libavcodec/msrledec.c

   1 /*
   2  * Microsoft RLE decoder
   3  * Copyright (C) 2008 Konstantin Shishkov
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * MS RLE decoder based on decoder by Mike Melanson and my own for TSCC
  25  * For more information about the MS RLE format, visit:
  26  *   http://www.multimedia.cx/msrle.txt
  27  */
  28
  29 #include "libavutil/intreadwrite.h"
  30 #include "avcodec.h"
  31 #include "msrledec.h"
  32
  33 #define FETCH_NEXT_STREAM_BYTE() \
  34     if (stream_ptr >= data_size) \
  35     { \
  36       av_log(avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (1)\n"); \
  37       return -1; \
  38     } \
  39     stream_byte = data[stream_ptr++];
  40
  41 static int msrle_decode_pal4(AVCodecContext *avctx, AVPicture *pic,
  42                               const uint8_t *data, int data_size)
  43 {
  44     int stream_ptr = 0;
  45     unsigned char rle_code;
  46     unsigned char extra_byte, odd_pixel;
  47     unsigned char stream_byte;
  48     unsigned int pixel_ptr = 0;
  49     int row_dec = pic->linesize[0];
  50     int row_ptr = (avctx->height - 1) * row_dec;
  51     int frame_size = row_dec * avctx->height;
  52     int i;
  53
  54     while (row_ptr >= 0) {
  55         FETCH_NEXT_STREAM_BYTE();
  56         rle_code = stream_byte;
  57         if (rle_code == 0) {
  58             /* fetch the next byte to see how to handle escape code */
  59             FETCH_NEXT_STREAM_BYTE();
  60             if (stream_byte == 0) {
  61                 /* line is done, goto the next one */
  62                 row_ptr -= row_dec;
  63                 pixel_ptr = 0;
  64             } else if (stream_byte == 1) {
  65                 /* decode is done */
  66                 return 0;
  67             } else if (stream_byte == 2) {
  68                 /* reposition frame decode coordinates */
  69                 FETCH_NEXT_STREAM_BYTE();
  70                 pixel_ptr += stream_byte;
  71                 FETCH_NEXT_STREAM_BYTE();
  72                 row_ptr -= stream_byte * row_dec;
  73             } else {
  74                 // copy pixels from encoded stream
  75                 odd_pixel =  stream_byte & 1;
  76                 rle_code = (stream_byte + 1) / 2;
  77                 extra_byte = rle_code & 0x01;
  78                 if (row_ptr + pixel_ptr + stream_byte > frame_size) {
  79                     av_log(avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
  80                     return -1;
  81                 }
  82
  83                 for (i = 0; i < rle_code; i++) {
  84                     if (pixel_ptr >= avctx->width)
  85                         break;
  86                     FETCH_NEXT_STREAM_BYTE();
  87                     pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
  88                     pixel_ptr++;
  89                     if (i + 1 == rle_code && odd_pixel)
  90                         break;
  91                     if (pixel_ptr >= avctx->width)
  92                         break;
  93                     pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
  94                     pixel_ptr++;
  95                 }
  96
  97                 // if the RLE code is odd, skip a byte in the stream
  98                 if (extra_byte)
  99                     stream_ptr++;
 100             }
 101         } else {
 102             // decode a run of data
 103             if (row_ptr + pixel_ptr + stream_byte > frame_size) {
 104                 av_log(avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
 105                 return -1;
 106             }
 107             FETCH_NEXT_STREAM_BYTE();
 108             for (i = 0; i < rle_code; i++) {
 109                 if (pixel_ptr >= avctx->width)
 110                     break;
 111                 if ((i & 1) == 0)
 112                     pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
 113                 else
 114                     pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
 115                 pixel_ptr++;
 116             }
 117         }
 118     }
 119
 120     /* one last sanity check on the way out */
 121     if (stream_ptr < data_size) {
 122         av_log(avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
 123             stream_ptr, data_size);
 124         return -1;
 125     }
 126
 127     return 0;
 128 }
 129
 130
 131 static int msrle_decode_8_16_24_32(AVCodecContext *avctx, AVPicture *pic, int depth,
 132                                     const uint8_t *data, int srcsize)
 133 {
 134     uint8_t *output, *output_end;
 135     const uint8_t* src = data;
 136     int p1, p2, line=avctx->height - 1, pos=0, i;
 137     uint16_t av_uninit(pix16);
 138     uint32_t av_uninit(pix32);
 139     unsigned int width= FFABS(pic->linesize[0]) / (depth >> 3);
