PeerStreamer

/*

 * ID3v2 header parser

 * Copyright (c) 2003 Fabrice Bellard

 *

 * This file is part of Libav.

 *

 * Libav 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.

 *

 * Libav 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 Libav; 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"

#include "libavutil/intreadwrite.h"

#include "metadata.h"

#include "avio_internal.h"

int ff_id3v2_match(const uint8_t *buf, const char * magic)

{

    return  buf[0]         == magic[0] &&

            buf[1]         == magic[1] &&

            buf[2]         == magic[2] &&

            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(AVIOContext *s, int len)

{

    int v = 0;

    while (len--)

        v = (v << 7) + (avio_r8(s) & 0x7F);

    return v;

}

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

{

    char *q, dst[512];

    const char *val = NULL;

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

    unsigned genre;

    unsigned int (*get)(AVIOContext*) = avio_rb16;

    dst[0] = 0;

    if (taglen < 1)

        return;

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

    switch (avio_r8(pb)) { /* encoding type */

    case ID3v2_ENCODING_ISO8859:

        q = dst;

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

            uint8_t tmp;

            PUT_UTF8(avio_r8(pb), tmp, *q++ = tmp;)

        }

        *q = 0;

        break;

    case ID3v2_ENCODING_UTF16BOM:

        taglen -= 2;

        switch (avio_rb16(pb)) {

        case 0xfffe:

            get = avio_rl16;

        case 0xfeff:

            break;

        default:

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

            return;

        }

        // fall-through

    case ID3v2_ENCODING_UTF16BE:

        q = dst;

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

            uint32_t ch;

            uint8_t tmp;

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

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

        }

        *q = 0;

        break;

    case ID3v2_ENCODING_UTF8:

        len = FFMIN(taglen, dstlen);

        avio_read(pb, dst, len);

        dst[len] = 0;

        break;

    default:

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

    }

    if (!(strcmp(key, "TCON") && strcmp(key, "TCO"))

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

        && genre <= ID3v1_GENRE_MAX)

        val = ff_id3v1_genre_str[genre];

    else if (!(strcmp(key, "TXXX") && strcmp(key, "TXX"))) {

        /* dst now contains two 0-terminated strings */

        dst[dstlen] = 0;

        len = strlen(dst);

        key = dst;

        val = dst + FFMIN(len + 1, dstlen);

    }

    else if (*dst)

        val = dst;

    if (val)

        av_metadata_set2(&s->metadata, key, val, AV_METADATA_DONT_OVERWRITE);

}

static int is_number(const char *str)

{

    while (*str >= '0' && *str <= '9') str++;

    return !*str;

}

static AVMetadataTag* get_date_tag(AVMetadata *m, const char *tag)

{

    AVMetadataTag *t;

    if ((t = av_metadata_get(m, tag, NULL, AV_METADATA_MATCH_CASE)) &&

        strlen(t->value) == 4 && is_number(t->value))

        return t;

    return NULL;

}

static void merge_date(AVMetadata **m)

{

    AVMetadataTag *t;

    char date[17] = {0};      // YYYY-MM-DD hh:mm

    if (!(t = get_date_tag(*m, "TYER")) &&

        !(t = get_date_tag(*m, "TYE")))

        return;

    av_strlcpy(date, t->value, 5);

    av_metadata_set2(m, "TYER", NULL, 0);

    av_metadata_set2(m, "TYE",  NULL, 0);

    if (!(t = get_date_tag(*m, "TDAT")) &&

        !(t = get_date_tag(*m, "TDA")))

        goto finish;

    snprintf(date + 4, sizeof(date) - 4, "-%.2s-%.2s", t->value + 2, t->value);

    av_metadata_set2(m, "TDAT", NULL, 0);

    av_metadata_set2(m, "TDA",  NULL, 0);

    if (!(t = get_date_tag(*m, "TIME")) &&

        !(t = get_date_tag(*m, "TIM")))

        goto finish;

    snprintf(date + 10, sizeof(date) - 10, " %.2s:%.2s", t->value, t->value + 2);

    av_metadata_set2(m, "TIME", NULL, 0);

    av_metadata_set2(m, "TIM",  NULL, 0);

finish:

    if (date[0])

        av_metadata_set2(m, "date", date, 0);

}

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

{

    int isv34, tlen, unsync;

    char tag[5];

    int64_t next, end = avio_tell(s->pb) + len;

    int taghdrlen;

    const char *reason = NULL;

    AVIOContext pb;

    unsigned char *buffer = NULL;

    int buffer_size = 0;

    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;

    }

    unsync = flags & 0x80;

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

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

    while (len >= taghdrlen) {

        unsigned int tflags;

        int tunsync = 0;

        if (isv34) {

            avio_read(s->pb, tag, 4);

            tag[4] = 0;

            if(version==3){

                tlen = avio_rb32(s->pb);

            }else

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

            tflags = avio_rb16(s->pb);

            tunsync = tflags & ID3v2_FLAG_UNSYNCH;

