/*
  * MxPEG decoder
  * Copyright (c) 2011 Anatoly Nenashev
  *
  * 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
  * MxPEG decoder
  */
 
 #include "mjpeg.h"
 #include "mjpegdec.h"
 
 typedef struct MXpegDecodeContext {
     MJpegDecodeContext jpg;
     AVFrame picture[2]; /* pictures array */
     int picture_index; /* index of current picture */
     int got_sof_data; /* true if SOF data successfully parsed */
     int got_mxm_bitmask; /* true if MXM bitmask available */
     uint8_t *mxm_bitmask; /* bitmask buffer */
     unsigned bitmask_size; /* size of bitmask */
     int has_complete_frame; /* true if has complete frame */
     uint8_t *completion_bitmask; /* completion bitmask of macroblocks */
     unsigned mb_width, mb_height; /* size of picture in MB's from MXM header */
 } MXpegDecodeContext;
 
 static av_cold int mxpeg_decode_init(AVCodecContext *avctx)
 {
     MXpegDecodeContext *s = avctx->priv_data;
 
     s->picture[0].reference = s->picture[1].reference = 3;
     s->jpg.picture_ptr      = &s->picture[0];

     return ff_mjpeg_decode_init(avctx);

 }
 
 static int mxpeg_decode_app(MXpegDecodeContext *s,
                             const uint8_t *buf_ptr, int buf_size)
 {
     int len;
     if (buf_size < 2)
         return 0;
     len = AV_RB16(buf_ptr);
     skip_bits(&s->jpg.gb, 8*FFMIN(len,buf_size));
 
     return 0;
 }
 
 static int mxpeg_decode_mxm(MXpegDecodeContext *s,
                             const uint8_t *buf_ptr, int buf_size)
 {
     unsigned bitmask_size, mb_count;
     int i;
 
     s->mb_width  = AV_RL16(buf_ptr+4);
     s->mb_height = AV_RL16(buf_ptr+6);
     mb_count = s->mb_width * s->mb_height;
 
     bitmask_size = (mb_count + 7) >> 3;
     if (bitmask_size > buf_size - 12) {
         av_log(s->jpg.avctx, AV_LOG_ERROR,
                "MXM bitmask is not complete\n");
         return AVERROR(EINVAL);
     }
 
     if (s->bitmask_size != bitmask_size) {
         s->bitmask_size = 0;
         av_freep(&s->mxm_bitmask);
         s->mxm_bitmask = av_malloc(bitmask_size);
         if (!s->mxm_bitmask) {
             av_log(s->jpg.avctx, AV_LOG_ERROR,
                    "MXM bitmask memory allocation error\n");
             return AVERROR(ENOMEM);
         }
 
         av_freep(&s->completion_bitmask);
         s->completion_bitmask = av_mallocz(bitmask_size);
         if (!s->completion_bitmask) {
             av_log(s->jpg.avctx, AV_LOG_ERROR,
                    "Completion bitmask memory allocation error\n");
             return AVERROR(ENOMEM);
         }
 
         s->bitmask_size = bitmask_size;
     }
 
     memcpy(s->mxm_bitmask, buf_ptr + 12, bitmask_size);
     s->got_mxm_bitmask = 1;
 
     if (!s->has_complete_frame) {
         uint8_t completion_check = 0xFF;
         for (i = 0; i < bitmask_size; ++i) {
             s->completion_bitmask[i] |= s->mxm_bitmask[i];
             completion_check &= s->completion_bitmask[i];
         }
         s->has_complete_frame = !(completion_check ^ 0xFF);
     }
 
     return 0;
 }
 
 static int mxpeg_decode_com(MXpegDecodeContext *s,
                             const uint8_t *buf_ptr, int buf_size)
 {
     int len, ret = 0;
     if (buf_size < 2)
         return 0;
     len = AV_RB16(buf_ptr);
     if (len > 14 && len <= buf_size && !strncmp(buf_ptr + 2, "MXM", 3)) {
         ret = mxpeg_decode_mxm(s, buf_ptr + 2, len - 2);
     }
     skip_bits(&s->jpg.gb, 8*FFMIN(len,buf_size));
 
     return ret;
 }
 
 static int mxpeg_check_dimensions(MXpegDecodeContext *s, MJpegDecodeContext *jpg,
                                   AVFrame *reference_ptr)
 {
     if ((jpg->width + 0x0F)>>4 != s->mb_width ||
         (jpg->height + 0x0F)>>4 != s->mb_height) {
         av_log(jpg->avctx, AV_LOG_ERROR,
                "Picture dimensions stored in SOF and MXM mismatch\n");
         return AVERROR(EINVAL);
     }
 
     if (reference_ptr->data[0]) {
         int i;
         for (i = 0; i < MAX_COMPONENTS; ++i) {
             if ( (!reference_ptr->data[i] ^ !jpg->picture_ptr->data[i]) ||
                  reference_ptr->linesize[i] != jpg->picture_ptr->linesize[i]) {
                 av_log(jpg->avctx, AV_LOG_ERROR,
                        "Dimensions of current and reference picture mismatch\n");
                 return AVERROR(EINVAL);
             }
         }
     }
 
     return 0;
 }
 
 static int mxpeg_decode_frame(AVCodecContext *avctx,
                           void *data, int *data_size,
                           AVPacket *avpkt)
 {
     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;
     MXpegDecodeContext *s = avctx->priv_data;
     MJpegDecodeContext *jpg = &s->jpg;
     const uint8_t *buf_end, *buf_ptr;
     const uint8_t *unescaped_buf_ptr;
     int unescaped_buf_size;
     int start_code;
     AVFrame *picture = data;
     int ret;
 
