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path: root/libavcodec/msrledec.c (plain)
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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, AVFrame *pic,
34 GetByteContext *gb)
35{
36 unsigned char rle_code;
37 unsigned char extra_byte, odd_pixel;
38 unsigned char stream_byte;
39 int pixel_ptr = 0;
40 int line = avctx->height - 1;
41 int i;
42
43 while (line >= 0 && pixel_ptr <= avctx->width) {
44 if (bytestream2_get_bytes_left(gb) <= 0) {
45 av_log(avctx, AV_LOG_ERROR,
46 "MS RLE: bytestream overrun, %dx%d left\n",
47 avctx->width - pixel_ptr, line);
48 return AVERROR_INVALIDDATA;
49 }
50 rle_code = stream_byte = bytestream2_get_byteu(gb);
51 if (rle_code == 0) {
52 /* fetch the next byte to see how to handle escape code */
53 stream_byte = bytestream2_get_byte(gb);
54 if (stream_byte == 0) {
55 /* line is done, goto the next one */
56 line--;
57 pixel_ptr = 0;
58 } else if (stream_byte == 1) {
59 /* decode is done */
60 return 0;
61 } else if (stream_byte == 2) {
62 /* reposition frame decode coordinates */
63 stream_byte = bytestream2_get_byte(gb);
64 pixel_ptr += stream_byte;
65 stream_byte = bytestream2_get_byte(gb);
66 line -= stream_byte;
67 } else {
68 // copy pixels from encoded stream
69 odd_pixel = stream_byte & 1;
70 rle_code = (stream_byte + 1) / 2;
71 extra_byte = rle_code & 0x01;
72 if (pixel_ptr + 2*rle_code - odd_pixel > avctx->width ||
73 bytestream2_get_bytes_left(gb) < rle_code) {
74 av_log(avctx, AV_LOG_ERROR,
75 "MS RLE: frame/stream ptr just went out of bounds (copy)\n");
76 return AVERROR_INVALIDDATA;
77 }
78
79 for (i = 0; i < rle_code; i++) {
80 if (pixel_ptr >= avctx->width)
81 break;
82 stream_byte = bytestream2_get_byteu(gb);
83 pic->data[0][line * pic->linesize[0] + pixel_ptr] = stream_byte >> 4;
84 pixel_ptr++;
85 if (i + 1 == rle_code && odd_pixel)
86 break;
87 if (pixel_ptr >= avctx->width)
88 break;
89 pic->data[0][line * pic->linesize[0] + pixel_ptr] = stream_byte & 0x0F;
90 pixel_ptr++;
91 }
92
93 // if the RLE code is odd, skip a byte in the stream
94 if (extra_byte)
95 bytestream2_skip(gb, 1);
96 }
97 } else {
98 // decode a run of data
99 if (pixel_ptr + rle_code > avctx->width + 1) {
100 av_log(avctx, AV_LOG_ERROR,
101 "MS RLE: frame ptr just went out of bounds (run) %d %d %d\n", pixel_ptr, rle_code, avctx->width);
102 return AVERROR_INVALIDDATA;
103 }
104 stream_byte = bytestream2_get_byte(gb);
105 for (i = 0; i < rle_code; i++) {
106 if (pixel_ptr >= avctx->width)
107 break;
108 if ((i & 1) == 0)
109 pic->data[0][line * pic->linesize[0] + pixel_ptr] = stream_byte >> 4;
110 else
111 pic->data[0][line * pic->linesize[0] + pixel_ptr] = stream_byte & 0x0F;
112 pixel_ptr++;
113 }
114 }
115 }
116
117 /* one last sanity check on the way out */
118 if (bytestream2_get_bytes_left(gb)) {
119 av_log(avctx, AV_LOG_ERROR,
120 "MS RLE: ended frame decode with %d bytes left over\n",
121 bytestream2_get_bytes_left(gb));
122 return AVERROR_INVALIDDATA;
123 }
124
125 return 0;
126}
127
128
129static int msrle_decode_8_16_24_32(AVCodecContext *avctx, AVFrame *pic,
130 int depth, GetByteContext *gb)
131{
132 uint8_t *output, *output_end;
133 int p1, p2, line=avctx->height - 1, pos=0, i;
134 uint16_t pix16;
135 uint32_t pix32;
136 unsigned int width= FFABS(pic->linesize[0]) / (depth >> 3);
137
138 output = pic->data[0] + (avctx->height - 1) * pic->linesize[0];
139 output_end = output + FFABS(pic->linesize[0]);
140
141 while (bytestream2_get_bytes_left(gb) > 0) {
142 p1 = bytestream2_get_byteu(gb);
143 if(p1 == 0) { //Escape code
144 p2 = bytestream2_get_byte(gb);
145 if(p2 == 0) { //End-of-line
146 if (--line < 0) {
147 if (bytestream2_get_be16(gb) == 1) { // end-of-picture
148 return 0;
149 } else {
150 av_log(avctx, AV_LOG_ERROR,
151 "Next line is beyond picture bounds (%d bytes left)\n",
152 bytestream2_get_bytes_left(gb));
153 return AVERROR_INVALIDDATA;
154 }
155 }
156 output = pic->data[0] + line * pic->linesize[0];
157 output_end = output + FFABS(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 output_end = pic->data[0] + line * pic->linesize[0] + FFABS(pic->linesize[0]);
173 continue;
174 }
175 // Copy data
176 if (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 bytestream2_get_bufferu(gb, output, p2 * (depth >> 3));
186 output += p2 * (depth >> 3);
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 if (output + p1 * (depth >> 3) > output_end)
207 continue;
208
209 switch(depth){
210 case 8:
211 pix[0] = bytestream2_get_byte(gb);
212 memset(output, pix[0], p1);
213 output += p1;
214 break;
215 case 16:
216 pix16 = bytestream2_get_le16(gb);
217 for(i = 0; i < p1; i++) {
218 *(uint16_t*)output = pix16;
219 output += 2;
220 }
221 break;
222 case 24:
223 pix[0] = bytestream2_get_byte(gb);
224 pix[1] = bytestream2_get_byte(gb);
225 pix[2] = bytestream2_get_byte(gb);
226 for(i = 0; i < p1; i++) {
227 *output++ = pix[0];
228 *output++ = pix[1];
229 *output++ = pix[2];
230 }
231 break;
232 case 32:
233 pix32 = bytestream2_get_le32(gb);
234 for(i = 0; i < p1; i++) {
235 *(uint32_t*)output = pix32;
236 output += 4;
237 }
238 break;
239 }
240 pos += p1;
241 }
242 }
243
244 av_log(avctx, AV_LOG_WARNING, "MS RLE warning: no end-of-picture code\n");
245 return 0;
246}
247
248
249int ff_msrle_decode(AVCodecContext *avctx, AVFrame *pic,
250 int depth, GetByteContext *gb)
251{
252 switch(depth){
253 case 4:
254 return msrle_decode_pal4(avctx, pic, gb);
255 case 8:
256 case 16:
257 case 24:
258 case 32:
259 return msrle_decode_8_16_24_32(avctx, pic, depth, gb);
260 default:
261 av_log(avctx, AV_LOG_ERROR, "Unknown depth %d\n", depth);
262 return -1;
263 }
264}
265
generated by cgit at 2024-05-17 04:45:32 (GMT)