/*
  * Microsoft RTP/ASF support.
  * Copyright (c) 2008 Ronald S. Bultje
  *
  * 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
  */
 
 /**

  * @file

  * @brief Microsoft RTP/ASF support
  * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
  */
 

 #include "libavutil/avassert.h"

 #include "libavutil/base64.h"
 #include "libavutil/avstring.h"
 #include "libavutil/intreadwrite.h"

 #include "rtp.h"

 #include "rtpdec_formats.h"

 #include "rtsp.h"
 #include "asf.h"

 #include "avio_internal.h"

 #include "internal.h"

 /**
  * From MSDN 2.2.1.4, we learn that ASF data packets over RTP should not
  * contain any padding. Unfortunately, the header min/max_pktsize are not
  * updated (thus making min_pktsize invalid). Here, we "fix" these faulty
  * min_pktsize values in the ASF file header.
  * @return 0 on success, <0 on failure (currently -1).
  */

 static int rtp_asf_fix_header(uint8_t *buf, int len)

 {
     uint8_t *p = buf, *end = buf + len;
 
     if (len < sizeof(ff_asf_guid) * 2 + 22 ||
         memcmp(p, ff_asf_header, sizeof(ff_asf_guid))) {
         return -1;
     }
     p += sizeof(ff_asf_guid) + 14;
     do {
         uint64_t chunksize = AV_RL64(p + sizeof(ff_asf_guid));

         int skip = 6 * 8 + 3 * 4 + sizeof(ff_asf_guid) * 2;

         if (memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) {
             if (chunksize > end - p)
                 return -1;
             p += chunksize;
             continue;
         }
 

         if (end - p < 8 + skip)
             break;

         /* skip most of the file header, to min_pktsize */

         p += skip;
         if (AV_RL32(p) == AV_RL32(p + 4)) {

             /* and set that to zero */
             AV_WL32(p, 0);
             return 0;
         }
         break;
     } while (end - p >= sizeof(ff_asf_guid) + 8);
 
     return -1;
 }
 
 /**

  * The following code is basically a buffered AVIOContext,

  * with the added benefit of returning -EAGAIN (instead of 0)
  * on packet boundaries, such that the ASF demuxer can return
  * safely and resume business at the next packet.
  */

 static int packetizer_read(void *opaque, uint8_t *buf, int buf_size)

 {
     return AVERROR(EAGAIN);
 }
 

 static void init_packetizer(AVIOContext *pb, uint8_t *buf, int len)

 {

     ffio_init_context(pb, buf, len, 0, NULL, packetizer_read, NULL, NULL);

 
     /* this "fills" the buffer with its current content */
     pb->pos     = len;
     pb->buf_end = buf + len;
 }
 

 int ff_wms_parse_sdp_a_line(AVFormatContext *s, const char *p)

 {

     int ret = 0;

     if (av_strstart(p, "pgmpu:data:application/vnd.ms.wms-hdr.asfv1;base64,", &p)) {

         AVIOContext pb = { 0 };

         RTSPState *rt = s->priv_data;

         AVDictionary *opts = NULL;

         int len = strlen(p) * 6 / 8;
         char *buf = av_mallocz(len);

         AVInputFormat *iformat;
 

         if (!buf)
             return AVERROR(ENOMEM);

         av_base64_decode(buf, p, len);
 

         if (rtp_asf_fix_header(buf, len) < 0)
             av_log(s, AV_LOG_ERROR,
                    "Failed to fix invalid RTSP-MS/ASF min_pktsize\n");
         init_packetizer(&pb, buf, len);

         if (rt->asf_ctx) {

             avformat_close_input(&rt->asf_ctx);

         }

         if (!(iformat = av_find_input_format("asf")))
             return AVERROR_DEMUXER_NOT_FOUND;

         rt->asf_ctx = avformat_alloc_context();
         if (!rt->asf_ctx) {
             av_free(buf);

             return AVERROR(ENOMEM);

         }

         rt->asf_ctx->pb      = &pb;

         av_dict_set(&opts, "no_resync_search", "1", 0);

         if ((ret = ff_copy_whiteblacklists(rt->asf_ctx, s)) < 0) {

             av_dict_free(&opts);
             return ret;
         }

         ret = avformat_open_input(&rt->asf_ctx, "", iformat, &opts);

         av_dict_free(&opts);

         if (ret < 0) {

             av_free(pb.buffer);

             return ret;

         }

         av_dict_copy(&s->metadata, rt->asf_ctx->metadata, 0);

         rt->asf_pb_pos = avio_tell(&pb);

         av_free(pb.buffer);

         rt->asf_ctx->pb = NULL;
     }

     return ret;

 }

 static int asfrtp_parse_sdp_line(AVFormatContext *s, int stream_index,
                                  PayloadContext *asf, const char *line)

 {

     if (stream_index < 0)
         return 0;

     if (av_strstart(line, "stream:", &line)) {
         RTSPState *rt = s->priv_data;
 
         s->streams[stream_index]->id = strtol(line, NULL, 10);
 
         if (rt->asf_ctx) {
             int i;
 
             for (i = 0; i < rt->asf_ctx->nb_streams; i++) {
                 if (s->streams[stream_index]->id == rt->asf_ctx->streams[i]->id) {

                     avcodec_parameters_copy(s->streams[stream_index]->codecpar,
                                             rt->asf_ctx->streams[i]->codecpar);

                     s->streams[stream_index]->need_parsing =
                         rt->asf_ctx->streams[i]->need_parsing;

                     avpriv_set_pts_info(s->streams[stream_index], 32, 1, 1000);

