/*
  * Feeble Files/ScummVM DXA decoder
  * Copyright (c) 2007 Konstantin Shishkov
  *
  * 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

  * DXA Video decoder
  */
 
 #include <stdio.h>
 #include <stdlib.h>
 

 #include "libavutil/intreadwrite.h"

 #include "avcodec.h"
 
 #include <zlib.h>
 
 /*
  * Decoder context
  */
 typedef struct DxaDecContext {
     AVCodecContext *avctx;
     AVFrame pic, prev;
 
     int dsize;
     uint8_t *decomp_buf;
     uint32_t pal[256];
 } DxaDecContext;
 
 static const int shift1[6] = { 0, 8, 8, 8, 4, 4 };
 static const int shift2[6] = { 0, 0, 8, 4, 0, 4 };
 
 static int decode_13(AVCodecContext *avctx, DxaDecContext *c, uint8_t* dst, uint8_t *src, uint8_t *ref)
 {
     uint8_t *code, *data, *mv, *msk, *tmp, *tmp2;
     int i, j, k;
     int type, x, y, d, d2;
     int stride = c->pic.linesize[0];
     uint32_t mask;
 
     code = src  + 12;
     data = code + ((avctx->width * avctx->height) >> 4);
     mv   = data + AV_RB32(src + 0);
     msk  = mv   + AV_RB32(src + 4);
 
     for(j = 0; j < avctx->height; j += 4){
         for(i = 0; i < avctx->width; i += 4){
             tmp  = dst + i;
             tmp2 = ref + i;
             type = *code++;
             switch(type){
             case 4: // motion compensation
                 x = (*mv) >> 4;    if(x & 8) x = 8 - x;
                 y = (*mv++) & 0xF; if(y & 8) y = 8 - y;
                 tmp2 += x + y*stride;
             case 0: // skip
             case 5: // skip in method 12
                 for(y = 0; y < 4; y++){
                     memcpy(tmp, tmp2, 4);
                     tmp  += stride;
                     tmp2 += stride;
                 }
                 break;
             case 1:  // masked change
             case 10: // masked change with only half of pixels changed
             case 11: // cases 10-15 are for method 12 only
             case 12:
             case 13:
             case 14:
             case 15:
                 if(type == 1){
                     mask = AV_RB16(msk);
                     msk += 2;
                 }else{
                     type -= 10;
                     mask = ((msk[0] & 0xF0) << shift1[type]) | ((msk[0] & 0xF) << shift2[type]);
                     msk++;
                 }
                 for(y = 0; y < 4; y++){
                     for(x = 0; x < 4; x++){
                         tmp[x] = (mask & 0x8000) ? *data++ : tmp2[x];
                         mask <<= 1;
                     }
                     tmp  += stride;
                     tmp2 += stride;
                 }
                 break;
             case 2: // fill block
                 for(y = 0; y < 4; y++){
                     memset(tmp, data[0], 4);
                     tmp += stride;
                 }
                 data++;
                 break;
             case 3: // raw block
                 for(y = 0; y < 4; y++){
                     memcpy(tmp, data, 4);
                     data += 4;
                     tmp  += stride;
                 }
                 break;
             case 8: // subblocks - method 13 only
                 mask = *msk++;
                 for(k = 0; k < 4; k++){
                     d  = ((k & 1) << 1) + ((k & 2) * stride);
                     d2 = ((k & 1) << 1) + ((k & 2) * stride);
                     tmp2 = ref + i + d2;
                     switch(mask & 0xC0){
                     case 0x80: // motion compensation
                         x = (*mv) >> 4;    if(x & 8) x = 8 - x;
                         y = (*mv++) & 0xF; if(y & 8) y = 8 - y;
                         tmp2 += x + y*stride;
                     case 0x00: // skip
                         tmp[d + 0         ] = tmp2[0];
                         tmp[d + 1         ] = tmp2[1];
                         tmp[d + 0 + stride] = tmp2[0 + stride];
                         tmp[d + 1 + stride] = tmp2[1 + stride];
                         break;
                     case 0x40: // fill
                         tmp[d + 0         ] = data[0];
                         tmp[d + 1         ] = data[0];
                         tmp[d + 0 + stride] = data[0];
                         tmp[d + 1 + stride] = data[0];
                         data++;
                         break;
                     case 0xC0: // raw
                         tmp[d + 0         ] = *data++;
                         tmp[d + 1         ] = *data++;
                         tmp[d + 0 + stride] = *data++;
                         tmp[d + 1 + stride] = *data++;
                         break;
                     }
                     mask <<= 2;
                 }
                 break;
             case 32: // vector quantization - 2 colors
                 mask = AV_RB16(msk);
                 msk += 2;
                 for(y = 0; y < 4; y++){
                     for(x = 0; x < 4; x++){
                         tmp[x] = data[mask & 1];
                         mask >>= 1;
                     }
                     tmp  += stride;
                     tmp2 += stride;
                 }
                 data += 2;
                 break;
             case 33: // vector quantization - 3 or 4 colors
             case 34:
                 mask = AV_RB32(msk);
                 msk += 4;
                 for(y = 0; y < 4; y++){
                     for(x = 0; x < 4; x++){
                         tmp[x] = data[mask & 3];
                         mask >>= 2;
                     }
                     tmp  += stride;
                     tmp2 += stride;
                 }
                 data += type - 30;
                 break;
             default:
                 av_log(avctx, AV_LOG_ERROR, "Unknown opcode %d\n", type);
                 return -1;
             }
         }
         dst += stride * 4;
         ref += stride * 4;
     }
     return 0;
 }
 

 static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)

