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 static int msrle_decode_pal4(AVCodecContext *avctx, AVPicture *pic,
  34                              GetByteContext *gb)
  35 {
  36     unsigned char rle_code;
  37     unsigned char extra_byte, odd_pixel;
  38     unsigned char stream_byte;
  39     unsigned int pixel_ptr = 0;
  40     int row_dec = pic->linesize[0];
  41     int row_ptr = (avctx->height - 1) * row_dec;
  42     int frame_size = row_dec * avctx->height;
  43     int i;
  44
  45     while (row_ptr >= 0) {
  46         if (bytestream2_get_bytes_left(gb) <= 0) {
  47             av_log(avctx, AV_LOG_ERROR,
  48                    "MS RLE: bytestream overrun, %d rows left\n",
  49                    row_ptr);
  50             return AVERROR_INVALIDDATA;
  51         }
  52         rle_code = stream_byte = bytestream2_get_byteu(gb);
  53         if (rle_code == 0) {
  54             /* fetch the next byte to see how to handle escape code */
  55             stream_byte = bytestream2_get_byte(gb);
  56             if (stream_byte == 0) {
  57                 /* line is done, goto the next one */
  58                 row_ptr -= row_dec;
  59                 pixel_ptr = 0;
  60             } else if (stream_byte == 1) {
  61                 /* decode is done */
  62                 return 0;
  63             } else if (stream_byte == 2) {
  64                 /* reposition frame decode coordinates */
  65                 stream_byte = bytestream2_get_byte(gb);
  66                 pixel_ptr += stream_byte;
  67                 stream_byte = bytestream2_get_byte(gb);
  68                 row_ptr -= stream_byte * row_dec;
  69             } else {
  70                 // copy pixels from encoded stream
  71                 odd_pixel =  stream_byte & 1;
  72                 rle_code = (stream_byte + 1) / 2;
  73                 extra_byte = rle_code & 0x01;
  74                 if (row_ptr + pixel_ptr + stream_byte > frame_size ||
  75                     bytestream2_get_bytes_left(gb) < rle_code) {
  76                     av_log(avctx, AV_LOG_ERROR,
  77                            "MS RLE: frame/stream ptr just went out of bounds (copy)\n");
  78                     return AVERROR_INVALIDDATA;
  79                 }
  80
  81                 for (i = 0; i < rle_code; i++) {
  82                     if (pixel_ptr >= avctx->width)
  83                         break;
  84                     stream_byte = bytestream2_get_byteu(gb);
  85                     pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
  86                     pixel_ptr++;
  87                     if (i + 1 == rle_code && odd_pixel)
  88                         break;
  89                     if (pixel_ptr >= avctx->width)
  90                         break;
  91                     pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
  92                     pixel_ptr++;
  93                 }
  94
  95                 // if the RLE code is odd, skip a byte in the stream
  96                 if (extra_byte)
  97                     bytestream2_skip(gb, 1);
  98             }
  99         } else {
 100             // decode a run of data
 101             if (row_ptr + pixel_ptr + stream_byte > frame_size) {
 102                 av_log(avctx, AV_LOG_ERROR,
 103                        "MS RLE: frame ptr just went out of bounds (run)\n");
 104                 return AVERROR_INVALIDDATA;
 105             }
 106             stream_byte = bytestream2_get_byte(gb);
 107             for (i = 0; i < rle_code; i++) {
 108                 if (pixel_ptr >= avctx->width)
 109                     break;
 110                 if ((i & 1) == 0)
 111                     pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
 112                 else
 113                     pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
 114                 pixel_ptr++;
 115             }
 116         }
 117     }
 118
 119     /* one last sanity check on the way out */
 120     if (bytestream2_get_bytes_left(gb)) {
 121         av_log(avctx, AV_LOG_ERROR,
 122                "MS RLE: ended frame decode with %d bytes left over\n",
 123                bytestream2_get_bytes_left(gb));
 124         return AVERROR_INVALIDDATA;
 125     }
 126
 127     return 0;
 128 }
 129
 130
 131 static int msrle_decode_8_16_24_32(AVCodecContext *avctx, AVPicture *pic,
 132                                    int depth, GetByteContext *gb)
 133 {
 134     uint8_t *output, *output_end;
 135     int p1, p2, line=avctx->height - 1, pos=0, i;
 136     uint16_t pix16;
 137     uint32_t pix32;
 138     unsigned int width= FFABS(pic->linesize[0]) / (depth >> 3);
 139
 140     output     = pic->data[0] + (avctx->height - 1) * pic->linesize[0];
 141     output_end = pic->data[0] +  avctx->height      * pic->linesize[0];
 142     while (bytestream2_get_bytes_left(gb) > 0) {
 143         p1 = bytestream2_get_byteu(gb);
 144         if(p1 == 0) { //Escape code
