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 *subtract_from = user_data;
573 GValue subtraction = { 0, };
576 if (!(other = gst_structure_id_get_value (subtract_from, field_id)))
577 /* field is missing in one set */
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 * minuend,
616 const GstStructure * subtrahend)
618 if ((minuend->name != subtrahend->name) ||
619 (gst_structure_n_fields (minuend) !=
620 gst_structure_n_fields (subtrahend))) {
624 return gst_structure_foreach ((GstStructure *) subtrahend,
625 gst_caps_structure_is_subset_field, (gpointer) minuend);
630 * @caps1: the #GstCaps that will be appended to
631 * @caps2: (transfer full): the #GstCaps to append
633 * Appends the structures contained in @caps2 to @caps1. The structures in
634 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
635 * freed. If either caps is ANY, the resulting caps will be ANY.
638 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
640 GstStructure *structure;
643 g_return_if_fail (GST_IS_CAPS (caps1));
644 g_return_if_fail (GST_IS_CAPS (caps2));
645 g_return_if_fail (IS_WRITABLE (caps1));
646 g_return_if_fail (IS_WRITABLE (caps2));
651 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))) {
652 /* FIXME: this leaks */
653 caps1->flags |= GST_CAPS_FLAGS_ANY;
654 for (i = caps2->structs->len - 1; i >= 0; i--) {
655 structure = gst_caps_remove_and_get_structure (caps2, i);
656 gst_structure_free (structure);
659 for (i = caps2->structs->len; i; i--) {
660 structure = gst_caps_remove_and_get_structure (caps2, 0);
661 gst_caps_append_structure_unchecked (caps1, structure);
664 gst_caps_unref (caps2); /* guaranteed to free it */
669 * @caps1: the #GstCaps that will take the new entries
670 * @caps2: (transfer full): the #GstCaps to merge in
672 * Appends the structures contained in @caps2 to @caps1 if they are not yet
673 * expressed by @caps1. The structures in @caps2 are not copied -- they are
674 * transferred to @caps1, and then @caps2 is freed.
675 * If either caps is ANY, the resulting caps will be ANY.
680 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
682 GstStructure *structure;
685 g_return_if_fail (GST_IS_CAPS (caps1));
686 g_return_if_fail (GST_IS_CAPS (caps2));
687 g_return_if_fail (IS_WRITABLE (caps1));
688 g_return_if_fail (IS_WRITABLE (caps2));
693 if (G_UNLIKELY (CAPS_IS_ANY (caps1))) {
694 for (i = caps2->structs->len - 1; i >= 0; i--) {
695 structure = gst_caps_remove_and_get_structure (caps2, i);
696 gst_structure_free (structure);
698 } else if (G_UNLIKELY (CAPS_IS_ANY (caps2))) {
699 caps1->flags |= GST_CAPS_FLAGS_ANY;
700 for (i = caps1->structs->len - 1; i >= 0; i--) {
701 structure = gst_caps_remove_and_get_structure (caps1, i);
702 gst_structure_free (structure);
705 for (i = caps2->structs->len; i; i--) {
706 structure = gst_caps_remove_and_get_structure (caps2, 0);
707 gst_caps_merge_structure (caps1, structure);
710 GstCaps *com = gst_caps_intersect (caps1, caps2);
711 GstCaps *add = gst_caps_subtract (caps2, com);
713 GST_DEBUG ("common : %d", gst_caps_get_size (com));
714 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
715 gst_caps_append (caps1, add);
716 gst_caps_unref (com);
719 gst_caps_unref (caps2); /* guaranteed to free it */
723 * gst_caps_append_structure:
724 * @caps: the #GstCaps that will be appended to
725 * @structure: (transfer full): the #GstStructure to append
727 * Appends @structure to @caps. The structure is not copied; @caps
728 * becomes the owner of @structure.
731 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
733 g_return_if_fail (GST_IS_CAPS (caps));
734 g_return_if_fail (IS_WRITABLE (caps));
736 if (G_LIKELY (structure)) {
737 g_return_if_fail (structure->parent_refcount == NULL);
740 STRUCTURE_POISON (structure);
743 gst_caps_append_structure_unchecked (caps, structure);
748 * gst_caps_remove_structure:
749 * @caps: the #GstCaps to remove from
750 * @idx: Index of the structure to remove
752 * removes the stucture with the given index from the list of structures
753 * contained in @caps.
756 gst_caps_remove_structure (GstCaps * caps, guint idx)
758 GstStructure *structure;
760 g_return_if_fail (caps != NULL);
761 g_return_if_fail (idx <= gst_caps_get_size (caps));
762 g_return_if_fail (IS_WRITABLE (caps));
764 structure = gst_caps_remove_and_get_structure (caps, idx);
765 gst_structure_free (structure);
769 * gst_caps_merge_structure:
770 * @caps: the #GstCaps that will the the new structure
771 * @structure: (transfer full): the #GstStructure to merge
773 * Appends @structure to @caps if its not already expressed by @caps. The
774 * structure is not copied; @caps becomes the owner of @structure.
