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 G_VALUE_COLLECT_INIT (&value, type, varargs, 0, &err);
970 if (G_UNLIKELY (err)) {
971 g_critical ("%s", err);
975 gst_caps_set_value (caps, field, &value);
977 g_value_unset (&value);
979 field = va_arg (varargs, const gchar *);
984 * gst_caps_set_simple:
985 * @caps: the #GstCaps to set
986 * @field: first field to set
987 * @...: additional parameters
989 * Sets fields in a #GstCaps. The arguments must be passed in the same
990 * manner as gst_structure_set(), and be NULL-terminated.
991 * <note>Prior to GStreamer version 0.10.26, this function failed when
992 * @caps was not simple. If your code needs to work with those versions
993 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
994 * is %TRUE for @caps.</note>
997 gst_caps_set_simple (GstCaps * caps, const char *field, ...)
1001 g_return_if_fail (GST_IS_CAPS (caps));
1002 g_return_if_fail (IS_WRITABLE (caps));
1004 va_start (var_args, field);
1005 gst_caps_set_simple_valist (caps, field, var_args);
1013 * @caps: the #GstCaps to test
1015 * Determines if @caps represents any media format.
1017 * Returns: TRUE if @caps represents any format.
1020 gst_caps_is_any (const GstCaps * caps)
1022 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1024 return (CAPS_IS_ANY (caps));
1028 * gst_caps_is_empty:
1029 * @caps: the #GstCaps to test
1031 * Determines if @caps represents no media formats.
1033 * Returns: TRUE if @caps represents no formats.
1036 gst_caps_is_empty (const GstCaps * caps)
1038 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1040 if (CAPS_IS_ANY (caps))
1043 return CAPS_IS_EMPTY_SIMPLE (caps);
1047 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
1050 return gst_value_is_fixed (value);
1054 * gst_caps_is_fixed:
1055 * @caps: the #GstCaps to test
1057 * Fixed #GstCaps describe exactly one format, that is, they have exactly
1058 * one structure, and each field in the structure describes a fixed type.
1059 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
1061 * Returns: TRUE if @caps is fixed
1064 gst_caps_is_fixed (const GstCaps * caps)
1066 GstStructure *structure;
1068 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1070 if (caps->structs->len != 1)
1073 structure = gst_caps_get_structure_unchecked (caps, 0);
1075 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
1079 * gst_caps_is_equal_fixed:
1080 * @caps1: the #GstCaps to test
1081 * @caps2: the #GstCaps to test
1083 * Tests if two #GstCaps are equal. This function only works on fixed
1086 * Returns: TRUE if the arguments represent the same format
1089 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
1091 GstStructure *struct1, *struct2;
1093 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
1094 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
1096 struct1 = gst_caps_get_structure_unchecked (caps1, 0);
1097 struct2 = gst_caps_get_structure_unchecked (caps2, 0);
1099 return gst_structure_is_equal (struct1, struct2);
1103 * gst_caps_is_always_compatible:
1104 * @caps1: the #GstCaps to test
1105 * @caps2: the #GstCaps to test
1107 * A given #GstCaps structure is always compatible with another if
1108 * every media format that is in the first is also contained in the
1109 * second. That is, @caps1 is a subset of @caps2.
1111 * Returns: TRUE if @caps1 is a subset of @caps2.
1114 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
1116 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1117 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1119 return gst_caps_is_subset (caps1, caps2);
1123 * gst_caps_is_subset:
1124 * @subset: a #GstCaps
1125 * @superset: a potentially greater #GstCaps
1127 * Checks if all caps represented by @subset are also represented by @superset.
1128 * <note>This function does not work reliably if optional properties for caps
1129 * are included on one caps and omitted on the other.</note>
1131 * Returns: %TRUE if @subset is a subset of @superset
1134 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
1139 g_return_val_if_fail (subset != NULL, FALSE);
1140 g_return_val_if_fail (superset != NULL, FALSE);
1142 if (CAPS_IS_EMPTY (subset) || CAPS_IS_ANY (superset))
1144 if (CAPS_IS_ANY (subset) || CAPS_IS_EMPTY (superset))
1147 caps = gst_caps_subtract (subset, superset);
1148 ret = CAPS_IS_EMPTY_SIMPLE (caps);
1149 gst_caps_unref (caps);
1154 * gst_caps_is_equal:
1155 * @caps1: a #GstCaps
1156 * @caps2: another #GstCaps
1158 * Checks if the given caps represent the same set of caps.