 145             p2 = bytestream2_get_byte(gb);
 146             if(p2 == 0) { //End-of-line
 147                 if (--line < 0) {
 148                     if (bytestream2_get_be16(gb) == 1) { // end-of-picture
 149                         return 0;
 150                     } else {
 151                         av_log(avctx, AV_LOG_ERROR,
 152                                "Next line is beyond picture bounds (%d bytes left)\n",
 153                                bytestream2_get_bytes_left(gb));
 154                         return AVERROR_INVALIDDATA;
 155                     }
 156                 }
 157                 output = pic->data[0] + line * pic->linesize[0];
 158                 pos = 0;
 159                 continue;
 160             } else if(p2 == 1) { //End-of-picture
 161                 return 0;
 162             } else if(p2 == 2) { //Skip
 163                 p1 = bytestream2_get_byte(gb);
 164                 p2 = bytestream2_get_byte(gb);
 165                 line -= p2;
 166                 pos += p1;
 167                 if (line < 0 || pos >= width){
 168                     av_log(avctx, AV_LOG_ERROR, "Skip beyond picture bounds\n");
 169                     return -1;
 170                 }
 171                 output = pic->data[0] + line * pic->linesize[0] + pos * (depth >> 3);
 172                 continue;
 173             }
 174             // Copy data
 175             if ((pic->linesize[0] > 0 && output + p2 * (depth >> 3) > output_end) ||
 176                 (pic->linesize[0] < 0 && output + p2 * (depth >> 3) < output_end)) {
 177                 bytestream2_skip(gb, 2 * (depth >> 3));
 178                 continue;
 179             } else if (bytestream2_get_bytes_left(gb) < p2 * (depth >> 3)) {
 180                 av_log(avctx, AV_LOG_ERROR, "bytestream overrun\n");
 181                 return AVERROR_INVALIDDATA;
 182             }
 183
 184             if ((depth == 8) || (depth == 24)) {
 185                 for(i = 0; i < p2 * (depth >> 3); i++) {
 186                     *output++ = bytestream2_get_byteu(gb);
 187                 }
 188                 // RLE8 copy is actually padded - and runs are not!
 189                 if(depth == 8 && (p2 & 1)) {
 190                     bytestream2_skip(gb, 1);
 191                 }
 192             } else if (depth == 16) {
 193                 for(i = 0; i < p2; i++) {
 194                     *(uint16_t*)output = bytestream2_get_le16u(gb);
 195                     output += 2;
 196                 }
 197             } else if (depth == 32) {
 198                 for(i = 0; i < p2; i++) {
 199                     *(uint32_t*)output = bytestream2_get_le32u(gb);
 200                     output += 4;
 201                 }
 202             }
 203             pos += p2;
 204         } else { //run of pixels
 205             uint8_t pix[3]; //original pixel
 206             switch(depth){
 207             case  8: pix[0] = bytestream2_get_byte(gb);
 208                      break;
 209             case 16: pix16  = bytestream2_get_le16(gb);
 210                      break;
 211             case 24: pix[0] = bytestream2_get_byte(gb);
 212                      pix[1] = bytestream2_get_byte(gb);
 213                      pix[2] = bytestream2_get_byte(gb);
 214                      break;
 215             case 32: pix32  = bytestream2_get_le32(gb);
 216                      break;
 217             }
 218             if ((pic->linesize[0] > 0 && output + p1 * (depth >> 3) > output_end) ||
 219                 (pic->linesize[0] < 0 && output + p1 * (depth >> 3) < output_end))
 220                 continue;
 221             for(i = 0; i < p1; i++) {
 222                 switch(depth){
 223                 case  8: *output++ = pix[0];
 224                          break;
 225                 case 16: *(uint16_t*)output = pix16;
 226                          output += 2;
 227                          break;
 228                 case 24: *output++ = pix[0];
 229                          *output++ = pix[1];
 230                          *output++ = pix[2];
 231                          break;
 232                 case 32: *(uint32_t*)output = pix32;
 233                          output += 4;
 234                          break;
 235                 }
 236             }
 237             pos += p1;
 238         }
 239     }
 240
 241     av_log(avctx, AV_LOG_WARNING, "MS RLE warning: no end-of-picture code\n");
 242     return 0;
 243 }
 244
 245
 246 int ff_msrle_decode(AVCodecContext *avctx, AVPicture *pic,
 247                     int depth, GetByteContext *gb)
 248 {
 249     switch(depth){
 250     case  4:
 251         return msrle_decode_pal4(avctx, pic, gb);
 252     case  8:
 253     case 16:
 254     case 24:
 255     case 32:
 256         return msrle_decode_8_16_24_32(avctx, pic, depth, gb);
 257     default:
 258         av_log(avctx, AV_LOG_ERROR, "Unknown depth %d\n", depth);
 259         return -1;
 260     }
 261 }