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avcodec/pnm_parser: Remember the length already scanned for ascii images

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Fixes: speed regression with xmap_samsung_gear_2560x1280.pgm
Found-by: Michael Koch
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-04-27 14:08:07 +02:00
parent 9fc1031ac2
commit 8019395889
1 changed files with 14 additions and 1 deletions
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15
libavcodec/pnm_parser.c
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@ -19,6 +19,7 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/ */
#include "libavutil/avassert.h"
#include "libavutil/imgutils.h" #include "libavutil/imgutils.h"
#include "parser.h" //for ParseContext #include "parser.h" //for ParseContext
@ -27,6 +28,7 @@
typedef struct PNMParseContext { typedef struct PNMParseContext {
ParseContext pc; ParseContext pc;
int remaining_bytes; int remaining_bytes;
int ascii_scan;
}PNMParseContext; }PNMParseContext;
static int pnm_parse(AVCodecParserContext *s, AVCodecContext *avctx, static int pnm_parse(AVCodecParserContext *s, AVCodecContext *avctx,
@ -77,17 +79,28 @@ retry:
} else if (pnmctx.type < 4) { } else if (pnmctx.type < 4) {
uint8_t *bs = pnmctx.bytestream; uint8_t *bs = pnmctx.bytestream;
const uint8_t *end = pnmctx.bytestream_end; const uint8_t *end = pnmctx.bytestream_end;
uint8_t *sync = bs;
if (pc->index) {
av_assert0(pnmpc->ascii_scan <= end - bs);
bs += pnmpc->ascii_scan;
}
while (bs < end) { while (bs < end) {
int c = *bs++; int c;
sync = bs;
c = *bs++;
if (c == '#') { if (c == '#') {
while (c != '\n' && bs < end) while (c != '\n' && bs < end)
c = *bs++; c = *bs++;
} else if (c == 'P') { } else if (c == 'P') {
next = bs - pnmctx.bytestream_start + skip - 1; next = bs - pnmctx.bytestream_start + skip - 1;
pnmpc->ascii_scan = 0;
break; break;
} }
} }
if (next == END_NOT_FOUND)
pnmpc->ascii_scan = sync - pnmctx.bytestream + skip;
} else { } else {
next = pnmctx.bytestream - pnmctx.bytestream_start + skip next = pnmctx.bytestream - pnmctx.bytestream_start + skip
+ av_image_get_buffer_size(avctx->pix_fmt, avctx->width, avctx->height, 1); + av_image_get_buffer_size(avctx->pix_fmt, avctx->width, avctx->height, 1);