1 /* GStreamer
2 * Copyright (C) 2003 David A. Schleef <ds@schleef.org>
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
18 */
19
20 #ifndef __GST_CAPS_H__
21 #define __GST_CAPS_H__
22
23 #include <gst/gstconfig.h>
24 #include <gst/gstminiobject.h>
25 #include <gst/gststructure.h>
26 #include <gst/gstcapsfeatures.h>
27 #include <gst/glib-compat.h>
28
29 G_BEGIN_DECLS
30
31 GST_API GType _gst_caps_type;
32
33 #define GST_TYPE_CAPS (_gst_caps_type)
34 #define GST_IS_CAPS(obj) (GST_IS_MINI_OBJECT_TYPE((obj), GST_TYPE_CAPS))
35 #define GST_CAPS_CAST(obj) ((GstCaps*)(obj))
36 #define GST_CAPS(obj) (GST_CAPS_CAST(obj))
37
38 #define GST_TYPE_STATIC_CAPS (gst_static_caps_get_type())
39
40 /**
41 * GstCapsFlags:
42 * @GST_CAPS_FLAG_ANY: Caps has no specific content, but can contain
43 * anything.
44 *
45 * Extra flags for a caps.
46 */
47 typedef enum {
48 GST_CAPS_FLAG_ANY = (GST_MINI_OBJECT_FLAG_LAST << 0)
49 } GstCapsFlags;
50
51 /**
52 * GstCapsIntersectMode:
53 * @GST_CAPS_INTERSECT_ZIG_ZAG : Zig-zags over both caps.
54 * @GST_CAPS_INTERSECT_FIRST : Keeps the first caps order.
55 *
56 * Modes of caps intersection
57 *
58 * @GST_CAPS_INTERSECT_ZIG_ZAG tries to preserve overall order of both caps
59 * by iterating on the caps' structures as the following matrix shows:
60 * |[
61 * caps1
62 * +-------------
63 * | 1 2 4 7
64 * caps2 | 3 5 8 10
65 * | 6 9 11 12
66 * ]|
67 * Used when there is no explicit precedence of one caps over the other. e.g.
68 * tee's sink pad getcaps function, it will probe its src pad peers' for their
69 * caps and intersect them with this mode.
70 *
71 * @GST_CAPS_INTERSECT_FIRST is useful when an element wants to preserve
72 * another element's caps priority order when intersecting with its own caps.
73 * Example: If caps1 is [A, B, C] and caps2 is [E, B, D, A], the result
74 * would be [A, B], maintaining the first caps priority on the intersection.
75 */
76 typedef enum {
77 GST_CAPS_INTERSECT_ZIG_ZAG = 0,
78 GST_CAPS_INTERSECT_FIRST = 1
79 } GstCapsIntersectMode;
80
81 /**
82 * GST_CAPS_ANY:
83 *
84 * Means that the element/pad can output 'anything'. Useful for elements
85 * that output unknown media, such as filesrc. This macro returns a singleton and
86 * should not be unreffed.
87 */
88 #define GST_CAPS_ANY _gst_caps_any
89 /**
90 * GST_CAPS_NONE:
91 *
92 * The opposite of %GST_CAPS_ANY: it means that the pad/element outputs an
93 * undefined media type that can not be detected. This macro returns a singleton
94 * and should not be unreffed.
95 */
96 #define GST_CAPS_NONE _gst_caps_none
97
98 /**
99 * GST_STATIC_CAPS_ANY:
100 *
101 * Creates a new #GstCaps static caps that matches anything.
102 * This can be used in pad templates.
103 */
104 #define GST_STATIC_CAPS_ANY GST_STATIC_CAPS("ANY")
105 /**
106 * GST_STATIC_CAPS_NONE:
107 *
108 * Creates a new #GstCaps static caps that matches nothing.
109 * This can be used in pad templates.
110 */
111 #define GST_STATIC_CAPS_NONE GST_STATIC_CAPS("NONE")
112
113 /**
114 * GST_CAPS_IS_SIMPLE:
115 * @caps: the #GstCaps instance to check
116 *
117 * Convenience macro that checks if the number of structures in the given caps
118 * is exactly one.
119 */
120 #define GST_CAPS_IS_SIMPLE(caps) (gst_caps_get_size(caps) == 1)
121
122 /**
123 * GST_STATIC_CAPS:
124 * @string: the string describing the caps
125 *
126 * Creates a new #GstCaps static caps from an input string.
127 * This can be used in pad templates.
