2 * Copyright (C) <2003> David A. Schleef <ds@schleef.org>
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.
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.
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., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
22 * @short_description: Structure describing sets of media formats
23 * @see_also: #GstStructure
25 * Caps (capabilities) are lighweight refcounted objects describing media types.
26 * They are composed of an array of #GstStructure.
28 * Caps are exposed on #GstPadTemplate to describe all possible types a
29 * given pad can handle. They are also stored in the #GstRegistry along with
30 * a description of the #GstElement.
32 * Caps are exposed on the element pads using the gst_pad_get_caps() pad
33 * function. This function describes the possible types that the pad can
34 * handle or produce at runtime.
36 * Caps are also attached to buffers to describe to content of the data
37 * pointed to by the buffer with gst_buffer_set_caps(). Caps attached to
38 * a #GstBuffer allow for format negotiation upstream and downstream.
40 * A #GstCaps can be constructed with the following code fragment:
43 * <title>Creating caps</title>
46 * caps = gst_caps_new_simple ("video/x-raw-yuv",
47 * "format", GST_TYPE_FOURCC, GST_MAKE_FOURCC ('I', '4', '2', '0'),
48 * "framerate", GST_TYPE_FRACTION, 25, 1,
49 * "pixel-aspect-ratio", GST_TYPE_FRACTION, 1, 1,
50 * "width", G_TYPE_INT, 320,
51 * "height", G_TYPE_INT, 240,
56 * A #GstCaps is fixed when it has no properties with ranges or lists. Use
57 * gst_caps_is_fixed() to test for fixed caps. Only fixed caps can be
58 * set on a #GstPad or #GstBuffer.
60 * Various methods exist to work with the media types such as subtracting
63 * Last reviewed on 2007-02-13 (0.10.10)
72 #include "gst_private.h"
74 #include <gobject/gvaluecollector.h>
76 #ifdef GST_DISABLE_DEPRECATED
77 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
78 xmlNodePtr gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent);
79 GstCaps *gst_caps_load_thyself (xmlNodePtr parent);
83 #define DEBUG_REFCOUNT
85 #define CAPS_POISON(caps) G_STMT_START{ \
87 GstCaps *_newcaps = gst_caps_copy (caps); \
88 gst_caps_unref(caps); \
92 #define STRUCTURE_POISON(structure) G_STMT_START{ \
94 GstStructure *_newstruct = gst_structure_copy (structure); \
95 gst_structure_free(structure); \
96 structure = _newstruct; \
99 #define IS_WRITABLE(caps) \
100 (g_atomic_int_get (&(caps)->refcount) == 1)
102 /* same as gst_caps_is_any () */
103 #define CAPS_IS_ANY(caps) \
104 ((caps)->flags & GST_CAPS_FLAGS_ANY)
106 /* same as gst_caps_is_empty () */
107 #define CAPS_IS_EMPTY(caps) \
108 (!CAPS_IS_ANY(caps) && CAPS_IS_EMPTY_SIMPLE(caps))
110 #define CAPS_IS_EMPTY_SIMPLE(caps) \
111 (((caps)->structs == NULL) || ((caps)->structs->len == 0))
113 /* quick way to get a caps structure at an index without doing a type or array
115 #define gst_caps_get_structure_unchecked(caps, index) \
116 ((GstStructure *)g_ptr_array_index ((caps)->structs, (index)))
117 /* quick way to append a structure without checking the args */
118 #define gst_caps_append_structure_unchecked(caps, structure) G_STMT_START{\
119 GstStructure *__s=structure; \
120 gst_structure_set_parent_refcount (__s, &caps->refcount); \
121 g_ptr_array_add (caps->structs, __s); \
124 /* lock to protect multiple invocations of static caps to caps conversion */
125 G_LOCK_DEFINE_STATIC (static_caps_lock);
127 static void gst_caps_transform_to_string (const GValue * src_value,
128 GValue * dest_value);
129 static gboolean gst_caps_from_string_inplace (GstCaps * caps,
130 const gchar * string);
131 static GstCaps *gst_caps_copy_conditional (GstCaps * src);
134 gst_caps_get_type (void)
136 static GType gst_caps_type = 0;
138 if (G_UNLIKELY (gst_caps_type == 0)) {
139 gst_caps_type = g_boxed_type_register_static ("GstCaps",
140 (GBoxedCopyFunc) gst_caps_copy_conditional,
141 (GBoxedFreeFunc) gst_caps_unref);
143 g_value_register_transform_func (gst_caps_type,
144 G_TYPE_STRING, gst_caps_transform_to_string);
147 return gst_caps_type;
150 /* creation/deletion */
153 * gst_caps_new_empty:
155 * Creates a new #GstCaps that is empty. That is, the returned
156 * #GstCaps contains no media formats.
157 * Caller is responsible for unreffing the returned caps.
159 * Returns: the new #GstCaps
162 gst_caps_new_empty (void)
164 GstCaps *caps = g_slice_new (GstCaps);
166 caps->type = GST_TYPE_CAPS;
169 caps->structs = g_ptr_array_new ();
170 /* the 32 has been determined by logging caps sizes in _gst_caps_free
171 * but g_ptr_array uses 16 anyway if it expands once, so this does not help
173 * caps->structs = g_ptr_array_sized_new (32);
176 #ifdef DEBUG_REFCOUNT
177 GST_CAT_LOG (GST_CAT_CAPS, "created caps %p", caps);
186 * Creates a new #GstCaps that indicates that it is compatible with
189 * Returns: the new #GstCaps
192 gst_caps_new_any (void)
194 GstCaps *caps = gst_caps_new_empty ();
196 caps->flags = GST_CAPS_FLAGS_ANY;
202 * gst_caps_new_simple:
203 * @media_type: the media type of the structure
204 * @fieldname: first field to set
205 * @...: additional arguments
207 * Creates a new #GstCaps that contains one #GstStructure. The
208 * structure is defined by the arguments, which have the same format
209 * as gst_structure_new().
210 * Caller is responsible for unreffing the returned caps.
212 * Returns: the new #GstCaps
215 gst_caps_new_simple (const char *media_type, const char *fieldname, ...)
218 GstStructure *structure;
221 caps = gst_caps_new_empty ();
223 va_start (var_args, fieldname);
224 structure = gst_structure_new_valist (media_type, fieldname, var_args);
227 gst_caps_append_structure_unchecked (caps, structure);
234 * @struct1: the first structure to add
235 * @...: additional structures to add
237 * Creates a new #GstCaps and adds all the structures listed as
238 * arguments. The list must be NULL-terminated. The structures
239 * are not copied; the returned #GstCaps owns the structures.
