/*
  * Electronic Arts CMV Video Decoder
  * Copyright (c) 2007-2008 Peter Ross
  *
  * 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 St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 /**

  * @file

  * Electronic Arts CMV Video Decoder

  * by Peter Ross (pross@xvid.org)

  *
  * Technical details here:
  * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_CMV
  */
 

 #include "libavutil/common.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/imgutils.h"

 #include "avcodec.h"

 #include "internal.h"

 
 typedef struct CmvContext {
     AVCodecContext *avctx;
     AVFrame frame;        ///< current
     AVFrame last_frame;   ///< last
     AVFrame last2_frame;  ///< second-last
     int width, height;
     unsigned int palette[AVPALETTE_COUNT];
 } CmvContext;
 
 static av_cold int cmv_decode_init(AVCodecContext *avctx){
     CmvContext *s = avctx->priv_data;

     avcodec_get_frame_defaults(&s->frame);
     avcodec_get_frame_defaults(&s->last_frame);
     avcodec_get_frame_defaults(&s->last2_frame);
 

     s->avctx = avctx;

     avctx->pix_fmt = AV_PIX_FMT_PAL8;

     return 0;
 }
 
 static void cmv_decode_intra(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
     unsigned char *dst = s->frame.data[0];
     int i;
 

     for (i=0; i < s->avctx->height && buf_end - buf >= s->avctx->width; i++) {

         memcpy(dst, buf, s->avctx->width);
         dst += s->frame.linesize[0];
         buf += s->avctx->width;
     }
 }
 
 static void cmv_motcomp(unsigned char *dst, int dst_stride,
                         const unsigned char *src, int src_stride,
                         int x, int y,
                         int xoffset, int yoffset,
                         int width, int height){
     int i,j;
 
     for(j=y;j<y+4;j++)
     for(i=x;i<x+4;i++)
     {
         if (i+xoffset>=0 && i+xoffset<width &&
             j+yoffset>=0 && j+yoffset<height) {
             dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];
         }else{
             dst[j*dst_stride + i] = 0;
         }
     }
 }
 
 static void cmv_decode_inter(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
     const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);
     int x,y,i;
 
     i = 0;
     for(y=0; y<s->avctx->height/4; y++)

     for(x=0; x<s->avctx->width/4 && buf_end - buf > i; x++) {

         if (buf[i]==0xFF) {
             unsigned char *dst = s->frame.data[0] + (y*4)*s->frame.linesize[0] + x*4;
             if (raw+16<buf_end && *raw==0xFF) { /* intra */
                 raw++;
                 memcpy(dst, raw, 4);
                 memcpy(dst+s->frame.linesize[0], raw+4, 4);
                 memcpy(dst+2*s->frame.linesize[0], raw+8, 4);
                 memcpy(dst+3*s->frame.linesize[0], raw+12, 4);
                 raw+=16;
             }else if(raw<buf_end) {  /* inter using second-last frame as reference */
                 int xoffset = (*raw & 0xF) - 7;
                 int yoffset = ((*raw >> 4)) - 7;

                 if (s->last2_frame.data[0])

                     cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
                                 s->last2_frame.data[0], s->last2_frame.linesize[0],
                                 x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);

                 raw++;
             }
         }else{  /* inter using last frame as reference */
             int xoffset = (buf[i] & 0xF) - 7;
             int yoffset = ((buf[i] >> 4)) - 7;

             if (s->last_frame.data[0])
                 cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
                           s->last_frame.data[0], s->last_frame.linesize[0],
                           x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);

         }
         i++;
     }
 }
 
 static void cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)
 {
     int pal_start, pal_count, i;
 

     if(buf_end - buf < 16) {

         av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");
         return;
     }
 
     s->width  = AV_RL16(&buf[4]);
     s->height = AV_RL16(&buf[6]);

     if (s->avctx->width!=s->width || s->avctx->height!=s->height) {

         avcodec_set_dimensions(s->avctx, s->width, s->height);

         if (s->frame.data[0])
             s->avctx->release_buffer(s->avctx, &s->frame);
         if (s->last_frame.data[0])
             s->avctx->release_buffer(s->avctx, &s->last_frame);
     }

 
     s->avctx->time_base.num = 1;
     s->avctx->time_base.den = AV_RL16(&buf[10]);
 
     pal_start = AV_RL16(&buf[12]);
     pal_count = AV_RL16(&buf[14]);
 
     buf += 16;

     for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {

         s->palette[i] = 0xFFU << 24 | AV_RB24(buf);

         buf += 3;
     }
 }
 
 #define EA_PREAMBLE_SIZE 8
 #define MVIh_TAG MKTAG('M', 'V', 'I', 'h')
 
 static int cmv_decode_frame(AVCodecContext *avctx,

                             void *data, int *got_frame,

                             AVPacket *avpkt)

 {

     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     CmvContext *s = avctx->priv_data;
     const uint8_t *buf_end = buf + buf_size;
 

     if (buf_end - buf < EA_PREAMBLE_SIZE)
         return AVERROR_INVALIDDATA;
 

     if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {

         unsigned size = AV_RL32(buf + 4);

         cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);

         if (size > buf_end - buf - EA_PREAMBLE_SIZE)
             return -1;
         buf += size;

     }
 

     if (av_image_check_size(s->width, s->height, 0, s->avctx))

         return -1;
 
     /* shuffle */
     if (s->last2_frame.data[0])
         avctx->release_buffer(avctx, &s->last2_frame);
     FFSWAP(AVFrame, s->last_frame, s->last2_frame);
     FFSWAP(AVFrame, s->frame, s->last_frame);
 

     s->frame.reference = 3;

     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID |
                             FF_BUFFER_HINTS_READABLE |
                             FF_BUFFER_HINTS_PRESERVE;

     if (ff_get_buffer(avctx, &s->frame)<0) {

         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return -1;
     }
 
     memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
 
     buf += EA_PREAMBLE_SIZE;
     if ((buf[0]&1)) {  // subtype
         cmv_decode_inter(s, buf+2, buf_end);
         s->frame.key_frame = 0;

         s->frame.pict_type = AV_PICTURE_TYPE_P;

     }else{
         s->frame.key_frame = 1;

         s->frame.pict_type = AV_PICTURE_TYPE_I;

         cmv_decode_intra(s, buf+2, buf_end);
     }
 

     *got_frame = 1;

     *(AVFrame*)data = s->frame;
 
     return buf_size;
 }
 
 static av_cold int cmv_decode_end(AVCodecContext *avctx){
     CmvContext *s = avctx->priv_data;
     if (s->frame.data[0])
         s->avctx->release_buffer(avctx, &s->frame);
     if (s->last_frame.data[0])
         s->avctx->release_buffer(avctx, &s->last_frame);
     if (s->last2_frame.data[0])
         s->avctx->release_buffer(avctx, &s->last2_frame);
 
     return 0;
 }
 

 AVCodec ff_eacmv_decoder = {

     .name           = "eacmv",
     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_CMV,

     .priv_data_size = sizeof(CmvContext),
     .init           = cmv_decode_init,
     .close          = cmv_decode_end,
     .decode         = cmv_decode_frame,
     .capabilities   = CODEC_CAP_DR1,

     .long_name      = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),

 };