777 gst_caps_merge_structure (GstCaps * caps, GstStructure * structure)
779 g_return_if_fail (GST_IS_CAPS (caps));
780 g_return_if_fail (IS_WRITABLE (caps));
782 if (G_LIKELY (structure)) {
783 GstStructure *structure1;
785 gboolean unique = TRUE;
787 g_return_if_fail (structure->parent_refcount == NULL);
790 STRUCTURE_POISON (structure);
793 /* check each structure */
794 for (i = caps->structs->len - 1; i >= 0; i--) {
795 structure1 = gst_caps_get_structure_unchecked (caps, i);
796 /* if structure is a subset of structure1, then skip it */
797 if (gst_caps_structure_is_subset (structure1, structure)) {
803 gst_caps_append_structure_unchecked (caps, structure);
805 gst_structure_free (structure);
814 * Gets the number of structures contained in @caps.
816 * Returns: the number of structures that @caps contains
819 gst_caps_get_size (const GstCaps * caps)
821 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
823 return caps->structs->len;
827 * gst_caps_get_structure:
829 * @index: the index of the structure
831 * Finds the structure in @caps that has the index @index, and
834 * WARNING: This function takes a const GstCaps *, but returns a
835 * non-const GstStructure *. This is for programming convenience --
836 * the caller should be aware that structures inside a constant
837 * #GstCaps should not be modified. However, if you know the caps
838 * are writable, either because you have just copied them or made
839 * them writable with gst_caps_make_writable(), you may modify the
840 * structure returned in the usual way, e.g. with functions like
841 * gst_structure_set().
843 * You do not need to free or unref the structure returned, it
844 * belongs to the #GstCaps.
846 * Returns: (transfer none): a pointer to the #GstStructure corresponding
850 gst_caps_get_structure (const GstCaps * caps, guint index)
852 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
853 g_return_val_if_fail (index < caps->structs->len, NULL);
855 return gst_caps_get_structure_unchecked (caps, index);
860 * @caps: the #GstCaps to copy
861 * @nth: the nth structure to copy
863 * Creates a new #GstCaps and appends a copy of the nth structure
864 * contained in @caps.
866 * Returns: (transfer full): the new #GstCaps
869 gst_caps_copy_nth (const GstCaps * caps, guint nth)
872 GstStructure *structure;
874 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
876 newcaps = gst_caps_new_empty ();
877 newcaps->flags = caps->flags;
879 if (G_LIKELY (caps->structs->len > nth)) {
880 structure = gst_caps_get_structure_unchecked (caps, nth);
881 gst_caps_append_structure_unchecked (newcaps,
882 gst_structure_copy (structure));
890 * @caps: the #GstCaps to truncate
892 * Destructively discard all but the first structure from @caps. Useful when
893 * fixating. @caps must be writable.
896 gst_caps_truncate (GstCaps * caps)
900 g_return_if_fail (GST_IS_CAPS (caps));
901 g_return_if_fail (IS_WRITABLE (caps));
903 i = caps->structs->len - 1;
906 gst_caps_remove_structure (caps, i--);
910 * gst_caps_set_value:
911 * @caps: a writable caps
912 * @field: name of the field to set
913 * @value: value to set the field to
915 * Sets the given @field on all structures of @caps to the given @value.
916 * This is a convenience function for calling gst_structure_set_value() on
917 * all structures of @caps.
922 gst_caps_set_value (GstCaps * caps, const char *field, const GValue * value)
926 g_return_if_fail (GST_IS_CAPS (caps));
927 g_return_if_fail (IS_WRITABLE (caps));
928 g_return_if_fail (field != NULL);
929 g_return_if_fail (G_IS_VALUE (value));
931 len = caps->structs->len;
932 for (i = 0; i < len; i++) {
933 GstStructure *structure = gst_caps_get_structure_unchecked (caps, i);
934 gst_structure_set_value (structure, field, value);
939 * gst_caps_set_simple_valist:
940 * @caps: the #GstCaps to set
941 * @field: first field to set
942 * @varargs: additional parameters
944 * Sets fields in a #GstCaps. The arguments must be passed in the same
945 * manner as gst_structure_set(), and be NULL-terminated.
