bytestream: add a new set of bytestream functions with overread checking
Signed-off-by: Justin Ruggles <justin.ruggles@gmail.com>
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				@ -26,6 +26,10 @@
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#include "libavutil/common.h"
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#include "libavutil/intreadwrite.h"
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typedef struct {
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    const uint8_t *buffer, *buffer_end;
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} GetByteContext;
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#define DEF_T(type, name, bytes, read, write)                             \
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static av_always_inline type bytestream_get_ ## name(const uint8_t **b){\
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    (*b) += bytes;\
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@ -34,6 +38,18 @@ static av_always_inline type bytestream_get_ ## name(const uint8_t **b){\
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static av_always_inline void bytestream_put_ ##name(uint8_t **b, const type value){\
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    write(*b, value);\
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    (*b) += bytes;\
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}\
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static av_always_inline type bytestream2_get_ ## name(GetByteContext *g)\
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{\
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    if (g->buffer_end - g->buffer < bytes)\
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        return 0;\
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    return bytestream_get_ ## name(&g->buffer);\
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}\
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static av_always_inline type bytestream2_peek_ ## name(GetByteContext *g)\
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{\
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    if (g->buffer_end - g->buffer < bytes)\
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        return 0;\
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    return read(g->buffer);\
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}
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#define DEF(name, bytes, read, write) \
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@ -55,6 +71,34 @@ DEF  (byte, 1, AV_RB8 , AV_WB8 )
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#undef DEF64
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#undef DEF_T
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static av_always_inline void bytestream2_init(GetByteContext *g,
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                                              const uint8_t *buf, int buf_size)
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{
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    g->buffer =  buf;
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    g->buffer_end = buf + buf_size;
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}
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static av_always_inline unsigned int bytestream2_get_bytes_left(GetByteContext *g)
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{
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    return g->buffer_end - g->buffer;
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}
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static av_always_inline void bytestream2_skip(GetByteContext *g,
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                                              unsigned int size)
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{
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    g->buffer += FFMIN(g->buffer_end - g->buffer, size);
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}
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static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g,
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                                                            uint8_t *dst,
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                                                            unsigned int size)
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{
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    int size2 = FFMIN(g->buffer_end - g->buffer, size);
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    memcpy(dst, g->buffer, size2);
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    g->buffer += size2;
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    return size2;
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}
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static av_always_inline unsigned int bytestream_get_buffer(const uint8_t **b, uint8_t *dst, unsigned int size)
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{
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    memcpy(dst, *b, size);
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