        } else {

            avio_read(s->pb, tag, 3);

            tag[3] = 0;

            tlen = avio_rb24(s->pb);

        }

        if (tlen < 0 || tlen > len - taghdrlen) {

            av_log(s, AV_LOG_WARNING, "Invalid size in frame %s, skipping the rest of tag.\n", tag);

            break;

        }

        len -= taghdrlen + tlen;

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

        if (tflags & ID3v2_FLAG_DATALEN) {

            avio_rb32(s->pb);

            tlen -= 4;

        }

        if (tflags & (ID3v2_FLAG_ENCRYPTION | ID3v2_FLAG_COMPRESSION)) {

            av_log(s, AV_LOG_WARNING, "Skipping encrypted/compressed ID3v2 frame %s.\n", tag);

            avio_skip(s->pb, tlen);

        } else if (tag[0] == 'T') {

            if (unsync || tunsync) {

                int i, j;

                av_fast_malloc(&buffer, &buffer_size, tlen);

                for (i = 0, j = 0; i < tlen; i++, j++) {

                    buffer[j] = avio_r8(s->pb);

                    if (j > 0 && !buffer[j] && buffer[j - 1] == 0xff) {

                        /* Unsynchronised byte, skip it */

                        j--;

                    }

                }

                ffio_init_context(&pb, buffer, j, 0, NULL, NULL, NULL, NULL);

                read_ttag(s, &pb, j, tag);

            } else {

                read_ttag(s, s->pb, tlen, tag);

            }

        }

        else if (!tag[0]) {

            if (tag[1])

                av_log(s, AV_LOG_WARNING, "invalid frame id, assuming padding");

            avio_skip(s->pb, tlen);

            break;

        }

        /* Skip to end of tag */

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

    }

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

        end += 10;

  error:

    if (reason)

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

    avio_seek(s->pb, end, SEEK_SET);

    av_free(buffer);

    return;

}

void ff_id3v2_read(AVFormatContext *s, const char *magic)

{

    int len, ret;

    uint8_t buf[ID3v2_HEADER_SIZE];

    int     found_header;

    int64_t off;

    do {

        /* save the current offset in case there's nothing to read/skip */

        off = avio_tell(s->pb);

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

        if (ret != ID3v2_HEADER_SIZE)

            break;

            found_header = ff_id3v2_match(buf, magic);

            if (found_header) {

            /* 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 {

            avio_seek(s->pb, off, SEEK_SET);

        }

    } while (found_header);

    ff_metadata_conv(&s->metadata, NULL, ff_id3v2_34_metadata_conv);

    ff_metadata_conv(&s->metadata, NULL, ff_id3v2_2_metadata_conv);

    ff_metadata_conv(&s->metadata, NULL, ff_id3v2_4_metadata_conv);

    merge_date(&s->metadata);

}

const AVMetadataConv ff_id3v2_34_metadata_conv[] = {

    { "TALB", "album"},

    { "TCOM", "composer"},

    { "TCON", "genre"},

    { "TCOP", "copyright"},

    { "TENC", "encoded_by"},

    { "TIT2", "title"},

    { "TLAN", "language"},

    { "TPE1", "artist"},

    { "TPE2", "album_artist"},

    { "TPE3", "performer"},

    { "TPOS", "disc"},

    { "TPUB", "publisher"},

    { "TRCK", "track"},

    { "TSSE", "encoder"},

    { 0 }

};

const AVMetadataConv ff_id3v2_4_metadata_conv[] = {

    { "TDRL", "date"},

    { "TDRC", "date"},

    { "TDEN", "creation_time"},

    { "TSOA", "album-sort"},

    { "TSOP", "artist-sort"},

    { "TSOT", "title-sort"},

    { 0 }

};

const AVMetadataConv ff_id3v2_2_metadata_conv[] = {

    { "TAL",  "album"},

    { "TCO",  "genre"},

    { "TT2",  "title"},

    { "TEN",  "encoded_by"},

    { "TP1",  "artist"},

    { "TP2",  "album_artist"},

    { "TP3",  "performer"},

    { "TRK",  "track"},

    { 0 }

};

const char ff_id3v2_tags[][4] = {

   "TALB", "TBPM", "TCOM", "TCON", "TCOP", "TDLY", "TENC", "TEXT",

   "TFLT", "TIT1", "TIT2", "TIT3", "TKEY", "TLAN", "TLEN", "TMED",

   "TOAL", "TOFN", "TOLY", "TOPE", "TOWN", "TPE1", "TPE2", "TPE3",

   "TPE4", "TPOS", "TPUB", "TRCK", "TRSN", "TRSO", "TSRC", "TSSE",

   { 0 },

};

const char ff_id3v2_4_tags[][4] = {

   "TDEN", "TDOR", "TDRC", "TDRL", "TDTG", "TIPL", "TMCL", "TMOO",

   "TPRO", "TSOA", "TSOP", "TSOT", "TSST",

   { 0 },

};

const char ff_id3v2_3_tags[][4] = {

   "TDAT", "TIME", "TORY", "TRDA", "TSIZ", "TYER",

   { 0 },

};