241 * Returns: the new #GstCaps
244 gst_caps_new_full (GstStructure * struct1, ...)
249 va_start (var_args, struct1);
250 caps = gst_caps_new_full_valist (struct1, var_args);
257 * gst_caps_new_full_valist:
258 * @structure: the first structure to add
259 * @var_args: additional structures to add
261 * Creates a new #GstCaps and adds all the structures listed as
262 * arguments. The list must be NULL-terminated. The structures
263 * are not copied; the returned #GstCaps owns the structures.
265 * Returns: the new #GstCaps
268 gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
272 caps = gst_caps_new_empty ();
275 gst_caps_append_structure_unchecked (caps, structure);
276 structure = va_arg (var_args, GstStructure *);
284 * @caps: the #GstCaps to copy
286 * Creates a new #GstCaps as a copy of the old @caps. The new caps will have a
287 * refcount of 1, owned by the caller. The structures are copied as well.
289 * Note that this function is the semantic equivalent of a gst_caps_ref()
290 * followed by a gst_caps_make_writable(). If you only want to hold on to a
291 * reference to the data, you should use gst_caps_ref().
293 * When you are finished with the caps, call gst_caps_unref() on it.
295 * Returns: the new #GstCaps
298 gst_caps_copy (const GstCaps * caps)
301 GstStructure *structure;
304 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
306 newcaps = gst_caps_new_empty ();
307 newcaps->flags = caps->flags;
308 n = caps->structs->len;
310 for (i = 0; i < n; i++) {
311 structure = gst_caps_get_structure_unchecked (caps, i);
312 gst_caps_append_structure_unchecked (newcaps,
313 gst_structure_copy (structure));
320 _gst_caps_free (GstCaps * caps)
322 GstStructure *structure;
325 /* The refcount must be 0, but since we're only called by gst_caps_unref,
326 * don't bother testing. */
327 len = caps->structs->len;
328 /* This can be used to get statistics about caps sizes */
329 /*GST_CAT_INFO (GST_CAT_CAPS, "caps size: %d", len); */
330 for (i = 0; i < len; i++) {
331 structure = (GstStructure *) gst_caps_get_structure_unchecked (caps, i);
332 gst_structure_set_parent_refcount (structure, NULL);
333 gst_structure_free (structure);
335 g_ptr_array_free (caps->structs, TRUE);
337 memset (caps, 0xff, sizeof (GstCaps));
340 #ifdef DEBUG_REFCOUNT
341 GST_CAT_LOG (GST_CAT_CAPS, "freeing caps %p", caps);
343 g_slice_free (GstCaps, caps);
347 * gst_caps_make_writable:
348 * @caps: the #GstCaps to make writable
350 * Returns a writable copy of @caps.
352 * If there is only one reference count on @caps, the caller must be the owner,
353 * and so this function will return the caps object unchanged. If on the other
354 * hand there is more than one reference on the object, a new caps object will
355 * be returned. The caller's reference on @caps will be removed, and instead the
356 * caller will own a reference to the returned object.
358 * In short, this function unrefs the caps in the argument and refs the caps
359 * that it returns. Don't access the argument after calling this function. See
360 * also: gst_caps_ref().
362 * Returns: the same #GstCaps object.
365 gst_caps_make_writable (GstCaps * caps)
369 g_return_val_if_fail (caps != NULL, NULL);
371 /* we are the only instance reffing this caps */
372 if (IS_WRITABLE (caps))
376 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy caps");
377 copy = gst_caps_copy (caps);
378 gst_caps_unref (caps);
385 * @caps: the #GstCaps to reference
387 * Add a reference to a #GstCaps object.
389 * From this point on, until the caller calls gst_caps_unref() or
390 * gst_caps_make_writable(), it is guaranteed that the caps object will not
391 * change. This means its structures won't change, etc. To use a #GstCaps
392 * object, you must always have a refcount on it -- either the one made
393 * implicitly by e.g. gst_caps_new_simple(), or via taking one explicitly with
396 * Returns: the same #GstCaps object.
399 gst_caps_ref (GstCaps * caps)
401 g_return_val_if_fail (caps != NULL, NULL);
403 #ifdef DEBUG_REFCOUNT
404 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
405 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) + 1);
407 g_return_val_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0, NULL);
409 g_atomic_int_inc (&caps->refcount);
416 * @caps: the #GstCaps to unref
418 * Unref a #GstCaps and and free all its structures and the
419 * structures' values when the refcount reaches 0.
422 gst_caps_unref (GstCaps * caps)
424 g_return_if_fail (caps != NULL);
426 #ifdef DEBUG_REFCOUNT
427 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
428 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) - 1);
431 g_return_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0);
433 /* if we ended up with the refcount at zero, free the caps */
434 if (G_UNLIKELY (g_atomic_int_dec_and_test (&caps->refcount)))
435 _gst_caps_free (caps);
439 gst_static_caps_get_type (void)
441 static GType staticcaps_type = 0;
443 if (G_UNLIKELY (staticcaps_type == 0)) {
444 staticcaps_type = g_pointer_type_register_static ("GstStaticCaps");
446 return staticcaps_type;
451 * gst_static_caps_get:
452 * @static_caps: the #GstStaticCaps to convert
454 * Converts a #GstStaticCaps to a #GstCaps.
456 * Returns: A pointer to the #GstCaps. Unref after usage. Since the
457 * core holds an additional ref to the returned caps,
458 * use gst_caps_make_writable() on the returned caps to modify it.
