/*
  * Beam Software VB 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

  * VB Video decoder
  */
 
 #include <stdio.h>
 #include <stdlib.h>
 
 #include "avcodec.h"
 #include "bytestream.h"

 #include "internal.h"

 
 enum VBFlags{
     VB_HAS_GMC     = 0x01,
     VB_HAS_AUDIO   = 0x04,
     VB_HAS_VIDEO   = 0x08,
     VB_HAS_PALETTE = 0x10,
     VB_HAS_LENGTH  = 0x20
 };
 
 typedef struct VBDecContext {
     AVCodecContext *avctx;
     AVFrame pic;
 
     uint8_t *frame, *prev_frame;

     uint32_t pal[AVPALETTE_COUNT];

     GetByteContext stream;

 } VBDecContext;
 
 static const uint16_t vb_patterns[64] = {
     0x0660, 0xFF00, 0xCCCC, 0xF000, 0x8888, 0x000F, 0x1111, 0xFEC8,
     0x8CEF, 0x137F, 0xF731, 0xC800, 0x008C, 0x0013, 0x3100, 0xCC00,
     0x00CC, 0x0033, 0x3300, 0x0FF0, 0x6666, 0x00F0, 0x0F00, 0x2222,
     0x4444, 0xF600, 0x8CC8, 0x006F, 0x1331, 0x318C, 0xC813, 0x33CC,
     0x6600, 0x0CC0, 0x0066, 0x0330, 0xF900, 0xC88C, 0x009F, 0x3113,
     0x6000, 0x0880, 0x0006, 0x0110, 0xCC88, 0xFC00, 0x00CF, 0x88CC,
     0x003F, 0x1133, 0x3311, 0xF300, 0x6FF6, 0x0603, 0x08C6, 0x8C63,
     0xC631, 0x6310, 0xC060, 0x0136, 0x136C, 0x36C8, 0x6C80, 0x324C
 };
 

 static void vb_decode_palette(VBDecContext *c, int data_size)

 {
     int start, size, i;
 

     start = bytestream2_get_byte(&c->stream);
     size = (bytestream2_get_byte(&c->stream) - 1) & 0xFF;

     if(start + size > 255){
         av_log(c->avctx, AV_LOG_ERROR, "Palette change runs beyond entry 256\n");
         return;
     }

     if(size*3+2 > data_size){
         av_log(c->avctx, AV_LOG_ERROR, "Palette data runs beyond chunk size\n");
         return;
     }

     for(i = start; i <= start + size; i++)

         c->pal[i] = 0xFFU << 24 | bytestream2_get_be24(&c->stream);

 }
 
 static inline int check_pixel(uint8_t *buf, uint8_t *start, uint8_t *end)
 {
     return buf >= start && buf < end;
 }
 
 static inline int check_line(uint8_t *buf, uint8_t *start, uint8_t *end)
 {
     return buf >= start && (buf + 4) <= end;
 }
 

 static int vb_decode_framedata(VBDecContext *c, int offset)

 {

     GetByteContext g;

     uint8_t *prev, *cur;
     int blk, blocks, t, blk2;
     int blocktypes = 0;
     int x, y, a, b;
     int pattype, pattern;
     const int width = c->avctx->width;
     uint8_t *pstart = c->prev_frame;
     uint8_t *pend = c->prev_frame + width*c->avctx->height;
 

     g = c->stream;
 

     prev = c->prev_frame + offset;
     cur = c->frame;
 
     blocks = (c->avctx->width >> 2) * (c->avctx->height >> 2);
     blk2 = 0;
     for(blk = 0; blk < blocks; blk++){

         if(!(blk & 3)) {

             blocktypes = bytestream2_get_byte(&g);

         }

         switch(blocktypes & 0xC0){
         case 0x00: //skip
             for(y = 0; y < 4; y++)
                 if(check_line(prev + y*width, pstart, pend))
                     memcpy(cur + y*width, prev + y*width, 4);
                 else
                     memset(cur + y*width, 0, 4);
             break;
         case 0x40:

             t = bytestream2_get_byte(&g);

             if(!t){ //raw block

                 if (bytestream2_get_bytes_left(&g) < 16) {

                     av_log(c->avctx, AV_LOG_ERROR, "Insufficient data\n");
                     return -1;
                 }

                 for(y = 0; y < 4; y++)

                     bytestream2_get_buffer(&g, cur + y * width, 4);

