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 #include <libxml/parser.h>
79 xmlNodePtr gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent);
80 GstCaps *gst_caps_load_thyself (xmlNodePtr parent);
84 #define DEBUG_REFCOUNT
86 #define CAPS_POISON(caps) G_STMT_START{ \
88 GstCaps *_newcaps = gst_caps_copy (caps); \
89 gst_caps_unref(caps); \
93 #define STRUCTURE_POISON(structure) G_STMT_START{ \
95 GstStructure *_newstruct = gst_structure_copy (structure); \
96 gst_structure_free(structure); \
97 structure = _newstruct; \
100 #define IS_WRITABLE(caps) \
101 (g_atomic_int_get (&(caps)->refcount) == 1)
103 /* same as gst_caps_is_any () */
104 #define CAPS_IS_ANY(caps) \
105 ((caps)->flags & GST_CAPS_FLAGS_ANY)
107 /* same as gst_caps_is_empty () */
108 #define CAPS_IS_EMPTY(caps) \
109 (!CAPS_IS_ANY(caps) && CAPS_IS_EMPTY_SIMPLE(caps))
111 #define CAPS_IS_EMPTY_SIMPLE(caps) \
112 (((caps)->structs == NULL) || ((caps)->structs->len == 0))
114 /* quick way to get a caps structure at an index without doing a type or array
116 #define gst_caps_get_structure_unchecked(caps, index) \
117 ((GstStructure *)g_ptr_array_index ((caps)->structs, (index)))
118 /* quick way to append a structure without checking the args */
119 #define gst_caps_append_structure_unchecked(caps, structure) G_STMT_START{\
120 GstStructure *__s=structure; \
121 gst_structure_set_parent_refcount (__s, &caps->refcount); \
122 g_ptr_array_add (caps->structs, __s); \
125 /* lock to protect multiple invocations of static caps to caps conversion */
126 G_LOCK_DEFINE_STATIC (static_caps_lock);
128 static void gst_caps_transform_to_string (const GValue * src_value,
129 GValue * dest_value);
130 static gboolean gst_caps_from_string_inplace (GstCaps * caps,
131 const gchar * string);
132 static GstCaps *gst_caps_copy_conditional (GstCaps * src);
135 gst_caps_get_type (void)
137 static GType gst_caps_type = 0;
139 if (G_UNLIKELY (gst_caps_type == 0)) {
140 gst_caps_type = g_boxed_type_register_static ("GstCaps",
141 (GBoxedCopyFunc) gst_caps_copy_conditional,
142 (GBoxedFreeFunc) gst_caps_unref);
144 g_value_register_transform_func (gst_caps_type,
145 G_TYPE_STRING, gst_caps_transform_to_string);
148 return gst_caps_type;
151 /* creation/deletion */
154 * gst_caps_new_empty:
156 * Creates a new #GstCaps that is empty. That is, the returned
157 * #GstCaps contains no media formats.
158 * Caller is responsible for unreffing the returned caps.
160 * Returns: (transfer full): the new #GstCaps
163 gst_caps_new_empty (void)
165 GstCaps *caps = g_slice_new (GstCaps);
167 caps->type = GST_TYPE_CAPS;
170 caps->structs = g_ptr_array_new ();
171 /* the 32 has been determined by logging caps sizes in _gst_caps_free
172 * but g_ptr_array uses 16 anyway if it expands once, so this does not help
174 * caps->structs = g_ptr_array_sized_new (32);
177 #ifdef DEBUG_REFCOUNT
178 GST_CAT_LOG (GST_CAT_CAPS, "created caps %p", caps);
187 * Creates a new #GstCaps that indicates that it is compatible with
190 * Returns: (transfer full): the new #GstCaps
193 gst_caps_new_any (void)
195 GstCaps *caps = gst_caps_new_empty ();
197 caps->flags = GST_CAPS_FLAGS_ANY;
203 * gst_caps_new_simple:
204 * @media_type: the media type of the structure
205 * @fieldname: first field to set
206 * @...: additional arguments
208 * Creates a new #GstCaps that contains one #GstStructure. The
209 * structure is defined by the arguments, which have the same format
210 * as gst_structure_new().
211 * Caller is responsible for unreffing the returned caps.
213 * Returns: (transfer full): the new #GstCaps
216 gst_caps_new_simple (const char *media_type, const char *fieldname, ...)
219 GstStructure *structure;
222 caps = gst_caps_new_empty ();
224 va_start (var_args, fieldname);
225 structure = gst_structure_new_valist (media_type, fieldname, var_args);
229 gst_caps_append_structure_unchecked (caps, structure);
231 gst_caps_replace (&caps, NULL);
238 * @struct1: the first structure to add
239 * @...: additional structures to add
241 * Creates a new #GstCaps and adds all the structures listed as
242 * arguments. The list must be NULL-terminated. The structures
243 * are not copied; the returned #GstCaps owns the structures.
245 * Returns: (transfer full): the new #GstCaps
248 gst_caps_new_full (GstStructure * struct1, ...)
253 va_start (var_args, struct1);
254 caps = gst_caps_new_full_valist (struct1, var_args);
261 * gst_caps_new_full_valist:
262 * @structure: the first structure to add
263 * @var_args: additional structures to add
265 * Creates a new #GstCaps and adds all the structures listed as
266 * arguments. The list must be NULL-terminated. The structures
267 * are not copied; the returned #GstCaps owns the structures.
269 * Returns: (transfer full): the new #GstCaps
272 gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
276 caps = gst_caps_new_empty ();
279 gst_caps_append_structure_unchecked (caps, structure);
280 structure = va_arg (var_args, GstStructure *);
288 * @caps: the #GstCaps to copy
290 * Creates a new #GstCaps as a copy of the old @caps. The new caps will have a
291 * refcount of 1, owned by the caller. The structures are copied as well.
293 * Note that this function is the semantic equivalent of a gst_caps_ref()
294 * followed by a gst_caps_make_writable(). If you only want to hold on to a
295 * reference to the data, you should use gst_caps_ref().
297 * When you are finished with the caps, call gst_caps_unref() on it.