461 gst_static_caps_get (GstStaticCaps * static_caps)
465 g_return_val_if_fail (static_caps != NULL, NULL);
467 caps = (GstCaps *) static_caps;
469 /* refcount is 0 when we need to convert */
470 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount) == 0)) {
474 G_LOCK (static_caps_lock);
475 /* check if other thread already updated */
476 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount) > 0))
479 string = static_caps->string;
481 if (G_UNLIKELY (string == NULL))
484 GST_CAT_LOG (GST_CAT_CAPS, "creating %p", static_caps);
486 /* we construct the caps on the stack, then copy over the struct into our
487 * real caps, refcount last. We do this because we must leave the refcount
488 * of the result caps to 0 so that other threads don't run away with the
489 * caps while we are constructing it. */
490 temp.type = GST_TYPE_CAPS;
492 temp.structs = g_ptr_array_new ();
494 /* initialize the caps to a refcount of 1 so the caps can be writable for
495 * the next statement */
498 /* convert to string */
499 if (G_UNLIKELY (!gst_caps_from_string_inplace (&temp, string)))
500 g_critical ("Could not convert static caps \"%s\"", string);
502 /* now copy stuff over to the real caps. */
503 caps->type = temp.type;
504 caps->flags = temp.flags;
505 caps->structs = temp.structs;
506 /* and bump the refcount so other threads can now read */
507 g_atomic_int_set (&caps->refcount, 1);
509 GST_CAT_LOG (GST_CAT_CAPS, "created %p", static_caps);
511 G_UNLOCK (static_caps_lock);
513 /* ref the caps, makes it not writable */
521 G_UNLOCK (static_caps_lock);
522 g_warning ("static caps %p string is NULL", static_caps);
529 static GstStructure *
530 gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
532 /* don't use index_fast, gst_caps_do_simplify relies on the order */
533 GstStructure *s = g_ptr_array_remove_index (caps->structs, idx);
535 gst_structure_set_parent_refcount (s, NULL);
540 * gst_caps_steal_structure:
541 * @caps: the #GstCaps to retrieve from
542 * @idx: Index of the structure to retrieve
544 * Retrieves the stucture with the given index from the list of structures
545 * contained in @caps. The caller becomes the owner of the returned structure.
547 * Returns: a pointer to the #GstStructure corresponding to @index.
552 gst_caps_steal_structure (GstCaps * caps, guint idx)
554 g_return_val_if_fail (caps != NULL, NULL);
555 g_return_val_if_fail (IS_WRITABLE (caps), NULL);
557 if (G_UNLIKELY (idx >= caps->structs->len))
560 return gst_caps_remove_and_get_structure (caps, idx);
564 gst_structure_is_equal_foreach (GQuark field_id, const GValue * val2,
567 GstStructure *struct1 = (GstStructure *) data;
568 const GValue *val1 = gst_structure_id_get_value (struct1, field_id);
570 if (G_UNLIKELY (val1 == NULL))
572 if (gst_value_compare (val1, val2) == GST_VALUE_EQUAL) {
580 gst_caps_structure_is_subset_field (GQuark field_id, const GValue * value,
583 GstStructure *subtract_from = user_data;
584 GValue subtraction = { 0, };
587 if (!(other = gst_structure_id_get_value (subtract_from, field_id)))
588 /* field is missing in one set */
591 /* equal values are subset */
592 if (gst_value_compare (other, value) == GST_VALUE_EQUAL)
600 * -> 1 - [1,2] = empty
604 * -> [1,2] - [1,3] = empty
608 * -> {1,3} - {1,2} = 3
611 * First caps subtraction needs to return a non-empty set, second
612 * subtractions needs to give en empty set.
614 if (gst_value_subtract (&subtraction, other, value)) {
615 g_value_unset (&subtraction);
616 /* !empty result, swapping must be empty */
617 if (!gst_value_subtract (&subtraction, value, other))
620 g_value_unset (&subtraction);
626 gst_caps_structure_is_subset (const GstStructure * minuend,
627 const GstStructure * subtrahend)
629 if ((minuend->name != subtrahend->name) ||
630 (gst_structure_n_fields (minuend) !=
631 gst_structure_n_fields (subtrahend))) {
635 return gst_structure_foreach ((GstStructure *) subtrahend,
636 gst_caps_structure_is_subset_field, (gpointer) minuend);
641 * @caps1: the #GstCaps that will be appended to
642 * @caps2: the #GstCaps to append
644 * Appends the structures contained in @caps2 to @caps1. The structures in
645 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
646 * freed. If either caps is ANY, the resulting caps will be ANY.
649 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
651 GstStructure *structure;
654 g_return_if_fail (GST_IS_CAPS (caps1));
655 g_return_if_fail (GST_IS_CAPS (caps2));
656 g_return_if_fail (IS_WRITABLE (caps1));
657 g_return_if_fail (IS_WRITABLE (caps2));
662 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))) {
663 /* FIXME: this leaks */
664 caps1->flags |= GST_CAPS_FLAGS_ANY;
665 for (i = caps2->structs->len - 1; i >= 0; i--) {
666 structure = gst_caps_remove_and_get_structure (caps2, i);
667 gst_structure_free (structure);
670 for (i = caps2->structs->len; i; i--) {
671 structure = gst_caps_remove_and_get_structure (caps2, 0);
672 gst_caps_append_structure_unchecked (caps1, structure);
675 gst_caps_unref (caps2); /* guaranteed to free it */
680 * @caps1: the #GstCaps that will take the new entries
681 * @caps2: the #GstCaps to merge in
683 * Appends the structures contained in @caps2 to @caps1 if they are not yet
684 * expressed by @caps1. The structures in @caps2 are not copied -- they are
685 * transferred to @caps1, and then @caps2 is freed.
686 * If either caps is ANY, the resulting caps will be ANY.
691 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
693 GstStructure *structure;
696 g_return_if_fail (GST_IS_CAPS (caps1));
697 g_return_if_fail (GST_IS_CAPS (caps2));
698 g_return_if_fail (IS_WRITABLE (caps1));
699 g_return_if_fail (IS_WRITABLE (caps2));
704 if (G_UNLIKELY (CAPS_IS_ANY (caps1))) {
705 for (i = caps2->structs->len - 1; i >= 0; i--) {
706 structure = gst_caps_remove_and_get_structure (caps2, i);
707 gst_structure_free (structure);
709 } else if (G_UNLIKELY (CAPS_IS_ANY (caps2))) {
710 caps1->flags |= GST_CAPS_FLAGS_ANY;
711 for (i = caps1->structs->len - 1; i >= 0; i--) {
712 structure = gst_caps_remove_and_get_structure (caps1, i);
713 gst_structure_free (structure);
716 for (i = caps2->structs->len; i; i--) {
717 structure = gst_caps_remove_and_get_structure (caps2, 0);
718 gst_caps_merge_structure (caps1, structure);
721 GstCaps *com = gst_caps_intersect (caps1, caps2);
722 GstCaps *add = gst_caps_subtract (caps2, com);
724 GST_DEBUG ("common : %d", gst_caps_get_size (com));
725 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
726 gst_caps_append (caps1, add);
727 gst_caps_unref (com);
730 gst_caps_unref (caps2); /* guaranteed to free it */
734 * gst_caps_append_structure:
735 * @caps: the #GstCaps that will be appended to
736 * @structure: the #GstStructure to append
738 * Appends @structure to @caps. The structure is not copied; @caps
739 * becomes the owner of @structure.