946 * <note>Prior to GStreamer version 0.10.26, this function failed when
947 * @caps was not simple. If your code needs to work with those versions
948 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
949 * is %TRUE for @caps.</note>
952 gst_caps_set_simple_valist (GstCaps * caps, const char *field, va_list varargs)
954 GValue value = { 0, };
956 g_return_if_fail (GST_IS_CAPS (caps));
957 g_return_if_fail (IS_WRITABLE (caps));
963 type = va_arg (varargs, GType);
965 if (G_UNLIKELY (type == G_TYPE_DATE)) {
966 g_warning ("Don't use G_TYPE_DATE, use GST_TYPE_DATE instead\n");
967 type = GST_TYPE_DATE;
969 #if GLIB_CHECK_VERSION(2,23,3)
970 G_VALUE_COLLECT_INIT (&value, type, varargs, 0, &err);
972 g_value_init (&value, type);
973 G_VALUE_COLLECT (&value, varargs, 0, &err);
975 if (G_UNLIKELY (err)) {
976 g_critical ("%s", err);
980 gst_caps_set_value (caps, field, &value);
982 g_value_unset (&value);
984 field = va_arg (varargs, const gchar *);
989 * gst_caps_set_simple:
990 * @caps: the #GstCaps to set
991 * @field: first field to set
992 * @...: additional parameters
994 * Sets fields in a #GstCaps. The arguments must be passed in the same
995 * manner as gst_structure_set(), and be NULL-terminated.
996 * <note>Prior to GStreamer version 0.10.26, this function failed when
997 * @caps was not simple. If your code needs to work with those versions
998 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
999 * is %TRUE for @caps.</note>
1002 gst_caps_set_simple (GstCaps * caps, const char *field, ...)
1006 g_return_if_fail (GST_IS_CAPS (caps));
1007 g_return_if_fail (IS_WRITABLE (caps));
1009 va_start (var_args, field);
1010 gst_caps_set_simple_valist (caps, field, var_args);
1018 * @caps: the #GstCaps to test
1020 * Determines if @caps represents any media format.
1022 * Returns: TRUE if @caps represents any format.
1025 gst_caps_is_any (const GstCaps * caps)
1027 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1029 return (CAPS_IS_ANY (caps));
1033 * gst_caps_is_empty:
1034 * @caps: the #GstCaps to test
1036 * Determines if @caps represents no media formats.
1038 * Returns: TRUE if @caps represents no formats.
1041 gst_caps_is_empty (const GstCaps * caps)
1043 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1045 if (CAPS_IS_ANY (caps))
1048 return CAPS_IS_EMPTY_SIMPLE (caps);
1052 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
1055 return gst_value_is_fixed (value);
1059 * gst_caps_is_fixed:
1060 * @caps: the #GstCaps to test
1062 * Fixed #GstCaps describe exactly one format, that is, they have exactly
1063 * one structure, and each field in the structure describes a fixed type.
1064 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
1066 * Returns: TRUE if @caps is fixed
1069 gst_caps_is_fixed (const GstCaps * caps)
1071 GstStructure *structure;
1073 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1075 if (caps->structs->len != 1)
1078 structure = gst_caps_get_structure_unchecked (caps, 0);
1080 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
1084 * gst_caps_is_equal_fixed:
1085 * @caps1: the #GstCaps to test
1086 * @caps2: the #GstCaps to test
1088 * Tests if two #GstCaps are equal. This function only works on fixed
1091 * Returns: TRUE if the arguments represent the same format
1094 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
1096 GstStructure *struct1, *struct2;
1098 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
1099 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
1101 struct1 = gst_caps_get_structure_unchecked (caps1, 0);
1102 struct2 = gst_caps_get_structure_unchecked (caps2, 0);
1104 return gst_structure_is_equal (struct1, struct2);
1108 * gst_caps_is_always_compatible:
1109 * @caps1: the #GstCaps to test
1110 * @caps2: the #GstCaps to test
1112 * A given #GstCaps structure is always compatible with another if
1113 * every media format that is in the first is also contained in the
1114 * second. That is, @caps1 is a subset of @caps2.
1116 * Returns: TRUE if @caps1 is a subset of @caps2.
1119 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
1121 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1122 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1124 return gst_caps_is_subset (caps1, caps2);
1128 * gst_caps_is_subset:
1129 * @subset: a #GstCaps
1130 * @superset: a potentially greater #GstCaps
1132 * Checks if all caps represented by @subset are also represented by @superset.
1133 * <note>This function does not work reliably if optional properties for caps
1134 * are included on one caps and omitted on the other.</note>
1136 * Returns: %TRUE if @subset is a subset of @superset
1139 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
1144 g_return_val_if_fail (subset != NULL, FALSE);
1145 g_return_val_if_fail (superset != NULL, FALSE);
1147 if (CAPS_IS_EMPTY (subset) || CAPS_IS_ANY (superset))
1149 if (CAPS_IS_ANY (subset) || CAPS_IS_EMPTY (superset))
1152 caps = gst_caps_subtract (subset, superset);
1153 ret = CAPS_IS_EMPTY_SIMPLE (caps);
1154 gst_caps_unref (caps);
1159 * gst_caps_is_equal:
1160 * @caps1: a #GstCaps
1161 * @caps2: another #GstCaps
1163 * Checks if the given caps represent the same set of caps.
1164 * <note>This function does not work reliably if optional properties for caps
1165 * are included on one caps and omitted on the other.</note>
1167 * This function deals correctly with passing NULL for any of the caps.
1169 * Returns: TRUE if both caps are equal.
