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avcodec: Add av_fast_padded_malloc().

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Wrapper around av_fast_malloc() that keeps FF_INPUT_BUFFER_PADDING_SIZE
zero-padded bytes at the end of the used buffer.

Based on a patch by Reimar Döffinger <Reimar.Doeffinger@gmx.de>.
This commit is contained in:
Janne Grunau 2012-01-31 15:40:11 +00:00
parent 378c5ef9ae
commit 316fc7443b
3 changed files with 27 additions and 0 deletions
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5
doc/APIchanges
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@ -13,6 +13,11 @@ libavutil: 2011-04-18
API changes, most recent first:
2012-02-01 - xxxxxxx - lavc 54.01.0
Add av_fast_padded_malloc() as alternative for av_realloc() when aligned
memory is required. The buffer will always have FF_INPUT_BUFFER_PADDING_SIZE
zero-padded bytes at the end.
2012-01-31 - xxxxxxx - lavf 54.01.0
Add avformat_get_riff_video_tags() and avformat_get_riff_audio_tags().

9
libavcodec/avcodec.h
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@ -4070,6 +4070,15 @@ void *av_fast_realloc(void *ptr, unsigned int *size, size_t min_size);
*/
void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size);
/**
* Allocate a buffer with padding, reusing the given one if large enough.
*
* Same behaviour av_fast_malloc but the buffer has additional
* FF_INPUT_PADDING_SIZE at the end which will always memset to 0.
*
*/
void av_fast_padded_malloc(void *ptr, unsigned int *size, size_t min_size);
/**
* Copy image src to dst. Wraps av_picture_data_copy() above.
*/

13
libavcodec/utils.c
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@ -80,6 +80,19 @@ void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size)
*size= min_size;
}
void av_fast_padded_malloc(void *ptr, unsigned int *size, size_t min_size)
{
void **p = ptr;
if (min_size > SIZE_MAX - FF_INPUT_BUFFER_PADDING_SIZE) {
av_freep(p);
*size = 0;
return;
}
av_fast_malloc(p, size, min_size + FF_INPUT_BUFFER_PADDING_SIZE);
if (*size)
memset((uint8_t *)*p + min_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
}
/* encoder management */
static AVCodec *first_avcodec = NULL;