(GetBitContext *s, int n)
 {
     register int tmp;
-#if CACHED_BITSTREAM_READER
-    av_assert2(n>0 && n<=25);
-    tmp = sign_extend(get_bits(s, n), n);
-#else
     OPEN_READER(re, s);
     av_assert2(n>0 && n<=25);
     UPDATE_CACHE(re, s);
     tmp = SHOW_SBITS(re, s, n);
     LAST_SKIP_BITS(re, s, n);
     CLOSE_READER(re, s);
-#endif
     return tmp;
 }
 
@@ -379,32 +325,12 @@ static inline int get_sbits(GetBitContext *s, int n)
 static inline unsigned int get_bits(GetBitContext *s, int n)
 {
     register unsigned int tmp;
-#if CACHED_BITSTREAM_READER
-
-    av_assert2(n>0 && n<=32);
-    if (n > s->bits_left) {
-#ifdef BITSTREAM_READER_LE
-        refill_32(s, 1);
-#else
-        refill_32(s, 0);
-#endif
-        if (s->bits_left < 32)
-            s->bits_left = n;
-    }
-
-#ifdef BITSTREAM_READER_LE
-    tmp = get_val(s, n, 1);
-#else
-    tmp = get_val(s, n, 0);
-#endif
-#else
     OPEN_READER(re, s);
     av_assert2(n>0 && n<=25);
     UPDATE_CACHE(re, s);
     tmp = SHOW_UBITS(re, s, n);
     LAST_SKIP_BITS(re, s, n);
     CLOSE_READER(re, s);
-#endif
     av_assert2(tmp < UINT64_C(1) << n);
     return tmp;
 }
@@ -419,16 +345,6 @@ static av_always_inline int get_bitsz(GetBitContext *s, int n)
 
 static inline unsigned int get_bits_le(GetBitContext *s, int n)
 {
-#if CACHED_BITSTREAM_READER
-    av_assert2(n>0 && n<=32);
-    if (n > s->bits_left) {
-        refill_32(s, 1);
-        if (s->bits_left < 32)
-            s->bits_left = n;
-    }
-
-    return get_val(s, n, 1);
-#else
     register int tmp;
     OPEN_READER(re, s);
     av_assert2(n>0 && n<=25);
@@ -437,7 +353,6 @@ static inline unsigned int get_bits_le(GetBitContext *s, int n)
     LAST_SKIP_BITS(re, s, n);
     CLOSE_READER(re, s);
     return tmp;
-#endif
 }
 
 /**
@@ -446,71 +361,22 @@ static inline unsigned int get_bits_le(GetBitContext *s, int n)
 static inline unsigned int show_bits(GetBitContext *s, int n)
 {
     register unsigned int tmp;
-#if CACHED_BITSTREAM_READER
-    if (n > s->bits_left)
-#ifdef BITSTREAM_READER_LE
-        refill_32(s, 1);
-#else
-        refill_32(s, 0);
-#endif
-
-    tmp = show_val(s, n);
-#else
     OPEN_READER_NOSIZE(re, s);
     av_assert2(n>0 && n<=25);
     UPDATE_CACHE(re, s);
     tmp = SHOW_UBITS(re, s, n);
-#endif
     return tmp;
 }
 
 static inline void skip_bits(GetBitContext *s, int n)
 {
-#if CACHED_BITSTREAM_READER
-    if (n < s->bits_left)
-        skip_remaining(s, n);
-    else {
-        n -= s->bits_left;
-        s->cache = 0;
-        s->bits_left = 0;
-
-        if (n >= 64) {
-            unsigned skip = (n / 8) * 8;
-
-            n -= skip;
-            s->index += skip;
-        }
-#ifdef BITSTREAM_READER_LE
-        refill_64(s, 1);
-#else
-        refill_64(s, 0);
-#endif
-        if (n)
-            skip_remaining(s, n);
-    }
-#else
     OPEN_READER(re, s);
     LAST_SKIP_BITS(re, s, n);
     CLOSE_READER(re, s);
-#endif
 }
 
 static inline unsigned int get_bits1(GetBitContext *s)
 {
-#if CACHED_BITSTREAM_READER
-    if (!s->bits_left)
-#ifdef BITSTREAM_READER_LE
-        refill_64(s, 1);
-#else
-        refill_64(s, 0);
-#endif
-
-#ifdef BITSTREAM_READER_LE
-    return get_val(s, 1, 1);
-#else
-    return get_val(s, 1, 0);
-#endif
-#else
     unsigned int index = s->index;
     uint8_t result     = s->buffer[index >> 3];
 #ifdef BITSTREAM_READER_LE
@@ -527,7 +393,6 @@ static inline unsigned int get_bits1(GetBitContext *s)
     s->index = index;
 
