X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fpnm_parser.c;h=f8eb2e7edab2dc4146c2a2be04b36ff7d79aac9b;hb=e625ae609206e0550ff733965c6f5447579320aa;hp=9bf1fdcece4873a23d48fa0fc6ce0c998b06f560;hpb=f05f210526a3dc2d9fa6b1c228e3907ebd1d43c6;p=ffmpeg

diff --git a/libavcodec/pnm_parser.c b/libavcodec/pnm_parser.c
index 9bf1fdcece4..f8eb2e7edab 100644
--- a/libavcodec/pnm_parser.c
+++ b/libavcodec/pnm_parser.c
@@ -19,24 +19,45 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include "libavutil/avassert.h"
 #include "libavutil/imgutils.h"
 
 #include "parser.h" //for ParseContext
 #include "pnm.h"
 
+typedef struct PNMParseContext {
+    ParseContext pc;
+    int remaining_bytes;
+    int ascii_scan;
+}PNMParseContext;
 
 static int pnm_parse(AVCodecParserContext *s, AVCodecContext *avctx,
                      const uint8_t **poutbuf, int *poutbuf_size,
                      const uint8_t *buf, int buf_size)
 {
-    ParseContext *pc = s->priv_data;
+    PNMParseContext *pnmpc = s->priv_data;
+    ParseContext *pc = &pnmpc->pc;
     PNMContext pnmctx;
-    int next;
+    int next = END_NOT_FOUND;
     int skip = 0;
 
-    for (; pc->overread > 0; pc->overread--) {
-        pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
+    if (pc->overread > 0) {
+        memmove(pc->buffer + pc->index, pc->buffer + pc->overread_index, pc->overread);
+        pc->index          += pc->overread;
+        pc->overread_index += pc->overread;
+        pc->overread = 0;
     }
+
+    if (pnmpc->remaining_bytes) {
+        int inc = FFMIN(pnmpc->remaining_bytes, buf_size);
+        skip += inc;
+        pnmpc->remaining_bytes -= inc;
+
+        if (!pnmpc->remaining_bytes)
+            next = skip;
+        goto end;
+    }
+
 retry:
     if (pc->index) {
         pnmctx.bytestream_start =
@@ -51,6 +72,7 @@ retry:
         if (pnmctx.bytestream < pnmctx.bytestream_end) {
             if (pc->index) {
                 pc->index = 0;
+                pnmpc->ascii_scan = 0;
             } else {
                 unsigned step = FFMAX(1, pnmctx.bytestream - pnmctx.bytestream_start);
 
@@ -58,18 +80,47 @@ retry:
             }
             goto retry;
         }
-        next = END_NOT_FOUND;
     } else if (pnmctx.type < 4) {
-        next = END_NOT_FOUND;
+              uint8_t *bs  = pnmctx.bytestream;
+        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) {
+            int c;
+            sync = bs;
+            c = *bs++;
+            if (c == '#')  {
+                uint8_t *match = memchr(bs, '\n', end-bs);
+                if (match)
+                    bs = match + 1;
+                else
+                    break;
+            } else if (c == 'P') {
+                next = bs - pnmctx.bytestream_start + skip - 1;
+                pnmpc->ascii_scan = 0;
+                break;
+            }
+        }
+        if (next == END_NOT_FOUND)
+            pnmpc->ascii_scan = sync - pnmctx.bytestream + skip;
     } else {
-        next = pnmctx.bytestream - pnmctx.bytestream_start + skip
-               + av_image_get_buffer_size(avctx->pix_fmt, avctx->width, avctx->height, 1);
-        if (pnmctx.bytestream_start != buf + skip)
-            next -= pc->index;
-        if (next > buf_size)
-            next = END_NOT_FOUND;
+        int ret = av_image_get_buffer_size(avctx->pix_fmt, avctx->width, avctx->height, 1);
+        next = pnmctx.bytestream - pnmctx.bytestream_start + skip;
+        if (ret >= 0 && next + (uint64_t)ret <= INT_MAX)
+            next += ret;
     }
-
+    if (next != END_NOT_FOUND && pnmctx.bytestream_start != buf + skip)
+        next -= pc->index;
+    if (next > buf_size) {
+        pnmpc->remaining_bytes = next - buf_size;
+        next = END_NOT_FOUND;
+    }
+end:
     if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
         *poutbuf      = NULL;
         *poutbuf_size = 0;
@@ -80,10 +131,10 @@ retry:
     return next;
 }
 
-AVCodecParser ff_pnm_parser = {
+const AVCodecParser ff_pnm_parser = {
     .codec_ids      = { AV_CODEC_ID_PGM, AV_CODEC_ID_PGMYUV, AV_CODEC_ID_PPM,
                         AV_CODEC_ID_PBM, AV_CODEC_ID_PAM },
-    .priv_data_size = sizeof(ParseContext),
+    .priv_data_size = sizeof(PNMParseContext),
     .parser_parse   = pnm_parse,
     .parser_close   = ff_parse_close,
 };