 {

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

     DxaDecContext * const c = avctx->priv_data;

     uint8_t *outptr, *srcptr, *tmpptr;
     unsigned long dsize;
     int i, j, compr;
     int stride;
     int orig_buf_size = buf_size;
     int pc = 0;
 
     /* make the palette available on the way out */
     if(buf[0]=='C' && buf[1]=='M' && buf[2]=='A' && buf[3]=='P'){
         int r, g, b;
 
         buf += 4;
         for(i = 0; i < 256; i++){
             r = *buf++;
             g = *buf++;
             b = *buf++;
             c->pal[i] = (r << 16) | (g << 8) | b;
         }
         pc = 1;
         buf_size -= 768+4;
     }
 
     if(avctx->get_buffer(avctx, &c->pic) < 0){
         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return -1;
     }
     memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
     c->pic.palette_has_changed = pc;
 
     outptr = c->pic.data[0];
     srcptr = c->decomp_buf;
     tmpptr = c->prev.data[0];
     stride = c->pic.linesize[0];
 
     if(buf[0]=='N' && buf[1]=='U' && buf[2]=='L' && buf[3]=='L')
         compr = -1;
     else
         compr = buf[4];
 
     dsize = c->dsize;
     if((compr != 4 && compr != -1) && uncompress(c->decomp_buf, &dsize, buf + 9, buf_size - 9) != Z_OK){
         av_log(avctx, AV_LOG_ERROR, "Uncompress failed!\n");
         return -1;
     }
     switch(compr){
     case -1:
         c->pic.key_frame = 0;

         c->pic.pict_type = AV_PICTURE_TYPE_P;

         if(c->prev.data[0])
             memcpy(c->pic.data[0], c->prev.data[0], c->pic.linesize[0] * avctx->height);
         else{ // Should happen only when first frame is 'NULL'
             memset(c->pic.data[0], 0, c->pic.linesize[0] * avctx->height);
             c->pic.key_frame = 1;

             c->pic.pict_type = AV_PICTURE_TYPE_I;

         }
         break;
     case 2:
     case 3:
     case 4:
     case 5:
         c->pic.key_frame = !(compr & 1);

         c->pic.pict_type = (compr & 1) ? AV_PICTURE_TYPE_P : AV_PICTURE_TYPE_I;

         for(j = 0; j < avctx->height; j++){
             if(compr & 1){
                 for(i = 0; i < avctx->width; i++)
                     outptr[i] = srcptr[i] ^ tmpptr[i];
                 tmpptr += stride;
             }else
                 memcpy(outptr, srcptr, avctx->width);
             outptr += stride;
             srcptr += avctx->width;
         }
         break;
     case 12: // ScummVM coding
     case 13:
         c->pic.key_frame = 0;

         c->pic.pict_type = AV_PICTURE_TYPE_P;

         decode_13(avctx, c, c->pic.data[0], srcptr, c->prev.data[0]);
         break;
     default:
         av_log(avctx, AV_LOG_ERROR, "Unknown/unsupported compression type %d\n", buf[4]);
         return -1;
     }
 
     FFSWAP(AVFrame, c->pic, c->prev);
     if(c->pic.data[0])
         avctx->release_buffer(avctx, &c->pic);
 
     *data_size = sizeof(AVFrame);
     *(AVFrame*)data = c->prev;
 
     /* always report that the buffer was completely consumed */
     return orig_buf_size;
 }
 

 static av_cold int decode_init(AVCodecContext *avctx)

 {

     DxaDecContext * const c = avctx->priv_data;

 
     c->avctx = avctx;
     avctx->pix_fmt = PIX_FMT_PAL8;
 

     avcodec_get_frame_defaults(&c->pic);
     avcodec_get_frame_defaults(&c->prev);
 

     c->dsize = avctx->width * avctx->height * 2;
     if((c->decomp_buf = av_malloc(c->dsize)) == NULL) {
         av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
         return -1;
     }
 
     return 0;
 }
 

 static av_cold int decode_end(AVCodecContext *avctx)

 {

     DxaDecContext * const c = avctx->priv_data;

 
     av_freep(&c->decomp_buf);
     if(c->prev.data[0])
         avctx->release_buffer(avctx, &c->prev);
     if(c->pic.data[0])
         avctx->release_buffer(avctx, &c->pic);
 
     return 0;
 }
 

 AVCodec ff_dxa_decoder = {

     "dxa",

     AVMEDIA_TYPE_VIDEO,

     CODEC_ID_DXA,
     sizeof(DxaDecContext),
     decode_init,
     NULL,
     decode_end,

     decode_frame,

     CODEC_CAP_DR1,

     .long_name = NULL_IF_CONFIG_SMALL("Feeble Files/ScummVM DXA"),

 };