[FFmpeg-devel] [PATCH 4/8] avformat/oggparsevorbis: Factor parsing a single VorbisComment out

[Andreas Rheinhardt]

Andreas Rheinhardt:
> This is in preparation for further commits.
> 
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> ---
>  libavformat/oggparsevorbis.c | 142 ++++++++++++++++++-----------------
>  1 file changed, 75 insertions(+), 67 deletions(-)
> 
> diff --git a/libavformat/oggparsevorbis.c b/libavformat/oggparsevorbis.c
> index c48658ceda..69c15c3dce 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)
> 
Will apply the rest of this patchset tomorrow unless there are objections.

- Andreas