/*
  * QPEG codec
  * Copyright (c) 2004 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 libavcodec/qpeg.c

  * QPEG codec.
  */

 #include "avcodec.h"
 
 typedef struct QpegContext{
     AVCodecContext *avctx;
     AVFrame pic;
     uint8_t *refdata;
 } QpegContext;
 

 static void qpeg_decode_intra(const uint8_t *src, uint8_t *dst, int size,

                             int stride, int width, int height)

 {
     int i;
     int code;
     int c0, c1;
     int run, copy;
     int filled = 0;

     int rows_to_go;

     rows_to_go = height;

     height--;
     dst = dst + height * stride;

     while((size > 0) && (rows_to_go > 0)) {

         code = *src++;
         size--;
         run = copy = 0;
         if(code == 0xFC) /* end-of-picture code */
             break;
         if(code >= 0xF8) { /* very long run */
             c0 = *src++;
             c1 = *src++;
             size -= 2;
             run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;
         } else if (code >= 0xF0) { /* long run */
             c0 = *src++;
             size--;
             run = ((code & 0xF) << 8) + c0 + 2;
         } else if (code >= 0xE0) { /* short run */
             run = (code & 0x1F) + 2;
         } else if (code >= 0xC0) { /* very long copy */
             c0 = *src++;
             c1 = *src++;
             size -= 2;
             copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;
         } else if (code >= 0x80) { /* long copy */
             c0 = *src++;
             size--;
             copy = ((code & 0x7F) << 8) + c0 + 1;
         } else { /* short copy */
             copy = code + 1;
         }

         /* perform actual run or copy */
         if(run) {
             int p;

             p = *src++;
             size--;
             for(i = 0; i < run; i++) {
                 dst[filled++] = p;
                 if (filled >= width) {
                     filled = 0;
                     dst -= stride;

                     rows_to_go--;
                     if(rows_to_go <= 0)
                         break;

                 }
             }
         } else {

             size -= copy;

             for(i = 0; i < copy; i++) {
                 dst[filled++] = *src++;
                 if (filled >= width) {
                     filled = 0;
                     dst -= stride;

                     rows_to_go--;
                     if(rows_to_go <= 0)
                         break;

                 }
             }
         }

     }
 }
 

 static const int qpeg_table_h[16] =

  { 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};

 static const int qpeg_table_w[16] =

  { 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};

 /* Decodes delta frames */

 static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,

                             int stride, int width, int height,

                             int delta, const uint8_t *ctable, uint8_t *refdata)

 {
     int i, j;
     int code;
     int filled = 0;

     int orig_height;

     /* copy prev frame */
     for(i = 0; i < height; i++)

         memcpy(refdata + (i * width), dst + (i * stride), width);

     orig_height = height;

     height--;
     dst = dst + height * stride;
 

     while((size > 0) && (height >= 0)) {

         code = *src++;
         size--;

         if(delta) {
             /* motion compensation */
             while((code & 0xF0) == 0xF0) {
                 if(delta == 1) {
                     int me_idx;
                     int me_w, me_h, me_x, me_y;
                     uint8_t *me_plane;
                     int corr, val;

                     /* get block size by index */
                     me_idx = code & 0xF;
                     me_w = qpeg_table_w[me_idx];
                     me_h = qpeg_table_h[me_idx];

                     /* extract motion vector */
                     corr = *src++;
                     size--;

                     val = corr >> 4;
                     if(val > 7)
                         val -= 16;
                     me_x = val;

                     val = corr & 0xF;
                     if(val > 7)
                         val -= 16;
                     me_y = val;

                     /* check motion vector */
                     if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||
                        (height - me_y - me_h < 0) || (height - me_y > orig_height) ||
                        (filled + me_w > width) || (height - me_h < 0))
                         av_log(NULL, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",
                                me_x, me_y, me_w, me_h, filled, height);
                     else {
                         /* do motion compensation */
                         me_plane = refdata + (filled + me_x) + (height - me_y) * width;
                         for(j = 0; j < me_h; j++) {
                             for(i = 0; i < me_w; i++)
                                 dst[filled + i - (j * stride)] = me_plane[i - (j * width)];
                         }