128 */
129 #define GST_STATIC_CAPS(string) \
130 { \
131 /* caps */ NULL, \
132 /* string */ string, \
133 GST_PADDING_INIT \
134 }
135
136 typedef struct _GstCaps GstCaps;
137 typedef struct _GstStaticCaps GstStaticCaps;
138
139 GST_API GstCaps * _gst_caps_any;
140
141 GST_API GstCaps * _gst_caps_none;
142 /**
143 * GST_CAPS_FLAGS:
144 * @caps: a #GstCaps.
145 *
146 * A flags word containing #GstCapsFlags flags set on this caps.
147 */
148 #define GST_CAPS_FLAGS(caps) GST_MINI_OBJECT_FLAGS(caps)
149
150 /* refcount */
151 /**
152 * GST_CAPS_REFCOUNT:
153 * @caps: a #GstCaps
154 *
155 * Get access to the reference count field of the caps
156 */
157 #define GST_CAPS_REFCOUNT(caps) GST_MINI_OBJECT_REFCOUNT(caps)
158 /**
159 * GST_CAPS_REFCOUNT_VALUE:
160 * @caps: a #GstCaps
161 *
162 * Get the reference count value of the caps.
163 */
164 #define GST_CAPS_REFCOUNT_VALUE(caps) GST_MINI_OBJECT_REFCOUNT_VALUE(caps)
165
166 /**
167 * GST_CAPS_FLAG_IS_SET:
168 * @caps: a #GstCaps.
169 * @flag: the #GstCapsFlags to check.
170 *
171 * Gives the status of a specific flag on a caps.
172 */
173 #define GST_CAPS_FLAG_IS_SET(caps,flag) GST_MINI_OBJECT_FLAG_IS_SET (caps, flag)
174 /**
175 * GST_CAPS_FLAG_SET:
176 * @caps: a #GstCaps.
177 * @flag: the #GstCapsFlags to set.
178 *
179 * Sets a caps flag on a caps.
180 */
181 #define GST_CAPS_FLAG_SET(caps,flag) GST_MINI_OBJECT_FLAG_SET (caps, flag)
182 /**
183 * GST_CAPS_FLAG_UNSET:
184 * @caps: a #GstCaps.
185 * @flag: the #GstCapsFlags to clear.
186 *
187 * Clears a caps flag.
188 */
189 #define GST_CAPS_FLAG_UNSET(caps,flag) GST_MINI_OBJECT_FLAG_UNSET (caps, flag)
190
191 /* refcounting */
192 /**
193 * gst_caps_ref:
194 * @caps: the #GstCaps to reference
195 *
196 * Add a reference to a #GstCaps object.
197 *
198 * From this point on, until the caller calls gst_caps_unref() or
199 * gst_caps_make_writable(), it is guaranteed that the caps object will not
200 * change. This means its structures won't change, etc. To use a #GstCaps
201 * object, you must always have a refcount on it -- either the one made
202 * implicitly by e.g. gst_caps_new_simple(), or via taking one explicitly with
203 * this function.
204 *
205 * Returns: the same #GstCaps object.
206 */
207 static inline GstCaps *
gst_caps_ref(GstCaps * caps)208 gst_caps_ref (GstCaps * caps)
209 {
210 return (GstCaps *) gst_mini_object_ref (GST_MINI_OBJECT_CAST (caps));
211 }
212
213 /**
214 * gst_caps_unref:
215 * @caps: a #GstCaps.
216 *
217 * Unref a #GstCaps and and free all its structures and the
218 * structures' values when the refcount reaches 0.
219 */
220 static inline void
gst_caps_unref(GstCaps * caps)221 gst_caps_unref (GstCaps * caps)
222 {
223 gst_mini_object_unref (GST_MINI_OBJECT_CAST (caps));
224 }
225
226 /**
227 * gst_clear_caps: (skip)
228 * @caps_ptr: a pointer to a #GstCaps reference
229 *
230 * Clears a reference to a #GstCaps.
231 *
232 * @caps_ptr must not be %NULL.
233 *
234 * If the reference is %NULL then this function does nothing. Otherwise, the
235 * reference count of the caps is decreased and the pointer is set to %NULL.