1159 * <note>This function does not work reliably if optional properties for caps
1160 * are included on one caps and omitted on the other.</note>
1162 * This function deals correctly with passing NULL for any of the caps.
1164 * Returns: TRUE if both caps are equal.
1167 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1169 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1170 * So there should be an assertion that caps1 and caps2 != NULL */
1172 /* NULL <-> NULL is allowed here */
1173 if (G_UNLIKELY (caps1 == caps2))
1176 /* one of them NULL => they are different (can't be both NULL because
1177 * we checked that above) */
1178 if (G_UNLIKELY (caps1 == NULL || caps2 == NULL))
1181 if (G_UNLIKELY (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2)))
1182 return gst_caps_is_equal_fixed (caps1, caps2);
1184 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1187 /* intersect operation */
1190 * gst_caps_can_intersect:
1191 * @caps1: a #GstCaps to intersect
1192 * @caps2: a #GstCaps to intersect
1194 * Tries intersecting @caps1 and @caps2 and reports whether the result would not
1197 * Returns: %TRUE if intersection would be not empty
1202 gst_caps_can_intersect (const GstCaps * caps1, const GstCaps * caps2)
1204 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1205 guint j, k, len1, len2;
1206 GstStructure *struct1;
1207 GstStructure *struct2;
1209 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1210 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1212 /* caps are exactly the same pointers */
1213 if (G_UNLIKELY (caps1 == caps2))
1216 /* empty caps on either side, return empty */
1217 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1220 /* one of the caps is any */
1221 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2)))
1224 /* run zigzag on top line then right line, this preserves the caps order
1225 * much better than a simple loop.
1227 * This algorithm zigzags over the caps structures as demonstrated in
1228 * the folowing matrix:
1231 * +------------- total distance: +-------------
1232 * | 1 2 4 7 0 | 0 1 2 3
1233 * caps2 | 3 5 8 10 1 | 1 2 3 4
1234 * | 6 9 11 12 2 | 2 3 4 5
1236 * First we iterate over the caps1 structures (top line) intersecting
1237 * the structures diagonally down, then we iterate over the caps2
1238 * structures. The result is that the intersections are ordered based on the
1239 * sum of the indexes in the list.
1241 len1 = caps1->structs->len;
1242 len2 = caps2->structs->len;
1243 for (i = 0; i < len1 + len2 - 1; i++) {
1244 /* superset index goes from 0 to sgst_caps_structure_intersectuperset->structs->len-1 */
1245 j = MIN (i, len1 - 1);
1246 /* subset index stays 0 until i reaches superset->structs->len, then it
1247 * counts up from 1 to subset->structs->len - 1 */
1250 /* now run the diagonal line, end condition is the left or bottom
1253 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1254 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1256 if (gst_structure_can_intersect (struct1, struct2)) {
1259 /* move down left */
1261 if (G_UNLIKELY (j == 0))
1262 break; /* so we don't roll back to G_MAXUINT */
1270 gst_caps_intersect_zig_zag (const GstCaps * caps1, const GstCaps * caps2)
1272 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1273 guint j, k, len1, len2;
1275 GstStructure *struct1;
1276 GstStructure *struct2;
1278 GstStructure *istruct;
1280 /* caps are exactly the same pointers, just copy one caps */
1281 if (G_UNLIKELY (caps1 == caps2))
1282 return gst_caps_copy (caps1);
1284 /* empty caps on either side, return empty */
1285 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1286 return gst_caps_new_empty ();
1288 /* one of the caps is any, just copy the other caps */
1289 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1290 return gst_caps_copy (caps2);
1291 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1292 return gst_caps_copy (caps1);
1294 dest = gst_caps_new_empty ();
1296 /* run zigzag on top line then right line, this preserves the caps order
1297 * much better than a simple loop.
1299 * This algorithm zigzags over the caps structures as demonstrated in
1300 * the folowing matrix:
1308 * First we iterate over the caps1 structures (top line) intersecting
1309 * the structures diagonally down, then we iterate over the caps2
1312 len1 = caps1->structs->len;
1313 len2 = caps2->structs->len;
1314 for (i = 0; i < len1 + len2 - 1; i++) {
1315 /* caps1 index goes from 0 to caps1->structs->len-1 */
1316 j = MIN (i, len1 - 1);
1317 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1318 * up from 1 to caps2->structs->len - 1 */
1321 /* now run the diagonal line, end condition is the left or bottom
1324 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1325 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1327 istruct = gst_structure_intersect (struct1, struct2);
1329 gst_caps_merge_structure (dest, istruct);
1330 /* move down left */
1332 if (G_UNLIKELY (j == 0))
1333 break; /* so we don't roll back to G_MAXUINT */
1341 * gst_caps_intersect_first:
1342 * @caps1: a #GstCaps to intersect
1343 * @caps2: a #GstCaps to intersect
1345 * Creates a new #GstCaps that contains all the formats that are common
1346 * to both @caps1 and @caps2.