                 }
            }
         }
     }
 
     return 0;
 }
 

 struct PayloadContext {

     AVIOContext *pktbuf, pb;

     uint8_t *buf;

 };
 
 /**
  * @return 0 when a packet was written into /p pkt, and no more data is left;
  *         1 when a packet was written into /p pkt, and more packets might be left;
  *        <0 when not enough data was provided to return a full packet, or on error.
  */

 static int asfrtp_parse_packet(AVFormatContext *s, PayloadContext *asf,
                                AVStream *st, AVPacket *pkt,
                                uint32_t *timestamp,

                                const uint8_t *buf, int len, uint16_t seq,
                                int flags)

 {

     AVIOContext *pb = &asf->pb;

     int res, mflags, len_off;
     RTSPState *rt = s->priv_data;
 
     if (!rt->asf_ctx)
         return -1;
 
     if (len > 0) {

         int off, out_len = 0;

 
         if (len < 4)
             return -1;
 

         av_freep(&asf->buf);
 

         ffio_init_context(pb, (uint8_t *)buf, len, 0, NULL, NULL, NULL, NULL);

         while (avio_tell(pb) + 4 < len) {
             int start_off = avio_tell(pb);

             mflags = avio_r8(pb);
             len_off = avio_rb24(pb);

             if (mflags & 0x20)   /**< relative timestamp */

                 avio_skip(pb, 4);

             if (mflags & 0x10)   /**< has duration */

                 avio_skip(pb, 4);

             if (mflags & 0x8)    /**< has location ID */

                 avio_skip(pb, 4);

             off = avio_tell(pb);

 
             if (!(mflags & 0x40)) {
                 /**
                  * If 0x40 is not set, the len_off field specifies an offset
                  * of this packet's payload data in the complete (reassembled)
                  * ASF packet. This is used to spread one ASF packet over
                  * multiple RTP packets.
                  */

                 if (asf->pktbuf && len_off != avio_tell(asf->pktbuf)) {

                     ffio_free_dyn_buf(&asf->pktbuf);

                 }
                 if (!len_off && !asf->pktbuf &&

                     (res = avio_open_dyn_buf(&asf->pktbuf)) < 0)

                     return res;
                 if (!asf->pktbuf)
                     return AVERROR(EIO);
 

                 avio_write(asf->pktbuf, buf + off, len - off);

                 avio_skip(pb, len - off);

                 if (!(flags & RTP_FLAG_MARKER))
                     return -1;

                 out_len     = avio_close_dyn_buf(asf->pktbuf, &asf->buf);

                 asf->pktbuf = NULL;

             } else {
                 /**
                  * If 0x40 is set, the len_off field specifies the length of
                  * the next ASF packet that can be read from this payload
                  * data alone. This is commonly the same as the payload size,
                  * but could be less in case of packet splitting (i.e.
                  * multiple ASF packets in one RTP packet).
                  */
 
                 int cur_len = start_off + len_off - off;
                 int prev_len = out_len;
                 out_len += cur_len;

                 if (FFMIN(cur_len, len - off) < 0)

                     return -1;

                 if ((res = av_reallocp(&asf->buf, out_len)) < 0)
                     return res;

                 memcpy(asf->buf + prev_len, buf + off,
                        FFMIN(cur_len, len - off));

                 avio_skip(pb, cur_len);

             }
         }
 
         init_packetizer(pb, asf->buf, out_len);
         pb->pos += rt->asf_pb_pos;
         pb->eof_reached = 0;
         rt->asf_ctx->pb = pb;
     }
 
     for (;;) {
         int i;
 

         res = ff_read_packet(rt->asf_ctx, pkt);

         rt->asf_pb_pos = avio_tell(pb);

         if (res != 0)
             break;
         for (i = 0; i < s->nb_streams; i++) {
             if (s->streams[i]->id == rt->asf_ctx->streams[pkt->stream_index]->id) {
                 pkt->stream_index = i;
                 return 1; // FIXME: return 0 if last packet
             }
         }

         av_packet_unref(pkt);

     }
 
     return res == 1 ? -1 : res;
 }
 

 static void asfrtp_close_context(PayloadContext *asf)

 {

     ffio_free_dyn_buf(&asf->pktbuf);

     av_freep(&asf->buf);
 }
 

 #define RTP_ASF_HANDLER(n, s, t) \
 RTPDynamicProtocolHandler ff_ms_rtp_ ## n ## _handler = { \

     .enc_name         = s, \
     .codec_type       = t, \

     .codec_id         = AV_CODEC_ID_NONE, \

     .priv_data_size   = sizeof(PayloadContext), \

     .parse_sdp_a_line = asfrtp_parse_sdp_line, \

     .close            = asfrtp_close_context, \

     .parse_packet     = asfrtp_parse_packet,   \

 }

 RTP_ASF_HANDLER(asf_pfv, "x-asf-pf",  AVMEDIA_TYPE_VIDEO);
 RTP_ASF_HANDLER(asf_pfa, "x-asf-pf",  AVMEDIA_TYPE_AUDIO);