Fix style: "if(" -> "if (".
[libav.git] / libavfilter / graphparser.c
1 /*
2 * filter graph parser
3 * copyright (c) 2008 Vitor Sessak
4 * copyright (c) 2007 Bobby Bingham
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 #include <ctype.h>
24 #include <string.h>
25
26 #include "graphparser.h"
27 #include "avfilter.h"
28 #include "avfiltergraph.h"
29 #include "parseutils.h"
30
31 #define WHITESPACES " \n\t"
32
33 static int link_filter(AVFilterContext *src, int srcpad,
34 AVFilterContext *dst, int dstpad,
35 AVClass *log_ctx)
36 {
37 if (avfilter_link(src, srcpad, dst, dstpad)) {
38 av_log(log_ctx, AV_LOG_ERROR,
39 "cannot create the link %s:%d -> %s:%d\n",
40 src->filter->name, srcpad, dst->filter->name, dstpad);
41 return -1;
42 }
43
44 return 0;
45 }
46
47 /**
48 * Parse "[linkname]"
49 * @param name a pointer (that need to be free'd after use) to the name between
50 * parenthesis
51 */
52 static char *parse_link_name(const char **buf, AVClass *log_ctx)
53 {
54 const char *start = *buf;
55 char *name;
56 (*buf)++;
57
58 name = av_get_token(buf, "]");
59
60 if (!name[0]) {
61 av_log(log_ctx, AV_LOG_ERROR,
62 "Bad (empty?) label found in the following: \"%s\".\n", start);
63 goto fail;
64 }
65
66 if (*(*buf)++ != ']') {
67 av_log(log_ctx, AV_LOG_ERROR,
68 "Mismatched '[' found in the following: \"%s\".\n", start);
69 fail:
70 av_freep(&name);
71 }
72
73 return name;
74 }
75
76 static AVFilterContext *create_filter(AVFilterGraph *ctx, int index,
77 const char *filt_name, const char *args,
78 AVClass *log_ctx)
79 {
80 AVFilterContext *filt_ctx;
81
82 AVFilter *filt;
83 char inst_name[30];
84 char tmp_args[256];
85
86 snprintf(inst_name, sizeof(inst_name), "Filter %d %s", index, filt_name);
87
88 filt = avfilter_get_by_name(filt_name);
89
90 if (!filt) {
91 av_log(log_ctx, AV_LOG_ERROR,
92 "no such filter: '%s'\n", filt_name);
93 return NULL;
94 }
95
96 filt_ctx = avfilter_open(filt, inst_name);
97 if (!filt_ctx) {
98 av_log(log_ctx, AV_LOG_ERROR,
99 "error creating filter '%s'\n", filt_name);
100 return NULL;
101 }
102
103 if (avfilter_graph_add_filter(ctx, filt_ctx) < 0) {
104 avfilter_destroy(filt_ctx);
105 return NULL;
106 }
107
108 if (!strcmp(filt_name, "scale") && !strstr(args, "flags")) {
109 snprintf(tmp_args, sizeof(tmp_args), "%s:%s",
110 args, ctx->scale_sws_opts);
111 args = tmp_args;
112 }
113
114 if (avfilter_init_filter(filt_ctx, args, NULL)) {
115 av_log(log_ctx, AV_LOG_ERROR,
116 "error initializing filter '%s' with args '%s'\n", filt_name, args);
117 return NULL;
118 }
119
120 return filt_ctx;
121 }
122
123 /**
124 * Parse "filter=params"
125 */
126 static AVFilterContext *parse_filter(const char **buf, AVFilterGraph *graph,
127 int index, AVClass *log_ctx)
128 {
129 char *opts = NULL;
130 char *name = av_get_token(buf, "=,;[\n");
131 AVFilterContext *ret;
132
133 if (**buf == '=') {
134 (*buf)++;
135 opts = av_get_token(buf, "[],;\n");
136 }
137
138 ret = create_filter(graph, index, name, opts, log_ctx);
139 av_free(name);
140 av_free(opts);
141 return ret;
142 }
143
144 static void free_inout(AVFilterInOut *head)
145 {
146 while (head) {
147 AVFilterInOut *next = head->next;
148 av_free(head->name);
149 av_free(head);
150 head = next;
151 }
152 }
153
154 static AVFilterInOut *extract_inout(const char *label, AVFilterInOut **links)
155 {
156 AVFilterInOut *ret;
157
158 while (*links && strcmp((*links)->name, label))
159 links = &((*links)->next);
160
161 ret = *links;
162
163 if (ret)
164 *links = ret->next;
165
166 return ret;
167 }
168
169 static void insert_inout(AVFilterInOut **inouts, AVFilterInOut *element)
170 {
171 element->next = *inouts;
172 *inouts = element;
173 }
174
175 static int link_filter_inouts(AVFilterContext *filter,
176 AVFilterInOut **curr_inputs,
177 AVFilterInOut **open_inputs, AVClass *log_ctx)
178 {
179 int pad = filter->input_count;
180
181 while (pad--) {
182 AVFilterInOut *p = *curr_inputs;
183 if (!p) {
184 av_log(log_ctx, AV_LOG_ERROR,
185 "Not enough inputs specified for the \"%s\" filter.\n",
186 filter->filter->name);
187 return -1;
188 }
189
190 *curr_inputs = (*curr_inputs)->next;
191
192 if (p->filter) {
193 if (link_filter(p->filter, p->pad_idx, filter, pad, log_ctx))
