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add bytestream2_tell() and bytestream2_seek() functions

This commit is contained in:
Justin Ruggles 2011-12-21 22:32:04 -05:00
parent f907615f08
commit 6e8bf6db48

View File

@ -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)