pcx.c
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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 Libav.
9  *
10  * Libav 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  * Libav 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 Libav; 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 
30 typedef struct PCXContext {
32 } PCXContext;
33 
34 static av_cold int pcx_init(AVCodecContext *avctx) {
35  PCXContext *s = avctx->priv_data;
36 
38  avctx->coded_frame= &s->picture;
39 
40  return 0;
41 }
42 
46 static const uint8_t *pcx_rle_decode(const uint8_t *src, uint8_t *dst,
47  unsigned int bytes_per_scanline, int compressed) {
48  unsigned int i = 0;
49  unsigned char run, value;
50 
51  if (compressed) {
52  while (i<bytes_per_scanline) {
53  run = 1;
54  value = *src++;
55  if (value >= 0xc0) {
56  run = value & 0x3f;
57  value = *src++;
58  }
59  while (i<bytes_per_scanline && run--)
60  dst[i++] = value;
61  }
62  } else {
63  memcpy(dst, src, bytes_per_scanline);
64  src += bytes_per_scanline;
65  }
66 
67  return src;
68 }
69 
70 static void pcx_palette(const uint8_t **src, uint32_t *dst, unsigned int pallen) {
71  unsigned int i;
72 
73  for (i=0; i<pallen; i++)
74  *dst++ = bytestream_get_be24(src);
75  if (pallen < 256)
76  memset(dst, 0, (256 - pallen) * sizeof(*dst));
77 }
78 
79 static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
80  AVPacket *avpkt) {
81  const uint8_t *buf = avpkt->data;
82  int buf_size = avpkt->size;
83  PCXContext * const s = avctx->priv_data;
84  AVFrame *picture = data;
85  AVFrame * const p = &s->picture;
86  int compressed, xmin, ymin, xmax, ymax;
87  unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
88  bytes_per_scanline;
89  uint8_t *ptr;
90  uint8_t const *bufstart = buf;
91  uint8_t *scanline;
92  int ret = -1;
93 
94  if (buf[0] != 0x0a || buf[1] > 5) {
95  av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
96  return -1;
97  }
98 
99  compressed = buf[2];
100  xmin = AV_RL16(buf+ 4);
101  ymin = AV_RL16(buf+ 6);
102  xmax = AV_RL16(buf+ 8);
103  ymax = AV_RL16(buf+10);
104 
105  if (xmax < xmin || ymax < ymin) {
106  av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
107  return -1;
108  }
109 
110  w = xmax - xmin + 1;
111  h = ymax - ymin + 1;
112 
113  bits_per_pixel = buf[3];
114  bytes_per_line = AV_RL16(buf+66);
115  nplanes = buf[65];
116  bytes_per_scanline = nplanes * bytes_per_line;
117 
118  if (bytes_per_scanline < w * bits_per_pixel * nplanes / 8) {
119  av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
120  return -1;
121  }
122 
123  switch ((nplanes<<8) + bits_per_pixel) {
124  case 0x0308:
125  avctx->pix_fmt = PIX_FMT_RGB24;
126  break;
127  case 0x0108:
128  case 0x0104:
129  case 0x0102:
130  case 0x0101:
131  case 0x0401:
132  case 0x0301:
133  case 0x0201:
134  avctx->pix_fmt = PIX_FMT_PAL8;
135  break;
136  default:
137  av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
138  return -1;
139  }
140 
141  buf += 128;
142 
143  if (p->data[0])
144  avctx->release_buffer(avctx, p);
145 
146  if (av_image_check_size(w, h, 0, avctx))
147  return -1;
148  if (w != avctx->width || h != avctx->height)
149  avcodec_set_dimensions(avctx, w, h);
150  if (avctx->get_buffer(avctx, p) < 0) {
151  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
152  return -1;
153  }
154 
156 
157  ptr = p->data[0];
158  stride = p->linesize[0];
159 
160  scanline = av_malloc(bytes_per_scanline);
161  if (!scanline)
162  return AVERROR(ENOMEM);
163 
164  if (nplanes == 3 && bits_per_pixel == 8) {
165  for (y=0; y<h; y++) {
166  buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
167 
168  for (x=0; x<w; x++) {
169  ptr[3*x ] = scanline[x ];
170  ptr[3*x+1] = scanline[x+ bytes_per_line ];
171  ptr[3*x+2] = scanline[x+(bytes_per_line<<1)];
172  }
173 
174  ptr += stride;
175  }
176 
177  } else if (nplanes == 1 && bits_per_pixel == 8) {
178  const uint8_t *palstart = bufstart + buf_size - 769;
179 
180  for (y=0; y<h; y++, ptr+=stride) {
181  buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
182  memcpy(ptr, scanline, w);
183  }
184 
185  if (buf != palstart) {
186  av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
187  buf = palstart;
188  }
189  if (*buf++ != 12) {
190  av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
191  goto end;
192  }
193 
194  } else if (nplanes == 1) { /* all packed formats, max. 16 colors */
195  GetBitContext s;
196 
197  for (y=0; y<h; y++) {
198  init_get_bits(&s, scanline, bytes_per_scanline<<3);
199 
200  buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
201 
202  for (x=0; x<w; x++)
203  ptr[x] = get_bits(&s, bits_per_pixel);
204  ptr += stride;
205  }
206 
207  } else { /* planar, 4, 8 or 16 colors */
208  int i;
209 
210  for (y=0; y<h; y++) {
211  buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
212 
213  for (x=0; x<w; x++) {
214  int m = 0x80 >> (x&7), v = 0;
215  for (i=nplanes - 1; i>=0; i--) {
216  v <<= 1;
217  v += !!(scanline[i*bytes_per_line + (x>>3)] & m);
218  }
219  ptr[x] = v;
220  }
221  ptr += stride;
222  }
223  }
224 
225  if (nplanes == 1 && bits_per_pixel == 8) {
226  pcx_palette(&buf, (uint32_t *) p->data[1], 256);
227  } else if (bits_per_pixel < 8) {
228  const uint8_t *palette = bufstart+16;
229  pcx_palette(&palette, (uint32_t *) p->data[1], 16);
230  }
231 
232  *picture = s->picture;
233  *data_size = sizeof(AVFrame);
234 
235  ret = buf - bufstart;
236 end:
237  av_free(scanline);
238  return ret;
239 }
240 
241 static av_cold int pcx_end(AVCodecContext *avctx) {
242  PCXContext *s = avctx->priv_data;
243 
244  if(s->picture.data[0])
245  avctx->release_buffer(avctx, &s->picture);
246 
247  return 0;
248 }
249 
251  .name = "pcx",
252  .type = AVMEDIA_TYPE_VIDEO,
253  .id = CODEC_ID_PCX,
254  .priv_data_size = sizeof(PCXContext),
255  .init = pcx_init,
256  .close = pcx_end,
258  .capabilities = CODEC_CAP_DR1,
259  .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
260 };