742 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
744 g_return_if_fail (GST_IS_CAPS (caps));
745 g_return_if_fail (IS_WRITABLE (caps));
747 if (G_LIKELY (structure)) {
748 g_return_if_fail (structure->parent_refcount == NULL);
751 STRUCTURE_POISON (structure);
754 gst_caps_append_structure_unchecked (caps, structure);
759 * gst_caps_remove_structure:
760 * @caps: the #GstCaps to remove from
761 * @idx: Index of the structure to remove
763 * removes the stucture with the given index from the list of structures
764 * contained in @caps.
767 gst_caps_remove_structure (GstCaps * caps, guint idx)
769 GstStructure *structure;
771 g_return_if_fail (caps != NULL);
772 g_return_if_fail (idx <= gst_caps_get_size (caps));
773 g_return_if_fail (IS_WRITABLE (caps));
775 structure = gst_caps_remove_and_get_structure (caps, idx);
776 gst_structure_free (structure);
780 * gst_caps_merge_structure:
781 * @caps: the #GstCaps that will the the new structure
782 * @structure: the #GstStructure to merge
784 * Appends @structure to @caps if its not already expressed by @caps. The
785 * structure is not copied; @caps becomes the owner of @structure.
788 gst_caps_merge_structure (GstCaps * caps, GstStructure * structure)
790 g_return_if_fail (GST_IS_CAPS (caps));
791 g_return_if_fail (IS_WRITABLE (caps));
793 if (G_LIKELY (structure)) {
794 GstStructure *structure1;
796 gboolean unique = TRUE;
798 g_return_if_fail (structure->parent_refcount == NULL);
801 STRUCTURE_POISON (structure);
804 /* check each structure */
805 for (i = caps->structs->len - 1; i >= 0; i--) {
806 structure1 = gst_caps_get_structure_unchecked (caps, i);
807 /* if structure is a subset of structure1, then skip it */
808 if (gst_caps_structure_is_subset (structure1, structure)) {
814 gst_caps_append_structure_unchecked (caps, structure);
816 gst_structure_free (structure);
825 * Gets the number of structures contained in @caps.
827 * Returns: the number of structures that @caps contains
830 gst_caps_get_size (const GstCaps * caps)
832 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
834 return caps->structs->len;
838 * gst_caps_get_structure:
840 * @index: the index of the structure
842 * Finds the structure in @caps that has the index @index, and
845 * WARNING: This function takes a const GstCaps *, but returns a
846 * non-const GstStructure *. This is for programming convenience --
847 * the caller should be aware that structures inside a constant
848 * #GstCaps should not be modified. However, if you know the caps
849 * are writable, either because you have just copied them or made
850 * them writable with gst_caps_make_writable(), you may modify the
851 * structure returned in the usual way, e.g. with functions like
852 * gst_structure_set().
854 * You do not need to free or unref the structure returned, it
855 * belongs to the #GstCaps.
857 * Returns: a pointer to the #GstStructure corresponding to @index
860 gst_caps_get_structure (const GstCaps * caps, guint index)
862 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
863 g_return_val_if_fail (index < caps->structs->len, NULL);
865 return gst_caps_get_structure_unchecked (caps, index);
870 * @caps: the #GstCaps to copy
871 * @nth: the nth structure to copy
873 * Creates a new #GstCaps and appends a copy of the nth structure
874 * contained in @caps.
876 * Returns: the new #GstCaps
879 gst_caps_copy_nth (const GstCaps * caps, guint nth)
882 GstStructure *structure;
884 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
886 newcaps = gst_caps_new_empty ();
887 newcaps->flags = caps->flags;
889 if (G_LIKELY (caps->structs->len > nth)) {
890 structure = gst_caps_get_structure_unchecked (caps, nth);
891 gst_caps_append_structure_unchecked (newcaps,
892 gst_structure_copy (structure));
900 * @caps: the #GstCaps to truncate
902 * Destructively discard all but the first structure from @caps. Useful when
903 * fixating. @caps must be writable.
906 gst_caps_truncate (GstCaps * caps)
910 g_return_if_fail (GST_IS_CAPS (caps));
911 g_return_if_fail (IS_WRITABLE (caps));
913 i = caps->structs->len - 1;
916 gst_caps_remove_structure (caps, i--);
920 * gst_caps_set_value:
921 * @caps: a writable caps
922 * @field: name of the field to set
923 * @value: value to set the field to
925 * Sets the given @field on all structures of @caps to the given @value.
926 * This is a convenience function for calling gst_structure_set_value() on
927 * all structures of @caps.
932 gst_caps_set_value (GstCaps * caps, const char *field, const GValue * value)
936 g_return_if_fail (GST_IS_CAPS (caps));
937 g_return_if_fail (IS_WRITABLE (caps));
938 g_return_if_fail (field != NULL);
939 g_return_if_fail (G_IS_VALUE (value));
941 len = caps->structs->len;
942 for (i = 0; i < len; i++) {
943 GstStructure *structure = gst_caps_get_structure_unchecked (caps, i);
944 gst_structure_set_value (structure, field, value);
949 * gst_caps_set_simple_valist:
950 * @caps: the #GstCaps to set
951 * @field: first field to set
952 * @varargs: additional parameters
954 * Sets fields in a #GstCaps. The arguments must be passed in the same
955 * manner as gst_structure_set(), and be NULL-terminated.
956 * <note>Prior to GStreamer version 0.10.26, this function failed when
957 * @caps was not simple. If your code needs to work with those versions
958 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
959 * is %TRUE for @caps.</note>
962 gst_caps_set_simple_valist (GstCaps * caps, const char *field, va_list varargs)
964 GValue value = { 0, };
966 g_return_if_fail (GST_IS_CAPS (caps));
967 g_return_if_fail (IS_WRITABLE (caps));
973 type = va_arg (varargs, GType);
975 if (G_UNLIKELY (type == G_TYPE_DATE)) {
976 g_warning ("Don't use G_TYPE_DATE, use GST_TYPE_DATE instead\n");
977 type = GST_TYPE_DATE;
979 #if GLIB_CHECK_VERSION(2,23,3)
980 G_VALUE_COLLECT_INIT (&value, type, varargs, 0, &err);
982 g_value_init (&value, type);
983 G_VALUE_COLLECT (&value, varargs, 0, &err);
985 if (G_UNLIKELY (err)) {
986 g_critical ("%s", err);
990 gst_caps_set_value (caps, field, &value);
992 g_value_unset (&value);
994 field = va_arg (varargs, const gchar *);
999 * gst_caps_set_simple:
1000 * @caps: the #GstCaps to set
1001 * @field: first field to set
1002 * @...: additional parameters
1004 * Sets fields in a #GstCaps. The arguments must be passed in the same
1005 * manner as gst_structure_set(), and be NULL-terminated.
