/*
  * Micrsoft RLE Decoder
  * Copyright (C) 2008 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/msrledec.c

  * MS RLE Decoder based on decoder by Mike Melanson and my own for TSCC
  * For more information about the MS RLE format, visit:
  *   http://www.multimedia.cx/msrle.txt
  */
 

 #include "libavutil/intreadwrite.h"

 #include "avcodec.h"
 
 #define FETCH_NEXT_STREAM_BYTE() \
     if (stream_ptr >= data_size) \
     { \
       av_log(avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (1)\n"); \
       return -1; \
     } \
     stream_byte = data[stream_ptr++];
 
 static int msrle_decode_pal4(AVCodecContext *avctx, AVPicture *pic,
                               const uint8_t *data, int data_size)
 {
     int stream_ptr = 0;
     unsigned char rle_code;
     unsigned char extra_byte, odd_pixel;
     unsigned char stream_byte;
     int pixel_ptr = 0;
     int row_dec = pic->linesize[0];
     int row_ptr = (avctx->height - 1) * row_dec;
     int frame_size = row_dec * avctx->height;
     int i;
 
     while (row_ptr >= 0) {
         FETCH_NEXT_STREAM_BYTE();
         rle_code = stream_byte;
         if (rle_code == 0) {
             /* fetch the next byte to see how to handle escape code */
             FETCH_NEXT_STREAM_BYTE();
             if (stream_byte == 0) {
                 /* line is done, goto the next one */
                 row_ptr -= row_dec;
                 pixel_ptr = 0;
             } else if (stream_byte == 1) {
                 /* decode is done */
                 return 0;
             } else if (stream_byte == 2) {
                 /* reposition frame decode coordinates */
                 FETCH_NEXT_STREAM_BYTE();
                 pixel_ptr += stream_byte;
                 FETCH_NEXT_STREAM_BYTE();
                 row_ptr -= stream_byte * row_dec;
         } else {
             // copy pixels from encoded stream
             odd_pixel =  stream_byte & 1;
             rle_code = (stream_byte + 1) / 2;
             extra_byte = rle_code & 0x01;
             if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
                 (row_ptr < 0)) {
                 av_log(avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
                 return -1;
             }
 
             for (i = 0; i < rle_code; i++) {
                 if (pixel_ptr >= avctx->width)
                     break;
                 FETCH_NEXT_STREAM_BYTE();
                 pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
                 pixel_ptr++;
                 if (i + 1 == rle_code && odd_pixel)
                     break;
                 if (pixel_ptr >= avctx->width)
                     break;
                 pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
                 pixel_ptr++;
             }
 
             // if the RLE code is odd, skip a byte in the stream
             if (extra_byte)
               stream_ptr++;
             }
         } else {
             // decode a run of data
             if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
                 (row_ptr < 0)) {
                 av_log(avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
                 return -1;
             }
             FETCH_NEXT_STREAM_BYTE();
             for (i = 0; i < rle_code; i++) {
                 if (pixel_ptr >= avctx->width)
                     break;
                 if ((i & 1) == 0)
                     pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
                 else
                     pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
                 pixel_ptr++;
             }
         }
     }
 
     /* one last sanity check on the way out */
     if (stream_ptr < data_size) {
         av_log(avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
             stream_ptr, data_size);
         return -1;
     }
 
     return 0;
 }
 
 
 static int msrle_decode_8_16_24_32(AVCodecContext *avctx, AVPicture *pic, int depth,
                                     const uint8_t *data, int srcsize)
 {
     uint8_t *output, *output_end;
     const uint8_t* src = data;
     int p1, p2, line=avctx->height, pos=0, i;

     uint16_t av_uninit(pix16);
     uint32_t av_uninit(pix32);

 
     output = pic->data[0] + (avctx->height - 1) * pic->linesize[0];
     output_end = pic->data[0] + (avctx->height) * pic->linesize[0];
     while(src < data + srcsize) {
         p1 = *src++;
         if(p1 == 0) { //Escape code
             p2 = *src++;
             if(p2 == 0) { //End-of-line
                 output = pic->data[0] + (--line) * pic->linesize[0];

                 if (line < 0){
                     av_log(avctx, AV_LOG_ERROR, "Next line is beyond picture bounds\n");

                     return -1;

                 }

                 pos = 0;
                 continue;
             } else if(p2 == 1) { //End-of-picture
                 return 0;
             } else if(p2 == 2) { //Skip
                 p1 = *src++;
                 p2 = *src++;
                 line -= p2;

                 if (line < 0){
                     av_log(avctx, AV_LOG_ERROR, "Skip beyond picture bounds\n");

                     return -1;

                 }

                 pos += p1;
                 output = pic->data[0] + line * pic->linesize[0] + pos * (depth >> 3);
                 continue;
             }
             // Copy data
             if (output + p2 * (depth >> 3) > output_end) {
                 src += p2 * (depth >> 3);
                 continue;
             }
             if ((depth == 8) || (depth == 24)) {
                 for(i = 0; i < p2 * (depth >> 3); i++) {
                     *output++ = *src++;
                 }
                 // RLE8 copy is actually padded - and runs are not!
                 if(depth == 8 && (p2 & 1)) {
                     src++;
                 }
             } else if (depth == 16) {
                 for(i = 0; i < p2; i++) {
                     pix16 = AV_RL16(src);
                     src += 2;
                     *(uint16_t*)output = pix16;
                     output += 2;
                 }
             } else if (depth == 32) {
                 for(i = 0; i < p2; i++) {
                     pix32 = AV_RL32(src);
                     src += 4;
                     *(uint32_t*)output = pix32;
                     output += 4;
                 }
             }
             pos += p2;
         } else { //Run of pixels

             uint8_t pix[3]; //original pixel

             switch(depth){
             case  8: pix[0] = *src++;
                      break;
             case 16: pix16 = AV_RL16(src);
                      src += 2;
                      break;
             case 24: pix[0] = *src++;
                      pix[1] = *src++;
                      pix[2] = *src++;
                      break;
             case 32: pix32 = AV_RL32(src);
                      src += 4;
                      break;
             }
             if (output + p1 * (depth >> 3) > output_end)
                 continue;
             for(i = 0; i < p1; i++) {
                 switch(depth){
                 case  8: *output++ = pix[0];
                          break;
                 case 16: *(uint16_t*)output = pix16;
                          output += 2;
                          break;
                 case 24: *output++ = pix[0];
                          *output++ = pix[1];
                          *output++ = pix[2];
                          break;
                 case 32: *(uint32_t*)output = pix32;
                          output += 4;
                          break;
                 }
             }
             pos += p1;
         }
     }
 
     av_log(avctx, AV_LOG_WARNING, "MS RLE warning: no End-of-picture code\n");
     return 0;
 }
 
 
 int ff_msrle_decode(AVCodecContext *avctx, AVPicture *pic, int depth,
                     const uint8_t* data, int data_size)
 {
     switch(depth){
     case  4:
         return msrle_decode_pal4(avctx, pic, data, data_size);
     case  8:
     case 16:
     case 24:
     case 32:
         return msrle_decode_8_16_24_32(avctx, pic, depth, data, data_size);
     default:
         av_log(avctx, AV_LOG_ERROR, "Unknown depth %d\n", depth);
         return -1;
     }
 }