[FFmpeg-cvslog] avformat/oggparsevorbis: Factor parsing a single VorbisComment out

[Andreas Rheinhardt]

ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at outlook.com> | Mon Aug 23 10:03:47 2021 +0200| [f1d89d6dd0aa825d48e9be13837d77e8c1964fe8] | committer: Andreas Rheinhardt

avformat/oggparsevorbis: Factor parsing a single VorbisComment out

This is in preparation for further commits.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f1d89d6dd0aa825d48e9be13837d77e8c1964fe8
---

 libavformat/oggparsevorbis.c | 142 +++++++++++++++++++++++--------------------
 1 file changed, 75 insertions(+), 67 deletions(-)

diff --git a/libavformat/oggparsevorbis.c b/libavformat/oggparsevorbis.c
index c48658ceda..103a8784ab 100644
--- a/libavformat/oggparsevorbis.c
+++ b/libavformat/oggparsevorbis.c
@@ -84,6 +84,77 @@ int ff_vorbis_stream_comment(AVFormatContext *as, AVStream *st,
     return updates;
 }
 
+static int vorbis_parse_single_comment(AVFormatContext *as, AVDictionary **m,
+                                       const uint8_t *buf, uint32_t size,
+                                       int *updates, int parse_picture)
+{
+    const char *t = buf, *v = memchr(t, '=', size);
+    char *tt, *ct;
+    int tl, vl;
+
+    if (!v)
+        return 0;
+
+    tl = v - t;
+    vl = size - tl - 1;
+    v++;
+
+    if (!tl || !vl)
+        return 0;
+
+    tt = av_malloc(tl + 1);
+    ct = av_malloc(vl + 1);
+    if (!tt || !ct) {
+        av_freep(&tt);
+        av_freep(&ct);
+        return AVERROR(ENOMEM);
+    }
+
+    memcpy(tt, t, tl);
+    tt[tl] = 0;
+
+    memcpy(ct, v, vl);
+    ct[vl] = 0;
+
+    /* The format in which the pictures are stored is the FLAC format.
+     * Xiph says: "The binary FLAC picture structure is base64 encoded
+     * and placed within a VorbisComment with the tag name
+     * 'METADATA_BLOCK_PICTURE'. This is the preferred and
+     * recommended way of embedding cover art within VorbisComments."
+     */
+    if (!av_strcasecmp(tt, "METADATA_BLOCK_PICTURE") && parse_picture) {
+        int ret, len = AV_BASE64_DECODE_SIZE(vl);
+        uint8_t *pict = av_malloc(len);
+
+        if (!pict) {
+            av_log(as, AV_LOG_WARNING, "out-of-memory error. Skipping cover art block.\n");
+            av_freep(&tt);
+            av_freep(&ct);
+            return 0;
+        }
+        ret = av_base64_decode(pict, ct, len);
+        av_freep(&tt);
+        av_freep(&ct);
+        if (ret > 0)
+            ret = ff_flac_parse_picture(as, pict, ret, 0);
+        av_freep(&pict);
+        if (ret < 0) {
+            av_log(as, AV_LOG_WARNING, "Failed to parse cover art block.\n");
+            return 0;
+        }
+    } else if (!ogm_chapter(as, tt, ct)) {
+        (*updates)++;
+        if (av_dict_get(*m, tt, NULL, 0)) {
+            av_dict_set(m, tt, ";", AV_DICT_APPEND);
+        }
+        av_dict_set(m, tt, ct,
+                    AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL |
+                    AV_DICT_APPEND);
+    }
+
+    return 0;
+}
+
 int ff_vorbis_comment(AVFormatContext *as, AVDictionary **m,
                       const uint8_t *buf, int size,
                       int parse_picture)
@@ -92,7 +163,7 @@ int ff_vorbis_comment(AVFormatContext *as, AVDictionary **m,
     const uint8_t *end = buf + size;
     int updates        = 0;
     unsigned n;
-    int s;
+    int s, ret;
 
     /* must have vendor_length and user_comment_list_length */
     if (size < 8)
@@ -108,79 +179,16 @@ int ff_vorbis_comment(AVFormatContext *as, AVDictionary **m,
     n = bytestream_get_le32(&p);
 
     while (end - p >= 4 && n > 0) {
-        const char *t, *v;
-        int tl, vl;
-
         s = bytestream_get_le32(&p);
 
         if (end - p < s || s < 0)
             break;
 
-        t  = p;
+        ret = vorbis_parse_single_comment(as, m, p, s, &updates, parse_picture);
+        if (ret < 0)
+            return ret;
         p += s;
         n--;
-
-        v = memchr(t, '=', s);
-        if (!v)
-            continue;
-
-        tl = v - t;
-        vl = s - tl - 1;
-        v++;
-
-        if (tl && vl) {
-            char *tt, *ct;
-
-            tt = av_malloc(tl + 1);
-            ct = av_malloc(vl + 1);
-            if (!tt || !ct) {
-                av_freep(&tt);
-                av_freep(&ct);
-                return AVERROR(ENOMEM);
-            }
-
-            memcpy(tt, t, tl);
-            tt[tl] = 0;
-
-            memcpy(ct, v, vl);
-            ct[vl] = 0;
-
-            /* The format in which the pictures are stored is the FLAC format.
-             * Xiph says: "The binary FLAC picture structure is base64 encoded
-             * and placed within a VorbisComment with the tag name
-             * 'METADATA_BLOCK_PICTURE'. This is the preferred and
-             * recommended way of embedding cover art within VorbisComments."
-             */
-            if (!av_strcasecmp(tt, "METADATA_BLOCK_PICTURE") && parse_picture) {
-                int ret, len = AV_BASE64_DECODE_SIZE(vl);
-                char *pict = av_malloc(len);
-
-                if (!pict) {
-                    av_log(as, AV_LOG_WARNING, "out-of-memory error. Skipping cover art block.\n");
-                    av_freep(&tt);
-                    av_freep(&ct);
-                    continue;
-                }
-                ret = av_base64_decode(pict, ct, len);
-                av_freep(&tt);
-                av_freep(&ct);
-                if (ret > 0)
-                    ret = ff_flac_parse_picture(as, pict, ret, 0);
-                av_freep(&pict);
-                if (ret < 0) {
-                    av_log(as, AV_LOG_WARNING, "Failed to parse cover art block.\n");
-                    continue;
-                }
-            } else if (!ogm_chapter(as, tt, ct)) {
-                updates++;
-                if (av_dict_get(*m, tt, NULL, 0)) {
-                    av_dict_set(m, tt, ";", AV_DICT_APPEND);
-                }
-                av_dict_set(m, tt, ct,
-                            AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL |
-                            AV_DICT_APPEND);
-            }
-        }
     }
 
     if (p != end)