/*
  * 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"

 #include "bytestream.h"

 #include "internal.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];

     GetByteContext gb;

 } MmContext;
 

 static av_cold int mm_decode_init(AVCodecContext *avctx)

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

     avctx->pix_fmt = AV_PIX_FMT_PAL8;

     s->frame = av_frame_alloc();
     if (!s->frame)
         return AVERROR(ENOMEM);

     return 0;
 }
 

 static int mm_decode_pal(MmContext *s)

 {
     int i;

 
     bytestream2_skip(&s->gb, 4);
     for (i = 0; i < 128; i++) {

         s->palette[i] = 0xFFU << 24 | bytestream2_get_be24(&s->gb);

         s->palette[i+128] = s->palette[i]<<2;
     }

 
     return 0;

 }
 

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

 static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)

 {

     int x = 0, y = 0;

     while (bytestream2_get_bytes_left(&s->gb) > 0) {

         int run_length, color;
 

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

             return 0;

         color = bytestream2_get_byte(&s->gb);
         if (color & 0x80) {

             run_length = 1;
         }else{

             run_length = (color & 0x7f) + 2;
             color = bytestream2_get_byte(&s->gb);

         }
 
         if (half_horiz)
             run_length *=2;
 

         if (run_length > s->avctx->width - x)
             return AVERROR_INVALIDDATA;
 

         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;

         }
     }

 
     return 0;

 }
 

 /**

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

 static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)

 {

     int data_off = bytestream2_get_le16(&s->gb);
     int y = 0;

     GetByteContext data_ptr;

     if (bytestream2_get_bytes_left(&s->gb) < data_off)
         return AVERROR_INVALIDDATA;

     bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
     while (s->gb.buffer < data_ptr.buffer_start) {

         int i, j;

         int length = bytestream2_get_byte(&s->gb);
         int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
         length &= 0x7F;

 
         if (length==0) {
             y += x;
             continue;
         }
 

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

             return 0;

         for(i=0; i<length; i++) {

             int replace_array = bytestream2_get_byte(&s->gb);

             for(j=0; j<8; j++) {

                 int replace = (replace_array >> (7-j)) & 1;

                 if (x + half_horiz >= s->avctx->width)
                     return AVERROR_INVALIDDATA;

                 if (replace) {

                     int color = bytestream2_get_byte(&data_ptr);

                     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;

                     }
                 }

                 x += 1 + half_horiz;

             }
         }
 

         y += 1 + half_vert;

     }

 
     return 0;

 }
 
 static int mm_decode_frame(AVCodecContext *avctx,

                             void *data, int *got_frame,

                             AVPacket *avpkt)

 {

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

     MmContext *s = avctx->priv_data;

     int type, res;

     if (buf_size < MM_PREAMBLE_SIZE)
         return AVERROR_INVALIDDATA;

     type = AV_RL16(&buf[0]);

     buf += MM_PREAMBLE_SIZE;
     buf_size -= MM_PREAMBLE_SIZE;

     bytestream2_init(&s->gb, buf, buf_size);

     if ((res = ff_reget_buffer(avctx, s->frame)) < 0)

         return res;

     switch(type) {

     case MM_TYPE_PALETTE   : res = mm_decode_pal(s); return avpkt->size;

     case MM_TYPE_INTRA     : res = mm_decode_intra(s, 0, 0); break;
     case MM_TYPE_INTRA_HH  : res = mm_decode_intra(s, 1, 0); break;
     case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
     case MM_TYPE_INTER     : res = mm_decode_inter(s, 0, 0); break;
     case MM_TYPE_INTER_HH  : res = mm_decode_inter(s, 1, 0); break;
     case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
     default:
         res = AVERROR_INVALIDDATA;
         break;

     }

     if (res < 0)
         return res;

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

     if ((res = av_frame_ref(data, s->frame)) < 0)

         return res;
 

     *got_frame      = 1;

     return avpkt->size;

 }
 

 static av_cold int mm_decode_end(AVCodecContext *avctx)

 {
     MmContext *s = avctx->priv_data;
 

     av_frame_free(&s->frame);

 
     return 0;
 }
 

 AVCodec ff_mmvideo_decoder = {

     .name           = "mmvideo",

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

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_MMVIDEO,

     .priv_data_size = sizeof(MmContext),
     .init           = mm_decode_init,
     .close          = mm_decode_end,
     .decode         = mm_decode_frame,
     .capabilities   = CODEC_CAP_DR1,

 };