299 * Returns: (transfer full): the new #GstCaps
302 gst_caps_copy (const GstCaps * caps)
305 GstStructure *structure;
308 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
310 newcaps = gst_caps_new_empty ();
311 newcaps->flags = caps->flags;
312 n = caps->structs->len;
314 for (i = 0; i < n; i++) {
315 structure = gst_caps_get_structure_unchecked (caps, i);
316 gst_caps_append_structure_unchecked (newcaps,
317 gst_structure_copy (structure));
324 _gst_caps_free (GstCaps * caps)
326 GstStructure *structure;
329 /* The refcount must be 0, but since we're only called by gst_caps_unref,
330 * don't bother testing. */
331 len = caps->structs->len;
332 /* This can be used to get statistics about caps sizes */
333 /*GST_CAT_INFO (GST_CAT_CAPS, "caps size: %d", len); */
334 for (i = 0; i < len; i++) {
335 structure = (GstStructure *) gst_caps_get_structure_unchecked (caps, i);
336 gst_structure_set_parent_refcount (structure, NULL);
337 gst_structure_free (structure);
339 g_ptr_array_free (caps->structs, TRUE);
341 memset (caps, 0xff, sizeof (GstCaps));
344 #ifdef DEBUG_REFCOUNT
345 GST_CAT_LOG (GST_CAT_CAPS, "freeing caps %p", caps);
347 g_slice_free (GstCaps, caps);
351 * gst_caps_make_writable:
352 * @caps: (transfer full): the #GstCaps to make writable
354 * Returns a writable copy of @caps.
356 * If there is only one reference count on @caps, the caller must be the owner,
357 * and so this function will return the caps object unchanged. If on the other
358 * hand there is more than one reference on the object, a new caps object will
359 * be returned. The caller's reference on @caps will be removed, and instead the
360 * caller will own a reference to the returned object.
362 * In short, this function unrefs the caps in the argument and refs the caps
363 * that it returns. Don't access the argument after calling this function. See
364 * also: gst_caps_ref().
366 * Returns: (transfer full): the same #GstCaps object.
369 gst_caps_make_writable (GstCaps * caps)
373 g_return_val_if_fail (caps != NULL, NULL);
375 /* we are the only instance reffing this caps */
376 if (IS_WRITABLE (caps))
380 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy caps");
381 copy = gst_caps_copy (caps);
382 gst_caps_unref (caps);
389 * @caps: the #GstCaps to reference
391 * Add a reference to a #GstCaps object.
393 * From this point on, until the caller calls gst_caps_unref() or
394 * gst_caps_make_writable(), it is guaranteed that the caps object will not
395 * change. This means its structures won't change, etc. To use a #GstCaps
396 * object, you must always have a refcount on it -- either the one made
397 * implicitly by e.g. gst_caps_new_simple(), or via taking one explicitly with
400 * Returns: (transfer full): the same #GstCaps object.
403 gst_caps_ref (GstCaps * caps)
405 g_return_val_if_fail (caps != NULL, NULL);
407 #ifdef DEBUG_REFCOUNT
408 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
409 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) + 1);
411 g_return_val_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0, NULL);
413 g_atomic_int_inc (&caps->refcount);
420 * @caps: (transfer full): the #GstCaps to unref
422 * Unref a #GstCaps and and free all its structures and the
423 * structures' values when the refcount reaches 0.
426 gst_caps_unref (GstCaps * caps)
428 g_return_if_fail (caps != NULL);
430 #ifdef DEBUG_REFCOUNT
431 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
432 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) - 1);
435 g_return_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0);
437 /* if we ended up with the refcount at zero, free the caps */
438 if (G_UNLIKELY (g_atomic_int_dec_and_test (&caps->refcount)))
439 _gst_caps_free (caps);
443 gst_static_caps_get_type (void)
445 static GType staticcaps_type = 0;
447 if (G_UNLIKELY (staticcaps_type == 0)) {
448 staticcaps_type = g_pointer_type_register_static ("GstStaticCaps");
450 return staticcaps_type;
455 * gst_static_caps_get:
456 * @static_caps: the #GstStaticCaps to convert
458 * Converts a #GstStaticCaps to a #GstCaps.
460 * Returns: (transfer full): a pointer to the #GstCaps. Unref after usage.
461 * Since the core holds an additional ref to the returned caps,
462 * use gst_caps_make_writable() on the returned caps to modify it.
465 gst_static_caps_get (GstStaticCaps * static_caps)
469 g_return_val_if_fail (static_caps != NULL, NULL);
471 caps = (GstCaps *) static_caps;
473 /* refcount is 0 when we need to convert */
474 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount) == 0)) {
478 G_LOCK (static_caps_lock);
479 /* check if other thread already updated */
480 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount) > 0))
483 string = static_caps->string;
485 if (G_UNLIKELY (string == NULL))
488 GST_CAT_LOG (GST_CAT_CAPS, "creating %p", static_caps);
490 /* we construct the caps on the stack, then copy over the struct into our
491 * real caps, refcount last. We do this because we must leave the refcount
492 * of the result caps to 0 so that other threads don't run away with the
493 * caps while we are constructing it. */
494 temp.type = GST_TYPE_CAPS;
496 temp.structs = g_ptr_array_new ();
498 /* initialize the caps to a refcount of 1 so the caps can be writable for
499 * the next statement */
502 /* convert to string */
503 if (G_UNLIKELY (!gst_caps_from_string_inplace (&temp, string)))
504 g_critical ("Could not convert static caps \"%s\"", string);
506 /* now copy stuff over to the real caps. */
507 caps->type = temp.type;
508 caps->flags = temp.flags;
509 caps->structs = temp.structs;
510 /* and bump the refcount so other threads can now read */
511 g_atomic_int_set (&caps->refcount, 1);
513 GST_CAT_LOG (GST_CAT_CAPS, "created %p", static_caps);
515 G_UNLOCK (static_caps_lock);
517 /* ref the caps, makes it not writable */
525 G_UNLOCK (static_caps_lock);
526 g_warning ("static caps %p string is NULL", static_caps);
533 static GstStructure *
534 gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
536 /* don't use index_fast, gst_caps_do_simplify relies on the order */
537 GstStructure *s = g_ptr_array_remove_index (caps->structs, idx);
539 gst_structure_set_parent_refcount (s, NULL);
544 * gst_caps_steal_structure:
545 * @caps: the #GstCaps to retrieve from
546 * @index: Index of the structure to retrieve
548 * Retrieves the stucture with the given index from the list of structures
549 * contained in @caps. The caller becomes the owner of the returned structure.
