[FFmpeg-devel] [PATCH 4/5] lavc/bitstream: make skip_remaining() public

Anton Khirnov anton at khirnov.net
Fri Jun 17 16:32:05 EEST 2022


Also rename it to bitstream_skip_cache(), which is more descriptive and
follows the naming conventions of tis API.
---
 libavcodec/bitstream.h          |  1 +
 libavcodec/bitstream_template.h | 19 ++++++++++++-------
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/libavcodec/bitstream.h b/libavcodec/bitstream.h
index 3fa63695d3..364245453b 100644
--- a/libavcodec/bitstream.h
+++ b/libavcodec/bitstream.h
@@ -116,6 +116,7 @@ static inline void bitstream_unget(BitstreamContext *bc, uint64_t value,
 #define bitstream_peek          bitstream_peek_be
 #define bitstream_peek_signed   bitstream_peek_signed_be
 #define bitstream_skip          bitstream_skip_be
+#define bitstream_skip_cache    bitstream_skip_cache_be
 #define bitstream_seek          bitstream_seek_be
 #define bitstream_align         bitstream_align_be
 #define bitstream_read_xbits    bitstream_read_xbits_be
diff --git a/libavcodec/bitstream_template.h b/libavcodec/bitstream_template.h
index 14a420139c..717473ca40 100644
--- a/libavcodec/bitstream_template.h
+++ b/libavcodec/bitstream_template.h
@@ -225,7 +225,12 @@ static inline int BS_FUNC(bitstream_peek_signed)(BitstreamContext *bc, unsigned
     return sign_extend(BS_FUNC(bitstream_peek)(bc, n), n);
 }
 
-static inline void BS_FUNC(skip_remaining)(BitstreamContext *bc, unsigned int n)
+/**
+ * Skip n bits from the cache. This may only be called if at least n bits are
+ * guaranteed to be in the cache, e.g. right after bitstream_peek(n).
+ * Otherwise use bitstream_skip().
+ */
+static inline void BS_FUNC(bitstream_skip_cache)(BitstreamContext *bc, unsigned int n)
 {
 #ifdef BITSTREAM_LE
     bc->bits >>= n;
@@ -241,7 +246,7 @@ static inline void BS_FUNC(skip_remaining)(BitstreamContext *bc, unsigned int n)
 static inline void BS_FUNC(bitstream_skip)(BitstreamContext *bc, unsigned int n)
 {
     if (n < bc->bits_left)
-        BS_FUNC(skip_remaining)(bc, n);
+        BS_FUNC(bitstream_skip_cache)(bc, n);
     else {
         n -= bc->bits_left;
         bc->bits      = 0;
@@ -255,7 +260,7 @@ static inline void BS_FUNC(bitstream_skip)(BitstreamContext *bc, unsigned int n)
         }
         BS_FUNC(refill_64)(bc);
         if (n)
-            BS_FUNC(skip_remaining)(bc, n);
+            BS_FUNC(bitstream_skip_cache)(bc, n);
     }
 }
 
@@ -291,7 +296,7 @@ static inline int BS_FUNC(bitstream_read_xbits)(BitstreamContext *bc, unsigned i
 {
     int32_t cache = BS_FUNC(bitstream_peek)(bc, 32);
     int sign = ~cache >> 31;
-    BS_FUNC(skip_remaining)(bc, n);
+    BS_FUNC(bitstream_skip_cache)(bc, n);
 
     return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign;
 }
@@ -374,14 +379,14 @@ static inline int BS_FUNC(bitstream_read_vlc)(BitstreamContext *bc, VLC_TYPE (*t
     int n        = table[idx][1];
 
     if (max_depth > 1 && n < 0) {
-        BS_FUNC(skip_remaining)(bc, bits);
+        BS_FUNC(bitstream_skip_cache)(bc, bits);
         code = BS_FUNC(set_idx)(bc, code, &n, &nb_bits, table);
         if (max_depth > 2 && n < 0) {
-            BS_FUNC(skip_remaining)(bc, nb_bits);
+            BS_FUNC(bitstream_skip_cache)(bc, nb_bits);
             code = BS_FUNC(set_idx)(bc, code, &n, &nb_bits, table);
         }
     }
-    BS_FUNC(skip_remaining)(bc, n);
+    BS_FUNC(bitstream_skip_cache)(bc, n);
 
     return code;
 }
-- 
2.34.1



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