/*
  * Electronic Arts TGV 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 libavcodec/eatgv.c

  * Electronic Arts TGV Video Decoder
  * by Peter Ross (suxen_drol at hotmail dot com)
  *
  * Technical details here:
  * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_TGV
  */
 
 #include "avcodec.h"
 #define ALT_BITSTREAM_READER_LE
 #include "bitstream.h"

 #include "libavutil/lzo.h"

 
 #define EA_PREAMBLE_SIZE    8
 #define kVGT_TAG MKTAG('k', 'V', 'G', 'T')
 
 typedef struct TgvContext {
     AVCodecContext *avctx;
     AVFrame frame;
     AVFrame last_frame;
     int width,height;
     unsigned int palette[AVPALETTE_COUNT];
 
     int (*mv_codebook)[2];
     unsigned char (*block_codebook)[16];
     int num_mvs;           ///< current length of mv_codebook
     int num_blocks_packed; ///< current length of block_codebook
 } TgvContext;
 
 static av_cold int tgv_decode_init(AVCodecContext *avctx){
     TgvContext *s = avctx->priv_data;
     s->avctx = avctx;
     avctx->time_base = (AVRational){1, 15};
     avctx->pix_fmt = PIX_FMT_PAL8;
     return 0;
 }
 
 /**
  * Unpack buffer
  * @return 0 on success, -1 on critical buffer underflow
  */
 static int unpack(const uint8_t *src, const uint8_t *src_end, unsigned char *dst, int width, int height) {
     unsigned char *dst_end = dst + width*height;

     int size, size1, size2, av_uninit(offset), run;

     unsigned char *dst_start = dst;
 
     if (src[0] & 0x01)
         src += 5;
     else
         src += 2;
 
     if (src+3>src_end)
         return -1;
     size = AV_RB24(src);
     src += 3;
 
     while(size>0 && src<src_end) {
 
         /* determine size1 and size2 */
         size1 = (src[0] & 3);
         if ( src[0] & 0x80 ) {  // 1
             if (src[0] & 0x40 ) {  // 11
                 if ( src[0] & 0x20 ) {  // 111
                     if ( src[0] < 0xFC )  // !(111111)
                         size1 = (((src[0] & 31) + 1) << 2);
                     src++;
                     size2 = 0;
                 } else {  // 110
                     offset = ((src[0] & 0x10) << 12) + AV_RB16(&src[1]) + 1;
                     size2 = ((src[0] & 0xC) << 6) + src[3] + 5;
                     src += 4;
                 }
             } else {  // 10
                 size1 = ( ( src[1] & 0xC0) >> 6 );
                 offset = (AV_RB16(&src[1]) & 0x3FFF) + 1;
                 size2 = (src[0] & 0x3F) + 4;
                 src += 3;
             }
         } else {  // 0
             offset = ((src[0] & 0x60) << 3) + src[1] + 1;
             size2 = ((src[0] & 0x1C) >> 2) + 3;
             src += 2;
         }
 
 
         /* fetch strip from src */
         if (size1>src_end-src)
             break;
 
         if (size1>0) {
             size -= size1;
             run = FFMIN(size1, dst_end-dst);
             memcpy(dst, src, run);
             dst += run;
             src += run;
         }
 
         if (size2>0) {
             if (dst-dst_start<offset)
                 return 0;
             size -= size2;
             run = FFMIN(size2, dst_end-dst);
             av_memcpy_backptr(dst, offset, run);
             dst += run;
         }
     }
 
     return 0;
 }
 
 /**
  * Decode inter-frame
  * @return 0 on success, -1 on critical buffer underflow
  */
 static int tgv_decode_inter(TgvContext * s, const uint8_t *buf, const uint8_t *buf_end){
     unsigned char *frame0_end = s->last_frame.data[0] + s->avctx->width*s->last_frame.linesize[0];
     int num_mvs;
     int num_blocks_raw;
     int num_blocks_packed;
     int vector_bits;
     int i,j,x,y;
     GetBitContext gb;
     int mvbits;
     const unsigned char *blocks_raw;
 
     if(buf+12>buf_end)
         return -1;
 
     num_mvs           = AV_RL16(&buf[0]);
     num_blocks_raw    = AV_RL16(&buf[2]);
     num_blocks_packed = AV_RL16(&buf[4]);
     vector_bits       = AV_RL16(&buf[6]);
     buf += 12;
 
     /* allocate codebook buffers as neccessary */
     if (num_mvs > s->num_mvs) {
         s->mv_codebook = av_realloc(s->mv_codebook, num_mvs*2*sizeof(int));
         s->num_mvs = num_mvs;
     }
 
     if (num_blocks_packed > s->num_blocks_packed) {
         s->block_codebook = av_realloc(s->block_codebook, num_blocks_packed*16*sizeof(unsigned char));
         s->num_blocks_packed = num_blocks_packed;
     }
 
     /* read motion vectors */
     mvbits = (num_mvs*2*10+31) & ~31;
 
     if (buf+(mvbits>>3)+16*num_blocks_raw+8*num_blocks_packed>buf_end)
         return -1;
 
     init_get_bits(&gb, buf, mvbits);
     for (i=0; i<num_mvs; i++) {
         s->mv_codebook[i][0] = get_sbits(&gb, 10);
         s->mv_codebook[i][1] = get_sbits(&gb, 10);
     }
     buf += mvbits>>3;
 
     /* note ptr to uncompressed blocks */
     blocks_raw = buf;
     buf += num_blocks_raw*16;
 
