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avcodec/pngdec: create a function to decode PLTE chunk.

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Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Benoit Fouet 2014-11-14 10:17:34 +01:00 committed by Michael Niedermayer
parent b35fa04152
commit 4f313a50ee
1 changed files with 24 additions and 17 deletions
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41
libavcodec/pngdec.c
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@ -671,6 +671,29 @@ static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s,
return 0;
}
static int decode_plte_chunk(AVCodecContext *avctx, PNGDecContext *s,
uint32_t length)
{
int n, i, r, g, b;
if ((length % 3) != 0 || length > 256 * 3)
return AVERROR_INVALIDDATA;
/* read the palette */
n = length / 3;
for (i = 0; i < n; i++) {
r = bytestream2_get_byte(&s->gb);
g = bytestream2_get_byte(&s->gb);
b = bytestream2_get_byte(&s->gb);
s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
}
for (; i < 256; i++)
s->palette[i] = (0xFFU << 24);
s->state |= PNG_PLTE;
bytestream2_skip(&s->gb, 4); /* crc */
return 0;
}
static int decode_frame_png(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
@ -744,24 +767,8 @@ static int decode_frame_png(AVCodecContext *avctx,
goto fail;
break;
case MKTAG('P', 'L', 'T', 'E'):
{
int n, i, r, g, b;
if ((length % 3) != 0 || length > 256 * 3)
if (decode_plte_chunk(avctx, s, length) < 0)
goto skip_tag;
/* read the palette */
n = length / 3;
for (i = 0; i < n; i++) {
r = bytestream2_get_byte(&s->gb);
g = bytestream2_get_byte(&s->gb);
b = bytestream2_get_byte(&s->gb);
s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
}
for (; i < 256; i++)
s->palette[i] = (0xFFU << 24);
s->state |= PNG_PLTE;
bytestream2_skip(&s->gb, 4); /* crc */
}
break;
case MKTAG('t', 'R', 'N', 'S'):
{