1348 * Unlike @gst_caps_intersect, the returned caps will be ordered in a similar
1349 * fashion as @caps1.
1351 * Returns: the new #GstCaps
1354 gst_caps_intersect_first (const GstCaps * caps1, const GstCaps * caps2)
1356 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1357 guint j, len1, len2;
1359 GstStructure *struct1;
1360 GstStructure *struct2;
1362 GstStructure *istruct;
1364 /* caps are exactly the same pointers, just copy one caps */
1365 if (G_UNLIKELY (caps1 == caps2))
1366 return gst_caps_copy (caps1);
1368 /* empty caps on either side, return empty */
1369 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1370 return gst_caps_new_empty ();
1372 /* one of the caps is any, just copy the other caps */
1373 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1374 return gst_caps_copy (caps2);
1375 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1376 return gst_caps_copy (caps1);
1378 dest = gst_caps_new_empty ();
1380 len1 = caps1->structs->len;
1381 len2 = caps2->structs->len;
1382 for (i = 0; i < len1; i++) {
1383 struct1 = gst_caps_get_structure_unchecked (caps1, i);
1384 for (j = 0; j < len2; j++) {
1385 struct2 = gst_caps_get_structure_unchecked (caps2, j);
1386 istruct = gst_structure_intersect (struct1, struct2);
1388 gst_caps_merge_structure (dest, istruct);
1396 * gst_caps_intersect_full:
1397 * @caps1: a #GstCaps to intersect
1398 * @caps2: a #GstCaps to intersect
1399 * @mode: The intersection algorithm/mode to use
1401 * Creates a new #GstCaps that contains all the formats that are common
1402 * to both @caps1 and @caps2, the order is defined by the #GstCapsIntersectMode
1405 * Returns: the new #GstCaps
1409 gst_caps_intersect_full (const GstCaps * caps1, const GstCaps * caps2,
1410 GstCapsIntersectMode mode)
1412 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1413 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1416 case GST_CAPS_INTERSECT_FIRST:
1417 return gst_caps_intersect_first (caps1, caps2);
1419 g_warning ("Unknown caps intersect mode: %d", mode);
1421 case GST_CAPS_INTERSECT_ZIG_ZAG:
1422 return gst_caps_intersect_zig_zag (caps1, caps2);
1427 * gst_caps_intersect:
1428 * @caps1: a #GstCaps to intersect
1429 * @caps2: a #GstCaps to intersect
1431 * Creates a new #GstCaps that contains all the formats that are common
1432 * to both @caps1 and @caps2. Defaults to %GST_CAPS_INTERSECT_ZIG_ZAG mode.
1434 * Returns: the new #GstCaps
1437 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1439 return gst_caps_intersect_full (caps1, caps2, GST_CAPS_INTERSECT_ZIG_ZAG);
1443 /* subtract operation */
1447 const GstStructure *subtract_from;
1453 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1456 SubtractionEntry *e = user_data;
1457 GValue subtraction = { 0, };
1458 const GValue *other;
1459 GstStructure *structure;
1461 other = gst_structure_id_get_value (e->subtract_from, field_id);
1465 if (!gst_value_subtract (&subtraction, other, value))
1467 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1468 g_value_unset (&subtraction);
1471 structure = gst_structure_copy (e->subtract_from);
1472 gst_structure_id_set_value (structure, field_id, &subtraction);
1473 g_value_unset (&subtraction);
1474 e->put_into = g_slist_prepend (e->put_into, structure);
1480 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1481 const GstStructure * subtrahend)
1486 e.subtract_from = minuend;
1489 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1490 gst_caps_structure_subtract_field, &e);
1496 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1497 gst_structure_free (walk->data);
1499 g_slist_free (e.put_into);
1505 * gst_caps_subtract:
1506 * @minuend: #GstCaps to substract from
1507 * @subtrahend: #GstCaps to substract
1509 * Subtracts the @subtrahend from the @minuend.