             }else{ // motion compensation
                 x = ((t & 0xF)^8) - 8;
                 y = ((t >> 4) ^8) - 8;
                 t = x + y*width;
                 for(y = 0; y < 4; y++)
                     if(check_line(prev + t + y*width, pstart, pend))
                         memcpy(cur + y*width, prev + t + y*width, 4);
                     else
                         memset(cur + y*width, 0, 4);
             }
             break;
         case 0x80: // fill

             t = bytestream2_get_byte(&g);

             for(y = 0; y < 4; y++)
                 memset(cur + y*width, t, 4);
             break;
         case 0xC0: // pattern fill

             t = bytestream2_get_byte(&g);

             pattype = t >> 6;
             pattern = vb_patterns[t & 0x3F];
             switch(pattype){
             case 0:

                 a = bytestream2_get_byte(&g);
                 b = bytestream2_get_byte(&g);

                 for(y = 0; y < 4; y++)
                     for(x = 0; x < 4; x++, pattern >>= 1)
                         cur[x + y*width] = (pattern & 1) ? b : a;
                 break;
             case 1:
                 pattern = ~pattern;
             case 2:

                 a = bytestream2_get_byte(&g);

                 for(y = 0; y < 4; y++)
                     for(x = 0; x < 4; x++, pattern >>= 1)
                         if(pattern & 1 && check_pixel(prev + x + y*width, pstart, pend))
                             cur[x + y*width] = prev[x + y*width];
                         else
                             cur[x + y*width] = a;
                 break;
             case 3:
                 av_log(c->avctx, AV_LOG_ERROR, "Invalid opcode seen @%d\n",blk);
                 return -1;
             }
             break;
         }
         blocktypes <<= 2;
         cur  += 4;
         prev += 4;
         blk2++;
         if(blk2 == (width >> 2)){
             blk2 = 0;
             cur  += width * 3;
             prev += width * 3;
         }
     }
     return 0;
 }
 

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

 {
     VBDecContext * const c = avctx->priv_data;
     uint8_t *outptr, *srcptr;
     int i, j;
     int flags;
     uint32_t size;
     int offset = 0;
 

     bytestream2_init(&c->stream, avpkt->data, avpkt->size);
 

     if(c->pic.data[0])
         avctx->release_buffer(avctx, &c->pic);

     c->pic.reference = 3;

     if(ff_get_buffer(avctx, &c->pic) < 0){

         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return -1;
     }
 

     flags = bytestream2_get_le16(&c->stream);

 
     if(flags & VB_HAS_GMC){

         i = (int16_t)bytestream2_get_le16(&c->stream);
         j = (int16_t)bytestream2_get_le16(&c->stream);

         offset = i + j * avctx->width;

     }

     if(flags & VB_HAS_VIDEO){

         size = bytestream2_get_le32(&c->stream);

         if(size > bytestream2_get_bytes_left(&c->stream)+4 || size<4){

             av_log(avctx, AV_LOG_ERROR, "Frame size invalid\n");

             return -1;
         }

         vb_decode_framedata(c, offset);
         bytestream2_skip(&c->stream, size - 4);

     }
     if(flags & VB_HAS_PALETTE){

         size = bytestream2_get_le32(&c->stream);

         vb_decode_palette(c, size);

     }
 
     memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
     c->pic.palette_has_changed = flags & VB_HAS_PALETTE;
 
     outptr = c->pic.data[0];
     srcptr = c->frame;
 
     for(i = 0; i < avctx->height; i++){
         memcpy(outptr, srcptr, avctx->width);
         srcptr += avctx->width;
         outptr += c->pic.linesize[0];
     }
 
     FFSWAP(uint8_t*, c->frame, c->prev_frame);
 

     *got_frame = 1;

     *(AVFrame*)data = c->pic;
 
     /* always report that the buffer was completely consumed */

     return avpkt->size;

 }
 

 static av_cold int decode_init(AVCodecContext *avctx)

 {
     VBDecContext * const c = avctx->priv_data;
 
     c->avctx = avctx;

     avctx->pix_fmt = AV_PIX_FMT_PAL8;

     avcodec_get_frame_defaults(&c->pic);

     c->frame      = av_mallocz(avctx->width * avctx->height);
     c->prev_frame = av_mallocz(avctx->width * avctx->height);

 
     return 0;
 }
 

 static av_cold int decode_end(AVCodecContext *avctx)

 {
     VBDecContext *c = avctx->priv_data;
 
     av_freep(&c->frame);
     av_freep(&c->prev_frame);
     if(c->pic.data[0])
         avctx->release_buffer(avctx, &c->pic);
 
     return 0;
 }
 

 AVCodec ff_vb_decoder = {

     .name           = "vb",
     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_VB,

     .priv_data_size = sizeof(VBDecContext),
     .init           = decode_init,
     .close          = decode_end,
     .decode         = decode_frame,

     .long_name      = NULL_IF_CONFIG_SMALL("Beam Software VB"),

     .capabilities   = CODEC_CAP_DR1,

 };