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bytestream: add a new set of bytestream functions with overread checking

Signed-off-by: Justin Ruggles <justin.ruggles@gmail.com>
tags/n0.10
Aneesh Dogra Justin Ruggles 13 years ago
parent
commit
fd22616c59
1 changed files with 44 additions and 0 deletions
  1. +44
    -0
      libavcodec/bytestream.h

+ 44
- 0
libavcodec/bytestream.h View File

@@ -26,6 +26,10 @@
#include "libavutil/common.h"
#include "libavutil/intreadwrite.h"

typedef struct {
const uint8_t *buffer, *buffer_end;
} GetByteContext;

#define DEF_T(type, name, bytes, read, write) \
static av_always_inline type bytestream_get_ ## name(const uint8_t **b){\
(*b) += bytes;\
@@ -34,6 +38,18 @@ static av_always_inline type bytestream_get_ ## name(const uint8_t **b){\
static av_always_inline void bytestream_put_ ##name(uint8_t **b, const type value){\
write(*b, value);\
(*b) += bytes;\
}\
static av_always_inline type bytestream2_get_ ## name(GetByteContext *g)\
{\
if (g->buffer_end - g->buffer < bytes)\
return 0;\
return bytestream_get_ ## name(&g->buffer);\
}\
static av_always_inline type bytestream2_peek_ ## name(GetByteContext *g)\
{\
if (g->buffer_end - g->buffer < bytes)\
return 0;\
return read(g->buffer);\
}

#define DEF(name, bytes, read, write) \
@@ -55,6 +71,34 @@ DEF (byte, 1, AV_RB8 , AV_WB8 )
#undef DEF64
#undef DEF_T

static av_always_inline void bytestream2_init(GetByteContext *g,
const uint8_t *buf, int buf_size)
{
g->buffer = buf;
g->buffer_end = buf + buf_size;
}

static av_always_inline unsigned int bytestream2_get_bytes_left(GetByteContext *g)
{
return g->buffer_end - g->buffer;
}

static av_always_inline void bytestream2_skip(GetByteContext *g,
unsigned int size)
{
g->buffer += FFMIN(g->buffer_end - g->buffer, size);
}

static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g,
uint8_t *dst,
unsigned int size)
{
int size2 = FFMIN(g->buffer_end - g->buffer, size);
memcpy(dst, g->buffer, size2);
g->buffer += size2;
return size2;
}

static av_always_inline unsigned int bytestream_get_buffer(const uint8_t **b, uint8_t *dst, unsigned int size)
{
memcpy(dst, *b, size);


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