1510 * <note>This function does not work reliably if optional properties for caps
1511 * are included on one caps and omitted on the other.</note>
1513 * Returns: the resulting caps
1516 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1521 GstCaps *dest = NULL, *src;
1523 g_return_val_if_fail (minuend != NULL, NULL);
1524 g_return_val_if_fail (subtrahend != NULL, NULL);
1526 if (CAPS_IS_EMPTY (minuend) || CAPS_IS_ANY (subtrahend)) {
1527 return gst_caps_new_empty ();
1529 if (CAPS_IS_EMPTY_SIMPLE (subtrahend))
1530 return gst_caps_copy (minuend);
1532 /* FIXME: Do we want this here or above?
1533 The reason we need this is that there is no definition about what
1534 ANY means for specific types, so it's not possible to reduce ANY partially
1535 You can only remove everything or nothing and that is done above.
1536 Note: there's a test that checks this behaviour. */
1537 g_return_val_if_fail (!CAPS_IS_ANY (minuend), NULL);
1538 sublen = subtrahend->structs->len;
1539 g_assert (sublen > 0);
1541 src = gst_caps_copy (minuend);
1542 for (i = 0; i < sublen; i++) {
1545 sub = gst_caps_get_structure_unchecked (subtrahend, i);
1547 gst_caps_unref (src);
1550 dest = gst_caps_new_empty ();
1551 srclen = src->structs->len;
1552 for (j = 0; j < srclen; j++) {
1553 min = gst_caps_get_structure_unchecked (src, j);
1554 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1557 if (gst_caps_structure_subtract (&list, min, sub)) {
1560 for (walk = list; walk; walk = g_slist_next (walk)) {
1561 gst_caps_append_structure_unchecked (dest,
1562 (GstStructure *) walk->data);
1564 g_slist_free (list);
1566 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1569 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1572 if (CAPS_IS_EMPTY_SIMPLE (dest)) {
1573 gst_caps_unref (src);
1578 gst_caps_unref (src);
1579 gst_caps_do_simplify (dest);
1583 /* union operation */
1586 static GstStructure *
1587 gst_caps_structure_union (const GstStructure * struct1,
1588 const GstStructure * struct2)
1592 const GstStructureField *field1;
1593 const GstStructureField *field2;
1596 /* FIXME this doesn't actually work */
1598 if (struct1->name != struct2->name)
1601 dest = gst_structure_id_empty_new (struct1->name);
1603 for (i = 0; i < struct1->fields->len; i++) {
1604 GValue dest_value = { 0 };
1606 field1 = GST_STRUCTURE_FIELD (struct1, i);
1607 field2 = gst_structure_id_get_field (struct2, field1->name);
1609 if (field2 == NULL) {
1612 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1613 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1616 ret = gst_value_compare (&field1->value, &field2->value);
1627 * @caps1: a #GstCaps to union
1628 * @caps2: a #GstCaps to union
1630 * Creates a new #GstCaps that contains all the formats that are in
1631 * either @caps1 and @caps2.
1633 * Returns: the new #GstCaps
1636 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1641 /* NULL pointers are no correct GstCaps */
1642 g_return_val_if_fail (caps1 != NULL, NULL);
1643 g_return_val_if_fail (caps2 != NULL, NULL);
1645 if (CAPS_IS_EMPTY (caps1))
1646 return gst_caps_copy (caps2);
1648 if (CAPS_IS_EMPTY (caps2))
1649 return gst_caps_copy (caps1);
1651 if (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))
1652 return gst_caps_new_any ();
1654 dest1 = gst_caps_copy (caps1);
1655 dest2 = gst_caps_copy (caps2);
1656 gst_caps_append (dest1, dest2);
1658 gst_caps_do_simplify (dest1);
1662 /* normalize/simplify operations */
1664 typedef struct _NormalizeForeach
1667 GstStructure *structure;
1672 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1674 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1678 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1679 guint len = gst_value_list_get_size (value);
1680 for (i = 1; i < len; i++) {
1681 const GValue *v = gst_value_list_get_value (value, i);
1682 GstStructure *structure = gst_structure_copy (nf->structure);
1684 gst_structure_id_set_value (structure, field_id, v);
1685 gst_caps_append_structure_unchecked (nf->caps, structure);
1688 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1689 gst_structure_id_set_value (nf->structure, field_id, &val);
1690 g_value_unset (&val);
1698 * gst_caps_normalize:
1699 * @caps: a #GstCaps to normalize
1701 * Creates a new #GstCaps that represents the same set of formats as
1702 * @caps, but contains no lists. Each list is expanded into separate
1705 * Returns: the new #GstCaps
1708 gst_caps_normalize (const GstCaps * caps)
1710 NormalizeForeach nf;
1714 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1716 newcaps = gst_caps_copy (caps);
1719 for (i = 0; i < gst_caps_get_size (newcaps); i++) {