     return result;
-#endif
 }
 
 static inline unsigned int show_bits1(GetBitContext *s)
@@ -548,10 +413,6 @@ static inline unsigned int get_bits_long(GetBitContext *s, int n)
     av_assert2(n>=0 && n<=32);
     if (!n) {
         return 0;
-#if CACHED_BITSTREAM_READER
-    }
-    return get_bits(s, n);
-#else
     } else if (n <= MIN_CACHE_BITS) {
         return get_bits(s, n);
     } else {
@@ -563,7 +424,6 @@ static inline unsigned int get_bits_long(GetBitContext *s, int n)
         return ret | get_bits(s, n - 16);
 #endif
     }
-#endif
 }
 
 /**
@@ -621,8 +481,17 @@ static inline unsigned int show_bits_long(GetBitContext *s, int n)
     }
 }
 
-static inline int init_get_bits_xe(GetBitContext *s, const uint8_t *buffer,
-                                   int bit_size, int is_le)
+
+/**
+ * Initialize GetBitContext.
+ * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
+ *        larger than 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
+ * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
+ */
+static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
+                                int bit_size)
 {
     int buffer_size;
     int ret = 0;
@@ -641,33 +510,9 @@ static inline int init_get_bits_xe(GetBitContext *s, const uint8_t *buffer,
     s->buffer_end         = buffer + buffer_size;
     s->index              = 0;
 
-#if CACHED_BITSTREAM_READER
-    s->cache              = 0;
-    s->bits_left          = 0;
-    refill_64(s, is_le);
-#endif
-
     return ret;
 }
 
-/**
- * Initialize GetBitContext.
- * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
- *        larger than 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
- * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
- */
-static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
-                                int bit_size)
-{
-#ifdef BITSTREAM_READER_LE
-    return init_get_bits_xe(s, buffer, bit_size, 1);
-#else
-    return init_get_bits_xe(s, buffer, bit_size, 0);
-#endif
-}
-
 /**
  * Initialize GetBitContext.
  * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
@@ -689,7 +534,7 @@ static inline int init_get_bits8_le(GetBitContext *s, const uint8_t *buffer,
 {
     if (byte_size > INT_MAX / 8 || byte_size < 0)
         byte_size = -1;
-    return init_get_bits_xe(s, buffer, byte_size * 8, 1);
+    return init_get_bits(s, buffer, byte_size * 8);
 }
 
 static inline const uint8_t *align_get_bits(GetBitContext *s)
@@ -774,19 +619,6 @@ static inline const uint8_t *align_get_bits(GetBitContext *s)
         SKIP_BITS(name, gb, n);                                 \
     } while (0)
 
-/* Return the LUT element for the given bitstream configuration. */
-static inline int set_idx(GetBitContext *s, int code, int *n, int *nb_bits,
-                          const VLCElem *table)
-{
-    unsigned idx;
-
-    *nb_bits = -*n;
-    idx = show_bits(s, *nb_bits) + code;
-    *n = table[idx].len;
-
-    return table[idx].sym;
-}
-
 /**
  * Parse a vlc code.
  * @param bits is the number of bits which will be read at once, must be
@@ -799,24 +631,6 @@ static inline int set_idx(GetBitContext *s, int code, int *n, int *nb_bits,
 static av_always_inline int get_vlc2(GetBitContext *s, const VLCElem *table,
                                      int bits, int max_depth)
 {
-#if CACHED_BITSTREAM_READER
-    int nb_bits;
-    unsigned idx = show_bits(s, bits);
-    int code = table[idx].sym;
-    int n    = table[idx].len;
-
-    if (max_depth > 1 && n < 0) {
-        skip_remaining(s, bits);
-        code = set_idx(s, code, &n, &nb_bits, table);
-        if (max_depth > 2 && n < 0) {
-            skip_remaining(s, nb_bits);
-            code = set_idx(s, code, &n, &nb_bits, table);
-        }
-    }
-    skip_remaining(s, n);
-
-    return code;
-#else
     int code;
 
     OPEN_READER(re, s);
@@ -827,7 +641,6 @@ static av_always_inline int get_vlc2(GetBitContext *s, const VLCElem *table,
     CLOSE_READER(re, s);
 
     return code;
-#endif
 }
 
 static inline int decode012(GetBitContext *gb)
@@ -867,4 +680,6 @@ static inline int skip_1stop_8data_bits(GetBitContext *gb)
     return 0;
 }
 
+#endif // CACHED_BITSTREAM_READER
+
 #endif /* AVCODEC_GET_BITS_H */