551 * Returns: (transfer full): a pointer to the #GstStructure corresponding
557 gst_caps_steal_structure (GstCaps * caps, guint index)
559 g_return_val_if_fail (caps != NULL, NULL);
560 g_return_val_if_fail (IS_WRITABLE (caps), NULL);
562 if (G_UNLIKELY (index >= caps->structs->len))
565 return gst_caps_remove_and_get_structure (caps, index);
569 gst_caps_structure_is_subset_field (GQuark field_id, const GValue * value,
572 GstStructure *superset = user_data;
573 GValue subtraction = { 0, };
576 if (!(other = gst_structure_id_get_value (superset, field_id)))
577 /* field is missing in the superset => is subset */
580 /* equal values are subset */
581 if (gst_value_compare (other, value) == GST_VALUE_EQUAL)
589 * -> 1 - [1,2] = empty
593 * -> [1,2] - [1,3] = empty
597 * -> {1,3} - {1,2} = 3
600 * First caps subtraction needs to return a non-empty set, second
601 * subtractions needs to give en empty set.
603 if (gst_value_subtract (&subtraction, other, value)) {
604 g_value_unset (&subtraction);
605 /* !empty result, swapping must be empty */
606 if (!gst_value_subtract (&subtraction, value, other))
609 g_value_unset (&subtraction);
615 gst_caps_structure_is_subset (const GstStructure * superset,
616 const GstStructure * subset)
618 if ((superset->name != subset->name) ||
619 (gst_structure_n_fields (superset) > gst_structure_n_fields (subset)))
622 return gst_structure_foreach ((GstStructure *) subset,
623 gst_caps_structure_is_subset_field, (gpointer) superset);
628 * @caps1: the #GstCaps that will be appended to
629 * @caps2: (transfer full): the #GstCaps to append
631 * Appends the structures contained in @caps2 to @caps1. The structures in
632 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
633 * freed. If either caps is ANY, the resulting caps will be ANY.
636 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
638 GstStructure *structure;
641 g_return_if_fail (GST_IS_CAPS (caps1));
642 g_return_if_fail (GST_IS_CAPS (caps2));
643 g_return_if_fail (IS_WRITABLE (caps1));
644 g_return_if_fail (IS_WRITABLE (caps2));
649 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))) {
650 /* FIXME: this leaks */
651 caps1->flags |= GST_CAPS_FLAGS_ANY;
652 for (i = caps2->structs->len - 1; i >= 0; i--) {
653 structure = gst_caps_remove_and_get_structure (caps2, i);
654 gst_structure_free (structure);
657 for (i = caps2->structs->len; i; i--) {
658 structure = gst_caps_remove_and_get_structure (caps2, 0);
659 gst_caps_append_structure_unchecked (caps1, structure);
662 gst_caps_unref (caps2); /* guaranteed to free it */
667 * @caps1: the #GstCaps that will take the new entries
668 * @caps2: (transfer full): the #GstCaps to merge in
670 * Appends the structures contained in @caps2 to @caps1 if they are not yet
671 * expressed by @caps1. The structures in @caps2 are not copied -- they are
672 * transferred to @caps1, and then @caps2 is freed.
673 * If either caps is ANY, the resulting caps will be ANY.
678 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
680 GstStructure *structure;
683 g_return_if_fail (GST_IS_CAPS (caps1));
684 g_return_if_fail (GST_IS_CAPS (caps2));
685 g_return_if_fail (IS_WRITABLE (caps1));
686 g_return_if_fail (IS_WRITABLE (caps2));
691 if (G_UNLIKELY (CAPS_IS_ANY (caps1))) {
692 for (i = caps2->structs->len - 1; i >= 0; i--) {
693 structure = gst_caps_remove_and_get_structure (caps2, i);
694 gst_structure_free (structure);
696 } else if (G_UNLIKELY (CAPS_IS_ANY (caps2))) {
697 caps1->flags |= GST_CAPS_FLAGS_ANY;
698 for (i = caps1->structs->len - 1; i >= 0; i--) {
699 structure = gst_caps_remove_and_get_structure (caps1, i);
700 gst_structure_free (structure);
703 for (i = caps2->structs->len; i; i--) {
704 structure = gst_caps_remove_and_get_structure (caps2, 0);
705 gst_caps_merge_structure (caps1, structure);
708 GstCaps *com = gst_caps_intersect (caps1, caps2);
709 GstCaps *add = gst_caps_subtract (caps2, com);
711 GST_DEBUG ("common : %d", gst_caps_get_size (com));
712 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
713 gst_caps_append (caps1, add);
714 gst_caps_unref (com);
717 gst_caps_unref (caps2); /* guaranteed to free it */
721 * gst_caps_append_structure:
722 * @caps: the #GstCaps that will be appended to
723 * @structure: (transfer full): the #GstStructure to append
725 * Appends @structure to @caps. The structure is not copied; @caps
726 * becomes the owner of @structure.
729 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
731 g_return_if_fail (GST_IS_CAPS (caps));
732 g_return_if_fail (IS_WRITABLE (caps));
734 if (G_LIKELY (structure)) {
735 g_return_if_fail (structure->parent_refcount == NULL);
738 STRUCTURE_POISON (structure);
741 gst_caps_append_structure_unchecked (caps, structure);
746 * gst_caps_remove_structure:
747 * @caps: the #GstCaps to remove from
748 * @idx: Index of the structure to remove
750 * removes the stucture with the given index from the list of structures
751 * contained in @caps.
754 gst_caps_remove_structure (GstCaps * caps, guint idx)
756 GstStructure *structure;
758 g_return_if_fail (caps != NULL);
759 g_return_if_fail (idx <= gst_caps_get_size (caps));
760 g_return_if_fail (IS_WRITABLE (caps));
762 structure = gst_caps_remove_and_get_structure (caps, idx);
763 gst_structure_free (structure);
767 * gst_caps_merge_structure:
768 * @caps: the #GstCaps that will the the new structure
769 * @structure: (transfer full): the #GstStructure to merge
771 * Appends @structure to @caps if its not already expressed by @caps. The
772 * structure is not copied; @caps becomes the owner of @structure.
