/*
  * American Laser Games MM Video Decoder

  * Copyright (c) 2006,2008 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 Street, Fifth Floor, Boston, MA 02110-1301 USA

  */
 
 /**

  * @file

  * American Laser Games MM Video Decoder

  * by Peter Ross (pross@xvid.org)

  *
  * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
  * including Mad Dog McCree and Crime Patrol.
  *
  * Technical details here:
  *  http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
  */
 

 #include "libavutil/intreadwrite.h"

 #include "avcodec.h"
 
 #define MM_PREAMBLE_SIZE    6
 
 #define MM_TYPE_INTER       0x5
 #define MM_TYPE_INTRA       0x8
 #define MM_TYPE_INTRA_HH    0xc
 #define MM_TYPE_INTER_HH    0xd
 #define MM_TYPE_INTRA_HHV   0xe
 #define MM_TYPE_INTER_HHV   0xf

 #define MM_TYPE_PALETTE     0x31

 
 typedef struct MmContext {
     AVCodecContext *avctx;
     AVFrame frame;

     int palette[AVPALETTE_COUNT];

 } MmContext;
 

 static av_cold int mm_decode_init(AVCodecContext *avctx)

 {
     MmContext *s = avctx->priv_data;
 
     s->avctx = avctx;
 
     avctx->pix_fmt = PIX_FMT_PAL8;
 

     avcodec_get_frame_defaults(&s->frame);

     s->frame.reference = 1;
 
     return 0;
 }
 

 static void mm_decode_pal(MmContext *s, const uint8_t *buf, const uint8_t *buf_end)
 {
     int i;
     buf += 4;
     for (i=0; i<128 && buf+2<buf_end; i++) {
         s->palette[i] = AV_RB24(buf);
         s->palette[i+128] = s->palette[i]<<2;
         buf += 3;
     }
 }
 

 /**
  * @param half_horiz Half horizontal resolution (0 or 1)
  * @param half_vert Half vertical resolution (0 or 1)
  */

 static void mm_decode_intra(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
 {
     int i, x, y;
     i=0; x=0; y=0;
 
     while(i<buf_size) {
         int run_length, color;
 

         if (y >= s->avctx->height)
             return;
 

         if (buf[i] & 0x80) {
             run_length = 1;
             color = buf[i];
             i++;
         }else{
             run_length = (buf[i] & 0x7f) + 2;
             color = buf[i+1];
             i+=2;
         }
 
         if (half_horiz)
             run_length *=2;
 
         if (color) {
             memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length);
             if (half_vert)
                 memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length);
         }
         x+= run_length;
 
         if (x >= s->avctx->width) {
             x=0;

             y += 1 + half_vert;

         }
     }
 }
 

 /*
  * @param half_horiz Half horizontal resolution (0 or 1)
  * @param half_vert Half vertical resolution (0 or 1)
  */

 static void mm_decode_inter(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
 {

     const int data_ptr = 2 + AV_RL16(&buf[0]);

     int d, r, y;
     d = data_ptr; r = 2; y = 0;
 
     while(r < data_ptr) {
         int i, j;
         int length = buf[r] & 0x7f;
         int x = buf[r+1] + ((buf[r] & 0x80) << 1);
         r += 2;
 
         if (length==0) {
             y += x;
             continue;
         }
 

         if (y + half_vert >= s->avctx->height)
             return;
 

         for(i=0; i<length; i++) {
             for(j=0; j<8; j++) {
                 int replace = (buf[r+i] >> (7-j)) & 1;
                 if (replace) {
                     int color = buf[d];
                     s->frame.data[0][y*s->frame.linesize[0] + x] = color;
                     if (half_horiz)
                         s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
                     if (half_vert) {
                         s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
                         if (half_horiz)
                             s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
                     }
                     d++;
                 }

                 x += 1 + half_horiz;

             }
         }
 
         r += length;

         y += 1 + half_vert;

     }
 }
 
 static int mm_decode_frame(AVCodecContext *avctx,
                             void *data, int *data_size,

                             AVPacket *avpkt)

 {

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

     MmContext *s = avctx->priv_data;

     const uint8_t *buf_end = buf+buf_size;

     int type;
 

     type = AV_RL16(&buf[0]);

     buf += MM_PREAMBLE_SIZE;
     buf_size -= MM_PREAMBLE_SIZE;
 

     if (avctx->reget_buffer(avctx, &s->frame) < 0) {
         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
         return -1;
     }
 

     switch(type) {

     case MM_TYPE_PALETTE   : mm_decode_pal(s, buf, buf_end); return buf_size;

     case MM_TYPE_INTRA     : mm_decode_intra(s, 0, 0, buf, buf_size); break;
     case MM_TYPE_INTRA_HH  : mm_decode_intra(s, 1, 0, buf, buf_size); break;
     case MM_TYPE_INTRA_HHV : mm_decode_intra(s, 1, 1, buf, buf_size); break;
     case MM_TYPE_INTER     : mm_decode_inter(s, 0, 0, buf, buf_size); break;
     case MM_TYPE_INTER_HH  : mm_decode_inter(s, 1, 0, buf, buf_size); break;
     case MM_TYPE_INTER_HHV : mm_decode_inter(s, 1, 1, buf, buf_size); break;
     default :
         return -1;
     }
 

     memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
 

     *data_size = sizeof(AVFrame);
     *(AVFrame*)data = s->frame;
 
     return buf_size;
 }
 

 static av_cold int mm_decode_end(AVCodecContext *avctx)

 {
     MmContext *s = avctx->priv_data;
 
     if(s->frame.data[0])
         avctx->release_buffer(avctx, &s->frame);
 
     return 0;
 }
 

 AVCodec ff_mmvideo_decoder = {

     "mmvideo",

     AVMEDIA_TYPE_VIDEO,

     CODEC_ID_MMVIDEO,
     sizeof(MmContext),
     mm_decode_init,
     NULL,
     mm_decode_end,
     mm_decode_frame,
     CODEC_CAP_DR1,

     .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),

 };