 140
 141     output     = pic->data[0] + (avctx->height - 1) * pic->linesize[0];
 142     output_end = pic->data[0] +  avctx->height      * pic->linesize[0];
 143     while(src < data + srcsize) {
 144         p1 = *src++;
 145         if(p1 == 0) { //Escape code
 146             p2 = *src++;
 147             if(p2 == 0) { //End-of-line
 148                 output = pic->data[0] + (--line) * pic->linesize[0];
 149                 if (line < 0 && !(src+1 < data + srcsize && AV_RB16(src) == 1)) {
 150                     av_log(avctx, AV_LOG_ERROR, "Next line is beyond picture bounds\n");
 151                     return -1;
 152                 }
 153                 pos = 0;
 154                 continue;
 155             } else if(p2 == 1) { //End-of-picture
 156                 return 0;
 157             } else if(p2 == 2) { //Skip
 158                 p1 = *src++;
 159                 p2 = *src++;
 160                 line -= p2;
 161                 pos += p1;
 162                 if (line < 0 || pos >= width){
 163                     av_log(avctx, AV_LOG_ERROR, "Skip beyond picture bounds\n");
 164                     return -1;
 165                 }
 166                 output = pic->data[0] + line * pic->linesize[0] + pos * (depth >> 3);
 167                 continue;
 168             }
 169             // Copy data
 170             if ((pic->linesize[0] > 0 && output + p2 * (depth >> 3) > output_end)
 171               ||(pic->linesize[0] < 0 && output + p2 * (depth >> 3) < output_end)) {
 172                 src += p2 * (depth >> 3);
 173                 continue;
 174             }
 175             if ((depth == 8) || (depth == 24)) {
 176                 for(i = 0; i < p2 * (depth >> 3); i++) {
 177                     *output++ = *src++;
 178                 }
 179                 // RLE8 copy is actually padded - and runs are not!
 180                 if(depth == 8 && (p2 & 1)) {
 181                     src++;
 182                 }
 183             } else if (depth == 16) {
 184                 for(i = 0; i < p2; i++) {
 185                     pix16 = AV_RL16(src);
 186                     src += 2;
 187                     *(uint16_t*)output = pix16;
 188                     output += 2;
 189                 }
 190             } else if (depth == 32) {
 191                 for(i = 0; i < p2; i++) {
 192                     pix32 = AV_RL32(src);
 193                     src += 4;
 194                     *(uint32_t*)output = pix32;
 195                     output += 4;
 196                 }
 197             }
 198             pos += p2;
 199         } else { //run of pixels
 200             uint8_t pix[3]; //original pixel
 201             switch(depth){
 202             case  8: pix[0] = *src++;
 203                      break;
 204             case 16: pix16 = AV_RL16(src);
 205                      src += 2;
 206                      break;
 207             case 24: pix[0] = *src++;
 208                      pix[1] = *src++;
 209                      pix[2] = *src++;
 210                      break;
 211             case 32: pix32 = AV_RL32(src);
 212                      src += 4;
 213                      break;
 214             }
 215             if ((pic->linesize[0] > 0 && output + p1 * (depth >> 3) > output_end)
 216               ||(pic->linesize[0] < 0 && output + p1 * (depth >> 3) < output_end))
 217                 continue;
 218             for(i = 0; i < p1; i++) {
 219                 switch(depth){
 220                 case  8: *output++ = pix[0];
 221                          break;
 222                 case 16: *(uint16_t*)output = pix16;
 223                          output += 2;
 224                          break;
 225                 case 24: *output++ = pix[0];
 226                          *output++ = pix[1];
 227                          *output++ = pix[2];
 228                          break;
 229                 case 32: *(uint32_t*)output = pix32;
 230                          output += 4;
 231                          break;
 232                 }
 233             }
 234             pos += p1;
 235         }
 236     }
 237
 238     av_log(avctx, AV_LOG_WARNING, "MS RLE warning: no end-of-picture code\n");
 239     return 0;
 240 }
 241
 242
 243 int ff_msrle_decode(AVCodecContext *avctx, AVPicture *pic, int depth,
 244                     const uint8_t* data, int data_size)
 245 {
 246     switch(depth){
 247     case  4:
 248         return msrle_decode_pal4(avctx, pic, data, data_size);
 249     case  8:
 250     case 16:
 251     case 24:
 252     case 32:
 253         return msrle_decode_8_16_24_32(avctx, pic, depth, data, data_size);
 254     default:
 255         av_log(avctx, AV_LOG_ERROR, "Unknown depth %d\n", depth);
 256         return -1;
 257     }
 258 }
 259