1006 * <note>Prior to GStreamer version 0.10.26, this function failed when
1007 * @caps was not simple. If your code needs to work with those versions
1008 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
1009 * is %TRUE for @caps.</note>
1012 gst_caps_set_simple (GstCaps * caps, const char *field, ...)
1016 g_return_if_fail (GST_IS_CAPS (caps));
1017 g_return_if_fail (IS_WRITABLE (caps));
1019 va_start (var_args, field);
1020 gst_caps_set_simple_valist (caps, field, var_args);
1028 * @caps: the #GstCaps to test
1030 * Determines if @caps represents any media format.
1032 * Returns: TRUE if @caps represents any format.
1035 gst_caps_is_any (const GstCaps * caps)
1037 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1039 return (CAPS_IS_ANY (caps));
1043 * gst_caps_is_empty:
1044 * @caps: the #GstCaps to test
1046 * Determines if @caps represents no media formats.
1048 * Returns: TRUE if @caps represents no formats.
1051 gst_caps_is_empty (const GstCaps * caps)
1053 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1055 if (CAPS_IS_ANY (caps))
1058 return CAPS_IS_EMPTY_SIMPLE (caps);
1062 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
1065 return gst_value_is_fixed (value);
1069 * gst_caps_is_fixed:
1070 * @caps: the #GstCaps to test
1072 * Fixed #GstCaps describe exactly one format, that is, they have exactly
1073 * one structure, and each field in the structure describes a fixed type.
1074 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
1076 * Returns: TRUE if @caps is fixed
1079 gst_caps_is_fixed (const GstCaps * caps)
1081 GstStructure *structure;
1083 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1085 if (caps->structs->len != 1)
1088 structure = gst_caps_get_structure_unchecked (caps, 0);
1090 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
1094 * gst_caps_is_equal_fixed:
1095 * @caps1: the #GstCaps to test
1096 * @caps2: the #GstCaps to test
1098 * Tests if two #GstCaps are equal. This function only works on fixed
1101 * Returns: TRUE if the arguments represent the same format
1104 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
1106 GstStructure *struct1, *struct2;
1108 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
1109 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
1111 struct1 = gst_caps_get_structure_unchecked (caps1, 0);
1112 struct2 = gst_caps_get_structure_unchecked (caps2, 0);
1114 if (struct1->name != struct2->name) {
1117 if (struct1->fields->len != struct2->fields->len) {
1121 return gst_structure_foreach (struct1, gst_structure_is_equal_foreach,
1126 * gst_caps_is_always_compatible:
1127 * @caps1: the #GstCaps to test
1128 * @caps2: the #GstCaps to test
1130 * A given #GstCaps structure is always compatible with another if
1131 * every media format that is in the first is also contained in the
1132 * second. That is, @caps1 is a subset of @caps2.
1134 * Returns: TRUE if @caps1 is a subset of @caps2.
1137 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
1139 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1140 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1142 return gst_caps_is_subset (caps1, caps2);
1146 * gst_caps_is_subset:
1147 * @subset: a #GstCaps
1148 * @superset: a potentially greater #GstCaps
1150 * Checks if all caps represented by @subset are also represented by @superset.
1151 * <note>This function does not work reliably if optional properties for caps
1152 * are included on one caps and omitted on the other.</note>
1154 * Returns: %TRUE if @subset is a subset of @superset
1157 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
1162 g_return_val_if_fail (subset != NULL, FALSE);
1163 g_return_val_if_fail (superset != NULL, FALSE);
1165 if (CAPS_IS_EMPTY (subset) || CAPS_IS_ANY (superset))
1167 if (CAPS_IS_ANY (subset) || CAPS_IS_EMPTY (superset))
1170 caps = gst_caps_subtract (subset, superset);
1171 ret = CAPS_IS_EMPTY_SIMPLE (caps);
1172 gst_caps_unref (caps);
1177 * gst_caps_is_equal:
1178 * @caps1: a #GstCaps
1179 * @caps2: another #GstCaps
1181 * Checks if the given caps represent the same set of caps.
1182 * <note>This function does not work reliably if optional properties for caps
1183 * are included on one caps and omitted on the other.</note>
1185 * This function deals correctly with passing NULL for any of the caps.
1187 * Returns: TRUE if both caps are equal.