1172 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1174 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1175 * So there should be an assertion that caps1 and caps2 != NULL */
1177 /* NULL <-> NULL is allowed here */
1178 if (G_UNLIKELY (caps1 == caps2))
1181 /* one of them NULL => they are different (can't be both NULL because
1182 * we checked that above) */
1183 if (G_UNLIKELY (caps1 == NULL || caps2 == NULL))
1186 if (G_UNLIKELY (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2)))
1187 return gst_caps_is_equal_fixed (caps1, caps2);
1189 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1192 /* intersect operation */
1197 const GstStructure *intersect;
1202 gst_caps_structure_intersect_field1 (GQuark id, const GValue * val1,
1205 IntersectData *idata = (IntersectData *) data;
1206 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1208 if (G_UNLIKELY (val2 == NULL)) {
1209 gst_structure_id_set_value (idata->dest, id, val1);
1211 GValue dest_value = { 0 };
1212 if (gst_value_intersect (&dest_value, val1, val2)) {
1213 gst_structure_id_set_value (idata->dest, id, &dest_value);
1214 g_value_unset (&dest_value);
1223 gst_caps_structure_intersect_field2 (GQuark id, const GValue * val1,
1226 IntersectData *idata = (IntersectData *) data;
1227 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1229 if (G_UNLIKELY (val2 == NULL)) {
1230 gst_structure_id_set_value (idata->dest, id, val1);
1235 static GstStructure *
1236 gst_caps_structure_intersect (const GstStructure * struct1,
1237 const GstStructure * struct2)
1241 g_assert (struct1 != NULL);
1242 g_assert (struct2 != NULL);
1244 if (G_UNLIKELY (struct1->name != struct2->name))
1247 /* copy fields from struct1 which we have not in struct2 to target
1248 * intersect if we have the field in both */
1249 data.dest = gst_structure_id_empty_new (struct1->name);
1250 data.intersect = struct2;
1251 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1252 gst_caps_structure_intersect_field1, &data)))
1255 /* copy fields from struct2 which we have not in struct1 to target */
1256 data.intersect = struct1;
1257 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct2,
1258 gst_caps_structure_intersect_field2, &data)))
1264 gst_structure_free (data.dest);
1269 gst_caps_structure_can_intersect_field (GQuark id, const GValue * val1,
1272 GstStructure *other = (GstStructure *) data;
1273 const GValue *val2 = gst_structure_id_get_value (other, id);
1275 if (G_LIKELY (val2)) {
1276 if (!gst_value_can_intersect (val1, val2)) {
1279 gint eq = gst_value_compare (val1, val2);
1281 if (eq == GST_VALUE_UNORDERED) {
1282 /* we need to try interseting */
1283 GValue dest_value = { 0 };
1284 if (gst_value_intersect (&dest_value, val1, val2)) {
1285 g_value_unset (&dest_value);
1289 } else if (eq != GST_VALUE_EQUAL) {
1298 gst_caps_structure_can_intersect (const GstStructure * struct1,
1299 const GstStructure * struct2)
1301 g_assert (struct1 != NULL);
1302 g_assert (struct2 != NULL);
1304 if (G_UNLIKELY (struct1->name != struct2->name))
1307 /* tries to intersect if we have the field in both */
1308 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1309 gst_caps_structure_can_intersect_field, (gpointer) struct2)))
1316 * gst_caps_can_intersect:
1317 * @caps1: a #GstCaps to intersect
1318 * @caps2: a #GstCaps to intersect
1320 * Tries intersecting @caps1 and @caps2 and reports whether the result would not
1323 * Returns: %TRUE if intersection would be not empty
1328 gst_caps_can_intersect (const GstCaps * caps1, const GstCaps * caps2)
1330 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1331 guint j, k, len1, len2;
1332 GstStructure *struct1;
1333 GstStructure *struct2;
1335 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1336 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1338 /* caps are exactly the same pointers */
1339 if (G_UNLIKELY (caps1 == caps2))
1342 /* empty caps on either side, return empty */
1343 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1346 /* one of the caps is any */
1347 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2)))
1350 /* run zigzag on top line then right line, this preserves the caps order
1351 * much better than a simple loop.
1353 * This algorithm zigzags over the caps structures as demonstrated in
1354 * the folowing matrix:
1357 * +------------- total distance: +-------------
1358 * | 1 2 4 7 0 | 0 1 2 3
1359 * caps2 | 3 5 8 10 1 | 1 2 3 4
1360 * | 6 9 11 12 2 | 2 3 4 5
1362 * First we iterate over the caps1 structures (top line) intersecting
1363 * the structures diagonally down, then we iterate over the caps2
1364 * structures. The result is that the intersections are ordered based on the
1365 * sum of the indexes in the list.
