[FFmpeg-cvslog] Revert "Avoid overflows when reading pgm files with maxval != 255 and != 65535."
Carl Eugen Hoyos
git at videolan.org
Mon Jul 29 00:07:28 CEST 2013
ffmpeg | branch: master | Carl Eugen Hoyos <cehoyos at ag.or.at> | Mon Jul 29 00:05:43 2013 +0200| [2c046c718aefbc9f8223e22f85bb119da4fea04d] | committer: Carl Eugen Hoyos
Revert "Avoid overflows when reading pgm files with maxval != 255 and != 65535."
The patch worked on little endian because pgm decoding was broken
but it was not correct in any way.
This reverts commit 7651c0e49b1f6e66120ef32570a87e3f09224574.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=2c046c718aefbc9f8223e22f85bb119da4fea04d
---
libavcodec/pnmdec.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/libavcodec/pnmdec.c b/libavcodec/pnmdec.c
index 96ed83e..d0c7295 100644
--- a/libavcodec/pnmdec.c
+++ b/libavcodec/pnmdec.c
@@ -35,7 +35,6 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
int i, j, n, linesize, h, upgrade = 0, is_mono = 0;
unsigned char *ptr;
int components, sample_len, ret;
- unsigned int maskval = 0;
s->bytestream_start =
s->bytestream = (uint8_t *)buf;
@@ -76,10 +75,8 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
n = avctx->width;
components=1;
sample_len=8;
- if (s->maxval < 255) {
+ if (s->maxval < 255)
upgrade = 1;
- maskval = (2 << av_log2(s->maxval)) - 1;
- }
goto do_read;
case AV_PIX_FMT_GRAY8A:
n = avctx->width * 2;
@@ -91,10 +88,8 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
n = avctx->width * 2;
components=1;
sample_len=16;
- if (s->maxval < 65535) {
+ if (s->maxval < 65535)
upgrade = 2;
- maskval = (2 << av_log2(s->maxval)) - 1;
- }
goto do_read;
case AV_PIX_FMT_MONOWHITE:
case AV_PIX_FMT_MONOBLACK:
@@ -141,11 +136,11 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
else if (upgrade == 1) {
unsigned int j, f = (255 * 128 + s->maxval / 2) / s->maxval;
for (j = 0; j < n; j++)
- ptr[j] = ((s->bytestream[j] & maskval) * f + 64) >> 7;
+ ptr[j] = (s->bytestream[j] * f + 64) >> 7;
} else if (upgrade == 2) {
unsigned int j, v, f = (65535 * 32768 + s->maxval / 2) / s->maxval;
for (j = 0; j < n / 2; j++) {
- v = av_be2ne16(((uint16_t *)s->bytestream)[j]) & maskval;
+ v = av_be2ne16(((uint16_t *)s->bytestream)[j]);
((uint16_t *)ptr)[j] = (v * f + 16384) >> 15;
}
}
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