1190 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1192 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1193 * So there should be an assertion that caps1 and caps2 != NULL */
1195 /* NULL <-> NULL is allowed here */
1196 if (G_UNLIKELY (caps1 == caps2))
1199 /* one of them NULL => they are different (can't be both NULL because
1200 * we checked that above) */
1201 if (G_UNLIKELY (caps1 == NULL || caps2 == NULL))
1204 if (G_UNLIKELY (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2)))
1205 return gst_caps_is_equal_fixed (caps1, caps2);
1207 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1210 /* intersect operation */
1215 const GstStructure *intersect;
1220 gst_caps_structure_intersect_field1 (GQuark id, const GValue * val1,
1223 IntersectData *idata = (IntersectData *) data;
1224 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1226 if (G_UNLIKELY (val2 == NULL)) {
1227 gst_structure_id_set_value (idata->dest, id, val1);
1229 GValue dest_value = { 0 };
1230 if (gst_value_intersect (&dest_value, val1, val2)) {
1231 gst_structure_id_set_value (idata->dest, id, &dest_value);
1232 g_value_unset (&dest_value);
1241 gst_caps_structure_intersect_field2 (GQuark id, const GValue * val1,
1244 IntersectData *idata = (IntersectData *) data;
1245 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1247 if (G_UNLIKELY (val2 == NULL)) {
1248 gst_structure_id_set_value (idata->dest, id, val1);
1253 static GstStructure *
1254 gst_caps_structure_intersect (const GstStructure * struct1,
1255 const GstStructure * struct2)
1259 g_assert (struct1 != NULL);
1260 g_assert (struct2 != NULL);
1262 if (G_UNLIKELY (struct1->name != struct2->name))
1265 /* copy fields from struct1 which we have not in struct2 to target
1266 * intersect if we have the field in both */
1267 data.dest = gst_structure_id_empty_new (struct1->name);
1268 data.intersect = struct2;
1269 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1270 gst_caps_structure_intersect_field1, &data)))
1273 /* copy fields from struct2 which we have not in struct1 to target */
1274 data.intersect = struct1;
1275 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct2,
1276 gst_caps_structure_intersect_field2, &data)))
1282 gst_structure_free (data.dest);
1287 gst_caps_structure_can_intersect_field (GQuark id, const GValue * val1,
1290 GstStructure *other = (GstStructure *) data;
1291 const GValue *val2 = gst_structure_id_get_value (other, id);
1293 if (G_LIKELY (val2)) {
1294 if (!gst_value_can_intersect (val1, val2)) {
1297 gint eq = gst_value_compare (val1, val2);
1299 if (eq == GST_VALUE_UNORDERED) {
1300 /* we need to try interseting */
1301 GValue dest_value = { 0 };
1302 if (gst_value_intersect (&dest_value, val1, val2)) {
1303 g_value_unset (&dest_value);
1307 } else if (eq != GST_VALUE_EQUAL) {
1316 gst_caps_structure_can_intersect (const GstStructure * struct1,
1317 const GstStructure * struct2)
1319 g_assert (struct1 != NULL);
1320 g_assert (struct2 != NULL);
1322 if (G_UNLIKELY (struct1->name != struct2->name))
1325 /* tries to intersect if we have the field in both */
1326 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1327 gst_caps_structure_can_intersect_field, (gpointer) struct2)))
1334 * gst_caps_can_intersect:
1335 * @caps1: a #GstCaps to intersect
1336 * @caps2: a #GstCaps to intersect
1338 * Tries intersecting @caps1 and @caps2 and reports wheter the result would not
1341 * Returns: %TRUE if intersection would be not empty
1346 gst_caps_can_intersect (const GstCaps * caps1, const GstCaps * caps2)
1348 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1349 guint j, k, len1, len2;
1350 GstStructure *struct1;
1351 GstStructure *struct2;
1353 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1354 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1356 /* caps are exactly the same pointers */
1357 if (G_UNLIKELY (caps1 == caps2))
1360 /* empty caps on either side, return empty */
1361 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1364 /* one of the caps is any */
1365 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2)))
1368 /* run zigzag on top line then right line, this preserves the caps order
1369 * much better than a simple loop.
1371 * This algorithm zigzags over the caps structures as demonstrated in
1372 * the folowing matrix:
1380 * First we iterate over the caps1 structures (top line) intersecting
1381 * the structures diagonally down, then we iterate over the caps2
1384 len1 = caps1->structs->len;
1385 len2 = caps2->structs->len;
1386 for (i = 0; i < len1 + len2 - 1; i++) {
1387 /* superset index goes from 0 to sgst_caps_structure_intersectuperset->structs->len-1 */
1388 j = MIN (i, len1 - 1);
1389 /* subset index stays 0 until i reaches superset->structs->len, then it
1390 * counts up from 1 to subset->structs->len - 1 */
1393 /* now run the diagonal line, end condition is the left or bottom
1396 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1397 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1399 if (gst_caps_structure_can_intersect (struct1, struct2)) {
1402 /* move down left */
1404 if (G_UNLIKELY (j == 0))
1405 break; /* so we don't roll back to G_MAXUINT */
1413 * gst_caps_intersect:
1414 * @caps1: a #GstCaps to intersect
1415 * @caps2: a #GstCaps to intersect
1417 * Creates a new #GstCaps that contains all the formats that are common
1418 * to both @caps1 and @caps2.
1420 * Returns: the new #GstCaps
1423 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1425 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1426 guint j, k, len1, len2;
1428 GstStructure *struct1;
1429 GstStructure *struct2;
1431 GstStructure *istruct;
1433 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1434 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1436 /* caps are exactly the same pointers, just copy one caps */
1437 if (G_UNLIKELY (caps1 == caps2))
1438 return gst_caps_copy (caps1);
1440 /* empty caps on either side, return empty */
1441 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1442 return gst_caps_new_empty ();
1444 /* one of the caps is any, just copy the other caps */
1445 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1446 return gst_caps_copy (caps2);
1447 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1448 return gst_caps_copy (caps1);
1450 dest = gst_caps_new_empty ();
1452 /* run zigzag on top line then right line, this preserves the caps order
1453 * much better than a simple loop.
1455 * This algorithm zigzags over the caps structures as demonstrated in
1456 * the folowing matrix:
1464 * First we iterate over the caps1 structures (top line) intersecting
1465 * the structures diagonally down, then we iterate over the caps2
1468 len1 = caps1->structs->len;
1469 len2 = caps2->structs->len;
1470 for (i = 0; i < len1 + len2 - 1; i++) {
1471 /* caps1 index goes from 0 to caps1->structs->len-1 */
1472 j = MIN (i, len1 - 1);
1473 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1474 * up from 1 to caps2->structs->len - 1 */
1477 /* now run the diagonal line, end condition is the left or bottom
1480 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1481 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1483 istruct = gst_caps_structure_intersect (struct1, struct2);
1485 gst_caps_append_structure (dest, istruct);
1486 /* move down left */
1488 if (G_UNLIKELY (j == 0))
1489 break; /* so we don't roll back to G_MAXUINT */
1496 /* subtract operation */
1500 const GstStructure *subtract_from;
1506 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1509 SubtractionEntry *e = user_data;
1510 GValue subtraction = { 0, };
1511 const GValue *other;
1512 GstStructure *structure;
1514 other = gst_structure_id_get_value (e->subtract_from, field_id);
1518 if (!gst_value_subtract (&subtraction, other, value))
1520 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1521 g_value_unset (&subtraction);
1524 structure = gst_structure_copy (e->subtract_from);
1525 gst_structure_id_set_value (structure, field_id, &subtraction);
1526 g_value_unset (&subtraction);
1527 e->put_into = g_slist_prepend (e->put_into, structure);
1533 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1534 const GstStructure * subtrahend)
1539 e.subtract_from = minuend;
1542 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1543 gst_caps_structure_subtract_field, &e);
1549 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1550 gst_structure_free (walk->data);
1552 g_slist_free (e.put_into);
1558 * gst_caps_subtract:
1559 * @minuend: #GstCaps to substract from
1560 * @subtrahend: #GstCaps to substract
1562 * Subtracts the @subtrahend from the @minuend.
