libavcodec/msrledec.c

   1 /*
   2  * Micrsoft RLE Decoder
   3  * Copyright (C) 2008 Konstantin Shishkov
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 libavcodec/msrledec.c
  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
  32 #define FETCH_NEXT_STREAM_BYTE() \
  33     if (stream_ptr >= data_size) \
  34     { \
  35       av_log(avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (1)\n"); \
  36       return -1; \
  37     } \
  38     stream_byte = data[stream_ptr++];
  39
  40 static int msrle_decode_pal4(AVCodecContext *avctx, AVPicture *pic,
  41                               const uint8_t *data, int data_size)
  42 {
  43     int stream_ptr = 0;
  44     unsigned char rle_code;
  45     unsigned char extra_byte, odd_pixel;
  46     unsigned char stream_byte;
  47     int pixel_ptr = 0;
  48     int row_dec = pic->linesize[0];
  49     int row_ptr = (avctx->height - 1) * row_dec;
  50     int frame_size = row_dec * avctx->height;
  51     int i;
  52
  53     while (row_ptr >= 0) {
  54         FETCH_NEXT_STREAM_BYTE();
  55         rle_code = stream_byte;
  56         if (rle_code == 0) {
  57             /* fetch the next byte to see how to handle escape code */
  58             FETCH_NEXT_STREAM_BYTE();
  59             if (stream_byte == 0) {
  60                 /* line is done, goto the next one */
  61                 row_ptr -= row_dec;
  62                 pixel_ptr = 0;
  63             } else if (stream_byte == 1) {
  64                 /* decode is done */
  65                 return 0;
  66             } else if (stream_byte == 2) {
  67                 /* reposition frame decode coordinates */
  68                 FETCH_NEXT_STREAM_BYTE();
  69                 pixel_ptr += stream_byte;
  70                 FETCH_NEXT_STREAM_BYTE();
  71                 row_ptr -= stream_byte * row_dec;
  72         } else {
  73             // copy pixels from encoded stream
  74             odd_pixel =  stream_byte & 1;
  75             rle_code = (stream_byte + 1) / 2;
  76             extra_byte = rle_code & 0x01;
  77             if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
  78                 (row_ptr < 0)) {
  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                 (row_ptr < 0)) {
 105                 av_log(avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
 106                 return -1;
 107             }
 108             FETCH_NEXT_STREAM_BYTE();
 109             for (i = 0; i < rle_code; i++) {
 110                 if (pixel_ptr >= avctx->width)
 111                     break;
 112                 if ((i & 1) == 0)
 113                     pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
 114                 else
 115                     pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
 116                 pixel_ptr++;
 117             }
 118         }
 119     }
 120
 121     /* one last sanity check on the way out */
 122     if (stream_ptr < data_size) {
 123         av_log(avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
 124             stream_ptr, data_size);
 125         return -1;
 126     }
 127
 128     return 0;
 129 }
 130
 131
 132 static int msrle_decode_8_16_24_32(AVCodecContext *avctx, AVPicture *pic, int depth,
 133                                     const uint8_t *data, int srcsize)
 134 {
 135     uint8_t *output, *output_end;
 136     const uint8_t* src = data;
 137     int p1, p2, line=avctx->height, pos=0, i;
 138     uint16_t pix16;
 139     uint32_t pix32;
 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){
 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                 if (line < 0){
 162                     av_log(avctx, AV_LOG_ERROR, "Skip beyond picture bounds\n");
 163                     return -1;
 164                 }
 165                 pos += p1;
 166                 output = pic->data[0] + line * pic->linesize[0] + pos * (depth >> 3);
 167                 continue;
 168             }
 169             // Copy data
 170             if (output + p2 * (depth >> 3) > output_end) {
 171                 src += p2 * (depth >> 3);
 172                 continue;
 173             }
 174             if ((depth == 8) || (depth == 24)) {
 175                 for(i = 0; i < p2 * (depth >> 3); i++) {
 176                     *output++ = *src++;
 177                 }
 178                 // RLE8 copy is actually padded - and runs are not!
 179                 if(depth == 8 && (p2 & 1)) {
 180                     src++;
 181                 }
 182             } else if (depth == 16) {
 183                 for(i = 0; i < p2; i++) {
 184                     pix16 = AV_RL16(src);
 185                     src += 2;
 186                     *(uint16_t*)output = pix16;
 187                     output += 2;
 188                 }
 189             } else if (depth == 32) {
 190                 for(i = 0; i < p2; i++) {
 191                     pix32 = AV_RL32(src);
 192                     src += 4;
 193                     *(uint32_t*)output = pix32;
 194                     output += 4;
 195                 }
 196             }
 197             pos += p2;
 198         } else { //Run of pixels
 199             uint8_t pix[3]; //original pixel
 200             switch(depth){
 201             case  8: pix[0] = *src++;
 202                      break;
 203             case 16: pix16 = AV_RL16(src);
 204                      src += 2;
 205                      break;
 206             case 24: pix[0] = *src++;
 207                      pix[1] = *src++;
 208                      pix[2] = *src++;
 209                      break;
 210             case 32: pix32 = AV_RL32(src);
 211                      src += 4;
 212                      break;
 213             }
 214             if (output + p1 * (depth >> 3) > output_end)
 215                 continue;
 216             for(i = 0; i < p1; i++) {
 217                 switch(depth){
 218                 case  8: *output++ = pix[0];
 219                          break;
 220                 case 16: *(uint16_t*)output = pix16;
 221                          output += 2;
 222                          break;
 223                 case 24: *output++ = pix[0];
 224                          *output++ = pix[1];
 225                          *output++ = pix[2];
 226                          break;
 227                 case 32: *(uint32_t*)output = pix32;
 228                          output += 4;
 229                          break;
 230                 }
 231             }
 232             pos += p1;
 233         }
 234     }
 235
 236     av_log(avctx, AV_LOG_WARNING, "MS RLE warning: no End-of-picture code\n");
 237     return 0;
 238 }
 239
 240
 241 int ff_msrle_decode(AVCodecContext *avctx, AVPicture *pic, int depth,
 242                     const uint8_t* data, int data_size)
 243 {
 244     switch(depth){
 245     case  4:
 246         return msrle_decode_pal4(avctx, pic, data, data_size);
 247     case  8:
 248     case 16:
 249     case 24:
 250     case 32:
 251         return msrle_decode_8_16_24_32(avctx, pic, depth, data, data_size);
 252     default:
 253         av_log(avctx, AV_LOG_ERROR, "Unknown depth %d\n", depth);
 254         return -1;
 255     }
 256 }
 257