775 gst_caps_merge_structure (GstCaps * caps, GstStructure * structure)
777 g_return_if_fail (GST_IS_CAPS (caps));
778 g_return_if_fail (IS_WRITABLE (caps));
780 if (G_LIKELY (structure)) {
781 GstStructure *structure1;
783 gboolean unique = TRUE;
785 g_return_if_fail (structure->parent_refcount == NULL);
788 STRUCTURE_POISON (structure);
791 /* check each structure */
792 for (i = caps->structs->len - 1; i >= 0; i--) {
793 structure1 = gst_caps_get_structure_unchecked (caps, i);
794 /* if structure is a subset of structure1, then skip it */
795 if (gst_caps_structure_is_subset (structure1, structure)) {
801 gst_caps_append_structure_unchecked (caps, structure);
803 gst_structure_free (structure);
812 * Gets the number of structures contained in @caps.
814 * Returns: the number of structures that @caps contains
817 gst_caps_get_size (const GstCaps * caps)
819 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
821 return caps->structs->len;
825 * gst_caps_get_structure:
827 * @index: the index of the structure
829 * Finds the structure in @caps that has the index @index, and
832 * WARNING: This function takes a const GstCaps *, but returns a
833 * non-const GstStructure *. This is for programming convenience --
834 * the caller should be aware that structures inside a constant
835 * #GstCaps should not be modified. However, if you know the caps
836 * are writable, either because you have just copied them or made
837 * them writable with gst_caps_make_writable(), you may modify the
838 * structure returned in the usual way, e.g. with functions like
839 * gst_structure_set().
841 * You do not need to free or unref the structure returned, it
842 * belongs to the #GstCaps.
844 * Returns: (transfer none): a pointer to the #GstStructure corresponding
848 gst_caps_get_structure (const GstCaps * caps, guint index)
850 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
851 g_return_val_if_fail (index < caps->structs->len, NULL);
853 return gst_caps_get_structure_unchecked (caps, index);
858 * @caps: the #GstCaps to copy
859 * @nth: the nth structure to copy
861 * Creates a new #GstCaps and appends a copy of the nth structure
862 * contained in @caps.
864 * Returns: (transfer full): the new #GstCaps
867 gst_caps_copy_nth (const GstCaps * caps, guint nth)
870 GstStructure *structure;
872 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
874 newcaps = gst_caps_new_empty ();
875 newcaps->flags = caps->flags;
877 if (G_LIKELY (caps->structs->len > nth)) {
878 structure = gst_caps_get_structure_unchecked (caps, nth);
879 gst_caps_append_structure_unchecked (newcaps,
880 gst_structure_copy (structure));
888 * @caps: the #GstCaps to truncate
890 * Destructively discard all but the first structure from @caps. Useful when
891 * fixating. @caps must be writable.
894 gst_caps_truncate (GstCaps * caps)
898 g_return_if_fail (GST_IS_CAPS (caps));
899 g_return_if_fail (IS_WRITABLE (caps));
901 i = caps->structs->len - 1;
904 gst_caps_remove_structure (caps, i--);
908 * gst_caps_set_value:
909 * @caps: a writable caps
910 * @field: name of the field to set
911 * @value: value to set the field to
913 * Sets the given @field on all structures of @caps to the given @value.
914 * This is a convenience function for calling gst_structure_set_value() on
915 * all structures of @caps.
920 gst_caps_set_value (GstCaps * caps, const char *field, const GValue * value)
924 g_return_if_fail (GST_IS_CAPS (caps));
925 g_return_if_fail (IS_WRITABLE (caps));
926 g_return_if_fail (field != NULL);
927 g_return_if_fail (G_IS_VALUE (value));
929 len = caps->structs->len;
930 for (i = 0; i < len; i++) {
931 GstStructure *structure = gst_caps_get_structure_unchecked (caps, i);
932 gst_structure_set_value (structure, field, value);
937 * gst_caps_set_simple_valist:
938 * @caps: the #GstCaps to set
939 * @field: first field to set
940 * @varargs: additional parameters
942 * Sets fields in a #GstCaps. The arguments must be passed in the same
943 * manner as gst_structure_set(), and be NULL-terminated.
944 * <note>Prior to GStreamer version 0.10.26, this function failed when
945 * @caps was not simple. If your code needs to work with those versions
946 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
947 * is %TRUE for @caps.</note>
950 gst_caps_set_simple_valist (GstCaps * caps, const char *field, va_list varargs)
952 GValue value = { 0, };
954 g_return_if_fail (GST_IS_CAPS (caps));
955 g_return_if_fail (IS_WRITABLE (caps));
961 type = va_arg (varargs, GType);
963 if (G_UNLIKELY (type == G_TYPE_DATE)) {
964 g_warning ("Don't use G_TYPE_DATE, use GST_TYPE_DATE instead\n");
965 type = GST_TYPE_DATE;
967 G_VALUE_COLLECT_INIT (&value, type, varargs, 0, &err);
968 if (G_UNLIKELY (err)) {
969 g_critical ("%s", err);
973 gst_caps_set_value (caps, field, &value);
975 g_value_unset (&value);
977 field = va_arg (varargs, const gchar *);
982 * gst_caps_set_simple:
983 * @caps: the #GstCaps to set
984 * @field: first field to set
985 * @...: additional parameters
987 * Sets fields in a #GstCaps. The arguments must be passed in the same
988 * manner as gst_structure_set(), and be NULL-terminated.
989 * <note>Prior to GStreamer version 0.10.26, this function failed when
990 * @caps was not simple. If your code needs to work with those versions
991 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
992 * is %TRUE for @caps.</note>
995 gst_caps_set_simple (GstCaps * caps, const char *field, ...)
999 g_return_if_fail (GST_IS_CAPS (caps));
1000 g_return_if_fail (IS_WRITABLE (caps));
1002 va_start (var_args, field);
1003 gst_caps_set_simple_valist (caps, field, var_args);
1011 * @caps: the #GstCaps to test
1013 * Determines if @caps represents any media format.
1015 * Returns: TRUE if @caps represents any format.
1018 gst_caps_is_any (const GstCaps * caps)
1020 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1022 return (CAPS_IS_ANY (caps));
1026 * gst_caps_is_empty:
1027 * @caps: the #GstCaps to test
1029 * Determines if @caps represents no media formats.