1563 * <note>This function does not work reliably if optional properties for caps
1564 * are included on one caps and omitted on the other.</note>
1566 * Returns: the resulting caps
1569 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1574 GstCaps *dest = NULL, *src;
1576 g_return_val_if_fail (minuend != NULL, NULL);
1577 g_return_val_if_fail (subtrahend != NULL, NULL);
1579 if (CAPS_IS_EMPTY (minuend) || CAPS_IS_ANY (subtrahend)) {
1580 return gst_caps_new_empty ();
1582 if (CAPS_IS_EMPTY_SIMPLE (subtrahend))
1583 return gst_caps_copy (minuend);
1585 /* FIXME: Do we want this here or above?
1586 The reason we need this is that there is no definition about what
1587 ANY means for specific types, so it's not possible to reduce ANY partially
1588 You can only remove everything or nothing and that is done above.
1589 Note: there's a test that checks this behaviour. */
1590 g_return_val_if_fail (!CAPS_IS_ANY (minuend), NULL);
1591 sublen = subtrahend->structs->len;
1592 g_assert (sublen > 0);
1594 src = gst_caps_copy (minuend);
1595 for (i = 0; i < sublen; i++) {
1598 sub = gst_caps_get_structure_unchecked (subtrahend, i);
1600 gst_caps_unref (src);
1603 dest = gst_caps_new_empty ();
1604 srclen = src->structs->len;
1605 for (j = 0; j < srclen; j++) {
1606 min = gst_caps_get_structure_unchecked (src, j);
1607 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1610 if (gst_caps_structure_subtract (&list, min, sub)) {
1613 for (walk = list; walk; walk = g_slist_next (walk)) {
1614 gst_caps_append_structure_unchecked (dest,
1615 (GstStructure *) walk->data);
1617 g_slist_free (list);
1619 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1622 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1625 if (CAPS_IS_EMPTY_SIMPLE (dest)) {
1626 gst_caps_unref (src);
1631 gst_caps_unref (src);
1632 gst_caps_do_simplify (dest);
1636 /* union operation */
1639 static GstStructure *
1640 gst_caps_structure_union (const GstStructure * struct1,
1641 const GstStructure * struct2)
1645 const GstStructureField *field1;
1646 const GstStructureField *field2;
1649 /* FIXME this doesn't actually work */
1651 if (struct1->name != struct2->name)
1654 dest = gst_structure_id_empty_new (struct1->name);
1656 for (i = 0; i < struct1->fields->len; i++) {
1657 GValue dest_value = { 0 };
1659 field1 = GST_STRUCTURE_FIELD (struct1, i);
1660 field2 = gst_structure_id_get_field (struct2, field1->name);
1662 if (field2 == NULL) {
1665 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1666 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1669 ret = gst_value_compare (&field1->value, &field2->value);
1680 * @caps1: a #GstCaps to union
1681 * @caps2: a #GstCaps to union
1683 * Creates a new #GstCaps that contains all the formats that are in
1684 * either @caps1 and @caps2.
1686 * Returns: the new #GstCaps
1689 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1694 /* NULL pointers are no correct GstCaps */
1695 g_return_val_if_fail (caps1 != NULL, NULL);
1696 g_return_val_if_fail (caps2 != NULL, NULL);
1698 if (CAPS_IS_EMPTY (caps1))
1699 return gst_caps_copy (caps2);
1701 if (CAPS_IS_EMPTY (caps2))
1702 return gst_caps_copy (caps1);
1704 if (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))
1705 return gst_caps_new_any ();
1707 dest1 = gst_caps_copy (caps1);
1708 dest2 = gst_caps_copy (caps2);
1709 gst_caps_append (dest1, dest2);
1711 gst_caps_do_simplify (dest1);
1715 /* normalize/simplify operations */
1717 typedef struct _NormalizeForeach
1720 GstStructure *structure;
1725 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1727 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1731 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1732 guint len = gst_value_list_get_size (value);
1733 for (i = 1; i < len; i++) {
1734 const GValue *v = gst_value_list_get_value (value, i);
1735 GstStructure *structure = gst_structure_copy (nf->structure);
1737 gst_structure_id_set_value (structure, field_id, v);
1738 gst_caps_append_structure_unchecked (nf->caps, structure);
1741 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1742 gst_structure_id_set_value (nf->structure, field_id, &val);
1743 g_value_unset (&val);
1751 * gst_caps_normalize:
1752 * @caps: a #GstCaps to normalize
1754 * Creates a new #GstCaps that represents the same set of formats as
1755 * @caps, but contains no lists. Each list is expanded into separate
1758 * Returns: the new #GstCaps
1761 gst_caps_normalize (const GstCaps * caps)
1763 NormalizeForeach nf;
1767 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1769 newcaps = gst_caps_copy (caps);
1771 nlen = newcaps->structs->len;
1773 for (i = 0; i < nlen; i++) {
1774 nf.structure = gst_caps_get_structure_unchecked (newcaps, i);
1776 while (!gst_structure_foreach (nf.structure,
1777 gst_caps_normalize_foreach, &nf));
1784 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1787 const GstStructure *struct1 = *((const GstStructure **) one);
1788 const GstStructure *struct2 = *((const GstStructure **) two);
1790 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1791 So what's the best way? */
1792 ret = strcmp (gst_structure_get_name (struct1),
1793 gst_structure_get_name (struct2));
1797 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1804 GstStructure *compare;
1809 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1812 UnionField *u = user_data;
1813 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1817 g_value_unset (&u->value);
1820 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1823 g_value_unset (&u->value);
1827 gst_value_union (&u->value, val, value);
1832 gst_caps_structure_simplify (GstStructure ** result,
1833 const GstStructure * simplify, GstStructure * compare)
1836 UnionField field = { 0, {0,}, NULL };
1838 /* try to subtract to get a real subset */
1839 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1840 switch (g_slist_length (list)) {
1845 *result = list->data;
1846 g_slist_free (list);
1852 for (walk = list; walk; walk = g_slist_next (walk)) {
1853 gst_structure_free (walk->data);
1855 g_slist_free (list);
1861 /* try to union both structs */
1862 field.compare = compare;
1863 if (gst_structure_foreach ((GstStructure *) simplify,
1864 gst_caps_structure_figure_out_union, &field)) {
1865 gboolean ret = FALSE;
1867 /* now we know all of simplify's fields are the same in compare
1868 * but at most one field: field.name */
1869 if (G_IS_VALUE (&field.value)) {
1870 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1871 gst_structure_id_set_value (compare, field.name, &field.value);
1875 g_value_unset (&field.value);
1876 } else if (gst_structure_n_fields (simplify) <=
1877 gst_structure_n_fields (compare)) {
1878 /* compare is just more specific, will be optimized away later */
1879 /* FIXME: do this here? */
1880 GST_LOG ("found a case that will be optimized later.");
1882 gchar *one = gst_structure_to_string (simplify);
1883 gchar *two = gst_structure_to_string (compare);
1886 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1898 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1899 GstStructure * new, gint i)
1901 gst_structure_set_parent_refcount (old, NULL);
1902 gst_structure_free (old);
1903 gst_structure_set_parent_refcount (new, &caps->refcount);
1904 g_ptr_array_index (caps->structs, i) = new;
1908 * gst_caps_do_simplify:
1909 * @caps: a #GstCaps to simplify
1911 * Modifies the given @caps inplace into a representation that represents the
1912 * same set of formats, but in a simpler form. Component structures that are
1913 * identical are merged. Component structures that have values that can be
1914 * merged are also merged.