     buf_ptr = buf;
     buf_end = buf + buf_size;
     jpg->got_picture = 0;
     s->got_mxm_bitmask = 0;
     while (buf_ptr < buf_end) {
         start_code = ff_mjpeg_find_marker(jpg, &buf_ptr, buf_end,
                                           &unescaped_buf_ptr, &unescaped_buf_size);
         if (start_code < 0)
             goto the_end;
         {
             init_get_bits(&jpg->gb, unescaped_buf_ptr, unescaped_buf_size*8);
 
             if (start_code >= APP0 && start_code <= APP15) {
                 mxpeg_decode_app(s, unescaped_buf_ptr, unescaped_buf_size);
             }
 
             switch (start_code) {
             case SOI:
                 if (jpg->got_picture) //emulating EOI
                     goto the_end;
                 break;
             case EOI:
                 goto the_end;
             case DQT:
                 ret = ff_mjpeg_decode_dqt(jpg);
                 if (ret < 0) {
                     av_log(avctx, AV_LOG_ERROR,
                            "quantization table decode error\n");
                     return ret;
                 }
                 break;
             case DHT:
                 ret = ff_mjpeg_decode_dht(jpg);
                 if (ret < 0) {
                     av_log(avctx, AV_LOG_ERROR,
                            "huffman table decode error\n");
                     return ret;
                 }
                 break;
             case COM:
                 ret = mxpeg_decode_com(s, unescaped_buf_ptr,
                                        unescaped_buf_size);
                 if (ret < 0)
                     return ret;
                 break;
             case SOF0:
                 s->got_sof_data = 0;
                 ret = ff_mjpeg_decode_sof(jpg);
                 if (ret < 0) {
                     av_log(avctx, AV_LOG_ERROR,
                            "SOF data decode error\n");
                     return ret;
                 }
                 if (jpg->interlaced) {
                     av_log(avctx, AV_LOG_ERROR,
                            "Interlaced mode not supported in MxPEG\n");
                     return AVERROR(EINVAL);
                 }
                 s->got_sof_data = 1;
                 break;
             case SOS:
                 if (!s->got_sof_data) {
                     av_log(avctx, AV_LOG_WARNING,
                            "Can not process SOS without SOF data, skipping\n");
                     break;
                 }
                 if (!jpg->got_picture) {
                     if (jpg->first_picture) {
                         av_log(avctx, AV_LOG_WARNING,
                                "First picture has no SOF, skipping\n");
                         break;
                     }
                     if (!s->got_mxm_bitmask){
                         av_log(avctx, AV_LOG_WARNING,
                                "Non-key frame has no MXM, skipping\n");
                         break;
                     }
                     /* use stored SOF data to allocate current picture */
                     if (jpg->picture_ptr->data[0])
                         avctx->release_buffer(avctx, jpg->picture_ptr);
                     if (avctx->get_buffer(avctx, jpg->picture_ptr) < 0) {
                         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
                         return AVERROR(ENOMEM);
                     }

                     jpg->picture_ptr->pict_type = AV_PICTURE_TYPE_P;

                     jpg->picture_ptr->key_frame = 0;
                     jpg->got_picture = 1;
                 } else {

                     jpg->picture_ptr->pict_type = AV_PICTURE_TYPE_I;

                     jpg->picture_ptr->key_frame = 1;
                 }
 
                 if (s->got_mxm_bitmask) {
                     AVFrame *reference_ptr = &s->picture[s->picture_index ^ 1];
                     if (mxpeg_check_dimensions(s, jpg, reference_ptr) < 0)
                         break;
 
                     /* allocate dummy reference picture if needed */
                     if (!reference_ptr->data[0] &&
                         avctx->get_buffer(avctx, reference_ptr) < 0) {
                         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
                         return AVERROR(ENOMEM);
                     }
 

                     ret = ff_mjpeg_decode_sos(jpg, s->mxm_bitmask, reference_ptr);

                     if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))

                         return ret;

                 } else {

                     ret = ff_mjpeg_decode_sos(jpg, NULL, NULL);

                     if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))

                         return ret;

                 }
 
                 break;
             }
 
             buf_ptr += (get_bits_count(&jpg->gb)+7) >> 3;
         }
 
     }
 
 the_end:
     if (jpg->got_picture) {
         *data_size = sizeof(AVFrame);
         *picture = *jpg->picture_ptr;
         s->picture_index ^= 1;
         jpg->picture_ptr = &s->picture[s->picture_index];
 
         if (!s->has_complete_frame) {
             if (!s->got_mxm_bitmask)
                 s->has_complete_frame = 1;
             else
                 *data_size = 0;
         }
     }
 
     return buf_ptr - buf;
 }
 
 static av_cold int mxpeg_decode_end(AVCodecContext *avctx)
 {
     MXpegDecodeContext *s = avctx->priv_data;
     MJpegDecodeContext *jpg = &s->jpg;
     int i;
 
     jpg->picture_ptr = NULL;
     ff_mjpeg_decode_end(avctx);
 
     for (i = 0; i < 2; ++i) {
         if (s->picture[i].data[0])
             avctx->release_buffer(avctx, &s->picture[i]);
     }
 
     av_freep(&s->mxm_bitmask);
     av_freep(&s->completion_bitmask);
 
     return 0;
 }
 
 AVCodec ff_mxpeg_decoder = {
     .name           = "mxpeg",
     .long_name      = NULL_IF_CONFIG_SMALL("Mobotix MxPEG video"),
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = CODEC_ID_MXPEG,
     .priv_data_size = sizeof(MXpegDecodeContext),
     .init           = mxpeg_decode_init,
     .close          = mxpeg_decode_end,
     .decode         = mxpeg_decode_frame,
     .capabilities   = CODEC_CAP_DR1,

     .max_lowres     = 3,

 };