1367 len1 = caps1->structs->len;
1368 len2 = caps2->structs->len;
1369 for (i = 0; i < len1 + len2 - 1; i++) {
1370 /* superset index goes from 0 to sgst_caps_structure_intersectuperset->structs->len-1 */
1371 j = MIN (i, len1 - 1);
1372 /* subset index stays 0 until i reaches superset->structs->len, then it
1373 * counts up from 1 to subset->structs->len - 1 */
1376 /* now run the diagonal line, end condition is the left or bottom
1379 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1380 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1382 if (gst_caps_structure_can_intersect (struct1, struct2)) {
1385 /* move down left */
1387 if (G_UNLIKELY (j == 0))
1388 break; /* so we don't roll back to G_MAXUINT */
1396 gst_caps_intersect_zig_zag (const GstCaps * caps1, const GstCaps * caps2)
1398 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1399 guint j, k, len1, len2;
1401 GstStructure *struct1;
1402 GstStructure *struct2;
1404 GstStructure *istruct;
1406 /* caps are exactly the same pointers, just copy one caps */
1407 if (G_UNLIKELY (caps1 == caps2))
1408 return gst_caps_copy (caps1);
1410 /* empty caps on either side, return empty */
1411 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1412 return gst_caps_new_empty ();
1414 /* one of the caps is any, just copy the other caps */
1415 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1416 return gst_caps_copy (caps2);
1417 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1418 return gst_caps_copy (caps1);
1420 dest = gst_caps_new_empty ();
1422 /* run zigzag on top line then right line, this preserves the caps order
1423 * much better than a simple loop.
1425 * This algorithm zigzags over the caps structures as demonstrated in
1426 * the folowing matrix:
1434 * First we iterate over the caps1 structures (top line) intersecting
1435 * the structures diagonally down, then we iterate over the caps2
1438 len1 = caps1->structs->len;
1439 len2 = caps2->structs->len;
1440 for (i = 0; i < len1 + len2 - 1; i++) {
1441 /* caps1 index goes from 0 to caps1->structs->len-1 */
1442 j = MIN (i, len1 - 1);
1443 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1444 * up from 1 to caps2->structs->len - 1 */
1447 /* now run the diagonal line, end condition is the left or bottom
1450 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1451 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1453 istruct = gst_caps_structure_intersect (struct1, struct2);
1455 gst_caps_merge_structure (dest, istruct);
1456 /* move down left */
1458 if (G_UNLIKELY (j == 0))
1459 break; /* so we don't roll back to G_MAXUINT */
1467 * gst_caps_intersect_first:
1468 * @caps1: a #GstCaps to intersect
1469 * @caps2: a #GstCaps to intersect
1471 * Creates a new #GstCaps that contains all the formats that are common
1472 * to both @caps1 and @caps2.
1474 * Unlike @gst_caps_intersect, the returned caps will be ordered in a similar
1475 * fashion as @caps1.
1477 * Returns: the new #GstCaps
1480 gst_caps_intersect_first (const GstCaps * caps1, const GstCaps * caps2)
1482 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1483 guint j, len1, len2;
1485 GstStructure *struct1;
1486 GstStructure *struct2;
1488 GstStructure *istruct;
1490 /* caps are exactly the same pointers, just copy one caps */
1491 if (G_UNLIKELY (caps1 == caps2))
1492 return gst_caps_copy (caps1);
1494 /* empty caps on either side, return empty */
1495 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1496 return gst_caps_new_empty ();
1498 /* one of the caps is any, just copy the other caps */
1499 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1500 return gst_caps_copy (caps2);
1501 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1502 return gst_caps_copy (caps1);
1504 dest = gst_caps_new_empty ();
1506 len1 = caps1->structs->len;
1507 len2 = caps2->structs->len;
1508 for (i = 0; i < len1; i++) {
1509 struct1 = gst_caps_get_structure_unchecked (caps1, i);
1510 for (j = 0; j < len2; j++) {
1511 struct2 = gst_caps_get_structure_unchecked (caps2, j);
1512 istruct = gst_caps_structure_intersect (struct1, struct2);
1514 gst_caps_merge_structure (dest, istruct);
1522 * gst_caps_intersect_full:
1523 * @caps1: a #GstCaps to intersect
1524 * @caps2: a #GstCaps to intersect
1525 * @mode: The intersection algorithm/mode to use
1527 * Creates a new #GstCaps that contains all the formats that are common
1528 * to both @caps1 and @caps2, the order is defined by the #GstCapsIntersectMode
1531 * Returns: the new #GstCaps
1535 gst_caps_intersect_full (const GstCaps * caps1, const GstCaps * caps2,
1536 GstCapsIntersectMode mode)
1538 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1539 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1542 case GST_CAPS_INTERSECT_FIRST:
1543 return gst_caps_intersect_first (caps1, caps2);
1545 g_warning ("Unknown caps intersect mode: %d", mode);
1547 case GST_CAPS_INTERSECT_ZIG_ZAG:
1548 return gst_caps_intersect_zig_zag (caps1, caps2);
1553 * gst_caps_intersect:
1554 * @caps1: a #GstCaps to intersect
1555 * @caps2: a #GstCaps to intersect
1557 * Creates a new #GstCaps that contains all the formats that are common
1558 * to both @caps1 and @caps2. Defaults to %GST_CAPS_INTERSECT_ZIG_ZAG mode.
