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Revert "4xm: Prevent buffer overreads."

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This reverts commit 295a7c0238. The
patch breaks decoding of regular files (e.g. fate-4xm-2).
This commit is contained in:
Ronald S. Bultje 2012-01-04 21:27:31 -08:00
parent 295a7c0238
commit 3fa646e859
1 changed files with 3 additions and 11 deletions
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14
libavcodec/4xm.c
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@ -614,24 +614,16 @@ static int decode_i2_frame(FourXContext *f, const uint8_t *buf, int length){
int x, y, x2, y2;
const int width= f->avctx->width;
const int height= f->avctx->height;
const int mbs = FFALIGN(width, 16) * FFALIGN(height, 16);
uint16_t *dst= (uint16_t*)f->current_picture.data[0];
const int stride= f->current_picture.linesize[0]>>1;
GetByteContext g3;
if(length < mbs * 8) {
av_log(f->avctx, AV_LOG_ERROR, "packet size too small\n");
return AVERROR_INVALIDDATA;
}
bytestream2_init(&g3, buf, length);
for(y=0; y<height; y+=16){
for(x=0; x<width; x+=16){
unsigned int color[4], bits;
memset(color, 0, sizeof(color));
//warning following is purely guessed ...
color[0]= bytestream2_get_le16u(&g3);
color[1]= bytestream2_get_le16u(&g3);
color[0]= bytestream_get_le16(&buf);
color[1]= bytestream_get_le16(&buf);
if(color[0]&0x8000) av_log(NULL, AV_LOG_ERROR, "unk bit 1\n");
if(color[1]&0x8000) av_log(NULL, AV_LOG_ERROR, "unk bit 2\n");
@ -639,7 +631,7 @@ static int decode_i2_frame(FourXContext *f, const uint8_t *buf, int length){
color[2]= mix(color[0], color[1]);
color[3]= mix(color[1], color[0]);
bits= bytestream2_get_le32u(&g3);
bits= bytestream_get_le32(&buf);
for(y2=0; y2<16; y2++){
for(x2=0; x2<16; x2++){
int index= 2*(x2>>2) + 8*(y2>>2);