1/* 2 * Microsoft 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 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 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 = output + FFABS(pic->linesize[0]); 142 143 while (bytestream2_get_bytes_left(gb) > 0) { 144 p1 = bytestream2_get_byteu(gb); 145 if(p1 == 0) { //Escape code 146 p2 = bytestream2_get_byte(gb); 147 if(p2 == 0) { //End-of-line 148 if (--line < 0) { 149 if (bytestream2_get_be16(gb) == 1) { // end-of-picture 150 return 0; 151 } else { 152 av_log(avctx, AV_LOG_ERROR, 153 "Next line is beyond picture bounds (%d bytes left)\n", 154 bytestream2_get_bytes_left(gb)); 155 return AVERROR_INVALIDDATA; 156 } 157 } 158 output = pic->data[0] + line * pic->linesize[0]; 159 output_end = output + FFABS(pic->linesize[0]); 160 pos = 0; 161 continue; 162 } else if(p2 == 1) { //End-of-picture 163 return 0; 164 } else if(p2 == 2) { //Skip 165 p1 = bytestream2_get_byte(gb); 166 p2 = bytestream2_get_byte(gb); 167 line -= p2; 168 pos += p1; 169 if (line < 0 || pos >= width){ 170 av_log(avctx, AV_LOG_ERROR, "Skip beyond picture bounds\n"); 171 return -1; 172 } 173 output = pic->data[0] + line * pic->linesize[0] + pos * (depth >> 3); 174 output_end = pic->data[0] + line * pic->linesize[0] + FFABS(pic->linesize[0]); 175 continue; 176 } 177 // Copy data 178 if (output + p2 * (depth >> 3) > output_end) { 179 bytestream2_skip(gb, 2 * (depth >> 3)); 180 continue; 181 } else if (bytestream2_get_bytes_left(gb) < p2 * (depth >> 3)) { 182 av_log(avctx, AV_LOG_ERROR, "bytestream overrun\n"); 183 return AVERROR_INVALIDDATA; 184 } 185 186 if ((depth == 8) || (depth == 24)) { 187 bytestream2_get_bufferu(gb, output, p2 * (depth >> 3)); 188 output += p2 * (depth >> 3); 189 190 // RLE8 copy is actually padded - and runs are not! 191 if(depth == 8 && (p2 & 1)) { 192 bytestream2_skip(gb, 1); 193 } 194 } else if (depth == 16) { 195 for(i = 0; i < p2; i++) { 196 *(uint16_t*)output = bytestream2_get_le16u(gb); 197 output += 2; 198 } 199 } else if (depth == 32) { 200 for(i = 0; i < p2; i++) { 201 *(uint32_t*)output = bytestream2_get_le32u(gb); 202 output += 4; 203 } 204 } 205 pos += p2; 206 } else { //run of pixels 207 uint8_t pix[3]; //original pixel 208 if (output + p1 * (depth >> 3) > output_end) 209 continue; 210 211 switch(depth){ 212 case 8: 213 pix[0] = bytestream2_get_byte(gb); 214 memset(output, pix[0], p1); 215 output += p1; 216 break; 217 case 16: 218 pix16 = bytestream2_get_le16(gb); 219 for(i = 0; i < p1; i++) { 220 *(uint16_t*)output = pix16; 221 output += 2; 222 } 223 break; 224 case 24: 225 pix[0] = bytestream2_get_byte(gb); 226 pix[1] = bytestream2_get_byte(gb); 227 pix[2] = bytestream2_get_byte(gb); 228 for(i = 0; i < p1; i++) { 229 *output++ = pix[0]; 230 *output++ = pix[1]; 231 *output++ = pix[2]; 232 } 233 break; 234 case 32: 235 pix32 = bytestream2_get_le32(gb); 236 for(i = 0; i < p1; i++) { 237 *(uint32_t*)output = pix32; 238 output += 4; 239 } 240 break; 241 } 242 pos += p1; 243 } 244 } 245 246 av_log(avctx, AV_LOG_WARNING, "MS RLE warning: no end-of-picture code\n"); 247 return 0; 248} 249 250 251int ff_msrle_decode(AVCodecContext *avctx, AVPicture *pic, 252 int depth, GetByteContext *gb) 253{ 254 switch(depth){ 255 case 4: 256 return msrle_decode_pal4(avctx, pic, gb); 257 case 8: 258 case 16: 259 case 24: 260 case 32: 261 return msrle_decode_8_16_24_32(avctx, pic, depth, gb); 262 default: 263 av_log(avctx, AV_LOG_ERROR, "Unknown depth %d\n", depth); 264 return -1; 265 } 266} 267