1916 * Returns: TRUE, if the caps could be simplified
1919 gst_caps_do_simplify (GstCaps * caps)
1921 GstStructure *simplify, *compare, *result = NULL;
1923 gboolean changed = FALSE;
1925 g_return_val_if_fail (caps != NULL, FALSE);
1926 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1928 if (gst_caps_get_size (caps) < 2)
1931 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1933 start = caps->structs->len - 1;
1934 for (i = caps->structs->len - 1; i >= 0; i--) {
1935 simplify = gst_caps_get_structure_unchecked (caps, i);
1936 if (gst_structure_get_name_id (simplify) !=
1937 gst_structure_get_name_id (gst_caps_get_structure_unchecked (caps,
1940 for (j = start; j >= 0; j--) {
1943 compare = gst_caps_get_structure_unchecked (caps, j);
1944 if (gst_structure_get_name_id (simplify) !=
1945 gst_structure_get_name_id (compare)) {
1948 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1950 gst_caps_switch_structures (caps, simplify, result, i);
1953 gst_caps_remove_structure (caps, i);
1965 /* gst_caps_do_simplify (caps); */
1971 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
1973 * gst_caps_save_thyself:
1974 * @caps: a #GstCaps structure
1975 * @parent: a XML parent node
1977 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
1979 * Returns: a XML node pointer
1982 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
1984 char *s = gst_caps_to_string (caps);
1986 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
1992 * gst_caps_load_thyself:
1993 * @parent: a XML node
1995 * Creates a #GstCaps from its XML serialization.
1997 * Returns: a new #GstCaps structure
2000 gst_caps_load_thyself (xmlNodePtr parent)
2002 if (strcmp ("caps", (char *) parent->name) == 0) {
2003 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
2014 * @caps: a pointer to #GstCaps
2015 * @newcaps: a #GstCaps to replace *caps
2017 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
2018 * pointed to by @caps, if applicable, then modifies @caps to point to
2019 * @newcaps. An additional ref on @newcaps is taken.
2021 * This function does not take any locks so you might want to lock
2022 * the object owning @caps pointer.
2025 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
2029 g_return_if_fail (caps != NULL);
2033 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p, %p -> %p", caps, oldcaps, newcaps);
2035 if (newcaps != oldcaps) {
2037 gst_caps_ref (newcaps);
2042 gst_caps_unref (oldcaps);
2047 * gst_caps_to_string:
2050 * Converts @caps to a string representation. This string representation
2051 * can be converted back to a #GstCaps by gst_caps_from_string().
2053 * For debugging purposes its easier to do something like this:
2055 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
2057 * This prints the caps in human readble form.
2059 * Returns: a newly allocated string representing @caps.
2062 gst_caps_to_string (const GstCaps * caps)
2064 guint i, slen, clen;
2067 /* NOTE: This function is potentially called by the debug system,
2068 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
2069 * should be careful to avoid recursion. This includes any functions
2070 * called by gst_caps_to_string. In particular, calls should
2071 * not use the GST_PTR_FORMAT extension. */
2074 return g_strdup ("NULL");
2076 if (CAPS_IS_ANY (caps)) {
2077 return g_strdup ("ANY");
2079 if (CAPS_IS_EMPTY_SIMPLE (caps)) {
2080 return g_strdup ("EMPTY");
2083 /* estimate a rough string length to avoid unnecessary reallocs in GString */
2085 clen = caps->structs->len;
2086 for (i = 0; i < clen; i++) {
2088 STRUCTURE_ESTIMATED_STRING_LEN (gst_caps_get_structure_unchecked (caps,
2092 s = g_string_sized_new (slen);
2093 for (i = 0; i < clen; i++) {
2094 GstStructure *structure;
2097 /* ';' is now added by gst_structure_to_string */
2098 g_string_append_c (s, ' ');
2101 structure = gst_caps_get_structure_unchecked (caps, i);
2102 priv_gst_structure_append_to_gstring (structure, s);
2104 if (s->len && s->str[s->len - 1] == ';') {
2105 /* remove latest ';' */
2106 s->str[--s->len] = '\0';
2108 return g_string_free (s, FALSE);
2112 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
2114 GstStructure *structure;
2117 if (strcmp ("ANY", string) == 0) {
2118 caps->flags = GST_CAPS_FLAGS_ANY;
2121 if (strcmp ("EMPTY", string) == 0) {
2125 structure = gst_structure_from_string (string, &s);
2126 if (structure == NULL) {
2129 gst_caps_append_structure_unchecked (caps, structure);
2133 while (g_ascii_isspace (*s))
2138 structure = gst_structure_from_string (s, &s);
2139 if (structure == NULL) {
2142 gst_caps_append_structure_unchecked (caps, structure);
2150 * gst_caps_from_string:
2151 * @string: a string to convert to #GstCaps
2153 * Converts @caps from a string representation.
2155 * Returns: a newly allocated #GstCaps
2158 gst_caps_from_string (const gchar * string)
2162 g_return_val_if_fail (string, FALSE);
2164 caps = gst_caps_new_empty ();
2165 if (gst_caps_from_string_inplace (caps, string)) {
2168 gst_caps_unref (caps);
2174 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
2176 g_return_if_fail (G_IS_VALUE (src_value));
2177 g_return_if_fail (G_IS_VALUE (dest_value));
2178 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
2179 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
2180 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
2182 dest_value->data[0].v_pointer =
2183 gst_caps_to_string (src_value->data[0].v_pointer);
2187 gst_caps_copy_conditional (GstCaps * src)
2190 return gst_caps_ref (src);