236 *
237 * Since: 1.16
238 */
239 static inline void
gst_clear_caps(GstCaps ** caps_ptr)240 gst_clear_caps (GstCaps ** caps_ptr)
241 {
242 gst_clear_mini_object ((GstMiniObject **) caps_ptr);
243 }
244
245 /* copy caps */
246 GST_API
247 GstCaps * gst_caps_copy (const GstCaps * caps);
248
249 #define gst_caps_copy(caps) GST_CAPS (gst_mini_object_copy (GST_MINI_OBJECT_CAST (caps)))
250
251 /**
252 * gst_caps_is_writable:
253 * @caps: a #GstCaps
254 *
255 * Tests if you can safely modify @caps. It is only safe to modify caps when
256 * there is only one owner of the caps - ie, the object is writable.
257 */
258 #define gst_caps_is_writable(caps) gst_mini_object_is_writable (GST_MINI_OBJECT_CAST (caps))
259
260 /**
261 * gst_caps_make_writable:
262 * @caps: (transfer full): a #GstCaps
263 *
264 * Returns a writable copy of @caps.
265 *
266 * If there is only one reference count on @caps, the caller must be the owner,
267 * and so this function will return the caps object unchanged. If on the other
268 * hand there is more than one reference on the object, a new caps object will
269 * be returned. The caller's reference on @caps will be removed, and instead the
270 * caller will own a reference to the returned object.
271 *
272 * In short, this function unrefs the caps in the argument and refs the caps
273 * that it returns. Don't access the argument after calling this function. See
274 * also: gst_caps_ref().
275 *
276 * Returns: (transfer full): a writable caps which may or may not be the
277 * same as @caps
278 */
279 #define gst_caps_make_writable(caps) GST_CAPS_CAST (gst_mini_object_make_writable (GST_MINI_OBJECT_CAST (caps)))
280
281 /**
282 * gst_caps_replace:
283 * @old_caps: (inout) (transfer full) (nullable): pointer to a pointer
284 * to a #GstCaps to be replaced.
285 * @new_caps: (transfer none) (allow-none): pointer to a #GstCaps that will
286 * replace the caps pointed to by @old_caps.
287 *
288 * Modifies a pointer to a #GstCaps to point to a different #GstCaps. The
289 * modification is done atomically (so this is useful for ensuring thread safety
290 * in some cases), and the reference counts are updated appropriately (the old
291 * caps is unreffed, the new is reffed).
292 *
293 * Either @new_caps or the #GstCaps pointed to by @old_caps may be %NULL.
294 *
295 * Returns: %TRUE if @new_caps was different from @old_caps
296 */
297 static inline gboolean
gst_caps_replace(GstCaps ** old_caps,GstCaps * new_caps)298 gst_caps_replace (GstCaps **old_caps, GstCaps *new_caps)
299 {
300 return gst_mini_object_replace ((GstMiniObject **) old_caps, (GstMiniObject *) new_caps);
301 }
302
303 /**
304 * gst_caps_take:
305 * @old_caps: (inout) (transfer full): pointer to a pointer to a #GstCaps to be
306 * replaced.
307 * @new_caps: (transfer full) (allow-none): pointer to a #GstCaps that will
308 * replace the caps pointed to by @old_caps.
309 *
310 * Modifies a pointer to a #GstCaps to point to a different #GstCaps. This
311 * function is similar to gst_caps_replace() except that it takes ownership
312 * of @new_caps.
313 *
314 * Returns: %TRUE if @new_caps was different from @old_caps
315 */
316 static inline gboolean
gst_caps_take(GstCaps ** old_caps,GstCaps * new_caps)317 gst_caps_take (GstCaps **old_caps, GstCaps *new_caps)
318 {
319 return gst_mini_object_take ((GstMiniObject **) old_caps, (GstMiniObject *) new_caps);
320 }
321
322 /**
323 * GstCaps:
324 * @mini_object: the parent type
325 *
326 * Object describing media types.
327 */
328 struct _GstCaps {
329 GstMiniObject mini_object;
330 };
331
332 /**
333 * GstStaticCaps:
334 * @caps: the cached #GstCaps
335 * @string: a string describing a caps
336 *
337 * Datastructure to initialize #GstCaps from a string description usually
338 * used in conjunction with GST_STATIC_CAPS() and gst_static_caps_get() to
339 * instantiate a #GstCaps.
340 */
341 struct _GstStaticCaps {
342 /*< public >*/
343 GstCaps *caps;
344 const char *string;
345
346 /*< private >*/
347 gpointer _gst_reserved[GST_PADDING];
348 };
349
350 /**
351 * GstCapsForeachFunc:
352 * @features: the #GstCapsFeatures
353 * @structure: the #GstStructure
354 * @user_data: user data
355 *
356 * A function that will be called in gst_caps_foreach(). The function may
357 * not modify @features or @structure.