1031 * Returns: TRUE if @caps represents no formats.
1034 gst_caps_is_empty (const GstCaps * caps)
1036 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1038 if (CAPS_IS_ANY (caps))
1041 return CAPS_IS_EMPTY_SIMPLE (caps);
1045 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
1048 return gst_value_is_fixed (value);
1052 * gst_caps_is_fixed:
1053 * @caps: the #GstCaps to test
1055 * Fixed #GstCaps describe exactly one format, that is, they have exactly
1056 * one structure, and each field in the structure describes a fixed type.
1057 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
1059 * Returns: TRUE if @caps is fixed
1062 gst_caps_is_fixed (const GstCaps * caps)
1064 GstStructure *structure;
1066 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1068 if (caps->structs->len != 1)
1071 structure = gst_caps_get_structure_unchecked (caps, 0);
1073 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
1077 * gst_caps_is_equal_fixed:
1078 * @caps1: the #GstCaps to test
1079 * @caps2: the #GstCaps to test
1081 * Tests if two #GstCaps are equal. This function only works on fixed
1084 * Returns: TRUE if the arguments represent the same format
1087 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
1089 GstStructure *struct1, *struct2;
1091 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
1092 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
1094 struct1 = gst_caps_get_structure_unchecked (caps1, 0);
1095 struct2 = gst_caps_get_structure_unchecked (caps2, 0);
1097 return gst_structure_is_equal (struct1, struct2);
1101 * gst_caps_is_always_compatible:
1102 * @caps1: the #GstCaps to test
1103 * @caps2: the #GstCaps to test
1105 * A given #GstCaps structure is always compatible with another if
1106 * every media format that is in the first is also contained in the
1107 * second. That is, @caps1 is a subset of @caps2.
1109 * Returns: TRUE if @caps1 is a subset of @caps2.
1112 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
1114 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1115 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1117 return gst_caps_is_subset (caps1, caps2);
1121 * gst_caps_is_subset:
1122 * @subset: a #GstCaps
1123 * @superset: a potentially greater #GstCaps
1125 * Checks if all caps represented by @subset are also represented by @superset.
1126 * <note>This function does not work reliably if optional properties for caps
1127 * are included on one caps and omitted on the other.</note>
1129 * Returns: %TRUE if @subset is a subset of @superset
1132 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
1137 g_return_val_if_fail (subset != NULL, FALSE);
1138 g_return_val_if_fail (superset != NULL, FALSE);
1140 if (CAPS_IS_EMPTY (subset) || CAPS_IS_ANY (superset))
1142 if (CAPS_IS_ANY (subset) || CAPS_IS_EMPTY (superset))
1145 caps = gst_caps_subtract (subset, superset);
1146 ret = CAPS_IS_EMPTY_SIMPLE (caps);
1147 gst_caps_unref (caps);
1152 * gst_caps_is_equal:
1153 * @caps1: a #GstCaps
1154 * @caps2: another #GstCaps
1156 * Checks if the given caps represent the same set of caps.
1157 * <note>This function does not work reliably if optional properties for caps
1158 * are included on one caps and omitted on the other.</note>
1160 * This function deals correctly with passing NULL for any of the caps.
1162 * Returns: TRUE if both caps are equal.
1165 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1167 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1168 * So there should be an assertion that caps1 and caps2 != NULL */
1170 /* NULL <-> NULL is allowed here */
1171 if (G_UNLIKELY (caps1 == caps2))
1174 /* one of them NULL => they are different (can't be both NULL because
1175 * we checked that above) */
1176 if (G_UNLIKELY (caps1 == NULL || caps2 == NULL))
1179 if (G_UNLIKELY (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2)))
1180 return gst_caps_is_equal_fixed (caps1, caps2);
1182 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1185 /* intersect operation */
1188 * gst_caps_can_intersect:
1189 * @caps1: a #GstCaps to intersect
1190 * @caps2: a #GstCaps to intersect
1192 * Tries intersecting @caps1 and @caps2 and reports whether the result would not
1195 * Returns: %TRUE if intersection would be not empty
1200 gst_caps_can_intersect (const GstCaps * caps1, const GstCaps * caps2)
1202 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1203 guint j, k, len1, len2;
1204 GstStructure *struct1;
1205 GstStructure *struct2;
1207 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1208 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1210 /* caps are exactly the same pointers */
1211 if (G_UNLIKELY (caps1 == caps2))
1214 /* empty caps on either side, return empty */
1215 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1218 /* one of the caps is any */
1219 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2)))
1222 /* run zigzag on top line then right line, this preserves the caps order
1223 * much better than a simple loop.
1225 * This algorithm zigzags over the caps structures as demonstrated in
1226 * the folowing matrix:
1229 * +------------- total distance: +-------------
1230 * | 1 2 4 7 0 | 0 1 2 3
1231 * caps2 | 3 5 8 10 1 | 1 2 3 4
1232 * | 6 9 11 12 2 | 2 3 4 5
1234 * First we iterate over the caps1 structures (top line) intersecting
1235 * the structures diagonally down, then we iterate over the caps2
1236 * structures. The result is that the intersections are ordered based on the
1237 * sum of the indexes in the list.
1239 len1 = caps1->structs->len;
1240 len2 = caps2->structs->len;
1241 for (i = 0; i < len1 + len2 - 1; i++) {
1242 /* superset index goes from 0 to sgst_caps_structure_intersectuperset->structs->len-1 */
1243 j = MIN (i, len1 - 1);
1244 /* subset index stays 0 until i reaches superset->structs->len, then it
1245 * counts up from 1 to subset->structs->len - 1 */
1248 /* now run the diagonal line, end condition is the left or bottom
1251 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1252 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1254 if (gst_structure_can_intersect (struct1, struct2)) {
1257 /* move down left */
1259 if (G_UNLIKELY (j == 0))
1260 break; /* so we don't roll back to G_MAXUINT */
1268 gst_caps_intersect_zig_zag (const GstCaps * caps1, const GstCaps * caps2)
1270 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1271 guint j, k, len1, len2;
1273 GstStructure *struct1;
1274 GstStructure *struct2;
1276 GstStructure *istruct;
1278 /* caps are exactly the same pointers, just copy one caps */
1279 if (G_UNLIKELY (caps1 == caps2))
1280 return gst_caps_copy (caps1);
1282 /* empty caps on either side, return empty */
1283 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1284 return gst_caps_new_empty ();
1286 /* one of the caps is any, just copy the other caps */
1287 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1288 return gst_caps_copy (caps2);
1289 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1290 return gst_caps_copy (caps1);
1292 dest = gst_caps_new_empty ();
1294 /* run zigzag on top line then right line, this preserves the caps order
1295 * much better than a simple loop.