     /* read compressed blocks */
     init_get_bits(&gb, buf, (buf_end-buf)<<3);
     for (i=0; i<num_blocks_packed; i++) {
         int tmp[4];
         for(j=0; j<4; j++)
             tmp[j] = get_bits(&gb, 8);
         for(j=0; j<16; j++)
             s->block_codebook[i][15-j] = tmp[get_bits(&gb, 2)];
     }
 
     /* read vectors and build frame */
     for(y=0; y<s->avctx->height/4; y++)
     for(x=0; x<s->avctx->width/4; x++) {
         unsigned int vector = get_bits(&gb, vector_bits);
         const unsigned char *src;
         int src_stride;
 
         if (vector < num_mvs) {
             src = s->last_frame.data[0] +
                   (y*4 + s->mv_codebook[vector][1])*s->last_frame.linesize[0] +
                    x*4 + s->mv_codebook[vector][0];
             src_stride = s->last_frame.linesize[0];
             if (src+3*src_stride+3>=frame0_end)
                 continue;
         }else{
             int offset = vector - num_mvs;
             if (offset<num_blocks_raw)
                 src = blocks_raw + 16*offset;
             else if (offset-num_blocks_raw<num_blocks_packed)
                 src = s->block_codebook[offset-num_blocks_raw];
             else
                 continue;
             src_stride = 4;
         }
 
         for(j=0; j<4; j++)
         for(i=0; i<4; i++)
             s->frame.data[0][ (y*4+j)*s->frame.linesize[0] + (x*4+i)  ] =
                src[j*src_stride + i];
     }
 
     return 0;
 }
 
 /** release AVFrame buffers if allocated */
 static void cond_release_buffer(AVFrame *pic)
 {
     if (pic->data[0]) {
         av_freep(&pic->data[0]);
         av_free(pic->data[1]);
     }
 }
 
 static int tgv_decode_frame(AVCodecContext *avctx,
                             void *data, int *data_size,
                             const uint8_t *buf, int buf_size)
 {
     TgvContext *s = avctx->priv_data;
     const uint8_t *buf_end = buf + buf_size;
     int chunk_type;
 
     chunk_type = AV_RL32(&buf[0]);
     buf += EA_PREAMBLE_SIZE;
 
     if (chunk_type==kVGT_TAG) {
         int pal_count, i;
         if(buf+12>buf_end) {
             av_log(avctx, AV_LOG_WARNING, "truncated header\n");
             return -1;
         }
 
         s->width  = AV_RL16(&buf[0]);
         s->height = AV_RL16(&buf[2]);
         if (s->avctx->width!=s->width || s->avctx->height!=s->height) {
             avcodec_set_dimensions(s->avctx, s->width, s->height);
             cond_release_buffer(&s->frame);
             cond_release_buffer(&s->last_frame);
         }
 
         pal_count = AV_RL16(&buf[6]);
         buf += 12;
         for(i=0; i<pal_count && i<AVPALETTE_COUNT && buf+2<buf_end; i++) {
             s->palette[i] = AV_RB24(buf);
             buf += 3;
         }
     }
 
     if (avcodec_check_dimensions(avctx, s->width, s->height))
         return -1;
 
     /* shuffle */
     FFSWAP(AVFrame, s->frame, s->last_frame);
     if (!s->frame.data[0]) {
         s->frame.reference = 1;
         s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
         s->frame.linesize[0] = s->width;
 
         /* allocate additional 12 bytes to accomodate av_memcpy_backptr() OUTBUF_PADDED optimisation */
         s->frame.data[0] = av_malloc(s->width*s->height + 12);
         if (!s->frame.data[0])
             return AVERROR_NOMEM;
         s->frame.data[1] = av_malloc(AVPALETTE_SIZE);
         if (!s->frame.data[1]) {
             av_freep(&s->frame.data[0]);
             return AVERROR_NOMEM;
         }
     }
     memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
 
     if(chunk_type==kVGT_TAG) {
         s->frame.key_frame = 1;
         s->frame.pict_type = FF_I_TYPE;
         if (unpack(buf, buf_end, s->frame.data[0], s->avctx->width, s->avctx->height)<0) {
             av_log(avctx, AV_LOG_WARNING, "truncated intra frame\n");
             return -1;
         }
     }else{
         if (!s->last_frame.data[0]) {
             av_log(avctx, AV_LOG_WARNING, "inter frame without corresponding intra frame\n");
             return buf_size;
         }
         s->frame.key_frame = 0;
         s->frame.pict_type = FF_P_TYPE;
         if (tgv_decode_inter(s, buf, buf_end)<0) {
             av_log(avctx, AV_LOG_WARNING, "truncated inter frame\n");
             return -1;
         }
     }
 
     *data_size = sizeof(AVFrame);
     *(AVFrame*)data = s->frame;
 
     return buf_size;
 }
 
 static av_cold int tgv_decode_end(AVCodecContext *avctx)
 {
     TgvContext *s = avctx->priv_data;
     cond_release_buffer(&s->frame);
     cond_release_buffer(&s->last_frame);
     av_free(s->mv_codebook);
     av_free(s->block_codebook);
     return 0;
 }
 
 AVCodec eatgv_decoder = {
     "eatgv",
     CODEC_TYPE_VIDEO,
     CODEC_ID_TGV,
     sizeof(TgvContext),
     tgv_decode_init,
     NULL,
     tgv_decode_end,
     tgv_decode_frame,

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

 };