1560 * Returns: the new #GstCaps
1563 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1565 return gst_caps_intersect_full (caps1, caps2, GST_CAPS_INTERSECT_ZIG_ZAG);
1569 /* subtract operation */
1573 const GstStructure *subtract_from;
1579 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1582 SubtractionEntry *e = user_data;
1583 GValue subtraction = { 0, };
1584 const GValue *other;
1585 GstStructure *structure;
1587 other = gst_structure_id_get_value (e->subtract_from, field_id);
1591 if (!gst_value_subtract (&subtraction, other, value))
1593 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1594 g_value_unset (&subtraction);
1597 structure = gst_structure_copy (e->subtract_from);
1598 gst_structure_id_set_value (structure, field_id, &subtraction);
1599 g_value_unset (&subtraction);
1600 e->put_into = g_slist_prepend (e->put_into, structure);
1606 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1607 const GstStructure * subtrahend)
1612 e.subtract_from = minuend;
1615 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1616 gst_caps_structure_subtract_field, &e);
1622 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1623 gst_structure_free (walk->data);
1625 g_slist_free (e.put_into);
1631 * gst_caps_subtract:
1632 * @minuend: #GstCaps to substract from
1633 * @subtrahend: #GstCaps to substract
1635 * Subtracts the @subtrahend from the @minuend.
1636 * <note>This function does not work reliably if optional properties for caps
1637 * are included on one caps and omitted on the other.</note>
1639 * Returns: the resulting caps
1642 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1647 GstCaps *dest = NULL, *src;
1649 g_return_val_if_fail (minuend != NULL, NULL);
1650 g_return_val_if_fail (subtrahend != NULL, NULL);
1652 if (CAPS_IS_EMPTY (minuend) || CAPS_IS_ANY (subtrahend)) {
1653 return gst_caps_new_empty ();
1655 if (CAPS_IS_EMPTY_SIMPLE (subtrahend))
1656 return gst_caps_copy (minuend);
1658 /* FIXME: Do we want this here or above?
1659 The reason we need this is that there is no definition about what
1660 ANY means for specific types, so it's not possible to reduce ANY partially
1661 You can only remove everything or nothing and that is done above.
1662 Note: there's a test that checks this behaviour. */
1663 g_return_val_if_fail (!CAPS_IS_ANY (minuend), NULL);
1664 sublen = subtrahend->structs->len;
1665 g_assert (sublen > 0);
1667 src = gst_caps_copy (minuend);
1668 for (i = 0; i < sublen; i++) {
1671 sub = gst_caps_get_structure_unchecked (subtrahend, i);
1673 gst_caps_unref (src);
1676 dest = gst_caps_new_empty ();
1677 srclen = src->structs->len;
1678 for (j = 0; j < srclen; j++) {
1679 min = gst_caps_get_structure_unchecked (src, j);
1680 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1683 if (gst_caps_structure_subtract (&list, min, sub)) {
1686 for (walk = list; walk; walk = g_slist_next (walk)) {
1687 gst_caps_append_structure_unchecked (dest,
1688 (GstStructure *) walk->data);
1690 g_slist_free (list);
1692 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1695 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1698 if (CAPS_IS_EMPTY_SIMPLE (dest)) {
1699 gst_caps_unref (src);
1704 gst_caps_unref (src);
1705 gst_caps_do_simplify (dest);
1709 /* union operation */
1712 static GstStructure *
1713 gst_caps_structure_union (const GstStructure * struct1,
1714 const GstStructure * struct2)
1718 const GstStructureField *field1;
1719 const GstStructureField *field2;
1722 /* FIXME this doesn't actually work */
1724 if (struct1->name != struct2->name)
1727 dest = gst_structure_id_empty_new (struct1->name);
1729 for (i = 0; i < struct1->fields->len; i++) {
1730 GValue dest_value = { 0 };
1732 field1 = GST_STRUCTURE_FIELD (struct1, i);
1733 field2 = gst_structure_id_get_field (struct2, field1->name);
1735 if (field2 == NULL) {
1738 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1739 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1742 ret = gst_value_compare (&field1->value, &field2->value);
1753 * @caps1: a #GstCaps to union
1754 * @caps2: a #GstCaps to union
1756 * Creates a new #GstCaps that contains all the formats that are in
1757 * either @caps1 and @caps2.
