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yop: simplify/sanitize the decoding loop 

Do not overwrite linesize set by get_buffer().

The last frame in the FATE test is not decoded anymore, since the file
is cut and a part of it is missing.
This commit is contained in:
Anton Khirnov 2012-11-15 22:03:00 +01:00
parent f6e395e132
commit c6303f8d70
2 changed files with 21 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
libavcodec/yop.c
View File

@ -36,7 +36,6 @@ typedef struct YopDecContext {
int num_pal_colors;
int first_color[2];
int frame_data_length;
int row_pos;
uint8_t *low_nibble;
uint8_t *srcptr;
@ -173,27 +172,12 @@ static uint8_t yop_get_next_nibble(YopDecContext *s)
return ret;
}
/**
* Take s->dstptr to the next macroblock in sequence.
*/
static void yop_next_macroblock(YopDecContext *s)
{
// If we are advancing to the next row of macroblocks
if (s->row_pos == s->frame.linesize[0] - 2) {
s->dstptr += s->frame.linesize[0];
s->row_pos = 0;
}else {
s->row_pos += 2;
}
s->dstptr += 2;
}
static int yop_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
AVPacket *avpkt)
{
YopDecContext *s = avctx->priv_data;
int tag, firstcolor, is_odd_frame;
int ret, i;
int ret, i, x, y;
uint32_t *palette;
if (s->frame.data[0])
@ -205,12 +189,9 @@ static int yop_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
return ret;
}
s->frame.linesize[0] = avctx->width;
s->dstbuf = s->frame.data[0];
s->dstptr = s->frame.data[0];
s->srcptr = avpkt->data + 4;
s->row_pos = 0;
s->low_nibble = NULL;
is_odd_frame = avpkt->data[0];
@ -224,23 +205,28 @@ static int yop_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
s->frame.palette_has_changed = 1;
while (s->dstptr - s->dstbuf <
avctx->width * avctx->height &&
s->srcptr - avpkt->data < avpkt->size) {
tag = yop_get_next_nibble(s);
if (tag != 0xf) {
yop_paint_block(s, tag);
}else {
tag = yop_get_next_nibble(s);
ret = yop_copy_previous_block(s, tag);
if (ret < 0) {
avctx->release_buffer(avctx, &s->frame);
return ret;
for (y = 0; y < avctx->height; y += 2) {
for (x = 0; x < avctx->width; x += 2) {
if (s->srcptr - avpkt->data >= avpkt->size) {
av_log(avctx, AV_LOG_ERROR, "Packet too small.\n");
return AVERROR_INVALIDDATA;
}
tag = yop_get_next_nibble(s);
if (tag != 0xf) {
yop_paint_block(s, tag);
} else {
tag = yop_get_next_nibble(s);
ret = yop_copy_previous_block(s, tag);
if (ret < 0) {
avctx->release_buffer(avctx, &s->frame);
return ret;
}
}
s->dstptr += 2;
}
yop_next_macroblock(s);
s->dstptr += 2*s->frame.linesize[0] - x;
}
*got_frame = 1;

1
tests/ref/fate/yop
View File

@ -5,4 +5,3 @@
0, 3, 3, 1, 302760, 0xc34b20bd
0, 4, 4, 1, 302760, 0x461d29a1
0, 5, 5, 1, 302760, 0x45abca02
0, 6, 6, 1, 302760, 0xb05448b9