358 *
359 * Returns: %TRUE if the foreach operation should continue, %FALSE if
360 * the foreach operation should stop with %FALSE.
361 *
362 * Since: 1.6
363 */
364 typedef gboolean (*GstCapsForeachFunc) (GstCapsFeatures *features,
365 GstStructure *structure,
366 gpointer user_data);
367
368 /**
369 * GstCapsMapFunc:
370 * @features: the #GstCapsFeatures
371 * @structure: the #GstStructure
372 * @user_data: user data
373 *
374 * A function that will be called in gst_caps_map_in_place(). The function
375 * may modify @features and @structure.
376 *
377 * Returns: %TRUE if the map operation should continue, %FALSE if
378 * the map operation should stop with %FALSE.
379 */
380 typedef gboolean (*GstCapsMapFunc) (GstCapsFeatures *features,
381 GstStructure *structure,
382 gpointer user_data);
383
384 /**
385 * GstCapsFilterMapFunc:
386 * @features: the #GstCapsFeatures
387 * @structure: the #GstStructure
388 * @user_data: user data
389 *
390 * A function that will be called in gst_caps_filter_and_map_in_place().
391 * The function may modify @features and @structure, and both will be
392 * removed from the caps if %FALSE is returned.
393 *
394 * Returns: %TRUE if the features and structure should be preserved,
395 * %FALSE if it should be removed.
396 */
397 typedef gboolean (*GstCapsFilterMapFunc) (GstCapsFeatures *features,
398 GstStructure *structure,
399 gpointer user_data);
400
401
402 GST_API
403 GType gst_caps_get_type (void);
404
405 GST_API
406 GstCaps * gst_caps_new_empty (void);
407
408 GST_API
409 GstCaps * gst_caps_new_any (void);
410
411 GST_API
412 GstCaps * gst_caps_new_empty_simple (const char *media_type) G_GNUC_WARN_UNUSED_RESULT;
413
414 GST_API
415 GstCaps * gst_caps_new_simple (const char *media_type,
416 const char *fieldname,
417 ...) G_GNUC_NULL_TERMINATED G_GNUC_WARN_UNUSED_RESULT;
418 GST_API
419 GstCaps * gst_caps_new_full (GstStructure *struct1,
420 ...) G_GNUC_NULL_TERMINATED G_GNUC_WARN_UNUSED_RESULT;
421 GST_API
422 GstCaps * gst_caps_new_full_valist (GstStructure *structure,
423 va_list var_args) G_GNUC_WARN_UNUSED_RESULT;
424 GST_API
425 GType gst_static_caps_get_type (void);
426
427 GST_API
428 GstCaps * gst_static_caps_get (GstStaticCaps *static_caps);
429
430 GST_API
431 void gst_static_caps_cleanup (GstStaticCaps *static_caps);
432
433 /* manipulation */
434
435 GST_API
436 void gst_caps_append (GstCaps *caps1,
437 GstCaps *caps2);
438 GST_API
439 void gst_caps_append_structure (GstCaps *caps,
440 GstStructure *structure);
441 GST_API
442 void gst_caps_append_structure_full (GstCaps *caps,
443 GstStructure *structure,
444 GstCapsFeatures *features);
445 GST_API
446 void gst_caps_remove_structure (GstCaps *caps, guint idx);
447
448 GST_API
449 GstCaps * gst_caps_merge (GstCaps *caps1,
450 GstCaps *caps2) G_GNUC_WARN_UNUSED_RESULT;
451 GST_API
452 GstCaps * gst_caps_merge_structure (GstCaps *caps,
453 GstStructure *structure) G_GNUC_WARN_UNUSED_RESULT;
454 GST_API
455 GstCaps * gst_caps_merge_structure_full (GstCaps *caps,
456 GstStructure *structure,
457 GstCapsFeatures *features) G_GNUC_WARN_UNUSED_RESULT;
458
459 GST_API
460 guint gst_caps_get_size (const GstCaps *caps);
461
462 GST_API
463 GstStructure * gst_caps_get_structure (const GstCaps *caps,
464 guint index);
465 GST_API
466 GstStructure * gst_caps_steal_structure (GstCaps *caps,
467 guint index) G_GNUC_WARN_UNUSED_RESULT;
