msrledec.c
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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 
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) {
56  rle_code = stream_byte;
57  if (rle_code == 0) {
58  /* fetch the next byte to see how to handle escape code */
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 */
70  pixel_ptr += 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;
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  }
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 
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 
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