This fixes error handling for BeOS, removing the need for some ifdefs.
[libav.git] / libavcodec / gifdec.c
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1/*
2 * GIF decoder
3 * Copyright (c) 2003 Fabrice Bellard.
4 * Copyright (c) 2006 Baptiste Coudurier.
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23//#define DEBUG
24
25#include "avcodec.h"
26#include "bytestream.h"
ffc5430b 27#include "lzw.h"
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28
29#define GCE_DISPOSAL_NONE 0
30#define GCE_DISPOSAL_INPLACE 1
31#define GCE_DISPOSAL_BACKGROUND 2
32#define GCE_DISPOSAL_RESTORE 3
33
34typedef struct GifState {
d54d396d 35 AVFrame picture;
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36 int screen_width;
37 int screen_height;
38 int bits_per_pixel;
39 int background_color_index;
40 int transparent_color_index;
41 int color_resolution;
d54d396d 42 uint32_t *image_palette;
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43
44 /* after the frame is displayed, the disposal method is used */
45 int gce_disposal;
46 /* delay during which the frame is shown */
47 int gce_delay;
48
49 /* LZW compatible decoder */
50 uint8_t *bytestream;
ffc5430b 51 LZWState *lzw;
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52
53 /* aux buffers */
54 uint8_t global_palette[256 * 3];
55 uint8_t local_palette[256 * 3];
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56} GifState;
57
58static const uint8_t gif87a_sig[6] = "GIF87a";
59static const uint8_t gif89a_sig[6] = "GIF89a";
60
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61static int gif_read_image(GifState *s)
62{
63 int left, top, width, height, bits_per_pixel, code_size, flags;
a7fb3a96 64 int is_interleaved, has_local_palette, y, pass, y1, linesize, n, i;
bc52b0c5 65 uint8_t *ptr, *spal, *palette, *ptr1;
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66
67 left = bytestream_get_le16(&s->bytestream);
68 top = bytestream_get_le16(&s->bytestream);
69 width = bytestream_get_le16(&s->bytestream);
70 height = bytestream_get_le16(&s->bytestream);
71 flags = bytestream_get_byte(&s->bytestream);
72 is_interleaved = flags & 0x40;
73 has_local_palette = flags & 0x80;
74 bits_per_pixel = (flags & 0x07) + 1;
75#ifdef DEBUG
1e22f00d 76 dprintf("gif: image x=%d y=%d w=%d h=%d\n", left, top, width, height);
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77#endif
78
79 if (has_local_palette) {
80 bytestream_get_buffer(&s->bytestream, s->local_palette, 3 * (1 << bits_per_pixel));
81 palette = s->local_palette;
82 } else {
83 palette = s->global_palette;
84 bits_per_pixel = s->bits_per_pixel;
85 }
86
87 /* verify that all the image is inside the screen dimensions */
88 if (left + width > s->screen_width ||
89 top + height > s->screen_height)
8fa36ae0 90 return AVERROR(EINVAL);
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91
92 /* build the palette */
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93 n = (1 << bits_per_pixel);
94 spal = palette;
95 for(i = 0; i < n; i++) {
96 s->image_palette[i] = (0xff << 24) |
97 (spal[0] << 16) | (spal[1] << 8) | (spal[2]);
98 spal += 3;
99 }
100 for(; i < 256; i++)
101 s->image_palette[i] = (0xff << 24);
102 /* handle transparency */
103 if (s->transparent_color_index >= 0)
104 s->image_palette[s->transparent_color_index] = 0;
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105
106 /* now get the image data */
107 code_size = bytestream_get_byte(&s->bytestream);
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108 //TODO: add proper data size
109 ff_lzw_decode_init(s->lzw, code_size, s->bytestream, 0, FF_LZW_GIF);
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110
111 /* read all the image */
d54d396d 112 linesize = s->picture.linesize[0];
b190aa89 113 ptr1 = s->picture.data[0] + top * linesize + left;
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114 ptr = ptr1;
115 pass = 0;
116 y1 = 0;
117 for (y = 0; y < height; y++) {
ffc5430b 118 ff_lzw_decode(s->lzw, ptr, width);
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119 if (is_interleaved) {
120 switch(pass) {
121 default:
122 case 0:
123 case 1:
124 y1 += 8;
125 ptr += linesize * 8;
126 if (y1 >= height) {
127 y1 = 4;
128 if (pass == 0)
129 ptr = ptr1 + linesize * 4;
130 else
131 ptr = ptr1 + linesize * 2;
132 pass++;
133 }
134 break;
135 case 2:
136 y1 += 4;
137 ptr += linesize * 4;
138 if (y1 >= height) {
139 y1 = 1;
140 ptr = ptr1 + linesize;
141 pass++;
142 }
143 break;
144 case 3:
145 y1 += 2;
146 ptr += linesize * 2;
147 break;
148 }
149 } else {
150 ptr += linesize;
151 }
152 }
06d392a7 153 /* read the garbage data until end marker is found */
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154 ff_lzw_decode_tail(s->lzw);
155 s->bytestream = ff_lzw_cur_ptr(s->lzw);
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156 return 0;
157}
158
159static int gif_read_extension(GifState *s)
160{
161 int ext_code, ext_len, i, gce_flags, gce_transparent_index;
162
163 /* extension */
164 ext_code = bytestream_get_byte(&s->bytestream);
165 ext_len = bytestream_get_byte(&s->bytestream);
166#ifdef DEBUG
1e22f00d 167 dprintf("gif: ext_code=0x%x len=%d\n", ext_code, ext_len);
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168#endif
169 switch(ext_code) {
170 case 0xf9:
171 if (ext_len != 4)
172 goto discard_ext;
