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 33static 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 131static 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 av_uninit(pix16); 137 uint32_t av_uninit(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 246int 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} 262 263