468 GST_API
469 void gst_caps_set_features (GstCaps *caps,
470 guint index,
471 GstCapsFeatures * features);
472 GST_API
473 void gst_caps_set_features_simple (GstCaps *caps,
474 GstCapsFeatures * features);
475
476 GST_API
477 GstCapsFeatures * gst_caps_get_features (const GstCaps *caps,
478 guint index);
479 GST_API
480 GstCaps * gst_caps_copy_nth (const GstCaps *caps, guint nth) G_GNUC_WARN_UNUSED_RESULT;
481
482 GST_API
483 GstCaps * gst_caps_truncate (GstCaps *caps) G_GNUC_WARN_UNUSED_RESULT;
484
485 GST_API
486 void gst_caps_set_value (GstCaps *caps,
487 const char *field,
488 const GValue *value);
489 GST_API
490 void gst_caps_set_simple (GstCaps *caps,
491 const char *field, ...) G_GNUC_NULL_TERMINATED;
492 GST_API
493 void gst_caps_set_simple_valist (GstCaps *caps,
494 const char *field,
495 va_list varargs);
496 GST_API
497 gboolean gst_caps_foreach (const GstCaps *caps,
498 GstCapsForeachFunc func,
499 gpointer user_data);
500 GST_API
501 gboolean gst_caps_map_in_place (GstCaps *caps,
502 GstCapsMapFunc func,
503 gpointer user_data);
504 GST_API
505 void gst_caps_filter_and_map_in_place (GstCaps *caps,
506 GstCapsFilterMapFunc func,
507 gpointer user_data);
508
509 /* tests */
510
511 GST_API
512 gboolean gst_caps_is_any (const GstCaps *caps);
513
514 GST_API
515 gboolean gst_caps_is_empty (const GstCaps *caps);
516
517 GST_API
518 gboolean gst_caps_is_fixed (const GstCaps *caps);
519
520 GST_API
521 gboolean gst_caps_is_always_compatible (const GstCaps *caps1,
522 const GstCaps *caps2);
523 GST_API
524 gboolean gst_caps_is_subset (const GstCaps *subset,
525 const GstCaps *superset);
526 GST_API
527 gboolean gst_caps_is_subset_structure (const GstCaps *caps,
528 const GstStructure *structure);
529 GST_API
530 gboolean gst_caps_is_subset_structure_full (const GstCaps *caps,
531 const GstStructure *structure,
532 const GstCapsFeatures *features);
533 GST_API
534 gboolean gst_caps_is_equal (const GstCaps *caps1,
535 const GstCaps *caps2);
536 GST_API
537 gboolean gst_caps_is_equal_fixed (const GstCaps *caps1,
538 const GstCaps *caps2);
539 GST_API
540 gboolean gst_caps_can_intersect (const GstCaps * caps1,
541 const GstCaps * caps2);
542 GST_API
543 gboolean gst_caps_is_strictly_equal (const GstCaps *caps1,
544 const GstCaps *caps2);
545
546
547 /* operations */
548
549 GST_API
550 GstCaps * gst_caps_intersect (GstCaps *caps1,
551 GstCaps *caps2) G_GNUC_WARN_UNUSED_RESULT;
552 GST_API
553 GstCaps * gst_caps_intersect_full (GstCaps *caps1,
554 GstCaps *caps2,
555 GstCapsIntersectMode mode) G_GNUC_WARN_UNUSED_RESULT;
556 GST_API
557 GstCaps * gst_caps_subtract (GstCaps *minuend,
558 GstCaps *subtrahend) G_GNUC_WARN_UNUSED_RESULT;
559 GST_API
560 GstCaps * gst_caps_normalize (GstCaps *caps) G_GNUC_WARN_UNUSED_RESULT;
561
562 GST_API
563 GstCaps * gst_caps_simplify (GstCaps *caps) G_GNUC_WARN_UNUSED_RESULT;
564
565 GST_API
566 GstCaps * gst_caps_fixate (GstCaps *caps) G_GNUC_WARN_UNUSED_RESULT;
567
568 /* utility */
569
570 GST_API
571 gchar * gst_caps_to_string (const GstCaps *caps) G_GNUC_MALLOC;
572
573 GST_API
574 GstCaps * gst_caps_from_string (const gchar *string) G_GNUC_WARN_UNUSED_RESULT;
575
576 #ifdef G_DEFINE_AUTOPTR_CLEANUP_FUNC
577 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstCaps, gst_caps_unref)
578 #endif
579
580 G_END_DECLS
581
582 #endif /* __GST_CAPS_H__ */
583