1759 * Returns: the new #GstCaps
1762 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1767 /* NULL pointers are no correct GstCaps */
1768 g_return_val_if_fail (caps1 != NULL, NULL);
1769 g_return_val_if_fail (caps2 != NULL, NULL);
1771 if (CAPS_IS_EMPTY (caps1))
1772 return gst_caps_copy (caps2);
1774 if (CAPS_IS_EMPTY (caps2))
1775 return gst_caps_copy (caps1);
1777 if (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))
1778 return gst_caps_new_any ();
1780 dest1 = gst_caps_copy (caps1);
1781 dest2 = gst_caps_copy (caps2);
1782 gst_caps_append (dest1, dest2);
1784 gst_caps_do_simplify (dest1);
1788 /* normalize/simplify operations */
1790 typedef struct _NormalizeForeach
1793 GstStructure *structure;
1798 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1800 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1804 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1805 guint len = gst_value_list_get_size (value);
1806 for (i = 1; i < len; i++) {
1807 const GValue *v = gst_value_list_get_value (value, i);
1808 GstStructure *structure = gst_structure_copy (nf->structure);
1810 gst_structure_id_set_value (structure, field_id, v);
1811 gst_caps_append_structure_unchecked (nf->caps, structure);
1814 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1815 gst_structure_id_set_value (nf->structure, field_id, &val);
1816 g_value_unset (&val);
1824 * gst_caps_normalize:
1825 * @caps: a #GstCaps to normalize
1827 * Creates a new #GstCaps that represents the same set of formats as
1828 * @caps, but contains no lists. Each list is expanded into separate
1831 * Returns: the new #GstCaps
1834 gst_caps_normalize (const GstCaps * caps)
1836 NormalizeForeach nf;
1840 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1842 newcaps = gst_caps_copy (caps);
1845 for (i = 0; i < gst_caps_get_size (newcaps); i++) {
1846 nf.structure = gst_caps_get_structure_unchecked (newcaps, i);
1848 while (!gst_structure_foreach (nf.structure,
1849 gst_caps_normalize_foreach, &nf));
1856 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1859 const GstStructure *struct1 = *((const GstStructure **) one);
1860 const GstStructure *struct2 = *((const GstStructure **) two);
1862 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1863 So what's the best way? */
1864 ret = strcmp (gst_structure_get_name (struct1),
1865 gst_structure_get_name (struct2));
1869 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1876 GstStructure *compare;
1881 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1884 UnionField *u = user_data;
1885 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1889 g_value_unset (&u->value);
1892 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1895 g_value_unset (&u->value);
1899 gst_value_union (&u->value, val, value);
1904 gst_caps_structure_simplify (GstStructure ** result,
1905 const GstStructure * simplify, GstStructure * compare)
1908 UnionField field = { 0, {0,}, NULL };
1910 /* try to subtract to get a real subset */
1911 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1912 if (list == NULL) { /* no result */
1915 } else if (list->next == NULL) { /* one result */
1916 *result = list->data;
1917 g_slist_free (list);
1919 } else { /* multiple results */
1920 g_slist_foreach (list, (GFunc) gst_structure_free, NULL);
1921 g_slist_free (list);
1926 /* try to union both structs */
1927 field.compare = compare;
1928 if (gst_structure_foreach ((GstStructure *) simplify,
1929 gst_caps_structure_figure_out_union, &field)) {
1930 gboolean ret = FALSE;
1932 /* now we know all of simplify's fields are the same in compare
1933 * but at most one field: field.name */
1934 if (G_IS_VALUE (&field.value)) {
1935 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1936 gst_structure_id_set_value (compare, field.name, &field.value);
1940 g_value_unset (&field.value);
1941 } else if (gst_structure_n_fields (simplify) <=
1942 gst_structure_n_fields (compare)) {
1943 /* compare is just more specific, will be optimized away later */
1944 /* FIXME: do this here? */
1945 GST_LOG ("found a case that will be optimized later.");
1947 gchar *one = gst_structure_to_string (simplify);
1948 gchar *two = gst_structure_to_string (compare);
1951 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1963 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1964 GstStructure * new, gint i)
1966 gst_structure_set_parent_refcount (old, NULL);
1967 gst_structure_free (old);
1968 gst_structure_set_parent_refcount (new, &caps->refcount);
1969 g_ptr_array_index (caps->structs, i) = new;
1973 * gst_caps_do_simplify:
1974 * @caps: a #GstCaps to simplify
1976 * Modifies the given @caps inplace into a representation that represents the
1977 * same set of formats, but in a simpler form. Component structures that are
1978 * identical are merged. Component structures that have values that can be
1979 * merged are also merged.
