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pnmdec: add support for mono images with non-space-separated pixel digits

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When the file to decode contains a sequence of binary values like
"1101110...", decode_frame() was reading the sequence of digits like a
unique integer value, which was resulting in integer overflows.

The change add support for parsing non-space-separated pixel digits
for mono formats, in particular fix decoding of file battrace.pbm, and
fix trac issue #154.
This commit is contained in:
Stefano Sabatini 2011-05-08 00:47:14 +02:00
parent b0e1d0d9ee
commit 4a745b4177
1 changed files with 8 additions and 1 deletions
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9
libavcodec/pnmdec.c
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@ -33,7 +33,7 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
PNMContext * const s = avctx->priv_data;
AVFrame *picture = data;
AVFrame * const p = (AVFrame*)&s->picture;
int i, j, n, linesize, h, upgrade = 0;
int i, j, n, linesize, h, upgrade = 0, is_mono = 0;
unsigned char *ptr;
int components, sample_len;
@ -88,6 +88,7 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
n = (avctx->width + 7) >> 3;
components=1;
sample_len=1;
is_mono = 1;
do_read:
ptr = p->data[0];
linesize = p->linesize[0];
@ -104,10 +105,16 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
s->bytestream++;
if(s->bytestream >= s->bytestream_end)
return -1;
if (is_mono) {
/* read a single digit */
v = (*s->bytestream++) - '0';
} else {
/* read a sequence of digits */
do{
v= 10*v + c;
c= (*s->bytestream++) - '0';
}while(c <= 9);
}
put_bits(&pb, sample_len, (((1<<sample_len)-1)*v + (s->maxval>>1))/s->maxval);
}
flush_put_bits(&pb);