1297 * This algorithm zigzags over the caps structures as demonstrated in
1298 * the folowing matrix:
1306 * First we iterate over the caps1 structures (top line) intersecting
1307 * the structures diagonally down, then we iterate over the caps2
1310 len1 = caps1->structs->len;
1311 len2 = caps2->structs->len;
1312 for (i = 0; i < len1 + len2 - 1; i++) {
1313 /* caps1 index goes from 0 to caps1->structs->len-1 */
1314 j = MIN (i, len1 - 1);
1315 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1316 * up from 1 to caps2->structs->len - 1 */
1319 /* now run the diagonal line, end condition is the left or bottom
1322 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1323 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1325 istruct = gst_structure_intersect (struct1, struct2);
1327 gst_caps_merge_structure (dest, istruct);
1328 /* move down left */
1330 if (G_UNLIKELY (j == 0))
1331 break; /* so we don't roll back to G_MAXUINT */
1339 * gst_caps_intersect_first:
1340 * @caps1: a #GstCaps to intersect
1341 * @caps2: a #GstCaps to intersect
1343 * Creates a new #GstCaps that contains all the formats that are common
1344 * to both @caps1 and @caps2.
1346 * Unlike @gst_caps_intersect, the returned caps will be ordered in a similar
1347 * fashion as @caps1.
1349 * Returns: the new #GstCaps
1352 gst_caps_intersect_first (const GstCaps * caps1, const GstCaps * caps2)
1354 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1355 guint j, len1, len2;
1357 GstStructure *struct1;
1358 GstStructure *struct2;
1360 GstStructure *istruct;
1362 /* caps are exactly the same pointers, just copy one caps */
1363 if (G_UNLIKELY (caps1 == caps2))
1364 return gst_caps_copy (caps1);
1366 /* empty caps on either side, return empty */
1367 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1368 return gst_caps_new_empty ();
1370 /* one of the caps is any, just copy the other caps */
1371 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1372 return gst_caps_copy (caps2);
1373 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1374 return gst_caps_copy (caps1);
1376 dest = gst_caps_new_empty ();
1378 len1 = caps1->structs->len;
1379 len2 = caps2->structs->len;
1380 for (i = 0; i < len1; i++) {
1381 struct1 = gst_caps_get_structure_unchecked (caps1, i);
1382 for (j = 0; j < len2; j++) {
1383 struct2 = gst_caps_get_structure_unchecked (caps2, j);
1384 istruct = gst_structure_intersect (struct1, struct2);
1386 gst_caps_merge_structure (dest, istruct);
1394 * gst_caps_intersect_full:
1395 * @caps1: a #GstCaps to intersect
1396 * @caps2: a #GstCaps to intersect
1397 * @mode: The intersection algorithm/mode to use
1399 * Creates a new #GstCaps that contains all the formats that are common
1400 * to both @caps1 and @caps2, the order is defined by the #GstCapsIntersectMode
1403 * Returns: the new #GstCaps
1407 gst_caps_intersect_full (const GstCaps * caps1, const GstCaps * caps2,
1408 GstCapsIntersectMode mode)
1410 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1411 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1414 case GST_CAPS_INTERSECT_FIRST:
1415 return gst_caps_intersect_first (caps1, caps2);
1417 g_warning ("Unknown caps intersect mode: %d", mode);
1419 case GST_CAPS_INTERSECT_ZIG_ZAG:
1420 return gst_caps_intersect_zig_zag (caps1, caps2);
1425 * gst_caps_intersect:
1426 * @caps1: a #GstCaps to intersect
1427 * @caps2: a #GstCaps to intersect
1429 * Creates a new #GstCaps that contains all the formats that are common
1430 * to both @caps1 and @caps2. Defaults to %GST_CAPS_INTERSECT_ZIG_ZAG mode.
1432 * Returns: the new #GstCaps
1435 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1437 return gst_caps_intersect_full (caps1, caps2, GST_CAPS_INTERSECT_ZIG_ZAG);
1441 /* subtract operation */
1445 const GstStructure *subtract_from;
1451 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1454 SubtractionEntry *e = user_data;
1455 GValue subtraction = { 0, };
1456 const GValue *other;
1457 GstStructure *structure;
1459 other = gst_structure_id_get_value (e->subtract_from, field_id);
1463 if (!gst_value_subtract (&subtraction, other, value))
1465 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1466 g_value_unset (&subtraction);
1469 structure = gst_structure_copy (e->subtract_from);
1470 gst_structure_id_set_value (structure, field_id, &subtraction);
1471 g_value_unset (&subtraction);
1472 e->put_into = g_slist_prepend (e->put_into, structure);
1478 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1479 const GstStructure * subtrahend)
1484 e.subtract_from = minuend;
1487 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1488 gst_caps_structure_subtract_field, &e);
1494 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1495 gst_structure_free (walk->data);
1497 g_slist_free (e.put_into);
1503 * gst_caps_subtract:
1504 * @minuend: #GstCaps to substract from
1505 * @subtrahend: #GstCaps to substract
1507 * Subtracts the @subtrahend from the @minuend.
1508 * <note>This function does not work reliably if optional properties for caps
1509 * are included on one caps and omitted on the other.</note>
1511 * Returns: the resulting caps
1514 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1519 GstCaps *dest = NULL, *src;
1521 g_return_val_if_fail (minuend != NULL, NULL);
1522 g_return_val_if_fail (subtrahend != NULL, NULL);
1524 if (CAPS_IS_EMPTY (minuend) || CAPS_IS_ANY (subtrahend)) {
1525 return gst_caps_new_empty ();
1527 if (CAPS_IS_EMPTY_SIMPLE (subtrahend))
1528 return gst_caps_copy (minuend);
1530 /* FIXME: Do we want this here or above?