                     }
                 }
                 code = *src++;
                 size--;
             }
         }

         if(code == 0xE0) /* end-of-picture code */
             break;
         if(code > 0xE0) { /* run code: 0xE1..0xFF */
             int p;

             code &= 0x1F;
             p = *src++;
             size--;
             for(i = 0; i <= code; i++) {
                 dst[filled++] = p;
                 if(filled >= width) {
                     filled = 0;
                     dst -= stride;
                     height--;
                 }
             }
         } else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */
             code &= 0x1F;

             for(i = 0; i <= code; i++) {
                 dst[filled++] = *src++;
                 if(filled >= width) {
                     filled = 0;
                     dst -= stride;
                     height--;
                 }
             }
             size -= code + 1;
         } else if(code >= 0x80) { /* skip code: 0x80..0xBF */
             int skip;

             code &= 0x3F;
             /* codes 0x80 and 0x81 are actually escape codes,
                skip value minus constant is in the next byte */
             if(!code)
                 skip = (*src++) + 64;
             else if(code == 1)
                 skip = (*src++) + 320;
             else
                 skip = code;
             filled += skip;
             while( filled >= width) {
                 filled -= width;
                 dst -= stride;
                 height--;

                 if(height < 0)
                     break;

             }
         } else {
             /* zero code treated as one-pixel skip */
             if(code)
                 dst[filled++] = ctable[code & 0x7F];
             else
                 filled++;
             if(filled >= width) {
                 filled = 0;
                 dst -= stride;
                 height--;
             }
         }

     }
 }
 

 static int decode_frame(AVCodecContext *avctx,

                         void *data, int *data_size,

                         const uint8_t *buf, int buf_size)

 {
     QpegContext * const a = avctx->priv_data;
     AVFrame * const p= (AVFrame*)&a->pic;
     uint8_t* outdata;
     int delta;

     if(p->data[0])
         avctx->release_buffer(avctx, p);
 
     p->reference= 0;
     if(avctx->get_buffer(avctx, p) < 0){
         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return -1;
     }
     outdata = a->pic.data[0];
     if(buf[0x85] == 0x10) {

         qpeg_decode_intra(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height);

     } else {

         delta = buf[0x85];
         qpeg_decode_inter(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height, delta, buf + 4, a->refdata);

     }
 
     /* make the palette available on the way out */
     memcpy(a->pic.data[1], a->avctx->palctrl->palette, AVPALETTE_SIZE);
     if (a->avctx->palctrl->palette_changed) {
         a->pic.palette_has_changed = 1;
         a->avctx->palctrl->palette_changed = 0;
     }
 
     *data_size = sizeof(AVFrame);
     *(AVFrame*)data = a->pic;

     return buf_size;
 }
 

 static av_cold int decode_init(AVCodecContext *avctx){

     QpegContext * const a = avctx->priv_data;

     a->avctx = avctx;
     avctx->pix_fmt= PIX_FMT_PAL8;
     a->pic.data[0] = NULL;
     a->refdata = av_malloc(avctx->width * avctx->height);
 
     return 0;
 }
 

 static av_cold int decode_end(AVCodecContext *avctx){

     QpegContext * const a = avctx->priv_data;

     AVFrame * const p= (AVFrame*)&a->pic;

     if(p->data[0])
         avctx->release_buffer(avctx, p);

 
     av_free(a->refdata);
     return 0;
 }
 
 AVCodec qpeg_decoder = {
     "qpeg",
     CODEC_TYPE_VIDEO,
     CODEC_ID_QPEG,
     sizeof(QpegContext),
     decode_init,
     NULL,
     decode_end,
     decode_frame,
     CODEC_CAP_DR1,

     .long_name = NULL_IF_CONFIG_SMALL("Q-team QPEG"),

 };