/*

  * Escape 130 video decoder

  * Copyright (C) 2008 Eli Friedman (eli.friedman <at> gmail.com)
  *
  * 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
  */
 

 #include "libavutil/attributes.h"
 #include "libavutil/mem.h"

 #define BITSTREAM_READER_LE

 #include "avcodec.h"

 #include "get_bits.h"

 #include "internal.h"
 

 typedef struct Escape130Context {

     uint8_t *old_y_avg;
 
     uint8_t *new_y, *old_y;
     uint8_t *new_u, *old_u;
     uint8_t *new_v, *old_v;
 
     uint8_t *buf1, *buf2;
     int     linesize[3];

 } Escape130Context;
 

 static const uint8_t offset_table[] = { 2, 4, 10, 20 };
 static const int8_t sign_table[64][4] = {
     {  0,  0,  0,  0 },
     { -1,  1,  0,  0 },
     {  1, -1,  0,  0 },
     { -1,  0,  1,  0 },
     { -1,  1,  1,  0 },
     {  0, -1,  1,  0 },
     {  1, -1,  1,  0 },
     { -1, -1,  1,  0 },
     {  1,  0, -1,  0 },
     {  0,  1, -1,  0 },
     {  1,  1, -1,  0 },
     { -1,  1, -1,  0 },
     {  1, -1, -1,  0 },
     { -1,  0,  0,  1 },
     { -1,  1,  0,  1 },
     {  0, -1,  0,  1 },
 
     {  0,  0,  0,  0 },
     {  1, -1,  0,  1 },
     { -1, -1,  0,  1 },
     { -1,  0,  1,  1 },
     { -1,  1,  1,  1 },
     {  0, -1,  1,  1 },
     {  1, -1,  1,  1 },
     { -1, -1,  1,  1 },
     {  0,  0, -1,  1 },
     {  1,  0, -1,  1 },
     { -1,  0, -1,  1 },
     {  0,  1, -1,  1 },
     {  1,  1, -1,  1 },
     { -1,  1, -1,  1 },
     {  0, -1, -1,  1 },
     {  1, -1, -1,  1 },
 
     {  0,  0,  0,  0 },
     { -1, -1, -1,  1 },
     {  1,  0,  0, -1 },
     {  0,  1,  0, -1 },
     {  1,  1,  0, -1 },
     { -1,  1,  0, -1 },
     {  1, -1,  0, -1 },
     {  0,  0,  1, -1 },
     {  1,  0,  1, -1 },
     { -1,  0,  1, -1 },
     {  0,  1,  1, -1 },
     {  1,  1,  1, -1 },
     { -1,  1,  1, -1 },
     {  0, -1,  1, -1 },
     {  1, -1,  1, -1 },
     { -1, -1,  1, -1 },
 
     {  0,  0,  0,  0 },
     {  1,  0, -1, -1 },
     {  0,  1, -1, -1 },
     {  1,  1, -1, -1 },
     { -1,  1, -1, -1 },
     {  1, -1, -1, -1 }
 };
 
 static const int8_t luma_adjust[] = { -4, -3, -2, -1, 1, 2, 3, 4 };
 
 static const int8_t chroma_adjust[2][8] = {
     { 1, 1, 0, -1, -1, -1,  0,  1 },
     { 0, 1, 1,  1,  0, -1, -1, -1 }
 };
 

 static const uint8_t chroma_vals[] = {

      20,  28,  36,  44,  52,  60,  68,  76,
      84,  92, 100, 106, 112, 116, 120, 124,
     128, 132, 136, 140, 144, 150, 156, 164,
     172, 180, 188, 196, 204, 212, 220, 228
 };
 

 static av_cold int escape130_decode_init(AVCodecContext *avctx)
 {

     Escape130Context *s = avctx->priv_data;

     avctx->pix_fmt = AV_PIX_FMT_YUV420P;

     if ((avctx->width & 1) || (avctx->height & 1)) {
         av_log(avctx, AV_LOG_ERROR,
                "Dimensions should be a multiple of two.\n");
         return AVERROR_INVALIDDATA;
     }
 
     s->old_y_avg = av_malloc(avctx->width * avctx->height / 4);
     s->buf1      = av_malloc(avctx->width * avctx->height * 3 / 2);
     s->buf2      = av_malloc(avctx->width * avctx->height * 3 / 2);
     if (!s->old_y_avg || !s->buf1 || !s->buf2) {
         av_freep(&s->old_y_avg);
         av_freep(&s->buf1);
         av_freep(&s->buf2);
         av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n");
         return AVERROR(ENOMEM);

