[FFmpeg-devel] [PATCH v1] avcodec/sbc_parser: Fix parser error when reading data slowly.

[javashu2012@gmail.com]

From: bevis <javashu2012@gmail.com>

When reading data is slow, such as 10 bytes at a time, the header bytes will be overwritten by the body data, resulting in an error in parsing the header.

Signed-off-by: bevis <javashu2012@gmail.com>
---
 libavcodec/sbc_parser.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/libavcodec/sbc_parser.c b/libavcodec/sbc_parser.c
index 2d427cc7cb..bf471cf878 100644
--- a/libavcodec/sbc_parser.c
+++ b/libavcodec/sbc_parser.c
@@ -81,26 +81,40 @@ static int sbc_parse(AVCodecParserContext *s, AVCodecContext *avctx,
 {
     SBCParseContext *pc = s->priv_data;
     int next;
+    int expected_header_size = sizeof(pc->header);
 
     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
         next = buf_size;
     } else {
-        if (pc->header_size) {
-            memcpy(pc->header + pc->header_size, buf,
-                   sizeof(pc->header) - pc->header_size);
-            next = sbc_parse_header(s, avctx, pc->header, sizeof(pc->header))
-                 - pc->buffered_size;
-            pc->header_size = 0;
-        } else {
+        if (!pc->header_size) {
             next = sbc_parse_header(s, avctx, buf, buf_size);
             if (next >= buf_size)
                 next = -1;
+        } else if (pc->header_size + buf_size >= expected_header_size) {
+            if (pc->header_size < expected_header_size) {
+                memcpy(pc->header + pc->header_size, buf,
+                       expected_header_size - pc->header_size);
+                pc->header_size = expected_header_size;
+            }
+            next = sbc_parse_header(s, avctx, pc->header, expected_header_size)
+                 - pc->buffered_size;
+            if (next >= buf_size) {
+                next = -1;
+            } else {
+                pc->header_size = 0;
+                pc->buffered_size = 0;
+            }
+        } else {
+            next = -1;
         }
 
         if (next < 0) {
-            pc->header_size = FFMIN(sizeof(pc->header), buf_size);
-            memcpy(pc->header, buf, pc->header_size);
-            pc->buffered_size = buf_size;
+            if (pc->header_size < expected_header_size) {
+                memcpy(pc->header + pc->header_size, buf,
+                       FFMIN(buf_size, expected_header_size - pc->header_size));
+                pc->header_size = FFMIN(expected_header_size, pc->header_size + buf_size);
+            }
+            pc->buffered_size += buf_size;
             next = END_NOT_FOUND;
         }
 
-- 
2.30.0

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