Subversion Repositories Kolibri OS

/*

 * Multipart JPEG format

 * Copyright (c) 2015 Luca Barbato

 *

 * 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 "libavutil/avstring.h"

#include "avformat.h"

#include "internal.h"

static int get_line(AVIOContext *pb, char *line, int line_size)

{

    int i = ff_get_line(pb, line, line_size);

    if (i > 1 && line[i - 2] == '\r')

        line[i - 2] = '\0';

    if (pb->error)

        return pb->error;

    if (pb->eof_reached)

        return AVERROR_EOF;

    return 0;

}

static int split_tag_value(char **tag, char **value, char *line)

{

    char *p = line;

    while (*p != '\0' && *p != ':')

        p++;

    if (*p != ':')

        return AVERROR_INVALIDDATA;

    *p   = '\0';

    *tag = line;

    p++;

    while (av_isspace(*p))

        p++;

    *value = p;

    return 0;

}

static int check_content_type(char *line)

{

    char *tag, *value;

    int ret = split_tag_value(&tag, &value, line);

    if (ret < 0)

        return ret;

    if (av_strcasecmp(tag, "Content-type") ||

        av_strcasecmp(value, "image/jpeg"))

        return AVERROR_INVALIDDATA;

    return 0;

}

static int mpjpeg_read_probe(AVProbeData *p)

{

    AVIOContext *pb;

    char line[128] = { 0 };

    int ret = 0;

    if (p->buf_size < 2 || p->buf[0] != '-' || p->buf[1] != '-')

        return 0;

    pb = avio_alloc_context(p->buf, p->buf_size, 0, NULL, NULL, NULL, NULL);

    if (!pb)

        return AVERROR(ENOMEM);

    while (!pb->eof_reached) {

        ret = get_line(pb, line, sizeof(line));

        if (ret < 0)

            break;

        ret = check_content_type(line);

        if (!ret) {

            ret = AVPROBE_SCORE_MAX;

            break;

        }

    }

    av_free(pb);

    return ret;

}

static int mpjpeg_read_header(AVFormatContext *s)

{

    AVStream *st;

    char boundary[70 + 2 + 1];

    int64_t pos = avio_tell(s->pb);

    int ret;

    ret = get_line(s->pb, boundary, sizeof(boundary));

    if (ret < 0)

        return ret;

    if (strncmp(boundary, "--", 2))

        return AVERROR_INVALIDDATA;

    st = avformat_new_stream(s, NULL);

    if (!st)

        return AVERROR(ENOMEM);

    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

    st->codec->codec_id   = AV_CODEC_ID_MJPEG;

    avpriv_set_pts_info(st, 60, 1, 25);

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

    return 0;

}

static int parse_content_length(const char *value)

{

    long int val = strtol(value, NULL, 10);

    if (val == LONG_MIN || val == LONG_MAX)

        return AVERROR(errno);

    if (val > INT_MAX)

        return AVERROR(ERANGE);

    return val;

}

static int parse_multipart_header(AVFormatContext *s)

{

    char line[128];

    int found_content_type = 0;

    int ret, size = -1;

    ret = get_line(s->pb, line, sizeof(line));

    if (ret < 0)

        return ret;

    if (strncmp(line, "--", 2))

        return AVERROR_INVALIDDATA;

    while (!s->pb->eof_reached) {

        char *tag, *value;

        ret = get_line(s->pb, line, sizeof(line));

        if (ret < 0)

            return ret;

        if (line[0] == '\0')

            break;

        ret = split_tag_value(&tag, &value, line);

        if (ret < 0)

            return ret;

        if (!av_strcasecmp(tag, "Content-type")) {

            if (av_strcasecmp(value, "image/jpeg")) {

                av_log(s, AV_LOG_ERROR,

                       "Unexpected %s : %s\n",

                       tag, value);

                return AVERROR_INVALIDDATA;

            } else

                found_content_type = 1;

        } else if (!av_strcasecmp(tag, "Content-Length")) {

            size = parse_content_length(value);

            if (size < 0)

                return size;

        }

    }

    if (!found_content_type || size < 0) {

        return AVERROR_INVALIDDATA;

    }

    return size;

}

static int mpjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    int ret;

    int size = parse_multipart_header(s);

    if (size < 0)

        return size;

    ret = av_get_packet(s->pb, pkt, size);

    if (ret < 0)

        return ret;

    // trailing empty line

    avio_skip(s->pb, 2);

    return 0;

}

AVInputFormat ff_mpjpeg_demuxer = {

    .name              = "mpjpeg",

    .long_name         = NULL_IF_CONFIG_SMALL("MIME multipart JPEG"),

    .mime_type         = "multipart/x-mixed-replace",

    .extensions        = "mjpg",

    .read_probe        = mpjpeg_read_probe,

    .read_header       = mpjpeg_read_header,

    .read_packet       = mpjpeg_read_packet,

};