     }
 

     s->linesize[0] = avctx->width;
     s->linesize[1] =
     s->linesize[2] = avctx->width / 2;
 
     s->new_y = s->buf1;
     s->new_u = s->new_y + avctx->width * avctx->height;
     s->new_v = s->new_u + avctx->width * avctx->height / 4;
     s->old_y = s->buf2;
     s->old_u = s->old_y + avctx->width * avctx->height;
     s->old_v = s->old_u + avctx->width * avctx->height / 4;
     memset(s->old_y, 0,    avctx->width * avctx->height);
     memset(s->old_u, 0x10, avctx->width * avctx->height / 4);
     memset(s->old_v, 0x10, avctx->width * avctx->height / 4);

     return 0;
 }
 
 static av_cold int escape130_decode_close(AVCodecContext *avctx)
 {
     Escape130Context *s = avctx->priv_data;
 

     av_freep(&s->old_y_avg);
     av_freep(&s->buf1);
     av_freep(&s->buf2);

     return 0;
 }
 

 static int decode_skip_count(GetBitContext* gb)
 {
     int value;
 

     if (get_bits_left(gb) < 1+3)

         return -1;
 
     value = get_bits1(gb);
     if (value)
         return 0;
 
     value = get_bits(gb, 3);
     if (value)
         return value;
 
     value = get_bits(gb, 8);
     if (value)
         return value + 7;
 
     value = get_bits(gb, 15);
     if (value)
         return value + 262;
 
     return -1;
 }
 

 static int escape130_decode_frame(AVCodecContext *avctx, void *data,
                                   int *got_frame, AVPacket *avpkt)

 {

     int buf_size        = avpkt->size;

     Escape130Context *s = avctx->priv_data;

     AVFrame *pic        = data;

     GetBitContext gb;

     int ret;

     uint8_t *old_y, *old_cb, *old_cr,

             *new_y, *new_cb, *new_cr;

     uint8_t *dstY, *dstU, *dstV;

     unsigned old_y_stride, old_cb_stride, old_cr_stride,
              new_y_stride, new_cb_stride, new_cr_stride;
     unsigned total_blocks = avctx->width * avctx->height / 4,

              block_index, block_x = 0;
     unsigned y[4] = { 0 }, cb = 0x10, cr = 0x10;
     int skip = -1, y_avg = 0, i, j;
     uint8_t *ya = s->old_y_avg;
 
     // first 16 bytes are header; no useful information in here
     if (buf_size <= 16) {
         av_log(avctx, AV_LOG_ERROR, "Insufficient frame data\n");
         return AVERROR_INVALIDDATA;
     }

     if ((ret = ff_get_buffer(avctx, pic, 0)) < 0)

         return ret;

     if ((ret = init_get_bits8(&gb, avpkt->data, avpkt->size)) < 0)
         return ret;
     skip_bits_long(&gb, 16 * 8);

 
     new_y  = s->new_y;
     new_cb = s->new_u;
     new_cr = s->new_v;
     new_y_stride  = s->linesize[0];
     new_cb_stride = s->linesize[1];
     new_cr_stride = s->linesize[2];
     old_y  = s->old_y;
     old_cb = s->old_u;
     old_cr = s->old_v;
     old_y_stride  = s->linesize[0];
     old_cb_stride = s->linesize[1];
     old_cr_stride = s->linesize[2];

 
     for (block_index = 0; block_index < total_blocks; block_index++) {
         // Note that this call will make us skip the rest of the blocks

         // if the frame ends prematurely.

