PeerStreamer

/*

 * ID3v2 header parser

 * Copyright (c) 2003 Fabrice Bellard

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "id3v2.h"

#include "id3v1.h"

#include "libavutil/avstring.h"

int ff_id3v2_match(const uint8_t *buf)

{

    return  buf[0] == 'I' &&

            buf[1] == 'D' &&

            buf[2] == '3' &&

            buf[3] != 0xff &&

            buf[4] != 0xff &&

            (buf[6] & 0x80) == 0 &&

            (buf[7] & 0x80) == 0 &&

            (buf[8] & 0x80) == 0 &&

            (buf[9] & 0x80) == 0;

}

int ff_id3v2_tag_len(const uint8_t * buf)

{

    int len = ((buf[6] & 0x7f) << 21) +

        ((buf[7] & 0x7f) << 14) +

        ((buf[8] & 0x7f) << 7) +

        (buf[9] & 0x7f) +

        ID3v2_HEADER_SIZE;

    if (buf[5] & 0x10)

        len += ID3v2_HEADER_SIZE;

    return len;

}

static unsigned int get_size(ByteIOContext *s, int len)

{

    int v=0;

    while(len--)

        v= (v<<7) + (get_byte(s)&0x7F);

    return v;

}

static void read_ttag(AVFormatContext *s, int taglen, const char *key)

{

    char *q, dst[512];

    int len, dstlen = sizeof(dst) - 1;

    unsigned genre;

    dst[0]= 0;

    if(taglen < 1)

        return;

    taglen--; /* account for encoding type byte */

    switch(get_byte(s->pb)) { /* encoding type */

    case 0:  /* ISO-8859-1 (0 - 255 maps directly into unicode) */

        q = dst;

        while(taglen--) {

            uint8_t tmp;

            PUT_UTF8(get_byte(s->pb), tmp, if (q - dst < dstlen - 1) *q++ = tmp;)

        }

        *q = '\0';

        break;

    case 3:  /* UTF-8 */

        len = FFMIN(taglen, dstlen-1);

        get_buffer(s->pb, dst, len);

        dst[len] = 0;

        break;

    }

    if (!strcmp(key, "genre")

        && (sscanf(dst, "(%d)", &genre) == 1 || sscanf(dst, "%d", &genre) == 1)

        && genre <= ID3v1_GENRE_MAX)

        av_strlcpy(dst, ff_id3v1_genre_str[genre], sizeof(dst));

    if (*dst)

        av_metadata_set(&s->metadata, key, dst);

}

void ff_id3v2_parse(AVFormatContext *s, int len, uint8_t version, uint8_t flags)

{

    int isv34, tlen;

    uint32_t tag;

    int64_t next;

    int taghdrlen;

    const char *reason;

    switch(version) {

    case 2:

        if(flags & 0x40) {

            reason = "compression";

            goto error;

        }

        isv34 = 0;

        taghdrlen = 6;

        break;

    case 3:

    case 4:

        isv34 = 1;

        taghdrlen = 10;

        break;

    default:

        reason = "version";

        goto error;

    }

    if(flags & 0x80) {

        reason = "unsynchronization";

        goto error;

    }

    if(isv34 && flags & 0x40) /* Extended header present, just skip over it */

        url_fskip(s->pb, get_size(s->pb, 4));

    while(len >= taghdrlen) {

        if(isv34) {

            tag  = get_be32(s->pb);

            tlen = get_size(s->pb, 4);

            get_be16(s->pb); /* flags */

        } else {

            tag  = get_be24(s->pb);

            tlen = get_size(s->pb, 3);

        }

        len -= taghdrlen + tlen;

        if(len < 0)

            break;

        next = url_ftell(s->pb) + tlen;

        switch(tag) {

        case MKBETAG('T', 'I', 'T', '2'):

        case MKBETAG(0,   'T', 'T', '2'):

            read_ttag(s, tlen, "title");

            break;

        case MKBETAG('T', 'P', 'E', '1'):

        case MKBETAG(0,   'T', 'P', '1'):

            read_ttag(s, tlen, "author");

            break;

        case MKBETAG('T', 'A', 'L', 'B'):

        case MKBETAG(0,   'T', 'A', 'L'):

            read_ttag(s, tlen, "album");

            break;

        case MKBETAG('T', 'C', 'O', 'N'):

        case MKBETAG(0,   'T', 'C', 'O'):

            read_ttag(s, tlen, "genre");

            break;

        case MKBETAG('T', 'C', 'O', 'P'):

        case MKBETAG(0,   'T', 'C', 'R'):

            read_ttag(s, tlen, "copyright");

            break;

        case MKBETAG('T', 'R', 'C', 'K'):

        case MKBETAG(0,   'T', 'R', 'K'):

            read_ttag(s, tlen, "track");

            break;

        case 0:

            /* padding, skip to end */

            url_fskip(s->pb, len);

            len = 0;

            continue;

        }

        /* Skip to end of tag */

        url_fseek(s->pb, next, SEEK_SET);

    }

    if(version == 4 && flags & 0x10) /* Footer preset, always 10 bytes, skip over it */

        url_fskip(s->pb, 10);

    return;

  error:

    av_log(s, AV_LOG_INFO, "ID3v2.%d tag skipped, cannot handle %s\n", version, reason);

    url_fskip(s->pb, len);

}