1531 The reason we need this is that there is no definition about what
1532 ANY means for specific types, so it's not possible to reduce ANY partially
1533 You can only remove everything or nothing and that is done above.
1534 Note: there's a test that checks this behaviour. */
1535 g_return_val_if_fail (!CAPS_IS_ANY (minuend), NULL);
1536 sublen = subtrahend->structs->len;
1537 g_assert (sublen > 0);
1539 src = gst_caps_copy (minuend);
1540 for (i = 0; i < sublen; i++) {
1543 sub = gst_caps_get_structure_unchecked (subtrahend, i);
1545 gst_caps_unref (src);
1548 dest = gst_caps_new_empty ();
1549 srclen = src->structs->len;
1550 for (j = 0; j < srclen; j++) {
1551 min = gst_caps_get_structure_unchecked (src, j);
1552 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1555 if (gst_caps_structure_subtract (&list, min, sub)) {
1558 for (walk = list; walk; walk = g_slist_next (walk)) {
1559 gst_caps_append_structure_unchecked (dest,
1560 (GstStructure *) walk->data);
1562 g_slist_free (list);
1564 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1567 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1570 if (CAPS_IS_EMPTY_SIMPLE (dest)) {
1571 gst_caps_unref (src);
1576 gst_caps_unref (src);
1577 gst_caps_do_simplify (dest);
1581 /* union operation */
1584 static GstStructure *
1585 gst_caps_structure_union (const GstStructure * struct1,
1586 const GstStructure * struct2)
1590 const GstStructureField *field1;
1591 const GstStructureField *field2;
1594 /* FIXME this doesn't actually work */
1596 if (struct1->name != struct2->name)
1599 dest = gst_structure_id_empty_new (struct1->name);
1601 for (i = 0; i < struct1->fields->len; i++) {
1602 GValue dest_value = { 0 };
1604 field1 = GST_STRUCTURE_FIELD (struct1, i);
1605 field2 = gst_structure_id_get_field (struct2, field1->name);
1607 if (field2 == NULL) {
1610 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1611 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1614 ret = gst_value_compare (&field1->value, &field2->value);
1625 * @caps1: a #GstCaps to union
1626 * @caps2: a #GstCaps to union
1628 * Creates a new #GstCaps that contains all the formats that are in
1629 * either @caps1 and @caps2.
1631 * Returns: the new #GstCaps
1634 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1639 /* NULL pointers are no correct GstCaps */
1640 g_return_val_if_fail (caps1 != NULL, NULL);
1641 g_return_val_if_fail (caps2 != NULL, NULL);
1643 if (CAPS_IS_EMPTY (caps1))
1644 return gst_caps_copy (caps2);
1646 if (CAPS_IS_EMPTY (caps2))
1647 return gst_caps_copy (caps1);
1649 if (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))
1650 return gst_caps_new_any ();
1652 dest1 = gst_caps_copy (caps1);
1653 dest2 = gst_caps_copy (caps2);
1654 gst_caps_append (dest1, dest2);
1656 gst_caps_do_simplify (dest1);
1660 /* normalize/simplify operations */
1662 typedef struct _NormalizeForeach
1665 GstStructure *structure;
1670 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1672 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1676 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1677 guint len = gst_value_list_get_size (value);
1678 for (i = 1; i < len; i++) {
1679 const GValue *v = gst_value_list_get_value (value, i);
1680 GstStructure *structure = gst_structure_copy (nf->structure);
1682 gst_structure_id_set_value (structure, field_id, v);
1683 gst_caps_append_structure_unchecked (nf->caps, structure);
1686 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1687 gst_structure_id_set_value (nf->structure, field_id, &val);
1688 g_value_unset (&val);
1696 * gst_caps_normalize:
1697 * @caps: a #GstCaps to normalize
1699 * Creates a new #GstCaps that represents the same set of formats as
1700 * @caps, but contains no lists. Each list is expanded into separate
1703 * Returns: the new #GstCaps
1706 gst_caps_normalize (const GstCaps * caps)
1708 NormalizeForeach nf;
1712 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1714 newcaps = gst_caps_copy (caps);
1717 for (i = 0; i < gst_caps_get_size (newcaps); i++) {
1718 nf.structure = gst_caps_get_structure_unchecked (newcaps, i);
1720 while (!gst_structure_foreach (nf.structure,
1721 gst_caps_normalize_foreach, &nf));
1728 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1731 const GstStructure *struct1 = *((const GstStructure **) one);
1732 const GstStructure *struct2 = *((const GstStructure **) two);
1734 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1735 So what's the best way? */
1736 ret = strcmp (gst_structure_get_name (struct1),
1737 gst_structure_get_name (struct2));
1741 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1748 GstStructure *compare;
1753 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1756 UnionField *u = user_data;
1757 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1761 g_value_unset (&u->value);
1764 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1767 g_value_unset (&u->value);
1771 gst_value_union (&u->value, val, value);
1776 gst_caps_structure_simplify (GstStructure ** result,
1777 const GstStructure * simplify, GstStructure * compare)
1780 UnionField field = { 0, {0,}, NULL };
1782 /* try to subtract to get a real subset */
1783 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1784 if (list == NULL) { /* no result */
1787 } else if (list->next == NULL) { /* one result */
1788 *result = list->data;
1789 g_slist_free (list);
1791 } else { /* multiple results */
1792 g_slist_foreach (list, (GFunc) gst_structure_free, NULL);
1793 g_slist_free (list);
1798 /* try to union both structs */
1799 field.compare = compare;
1800 if (gst_structure_foreach ((GstStructure *) simplify,
1801 gst_caps_structure_figure_out_union, &field)) {
1802 gboolean ret = FALSE;
1804 /* now we know all of simplify's fields are the same in compare
1805 * but at most one field: field.name */
1806 if (G_IS_VALUE (&field.value)) {
1807 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1808 gst_structure_id_set_value (compare, field.name, &field.value);
1812 g_value_unset (&field.value);
1813 } else if (gst_structure_n_fields (simplify) <=
1814 gst_structure_n_fields (compare)) {
1815 /* compare is just more specific, will be optimized away later */
1816 /* FIXME: do this here? */
1817 GST_LOG ("found a case that will be optimized later.");
1819 gchar *one = gst_structure_to_string (simplify);
1820 gchar *two = gst_structure_to_string (compare);
1823 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1835 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1836 GstStructure * new, gint i)
1838 gst_structure_set_parent_refcount (old, NULL);
1839 gst_structure_free (old);
1840 gst_structure_set_parent_refcount (new, &caps->refcount);
1841 g_ptr_array_index (caps->structs, i) = new;
1845 * gst_caps_do_simplify:
1846 * @caps: a #GstCaps to simplify
1848 * Modifies the given @caps inplace into a representation that represents the
1849 * same set of formats, but in a simpler form. Component structures that are
1850 * identical are merged. Component structures that have values that can be
1851 * merged are also merged.