1981 * Returns: TRUE, if the caps could be simplified
1984 gst_caps_do_simplify (GstCaps * caps)
1986 GstStructure *simplify, *compare, *result = NULL;
1988 gboolean changed = FALSE;
1990 g_return_val_if_fail (caps != NULL, FALSE);
1991 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1993 if (gst_caps_get_size (caps) < 2)
1996 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1998 start = caps->structs->len - 1;
1999 for (i = caps->structs->len - 1; i >= 0; i--) {
2000 simplify = gst_caps_get_structure_unchecked (caps, i);
2001 if (gst_structure_get_name_id (simplify) !=
2002 gst_structure_get_name_id (gst_caps_get_structure_unchecked (caps,
2005 for (j = start; j >= 0; j--) {
2008 compare = gst_caps_get_structure_unchecked (caps, j);
2009 if (gst_structure_get_name_id (simplify) !=
2010 gst_structure_get_name_id (compare)) {
2013 if (gst_caps_structure_simplify (&result, simplify, compare)) {
2015 gst_caps_switch_structures (caps, simplify, result, i);
2018 gst_caps_remove_structure (caps, i);
2030 /* gst_caps_do_simplify (caps); */
2036 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
2038 * gst_caps_save_thyself:
2039 * @caps: a #GstCaps structure
2040 * @parent: a XML parent node
2042 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
2044 * Returns: a XML node pointer
2047 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
2049 char *s = gst_caps_to_string (caps);
2051 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
2057 * gst_caps_load_thyself:
2058 * @parent: a XML node
2060 * Creates a #GstCaps from its XML serialization.
2062 * Returns: a new #GstCaps structure
2065 gst_caps_load_thyself (xmlNodePtr parent)
2067 if (strcmp ("caps", (char *) parent->name) == 0) {
2068 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
2079 * @caps: (inout) (transfer full): a pointer to #GstCaps
2080 * @newcaps: a #GstCaps to replace *caps
2082 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
2083 * pointed to by @caps, if applicable, then modifies @caps to point to
2084 * @newcaps. An additional ref on @newcaps is taken.
2086 * This function does not take any locks so you might want to lock
2087 * the object owning @caps pointer.
2090 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
2094 g_return_if_fail (caps != NULL);
2098 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p, %p -> %p", caps, oldcaps, newcaps);
2100 if (newcaps != oldcaps) {
2102 gst_caps_ref (newcaps);
2107 gst_caps_unref (oldcaps);
2112 * gst_caps_to_string:
2115 * Converts @caps to a string representation. This string representation
2116 * can be converted back to a #GstCaps by gst_caps_from_string().
2118 * For debugging purposes its easier to do something like this:
2120 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
2122 * This prints the caps in human readble form.
2124 * Returns: (transfer full): a newly allocated string representing @caps.
2127 gst_caps_to_string (const GstCaps * caps)
2129 guint i, slen, clen;
2132 /* NOTE: This function is potentially called by the debug system,
2133 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
2134 * should be careful to avoid recursion. This includes any functions
2135 * called by gst_caps_to_string. In particular, calls should
2136 * not use the GST_PTR_FORMAT extension. */
2139 return g_strdup ("NULL");
2141 if (CAPS_IS_ANY (caps)) {
2142 return g_strdup ("ANY");
2144 if (CAPS_IS_EMPTY_SIMPLE (caps)) {
2145 return g_strdup ("EMPTY");
2148 /* estimate a rough string length to avoid unnecessary reallocs in GString */
2150 clen = caps->structs->len;
2151 for (i = 0; i < clen; i++) {
2153 STRUCTURE_ESTIMATED_STRING_LEN (gst_caps_get_structure_unchecked (caps,
2157 s = g_string_sized_new (slen);
2158 for (i = 0; i < clen; i++) {
2159 GstStructure *structure;
2162 /* ';' is now added by gst_structure_to_string */
2163 g_string_append_c (s, ' ');
2166 structure = gst_caps_get_structure_unchecked (caps, i);
2167 priv_gst_structure_append_to_gstring (structure, s);
2169 if (s->len && s->str[s->len - 1] == ';') {
2170 /* remove latest ';' */
2171 s->str[--s->len] = '\0';
2173 return g_string_free (s, FALSE);
2177 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
2179 GstStructure *structure;
2182 if (strcmp ("ANY", string) == 0) {
2183 caps->flags = GST_CAPS_FLAGS_ANY;
2186 if (strcmp ("EMPTY", string) == 0) {
2190 structure = gst_structure_from_string (string, &s);
2191 if (structure == NULL) {
2194 gst_caps_append_structure_unchecked (caps, structure);
2198 while (g_ascii_isspace (*s))
2203 structure = gst_structure_from_string (s, &s);
2204 if (structure == NULL) {
2207 gst_caps_append_structure_unchecked (caps, structure);
2215 * gst_caps_from_string:
2216 * @string: a string to convert to #GstCaps
2218 * Converts @caps from a string representation.
2220 * Returns: (transfer full): a newly allocated #GstCaps
2223 gst_caps_from_string (const gchar * string)
2227 g_return_val_if_fail (string, FALSE);
2229 caps = gst_caps_new_empty ();
2230 if (gst_caps_from_string_inplace (caps, string)) {
2233 gst_caps_unref (caps);
2239 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
2241 g_return_if_fail (G_IS_VALUE (src_value));
2242 g_return_if_fail (G_IS_VALUE (dest_value));
2243 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
2244 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
2245 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
2247 dest_value->data[0].v_pointer =
2248 gst_caps_to_string (src_value->data[0].v_pointer);
2252 gst_caps_copy_conditional (GstCaps * src)
2255 return gst_caps_ref (src);