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authorJustin Ruggles <justin.ruggles@gmail.com>2011-12-21 22:32:04 -0500
committerJustin Ruggles <justin.ruggles@gmail.com>2012-01-05 23:36:36 -0500
commit6e8bf6db489f66d6fa553fa04904464af768c540 (patch)
tree6c6f9efe586e3656fd40e1503569299792ab7b96 /libavcodec
parentf907615f0813e8499f06a7eebccf1c63fce87c8e (diff)
downloadffmpeg-6e8bf6db489f66d6fa553fa04904464af768c540.tar.gz
add bytestream2_tell() and bytestream2_seek() functions
Diffstat (limited to 'libavcodec')
-rw-r--r--libavcodec/bytestream.h31
1 files changed, 30 insertions, 1 deletions
diff --git a/libavcodec/bytestream.h b/libavcodec/bytestream.h
index 8fbceacc4f..9ec74cf9a7 100644
--- a/libavcodec/bytestream.h
+++ b/libavcodec/bytestream.h
@@ -27,7 +27,7 @@
#include "libavutil/intreadwrite.h"
typedef struct {
- const uint8_t *buffer, *buffer_end;
+ const uint8_t *buffer, *buffer_end, *buffer_start;
} GetByteContext;
#define DEF_T(type, name, bytes, read, write) \
@@ -79,6 +79,7 @@ static av_always_inline void bytestream2_init(GetByteContext *g,
const uint8_t *buf, int buf_size)
{
g->buffer = buf;
+ g->buffer_start = buf;
g->buffer_end = buf + buf_size;
}
@@ -93,6 +94,34 @@ static av_always_inline void bytestream2_skip(GetByteContext *g,
g->buffer += FFMIN(g->buffer_end - g->buffer, size);
}
+static av_always_inline int bytestream2_tell(GetByteContext *g)
+{
+ return (int)(g->buffer - g->buffer_start);
+}
+
+static av_always_inline int bytestream2_seek(GetByteContext *g, int offset,
+ int whence)
+{
+ switch (whence) {
+ case SEEK_CUR:
+ offset = av_clip(offset, -(g->buffer - g->buffer_start),
+ g->buffer_end - g->buffer);
+ g->buffer += offset;
+ break;
+ case SEEK_END:
+ offset = av_clip(offset, -(g->buffer_end - g->buffer_start), 0);
+ g->buffer = g->buffer_end + offset;
+ break;
+ case SEEK_SET:
+ offset = av_clip(offset, 0, g->buffer_end - g->buffer_start);
+ g->buffer = g->buffer_start + offset;
+ break;
+ default:
+ return AVERROR(EINVAL);
+ }
+ return bytestream2_tell(g);
+}
+
static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g,
uint8_t *dst,
unsigned int size)