1853 * Returns: TRUE, if the caps could be simplified
1856 gst_caps_do_simplify (GstCaps * caps)
1858 GstStructure *simplify, *compare, *result = NULL;
1860 gboolean changed = FALSE;
1862 g_return_val_if_fail (caps != NULL, FALSE);
1863 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1865 if (gst_caps_get_size (caps) < 2)
1868 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1870 start = caps->structs->len - 1;
1871 for (i = caps->structs->len - 1; i >= 0; i--) {
1872 simplify = gst_caps_get_structure_unchecked (caps, i);
1873 if (gst_structure_get_name_id (simplify) !=
1874 gst_structure_get_name_id (gst_caps_get_structure_unchecked (caps,
1877 for (j = start; j >= 0; j--) {
1880 compare = gst_caps_get_structure_unchecked (caps, j);
1881 if (gst_structure_get_name_id (simplify) !=
1882 gst_structure_get_name_id (compare)) {
1885 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1887 gst_caps_switch_structures (caps, simplify, result, i);
1890 gst_caps_remove_structure (caps, i);
1902 /* gst_caps_do_simplify (caps); */
1908 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
1910 * gst_caps_save_thyself:
1911 * @caps: a #GstCaps structure
1912 * @parent: a XML parent node
1914 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
1916 * Returns: a XML node pointer
1919 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
1921 char *s = gst_caps_to_string (caps);
1923 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
1929 * gst_caps_load_thyself:
1930 * @parent: a XML node
1932 * Creates a #GstCaps from its XML serialization.
1934 * Returns: a new #GstCaps structure
1937 gst_caps_load_thyself (xmlNodePtr parent)
1939 if (strcmp ("caps", (char *) parent->name) == 0) {
1940 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
1951 * @caps: (inout) (transfer full): a pointer to #GstCaps
1952 * @newcaps: a #GstCaps to replace *caps
1954 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
1955 * pointed to by @caps, if applicable, then modifies @caps to point to
1956 * @newcaps. An additional ref on @newcaps is taken.
1958 * This function does not take any locks so you might want to lock
1959 * the object owning @caps pointer.
1962 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
1966 g_return_if_fail (caps != NULL);
1970 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p, %p -> %p", caps, oldcaps, newcaps);
1972 if (newcaps != oldcaps) {
1974 gst_caps_ref (newcaps);
1979 gst_caps_unref (oldcaps);
1984 * gst_caps_to_string:
1987 * Converts @caps to a string representation. This string representation
1988 * can be converted back to a #GstCaps by gst_caps_from_string().
1990 * For debugging purposes its easier to do something like this:
1992 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
1994 * This prints the caps in human readble form.
1996 * Returns: (transfer full): a newly allocated string representing @caps.
1999 gst_caps_to_string (const GstCaps * caps)
2001 guint i, slen, clen;
2004 /* NOTE: This function is potentially called by the debug system,
2005 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
2006 * should be careful to avoid recursion. This includes any functions
2007 * called by gst_caps_to_string. In particular, calls should
2008 * not use the GST_PTR_FORMAT extension. */
2011 return g_strdup ("NULL");
2013 if (CAPS_IS_ANY (caps)) {
2014 return g_strdup ("ANY");
2016 if (CAPS_IS_EMPTY_SIMPLE (caps)) {
2017 return g_strdup ("EMPTY");
2020 /* estimate a rough string length to avoid unnecessary reallocs in GString */
2022 clen = caps->structs->len;
2023 for (i = 0; i < clen; i++) {
2025 STRUCTURE_ESTIMATED_STRING_LEN (gst_caps_get_structure_unchecked (caps,
2029 s = g_string_sized_new (slen);
2030 for (i = 0; i < clen; i++) {
2031 GstStructure *structure;
2034 /* ';' is now added by gst_structure_to_string */
2035 g_string_append_c (s, ' ');
2038 structure = gst_caps_get_structure_unchecked (caps, i);
2039 priv_gst_structure_append_to_gstring (structure, s);
2041 if (s->len && s->str[s->len - 1] == ';') {
2042 /* remove latest ';' */
2043 s->str[--s->len] = '\0';
2045 return g_string_free (s, FALSE);
2049 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
2051 GstStructure *structure;
2054 if (strcmp ("ANY", string) == 0) {
2055 caps->flags = GST_CAPS_FLAGS_ANY;
2058 if (strcmp ("EMPTY", string) == 0) {
2062 structure = gst_structure_from_string (string, &s);
2063 if (structure == NULL) {
2066 gst_caps_append_structure_unchecked (caps, structure);
2070 while (g_ascii_isspace (*s))
2075 structure = gst_structure_from_string (s, &s);
2076 if (structure == NULL) {
2079 gst_caps_append_structure_unchecked (caps, structure);
2087 * gst_caps_from_string:
2088 * @string: a string to convert to #GstCaps
2090 * Converts @caps from a string representation.
2092 * Returns: (transfer full): a newly allocated #GstCaps
2095 gst_caps_from_string (const gchar * string)
2099 g_return_val_if_fail (string, FALSE);
2101 caps = gst_caps_new_empty ();
2102 if (gst_caps_from_string_inplace (caps, string)) {
2105 gst_caps_unref (caps);
2111 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
2113 g_return_if_fail (G_IS_VALUE (src_value));
2114 g_return_if_fail (G_IS_VALUE (dest_value));
2115 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
2116 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
2117 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
2119 dest_value->data[0].v_pointer =
2120 gst_caps_to_string (src_value->data[0].v_pointer);
2124 gst_caps_copy_conditional (GstCaps * src)
2127 return gst_caps_ref (src);