         if (skip == -1)
             skip = decode_skip_count(&gb);

         if (skip == -1) {
             av_log(avctx, AV_LOG_ERROR, "Error decoding skip value\n");
             return AVERROR_INVALIDDATA;
         }

 
         if (skip) {

             y[0] = old_y[0];
             y[1] = old_y[1];
             y[2] = old_y[old_y_stride];
             y[3] = old_y[old_y_stride + 1];
             y_avg = ya[0];
             cb = old_cb[0];
             cr = old_cr[0];

         } else {
             if (get_bits1(&gb)) {

                 unsigned sign_selector       = get_bits(&gb, 6);

                 unsigned difference_selector = get_bits(&gb, 2);

                 y_avg = 2 * get_bits(&gb, 5);

                 for (i = 0; i < 4; i++) {

                     y[i] = av_clip(y_avg + offset_table[difference_selector] *
                                    sign_table[sign_selector][i], 0, 63);

                 }
             } else if (get_bits1(&gb)) {
                 if (get_bits1(&gb)) {

                     y_avg = get_bits(&gb, 6);

                 } else {
                     unsigned adjust_index = get_bits(&gb, 3);

                     y_avg = (y_avg + luma_adjust[adjust_index]) & 63;

                 }

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

                     y[i] = y_avg;

             }
 
             if (get_bits1(&gb)) {
                 if (get_bits1(&gb)) {
                     cb = get_bits(&gb, 5);
                     cr = get_bits(&gb, 5);
                 } else {
                     unsigned adjust_index = get_bits(&gb, 3);

                     cb = (cb + chroma_adjust[0][adjust_index]) & 31;
                     cr = (cr + chroma_adjust[1][adjust_index]) & 31;

                 }
             }
         }

         *ya++ = y_avg;
 
         new_y[0]                = y[0];
         new_y[1]                = y[1];
         new_y[new_y_stride]     = y[2];
         new_y[new_y_stride + 1] = y[3];
         *new_cb = cb;
         *new_cr = cr;
 
         old_y += 2;
         old_cb++;
         old_cr++;
         new_y += 2;
         new_cb++;
         new_cr++;
         block_x++;
         if (block_x * 2 == avctx->width) {
             block_x = 0;
             old_y  += old_y_stride * 2  - avctx->width;
             old_cb += old_cb_stride     - avctx->width / 2;
             old_cr += old_cr_stride     - avctx->width / 2;

             new_y  += new_y_stride * 2  - avctx->width;

             new_cb += new_cb_stride     - avctx->width / 2;
             new_cr += new_cr_stride     - avctx->width / 2;

         }
 
         skip--;
     }
 

     new_y  = s->new_y;
     new_cb = s->new_u;
     new_cr = s->new_v;
     dstY   = pic->data[0];
     dstU   = pic->data[1];
     dstV   = pic->data[2];
     for (j = 0; j < avctx->height; j++) {
         for (i = 0; i < avctx->width; i++)
             dstY[i] = new_y[i] << 2;
         dstY  += pic->linesize[0];
         new_y += new_y_stride;
     }
     for (j = 0; j < avctx->height / 2; j++) {
         for (i = 0; i < avctx->width / 2; i++) {
             dstU[i] = chroma_vals[new_cb[i]];
             dstV[i] = chroma_vals[new_cr[i]];
         }
         dstU   += pic->linesize[1];
         dstV   += pic->linesize[2];
         new_cb += new_cb_stride;
         new_cr += new_cr_stride;
     }
 

     ff_dlog(avctx, "Frame data: provided %d bytes, used %d bytes\n",

             buf_size, get_bits_count(&gb) >> 3);

     FFSWAP(uint8_t*, s->old_y, s->new_y);
     FFSWAP(uint8_t*, s->old_u, s->new_u);
     FFSWAP(uint8_t*, s->old_v, s->new_v);

     *got_frame = 1;

 
     return buf_size;
 }
 

 AVCodec ff_escape130_decoder = {
     .name           = "escape130",

     .long_name      = NULL_IF_CONFIG_SMALL("Escape 130"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_ESCAPE130,

     .priv_data_size = sizeof(Escape130Context),
     .init           = escape130_decode_init,
     .close          = escape130_decode_close,
     .decode         = escape130_decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

 };