/*
  * Electronic Arts Madcow Video Decoder
  * Copyright (c) 2007-2009 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

  * Electronic Arts Madcow Video Decoder

  * @author Peter Ross <pross@xvid.org>

  *

  * @see technical details at

  * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_MAD
  */
 
 #include "avcodec.h"
 #include "get_bits.h"
 #include "aandcttab.h"

 #include "eaidct.h"

 #include "internal.h"

 #include "mpeg12.h"
 #include "mpeg12data.h"

 #include "libavutil/imgutils.h"

 
 #define EA_PREAMBLE_SIZE    8
 #define MADk_TAG MKTAG('M', 'A', 'D', 'k')    /* MAD i-frame */
 #define MADm_TAG MKTAG('M', 'A', 'D', 'm')    /* MAD p-frame */
 #define MADe_TAG MKTAG('M', 'A', 'D', 'e')    /* MAD lqp-frame */
 
 typedef struct MadContext {

     AVCodecContext *avctx;
     DSPContext dsp;

     AVFrame frame;
     AVFrame last_frame;

     GetBitContext gb;

     void *bitstream_buf;
     unsigned int bitstream_buf_size;

     DECLARE_ALIGNED(16, int16_t, block)[64];

     ScanTable scantable;
     uint16_t quant_matrix[64];
     int mb_x;
     int mb_y;

 } MadContext;
 
 static av_cold int decode_init(AVCodecContext *avctx)
 {

     MadContext *s = avctx->priv_data;

     s->avctx = avctx;

     avctx->pix_fmt = AV_PIX_FMT_YUV420P;

     ff_dsputil_init(&s->dsp, avctx);

     ff_init_scantable_permutation(s->dsp.idct_permutation, FF_NO_IDCT_PERM);

     ff_init_scantable(s->dsp.idct_permutation, &s->scantable, ff_zigzag_direct);

     ff_mpeg12_init_vlcs();
     return 0;
 }
 
 static inline void comp(unsigned char *dst, int dst_stride,
                         unsigned char *src, int src_stride, int add)
 {
     int j, i;
     for (j=0; j<8; j++)
         for (i=0; i<8; i++)
             dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
 }
 
 static inline void comp_block(MadContext *t, int mb_x, int mb_y,
                               int j, int mv_x, int mv_y, int add)
 {
     if (j < 4) {

         unsigned offset = (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame.linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x;

         if (offset >= (t->avctx->height - 7) * t->last_frame.linesize[0] - 7)

             return;

         comp(t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
              t->frame.linesize[0],

              t->last_frame.data[0] + offset,

              t->last_frame.linesize[0], add);

     } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {

         int index = j - 3;

         unsigned offset = (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2);

         if (offset >= (t->avctx->height/2 - 7) * t->last_frame.linesize[index] - 7)

             return;

         comp(t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x * 8,
              t->frame.linesize[index],

              t->last_frame.data[index] + offset,

              t->last_frame.linesize[index], add);
     }
 }
 

 static inline void idct_put(MadContext *t, int16_t *block, int mb_x, int mb_y, int j)

 {
     if (j < 4) {

         ff_ea_idct_put_c(

             t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
             t->frame.linesize[0], block);

     } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {

         int index = j - 3;

         ff_ea_idct_put_c(

             t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x*8,
             t->frame.linesize[index], block);
     }
 }
 

 static inline int decode_block_intra(MadContext *s, int16_t * block)

 {
     int level, i, j, run;
     RLTable *rl = &ff_rl_mpeg1;

     const uint8_t *scantable = s->scantable.permutated;
     int16_t *quant_matrix = s->quant_matrix;

 
     block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
 
     /* The RL decoder is derived from mpeg1_decode_block_intra;
        Escaped level and run values a decoded differently */

     i = 0;

     {
         OPEN_READER(re, &s->gb);
         /* now quantify & encode AC coefficients */
         for (;;) {
             UPDATE_CACHE(re, &s->gb);
             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
 
             if (level == 127) {
                 break;
             } else if (level != 0) {
                 i += run;
                 j = scantable[i];
                 level = (level*quant_matrix[j]) >> 4;
                 level = (level-1)|1;
                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
                 LAST_SKIP_BITS(re, &s->gb, 1);
             } else {
                 /* escape */
                 UPDATE_CACHE(re, &s->gb);
                 level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
 
                 UPDATE_CACHE(re, &s->gb);
                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
 
                 i += run;
                 j = scantable[i];
                 if (level < 0) {
                     level = -level;
                     level = (level*quant_matrix[j]) >> 4;
                     level = (level-1)|1;
                     level = -level;
                 } else {
                     level = (level*quant_matrix[j]) >> 4;
                     level = (level-1)|1;
                 }
             }
             if (i > 63) {
                 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);

                 return -1;