194 return -1;
195 av_free(p->name);
196 av_free(p);
197 } else {
198 p->filter = filter;
199 p->pad_idx = pad;
200 insert_inout(open_inputs, p);
201 }
202 }
203
204 if (*curr_inputs) {
205 av_log(log_ctx, AV_LOG_ERROR,
206 "Too many inputs specified for the \"%s\" filter.\n",
207 filter->filter->name);
208 return -1;
209 }
210
211 pad = filter->output_count;
212 while (pad--) {
213 AVFilterInOut *currlinkn = av_mallocz(sizeof(AVFilterInOut));
214 currlinkn->filter = filter;
215 currlinkn->pad_idx = pad;
216 insert_inout(curr_inputs, currlinkn);
217 }
218
219 return 0;
220 }
221
222 static int parse_inputs(const char **buf, AVFilterInOut **curr_inputs,
223 AVFilterInOut **open_outputs, AVClass *log_ctx)
224 {
225 int pad = 0;
226
227 while (**buf == '[') {
228 char *name = parse_link_name(buf, log_ctx);
229 AVFilterInOut *match;
230
231 if (!name)
232 return -1;
233
234 /* First check if the label is not in the open_outputs list */
235 match = extract_inout(name, open_outputs);
236
237 if (match) {
238 av_free(name);
239 } else {
240 /* Not in the list, so add it as an input */
241 match = av_mallocz(sizeof(AVFilterInOut));
242 match->name = name;
243 match->pad_idx = pad;
244 }
245
246 insert_inout(curr_inputs, match);
247
248 *buf += strspn(*buf, WHITESPACES);
249 pad++;
250 }
251
252 return pad;
253 }
254
255 static int parse_outputs(const char **buf, AVFilterInOut **curr_inputs,
256 AVFilterInOut **open_inputs,
257 AVFilterInOut **open_outputs, AVClass *log_ctx)
258 {
259 int pad = 0;
260
261 while (**buf == '[') {
262 char *name = parse_link_name(buf, log_ctx);
263 AVFilterInOut *match;
264
265 AVFilterInOut *input = *curr_inputs;
266 *curr_inputs = (*curr_inputs)->next;
267
268 if (!name)
269 return -1;
270
271 /* First check if the label is not in the open_inputs list */
272 match = extract_inout(name, open_inputs);
273
274 if (match) {
275 if (link_filter(input->filter, input->pad_idx,
276 match->filter, match->pad_idx, log_ctx) < 0)
277 return -1;
278 av_free(match->name);
279 av_free(name);
280 av_free(match);
281 av_free(input);
282 } else {
283 /* Not in the list, so add the first input as a open_output */
284 input->name = name;
285 insert_inout(open_outputs, input);
286 }
287 *buf += strspn(*buf, WHITESPACES);
288 pad++;
289 }
290
291 return pad;
292 }
293
294 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
295 AVFilterInOut *open_inputs,
296 AVFilterInOut *open_outputs, AVClass *log_ctx)
297 {
298 int index = 0;
299 char chr = 0;
300
301 AVFilterInOut *curr_inputs = NULL;
302
303 do {
304 AVFilterContext *filter;
305 filters += strspn(filters, WHITESPACES);
306
307 if (parse_inputs(&filters, &curr_inputs, &open_outputs, log_ctx) < 0)
308 goto fail;
309
310 filter = parse_filter(&filters, graph, index, log_ctx);
311
312 if (!filter)
313 goto fail;
314
315 if (filter->input_count == 1 && !curr_inputs && !index) {
316 /* First input can be omitted if it is "[in]" */
317 const char *tmp = "[in]";
318 if(parse_inputs(&tmp, &curr_inputs, &open_outputs, log_ctx) < 0)
319 goto fail;
320 }
321
322 if (link_filter_inouts(filter, &curr_inputs, &open_inputs, log_ctx) < 0)
323 goto fail;
324
325 if (parse_outputs(&filters, &curr_inputs, &open_inputs, &open_outputs,
326 log_ctx) < 0)
327 goto fail;
328
329 filters += strspn(filters, WHITESPACES);
330 chr = *filters++;
331
332 if (chr == ';' && curr_inputs) {
333 av_log(log_ctx, AV_LOG_ERROR,
334 "Could not find a output to link when parsing \"%s\"\n",
335 filters - 1);
336 goto fail;
337 }
338 index++;
339 } while (chr == ',' || chr == ';');
340
341 if (chr) {
342 av_log(log_ctx, AV_LOG_ERROR,
343 "Unable to parse graph description substring: \"%s\"\n",
344 filters - 1);
345 goto fail;
346 }
347
348 if (open_inputs && !strcmp(open_inputs->name, "out") && curr_inputs) {
349 /* Last output can be omitted if it is "[out]" */
350 const char *tmp = "[out]";
351 if (parse_outputs(&tmp, &curr_inputs, &open_inputs,
352 &open_outputs, log_ctx) < 0)
353 goto fail;
354 }
355
356 return 0;
357
358 fail:
359 avfilter_graph_destroy(graph);
360 free_inout(open_inputs);
361 free_inout(open_outputs);
362 free_inout(curr_inputs);
363 return -1;
364 }