1720 nf.structure = gst_caps_get_structure_unchecked (newcaps, i);
1722 while (!gst_structure_foreach (nf.structure,
1723 gst_caps_normalize_foreach, &nf));
1730 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1733 const GstStructure *struct1 = *((const GstStructure **) one);
1734 const GstStructure *struct2 = *((const GstStructure **) two);
1736 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1737 So what's the best way? */
1738 ret = strcmp (gst_structure_get_name (struct1),
1739 gst_structure_get_name (struct2));
1743 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1750 GstStructure *compare;
1755 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1758 UnionField *u = user_data;
1759 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1763 g_value_unset (&u->value);
1766 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1769 g_value_unset (&u->value);
1773 gst_value_union (&u->value, val, value);
1778 gst_caps_structure_simplify (GstStructure ** result,
1779 const GstStructure * simplify, GstStructure * compare)
1782 UnionField field = { 0, {0,}, NULL };
1784 /* try to subtract to get a real subset */
1785 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1786 if (list == NULL) { /* no result */
1789 } else if (list->next == NULL) { /* one result */
1790 *result = list->data;
1791 g_slist_free (list);
1793 } else { /* multiple results */
1794 g_slist_foreach (list, (GFunc) gst_structure_free, NULL);
1795 g_slist_free (list);
1800 /* try to union both structs */
1801 field.compare = compare;
1802 if (gst_structure_foreach ((GstStructure *) simplify,
1803 gst_caps_structure_figure_out_union, &field)) {
1804 gboolean ret = FALSE;
1806 /* now we know all of simplify's fields are the same in compare
1807 * but at most one field: field.name */
1808 if (G_IS_VALUE (&field.value)) {
1809 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1810 gst_structure_id_set_value (compare, field.name, &field.value);
1814 g_value_unset (&field.value);
1815 } else if (gst_structure_n_fields (simplify) <=
1816 gst_structure_n_fields (compare)) {
1817 /* compare is just more specific, will be optimized away later */
1818 /* FIXME: do this here? */
1819 GST_LOG ("found a case that will be optimized later.");
1821 gchar *one = gst_structure_to_string (simplify);
1822 gchar *two = gst_structure_to_string (compare);
1825 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1837 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1838 GstStructure * new, gint i)
1840 gst_structure_set_parent_refcount (old, NULL);
1841 gst_structure_free (old);
1842 gst_structure_set_parent_refcount (new, &caps->refcount);
1843 g_ptr_array_index (caps->structs, i) = new;
1847 * gst_caps_do_simplify:
1848 * @caps: a #GstCaps to simplify
1850 * Modifies the given @caps inplace into a representation that represents the
1851 * same set of formats, but in a simpler form. Component structures that are
1852 * identical are merged. Component structures that have values that can be
1853 * merged are also merged.
1855 * Returns: TRUE, if the caps could be simplified
1858 gst_caps_do_simplify (GstCaps * caps)
1860 GstStructure *simplify, *compare, *result = NULL;
1862 gboolean changed = FALSE;
1864 g_return_val_if_fail (caps != NULL, FALSE);
1865 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1867 if (gst_caps_get_size (caps) < 2)
1870 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1872 start = caps->structs->len - 1;
1873 for (i = caps->structs->len - 1; i >= 0; i--) {
1874 simplify = gst_caps_get_structure_unchecked (caps, i);
1875 if (gst_structure_get_name_id (simplify) !=
1876 gst_structure_get_name_id (gst_caps_get_structure_unchecked (caps,
1879 for (j = start; j >= 0; j--) {
1882 compare = gst_caps_get_structure_unchecked (caps, j);
1883 if (gst_structure_get_name_id (simplify) !=
1884 gst_structure_get_name_id (compare)) {
1887 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1889 gst_caps_switch_structures (caps, simplify, result, i);
1892 gst_caps_remove_structure (caps, i);
1904 /* gst_caps_do_simplify (caps); */
1910 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
1912 * gst_caps_save_thyself:
1913 * @caps: a #GstCaps structure
1914 * @parent: a XML parent node
1916 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
1918 * Returns: a XML node pointer
1921 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
1923 char *s = gst_caps_to_string (caps);
1925 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
1931 * gst_caps_load_thyself:
1932 * @parent: a XML node
1934 * Creates a #GstCaps from its XML serialization.
