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path: root/libavcodec/pcx.c (plain)
blob: 58a5e1e068216465bbe15b203d175c7d31242e9c
1/*
2 * PC Paintbrush PCX (.pcx) image decoder
3 * Copyright (c) 2007, 2008 Ivo van Poorten
4 *
5 * This decoder does not support CGA palettes. I am unable to find samples
6 * and Netpbm cannot generate them.
7 *
8 * This file is part of FFmpeg.
9 *
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
14 *
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
19 *
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25#include "libavutil/imgutils.h"
26#include "avcodec.h"
27#include "bytestream.h"
28#include "get_bits.h"
29#include "internal.h"
30
31#define PCX_HEADER_SIZE 128
32
33static void pcx_rle_decode(GetByteContext *gb,
34 uint8_t *dst,
35 unsigned int bytes_per_scanline,
36 int compressed)
37{
38 unsigned int i = 0;
39 unsigned char run, value;
40
41 if (compressed) {
42 while (i < bytes_per_scanline && bytestream2_get_bytes_left(gb)>0) {
43 run = 1;
44 value = bytestream2_get_byte(gb);
45 if (value >= 0xc0 && bytestream2_get_bytes_left(gb)>0) {
46 run = value & 0x3f;
47 value = bytestream2_get_byte(gb);
48 }
49 while (i < bytes_per_scanline && run--)
50 dst[i++] = value;
51 }
52 } else {
53 bytestream2_get_buffer(gb, dst, bytes_per_scanline);
54 }
55}
56
57static void pcx_palette(GetByteContext *gb, uint32_t *dst, int pallen)
58{
59 int i;
60
61 pallen = FFMIN(pallen, bytestream2_get_bytes_left(gb) / 3);
62 for (i = 0; i < pallen; i++)
63 *dst++ = 0xFF000000 | bytestream2_get_be24u(gb);
64 if (pallen < 256)
65 memset(dst, 0, (256 - pallen) * sizeof(*dst));
66}
67
68static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
69 AVPacket *avpkt)
70{
71 GetByteContext gb;
72 AVFrame * const p = data;
73 int compressed, xmin, ymin, xmax, ymax;
74 int ret;
75 unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
76 bytes_per_scanline;
77 uint8_t *ptr, *scanline;
78
79 if (avpkt->size < PCX_HEADER_SIZE) {
80 av_log(avctx, AV_LOG_ERROR, "Packet too small\n");
81 return AVERROR_INVALIDDATA;
82 }
83
84 bytestream2_init(&gb, avpkt->data, avpkt->size);
85
86 if (bytestream2_get_byteu(&gb) != 0x0a || bytestream2_get_byteu(&gb) > 5) {
87 av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
88 return AVERROR_INVALIDDATA;
89 }
90
91 compressed = bytestream2_get_byteu(&gb);
92 bits_per_pixel = bytestream2_get_byteu(&gb);
93 xmin = bytestream2_get_le16u(&gb);
94 ymin = bytestream2_get_le16u(&gb);
95 xmax = bytestream2_get_le16u(&gb);
96 ymax = bytestream2_get_le16u(&gb);
97 avctx->sample_aspect_ratio.num = bytestream2_get_le16u(&gb);
98 avctx->sample_aspect_ratio.den = bytestream2_get_le16u(&gb);
99
100 if (xmax < xmin || ymax < ymin) {
101 av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
102 return AVERROR_INVALIDDATA;
103 }
104
105 w = xmax - xmin + 1;
106 h = ymax - ymin + 1;
107
108 bytestream2_skipu(&gb, 49);
109 nplanes = bytestream2_get_byteu(&gb);
110 bytes_per_line = bytestream2_get_le16u(&gb);
111 bytes_per_scanline = nplanes * bytes_per_line;
112
113 if (bytes_per_scanline < (w * bits_per_pixel * nplanes + 7) / 8 ||
114 (!compressed && bytes_per_scanline > bytestream2_get_bytes_left(&gb) / h)) {
115 av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
116 return AVERROR_INVALIDDATA;
117 }
118
119 switch ((nplanes << 8) + bits_per_pixel) {
120 case 0x0308:
121 avctx->pix_fmt = AV_PIX_FMT_RGB24;