173 s->transparent_color_index = -1;
174 gce_flags = bytestream_get_byte(&s->bytestream);
175 s->gce_delay = bytestream_get_le16(&s->bytestream);
176 gce_transparent_index = bytestream_get_byte(&s->bytestream);
177 if (gce_flags & 0x01)
178 s->transparent_color_index = gce_transparent_index;
179 else
180 s->transparent_color_index = -1;
181 s->gce_disposal = (gce_flags >> 2) & 0x7;
182#ifdef DEBUG
1e22f00d 183 dprintf("gif: gce_flags=%x delay=%d tcolor=%d disposal=%d\n",
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184 gce_flags, s->gce_delay,
185 s->transparent_color_index, s->gce_disposal);
186#endif
187 ext_len = bytestream_get_byte(&s->bytestream);
188 break;
189 }
190
191 /* NOTE: many extension blocks can come after */
192 discard_ext:
193 while (ext_len != 0) {
194 for (i = 0; i < ext_len; i++)
195 bytestream_get_byte(&s->bytestream);
196 ext_len = bytestream_get_byte(&s->bytestream);
197#ifdef DEBUG
1e22f00d 198 dprintf("gif: ext_len1=%d\n", ext_len);
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199#endif
200 }
201 return 0;
202}
203
204static int gif_read_header1(GifState *s)
205{
206 uint8_t sig[6];
a7fb3a96 207 int v, n;
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208 int has_global_palette;
209
210 /* read gif signature */
211 bytestream_get_buffer(&s->bytestream, sig, 6);
212 if (memcmp(sig, gif87a_sig, 6) != 0 &&
213 memcmp(sig, gif89a_sig, 6) != 0)
214 return -1;
215
216 /* read screen header */
217 s->transparent_color_index = -1;
218 s->screen_width = bytestream_get_le16(&s->bytestream);
219 s->screen_height = bytestream_get_le16(&s->bytestream);
220 if( (unsigned)s->screen_width > 32767
221 || (unsigned)s->screen_height > 32767){
222 av_log(NULL, AV_LOG_ERROR, "picture size too large\n");
223 return -1;
224 }
225
226 v = bytestream_get_byte(&s->bytestream);
227 s->color_resolution = ((v & 0x70) >> 4) + 1;
228 has_global_palette = (v & 0x80);
229 s->bits_per_pixel = (v & 0x07) + 1;
230 s->background_color_index = bytestream_get_byte(&s->bytestream);
231 bytestream_get_byte(&s->bytestream); /* ignored */
232#ifdef DEBUG
1e22f00d 233 dprintf("gif: screen_w=%d screen_h=%d bpp=%d global_palette=%d\n",
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234 s->screen_width, s->screen_height, s->bits_per_pixel,
235 has_global_palette);
236#endif
237 if (has_global_palette) {
238 n = 1 << s->bits_per_pixel;
239 bytestream_get_buffer(&s->bytestream, s->global_palette, n * 3);
240 }
241 return 0;
242}
243
244static int gif_parse_next_image(GifState *s)
245{
246 int ret, code;
247
248 for (;;) {
249 code = bytestream_get_byte(&s->bytestream);
250#ifdef DEBUG
1e22f00d 251 dprintf("gif: code=%02x '%c'\n", code, code);
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252#endif
253 switch (code) {
254 case ',':
255 if (gif_read_image(s) < 0)
256 return -1;
257 ret = 0;
258 goto the_end;
259 case ';':
260 /* end of image */
261 ret = -1;
262 goto the_end;
263 case '!':
264 if (gif_read_extension(s) < 0)
265 return -1;
266 break;
267 case EOF:
268 default:
269 /* error or errneous EOF */
270 ret = -1;
271 goto the_end;
272 }
273 }
274 the_end:
275 return ret;
276}
277
278static int gif_decode_init(AVCodecContext *avctx)
279{
280 GifState *s = avctx->priv_data;
281
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282 avcodec_get_frame_defaults(&s->picture);
283 avctx->coded_frame= &s->picture;
284 s->picture.data[0] = NULL;
ffc5430b 285 ff_lzw_decode_open(&s->lzw);
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286 return 0;
287}
288
289static int gif_decode_frame(AVCodecContext *avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
290{
291 GifState *s = avctx->priv_data;
292 AVFrame *picture = data;
293 int ret;
294
295 s->bytestream = buf;
296 if (gif_read_header1(s) < 0)
297 return -1;
298
06d392a7 299 avctx->pix_fmt = PIX_FMT_PAL8;
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300 if (avcodec_check_dimensions(avctx, s->screen_width, s->screen_height))
301 return -1;
302 avcodec_set_dimensions(avctx, s->screen_width, s->screen_height);
06d392a7 303
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304 if (s->picture.data[0])
305 avctx->release_buffer(avctx, &s->picture);
306 if (avctx->get_buffer(avctx, &s->picture) < 0) {
307 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
308 return -1;
309 }
310 s->image_palette = (uint32_t *)s->picture.data[1];
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311 ret = gif_parse_next_image(s);
312 if (ret < 0)
313 return ret;
314
d54d396d 315 *picture = s->picture;
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316 *data_size = sizeof(AVPicture);
317 return 0;
318}
319
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320static int gif_decode_close(AVCodecContext *avctx)
321{
322 GifState *s = avctx->priv_data;
323
ffc5430b 324 ff_lzw_decode_close(&s->lzw);
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325 if(s->picture.data[0])
326 avctx->release_buffer(avctx, &s->picture);
327 return 0;
328}
329
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330AVCodec gif_decoder = {
331 "gif",
332 CODEC_TYPE_VIDEO,
333 CODEC_ID_GIF,
334 sizeof(GifState),
335 gif_decode_init,
336 NULL,
d54d396d 337 gif_decode_close,
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338 gif_decode_frame,
339};