             }
 
             block[j] = level;
         }
         CLOSE_READER(re, &s->gb);
     }

     return 0;

 }
 
 static int decode_motion(GetBitContext *gb)
 {
     int value = 0;
     if (get_bits1(gb)) {
         if (get_bits1(gb))
             value = -17;
         value += get_bits(gb, 4) + 1;
     }
     return value;
 }
 

 static int decode_mb(MadContext *s, int inter)

 {
     int mv_map = 0;
     int mv_x, mv_y;
     int j;
 
     if (inter) {
         int v = decode210(&s->gb);
         if (v < 2) {
             mv_map = v ? get_bits(&s->gb, 6) : 63;
             mv_x = decode_motion(&s->gb);
             mv_y = decode_motion(&s->gb);
         }
     }
 
     for (j=0; j<6; j++) {
         if (mv_map & (1<<j)) {  // mv_x and mv_y are guarded by mv_map
             int add = 2*decode_motion(&s->gb);

             if (s->last_frame.data[0])
                 comp_block(s, s->mb_x, s->mb_y, j, mv_x, mv_y, add);

         } else {

             s->dsp.clear_block(s->block);

             if(decode_block_intra(s, s->block) < 0)

                 return -1;

             idct_put(s, s->block, s->mb_x, s->mb_y, j);

         }
     }

     return 0;

 }
 

 static void calc_quant_matrix(MadContext *s, int qscale)

 {
     int i;
 

     s->quant_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11;
     for (i=1; i<64; i++)
         s->quant_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;

 }
 
 static int decode_frame(AVCodecContext *avctx,

                         void *data, int *got_frame,

                         AVPacket *avpkt)
 {
     const uint8_t *buf = avpkt->data;
     int buf_size       = avpkt->size;
     const uint8_t *buf_end = buf+buf_size;

     MadContext *s     = avctx->priv_data;

     int width, height, ret;

     int chunk_type;
     int inter;
 

     if (buf_size < 26) {

         av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");

         *got_frame = 0;

         return AVERROR_INVALIDDATA;

     }
 
     chunk_type = AV_RL32(&buf[0]);
     inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
     buf += 8;
 
     av_reduce(&avctx->time_base.num, &avctx->time_base.den,
               AV_RL16(&buf[6]), 1000, 1<<30);
 

     width  = AV_RL16(&buf[8]);
     height = AV_RL16(&buf[10]);
     calc_quant_matrix(s, buf[13]);

     buf += 16;
 

     if (avctx->width != width || avctx->height != height) {

         if((width * height)/2048*7 > buf_end-buf)

             return AVERROR_INVALIDDATA;
         if ((ret = av_image_check_size(width, height, 0, avctx)) < 0)
             return ret;

         avcodec_set_dimensions(avctx, width, height);
         if (s->frame.data[0])
             avctx->release_buffer(avctx, &s->frame);

         if (s->last_frame.data[0])
             avctx->release_buffer(avctx, &s->last_frame);

     }
 

     s->frame.reference = 3;

     if (!s->frame.data[0]) {

         if ((ret = ff_get_buffer(avctx, &s->frame)) < 0) {

             av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

             return ret;

         }
     }
 

     av_fast_padded_malloc(&s->bitstream_buf, &s->bitstream_buf_size,
                           buf_end - buf);

     if (!s->bitstream_buf)

         return AVERROR(ENOMEM);

     s->dsp.bswap16_buf(s->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);

     memset((uint8_t*)s->bitstream_buf + (buf_end-buf), 0, FF_INPUT_BUFFER_PADDING_SIZE);

     init_get_bits(&s->gb, s->bitstream_buf, 8*(buf_end-buf));

 
     for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
         for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)

             if(decode_mb(s, inter) < 0)

                 return AVERROR_INVALIDDATA;

     *got_frame = 1;

     *(AVFrame*)data = s->frame;

 
     if (chunk_type != MADe_TAG)

         FFSWAP(AVFrame, s->frame, s->last_frame);

 
     return buf_size;
 }
 
 static av_cold int decode_end(AVCodecContext *avctx)
 {
     MadContext *t = avctx->priv_data;
     if (t->frame.data[0])
         avctx->release_buffer(avctx, &t->frame);
     if (t->last_frame.data[0])
         avctx->release_buffer(avctx, &t->last_frame);
     av_free(t->bitstream_buf);
     return 0;
 }
 

 AVCodec ff_eamad_decoder = {

     .name           = "eamad",
     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_MAD,

     .priv_data_size = sizeof(MadContext),
     .init           = decode_init,
     .close          = decode_end,
     .decode         = decode_frame,
     .capabilities   = CODEC_CAP_DR1,

     .long_name      = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video")

 };