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rv34dsp: avoid use of crop table for idct. 

Fixes out of array read.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2012-03-01 07:06:53 +01:00
parent 8263212e86
commit fd88a25701
1 changed files with 4 additions and 5 deletions
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9
libavcodec/rv34dsp.c
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@ -55,7 +55,6 @@ static av_always_inline void rv34_row_transform(int temp[16], DCTELEM *block)
*/
static void rv34_idct_add_c(uint8_t *dst, ptrdiff_t stride, DCTELEM *block){
int temp[16];
uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
int i;
rv34_row_transform(temp, block);
@ -67,10 +66,10 @@ static void rv34_idct_add_c(uint8_t *dst, ptrdiff_t stride, DCTELEM *block){
const int z2 = 7* temp[4*1+i] - 17*temp[4*3+i];
const int z3 = 17* temp[4*1+i] + 7*temp[4*3+i];
dst[0] = cm[ dst[0] + ( (z0 + z3) >> 10 ) ];
dst[1] = cm[ dst[1] + ( (z1 + z2) >> 10 ) ];
dst[2] = cm[ dst[2] + ( (z1 - z2) >> 10 ) ];
dst[3] = cm[ dst[3] + ( (z0 - z3) >> 10 ) ];
dst[0] = av_clip_uint8( dst[0] + ( (z0 + z3) >> 10 ) );
dst[1] = av_clip_uint8( dst[1] + ( (z1 + z2) >> 10 ) );
dst[2] = av_clip_uint8( dst[2] + ( (z1 - z2) >> 10 ) );
dst[3] = av_clip_uint8( dst[3] + ( (z0 - z3) >> 10 ) );
dst += stride;
}