122 break;
123 case 0x0108:
124 case 0x0104:
125 case 0x0102:
126 case 0x0101:
127 case 0x0401:
128 case 0x0301:
129 case 0x0201:
130 avctx->pix_fmt = AV_PIX_FMT_PAL8;
131 break;
132 default:
133 av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
134 return AVERROR_INVALIDDATA;
135 }
136
137 bytestream2_skipu(&gb, 60);
138
139 if ((ret = ff_set_dimensions(avctx, w, h)) < 0)
140 return ret;
141
142 if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
143 return ret;
144
145 p->pict_type = AV_PICTURE_TYPE_I;
146
147 ptr = p->data[0];
148 stride = p->linesize[0];
149
150 scanline = av_malloc(bytes_per_scanline + AV_INPUT_BUFFER_PADDING_SIZE);
151 if (!scanline)
152 return AVERROR(ENOMEM);
153
154 if (nplanes == 3 && bits_per_pixel == 8) {
155 for (y = 0; y < h; y++) {
156 pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
157
158 for (x = 0; x < w; x++) {
159 ptr[3 * x] = scanline[x];
160 ptr[3 * x + 1] = scanline[x + bytes_per_line];
161 ptr[3 * x + 2] = scanline[x + (bytes_per_line << 1)];
162 }
163
164 ptr += stride;
165 }
166 } else if (nplanes == 1 && bits_per_pixel == 8) {
167 int palstart = avpkt->size - 769;
168
169 if (avpkt->size < 769) {
170 av_log(avctx, AV_LOG_ERROR, "File is too short\n");
171 ret = avctx->err_recognition & AV_EF_EXPLODE ?
172 AVERROR_INVALIDDATA : avpkt->size;
173 goto end;
174 }
175
176 for (y = 0; y < h; y++, ptr += stride) {
177 pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
178 memcpy(ptr, scanline, w);
179 }
180
181 if (bytestream2_tell(&gb) != palstart) {
182 av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
183 bytestream2_seek(&gb, palstart, SEEK_SET);
184 }
185 if (bytestream2_get_byte(&gb) != 12) {
186 av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
187 ret = avctx->err_recognition & AV_EF_EXPLODE ?
188 AVERROR_INVALIDDATA : avpkt->size;
189 goto end;
190 }
191 } else if (nplanes == 1) { /* all packed formats, max. 16 colors */
192 GetBitContext s;
193
194 for (y = 0; y < h; y++) {
195 init_get_bits8(&s, scanline, bytes_per_scanline);
196
197 pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
198
199 for (x = 0; x < w; x++)
200 ptr[x] = get_bits(&s, bits_per_pixel);
201 ptr += stride;
202 }
203 } else { /* planar, 4, 8 or 16 colors */
204 int i;
205
206 for (y = 0; y < h; y++) {
207 pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
208
209 for (x = 0; x < w; x++) {
210 int m = 0x80 >> (x & 7), v = 0;
211 for (i = nplanes - 1; i >= 0; i--) {
212 v <<= 1;
213 v += !!(scanline[i * bytes_per_line + (x >> 3)] & m);
214 }
215 ptr[x] = v;
216 }
217 ptr += stride;
218 }
219 }
220
221 ret = bytestream2_tell(&gb);
222 if (nplanes == 1 && bits_per_pixel == 8) {
223 pcx_palette(&gb, (uint32_t *)p->data[1], 256);
224 ret += 256 * 3;
225 } else if (bits_per_pixel * nplanes == 1) {
226 AV_WN32A(p->data[1] , 0xFF000000);
227 AV_WN32A(p->data[1]+4, 0xFFFFFFFF);
228 } else if (bits_per_pixel < 8) {
229 bytestream2_seek(&gb, 16, SEEK_SET);
230 pcx_palette(&gb, (uint32_t *)p->data[1], 16);
231 }
232
233 *got_frame = 1;
234
235end:
236 av_free(scanline);
237 return ret;
238}
239
240AVCodec ff_pcx_decoder = {
241 .name = "pcx",
242 .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
243 .type = AVMEDIA_TYPE_VIDEO,
244 .id = AV_CODEC_ID_PCX,
245 .decode = pcx_decode_frame,
246 .capabilities = AV_CODEC_CAP_DR1,
247};
248
generated by cgit at 2024-05-17 06:11:35 (GMT)