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;

}

void ff_id3v2_read(AVFormatContext *s)

{

    int len, ret;

    uint8_t buf[ID3v2_HEADER_SIZE];

    ret = get_buffer(s->pb, buf, ID3v2_HEADER_SIZE);

    if (ret != ID3v2_HEADER_SIZE)

        return;

    if (ff_id3v2_match(buf)) {

        /* parse ID3v2 header */

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

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

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

            (buf[9] & 0x7f);

        ff_id3v2_parse(s, len, buf[3], buf[5]);

    } else {

        url_fseek(s->pb, 0, SEEK_SET);

    }

}

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;

    unsigned int (*get)(ByteIOContext*) = get_be16;

    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-- && q - dst < dstlen - 7) {

            uint8_t tmp;

            PUT_UTF8(get_byte(s->pb), tmp, *q++ = tmp;)

        }

        *q = 0;

        break;

    case 1:  /* UTF-16 with BOM */

        taglen -= 2;

        switch (get_be16(s->pb)) {

        case 0xfffe:

            get = get_le16;

        case 0xfeff:

            break;

        default:

            av_log(s, AV_LOG_ERROR, "Incorrect BOM value in tag %s.\n", key);

            return;

        }

        // fall-through

    case 2:  /* UTF-16BE without BOM */

        q = dst;

        while (taglen > 1 && q - dst < dstlen - 7) {

            uint32_t ch;

            uint8_t tmp;

            GET_UTF16(ch, ((taglen -= 2) >= 0 ? get(s->pb) : 0), break;)

            PUT_UTF8(ch, tmp, *q++ = tmp;)

        }

        *q = 0;

        break;

    case 3:  /* UTF-8 */

        len = FFMIN(taglen, dstlen - 1);

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

        dst[len] = 0;

        break;

    default:

        av_log(s, AV_LOG_WARNING, "Unknown encoding in tag %s\n.", key);

    }

    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);

            if(version==3){

                tlen = get_be32(s->pb);

            }else

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

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

        } else {

            tag  = get_be24(s->pb);

            tlen = get_be24(s->pb);

        }

        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);

}