1936 * Returns: a new #GstCaps structure
1939 gst_caps_load_thyself (xmlNodePtr parent)
1941 if (strcmp ("caps", (char *) parent->name) == 0) {
1942 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
1953 * @caps: (inout) (transfer full): a pointer to #GstCaps
1954 * @newcaps: a #GstCaps to replace *caps
1956 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
1957 * pointed to by @caps, if applicable, then modifies @caps to point to
1958 * @newcaps. An additional ref on @newcaps is taken.
1960 * This function does not take any locks so you might want to lock
1961 * the object owning @caps pointer.
1964 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
1968 g_return_if_fail (caps != NULL);
1972 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p, %p -> %p", caps, oldcaps, newcaps);
1974 if (newcaps != oldcaps) {
1976 gst_caps_ref (newcaps);
1981 gst_caps_unref (oldcaps);
1986 * gst_caps_to_string:
1989 * Converts @caps to a string representation. This string representation
1990 * can be converted back to a #GstCaps by gst_caps_from_string().
1992 * For debugging purposes its easier to do something like this:
1994 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
1996 * This prints the caps in human readble form.
1998 * Returns: (transfer full): a newly allocated string representing @caps.
2001 gst_caps_to_string (const GstCaps * caps)
2003 guint i, slen, clen;
2006 /* NOTE: This function is potentially called by the debug system,
2007 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
2008 * should be careful to avoid recursion. This includes any functions
2009 * called by gst_caps_to_string. In particular, calls should
2010 * not use the GST_PTR_FORMAT extension. */
2013 return g_strdup ("NULL");
2015 if (CAPS_IS_ANY (caps)) {
2016 return g_strdup ("ANY");
2018 if (CAPS_IS_EMPTY_SIMPLE (caps)) {
2019 return g_strdup ("EMPTY");
2022 /* estimate a rough string length to avoid unnecessary reallocs in GString */
2024 clen = caps->structs->len;
2025 for (i = 0; i < clen; i++) {
2027 STRUCTURE_ESTIMATED_STRING_LEN (gst_caps_get_structure_unchecked (caps,
2031 s = g_string_sized_new (slen);
2032 for (i = 0; i < clen; i++) {
2033 GstStructure *structure;
2036 /* ';' is now added by gst_structure_to_string */
2037 g_string_append_c (s, ' ');
2040 structure = gst_caps_get_structure_unchecked (caps, i);
2041 priv_gst_structure_append_to_gstring (structure, s);
2043 if (s->len && s->str[s->len - 1] == ';') {
2044 /* remove latest ';' */
2045 s->str[--s->len] = '\0';
2047 return g_string_free (s, FALSE);
2051 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
2053 GstStructure *structure;
2056 if (strcmp ("ANY", string) == 0) {
2057 caps->flags = GST_CAPS_FLAGS_ANY;
2060 if (strcmp ("EMPTY", string) == 0) {
2064 structure = gst_structure_from_string (string, &s);
2065 if (structure == NULL) {
2068 gst_caps_append_structure_unchecked (caps, structure);
2072 while (g_ascii_isspace (*s))
2077 structure = gst_structure_from_string (s, &s);
2078 if (structure == NULL) {
2081 gst_caps_append_structure_unchecked (caps, structure);
2089 * gst_caps_from_string:
2090 * @string: a string to convert to #GstCaps
2092 * Converts @caps from a string representation.
2094 * Returns: (transfer full): a newly allocated #GstCaps
2097 gst_caps_from_string (const gchar * string)
2101 g_return_val_if_fail (string, FALSE);
2103 caps = gst_caps_new_empty ();
2104 if (gst_caps_from_string_inplace (caps, string)) {
2107 gst_caps_unref (caps);
2113 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
2115 g_return_if_fail (G_IS_VALUE (src_value));
2116 g_return_if_fail (G_IS_VALUE (dest_value));
2117 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
2118 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
2119 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
2121 dest_value->data[0].v_pointer =
2122 gst_caps_to_string (src_value->data[0].v_pointer);
2126 gst_caps_copy_conditional (GstCaps * src)
2129 return gst_caps_ref (src);