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 registry along with
30 * a description of the element.
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", G_TYPE_DOUBLE, 25.0,
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 2005-11-23 (0.9.5)
72 #include "gst_private.h"
75 #define DEBUG_REFCOUNT
77 #define CAPS_POISON(caps) G_STMT_START{ \
79 GstCaps *_newcaps = gst_caps_copy (caps); \
80 gst_caps_unref(caps); \
84 #define STRUCTURE_POISON(structure) G_STMT_START{ \
86 GstStructure *_newstruct = gst_structure_copy (structure); \
87 gst_structure_free(structure); \
88 structure = _newstruct; \
91 #define IS_WRITABLE(caps) \
92 (g_atomic_int_get (&(caps)->refcount) == 1)
94 #if GLIB_CHECK_VERSION (2, 10, 0)
95 #define ALLOC_CAPS() g_slice_new (GstCaps)
96 #define FREE_CAPS(caps) g_slice_free (GstCaps, caps)
98 #define ALLOC_CAPS() g_new (GstCaps, 1)
99 #define FREE_CAPS(caps) g_free (caps)
102 /* lock to protect multiple invocations of static caps to caps conversion */
103 G_LOCK_DEFINE_STATIC (static_caps_lock);
105 static void gst_caps_transform_to_string (const GValue * src_value,
106 GValue * dest_value);
107 static gboolean gst_caps_from_string_inplace (GstCaps * caps,
108 const gchar * string);
109 static GstCaps *gst_caps_copy_conditional (GstCaps * src);
112 gst_caps_get_type (void)
114 static GType gst_caps_type = 0;
116 if (G_UNLIKELY (gst_caps_type == 0)) {
117 gst_caps_type = g_boxed_type_register_static ("GstCaps",
118 (GBoxedCopyFunc) gst_caps_copy_conditional,
119 (GBoxedFreeFunc) gst_caps_unref);
121 g_value_register_transform_func (gst_caps_type,
122 G_TYPE_STRING, gst_caps_transform_to_string);
125 return gst_caps_type;
128 /* creation/deletion */
131 * gst_caps_new_empty:
133 * Creates a new #GstCaps that is empty. That is, the returned
134 * #GstCaps contains no media formats.
135 * Caller is responsible for unreffing the returned caps.
137 * Returns: the new #GstCaps
140 gst_caps_new_empty (void)
142 GstCaps *caps = ALLOC_CAPS ();
144 caps->type = GST_TYPE_CAPS;
147 caps->structs = g_ptr_array_new ();
149 #ifdef DEBUG_REFCOUNT
150 GST_CAT_LOG (GST_CAT_CAPS, "created caps %p", caps);
159 * Creates a new #GstCaps that indicates that it is compatible with
162 * Returns: the new #GstCaps
165 gst_caps_new_any (void)
167 GstCaps *caps = gst_caps_new_empty ();
169 caps->flags = GST_CAPS_FLAGS_ANY;
175 * gst_caps_new_simple:
176 * @media_type: the media type of the structure
177 * @fieldname: first field to set
178 * @...: additional arguments
180 * Creates a new #GstCaps that contains one #GstStructure. The
181 * structure is defined by the arguments, which have the same format
182 * as gst_structure_new().
183 * Caller is responsible for unreffing the returned caps.
185 * Returns: the new #GstCaps
188 gst_caps_new_simple (const char *media_type, const char *fieldname, ...)
191 GstStructure *structure;
194 caps = gst_caps_new_empty ();
196 va_start (var_args, fieldname);
197 structure = gst_structure_new_valist (media_type, fieldname, var_args);
200 gst_caps_append_structure (caps, structure);
207 * @struct1: the first structure to add
208 * @...: additional structures to add
210 * Creates a new #GstCaps and adds all the structures listed as
211 * arguments. The list must be NULL-terminated. The structures
212 * are not copied; the returned #GstCaps owns the structures.
214 * Returns: the new #GstCaps
217 gst_caps_new_full (GstStructure * struct1, ...)
222 va_start (var_args, struct1);
223 caps = gst_caps_new_full_valist (struct1, var_args);
230 * gst_caps_new_full_valist:
231 * @structure: the first structure to add
232 * @var_args: additional structures to add
234 * Creates a new #GstCaps and adds all the structures listed as
235 * arguments. The list must be NULL-terminated. The structures
236 * are not copied; the returned #GstCaps owns the structures.
238 * Returns: the new #GstCaps
241 gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
245 caps = gst_caps_new_empty ();
248 gst_caps_append_structure (caps, structure);
249 structure = va_arg (var_args, GstStructure *);
257 * @caps: the #GstCaps to copy
259 * Creates a new #GstCaps as a copy of the old @caps. The new caps will have a
260 * refcount of 1, owned by the caller. The structures are copied as well.
262 * Note that this function is the semantic equivalent of a gst_caps_ref()
263 * followed by a gst_caps_make_writable(). If you only want to hold on to a
264 * reference to the data, you should use gst_caps_ref().
266 * When you are finished with the caps, call gst_caps_unref() on it.
268 * Returns: the new #GstCaps
271 gst_caps_copy (const GstCaps * caps)
274 GstStructure *structure;
277 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
279 newcaps = gst_caps_new_empty ();
280 newcaps->flags = caps->flags;
282 for (i = 0; i < caps->structs->len; i++) {
283 structure = gst_caps_get_structure (caps, i);
284 gst_caps_append_structure (newcaps, gst_structure_copy (structure));
291 _gst_caps_free (GstCaps * caps)
293 GstStructure *structure;
296 /* The refcount must be 0, but since we're only called by gst_caps_unref,
297 * don't bother testing. */
299 for (i = 0; i < caps->structs->len; i++) {
300 structure = (GstStructure *) gst_caps_get_structure (caps, i);
301 gst_structure_set_parent_refcount (structure, NULL);
302 gst_structure_free (structure);
304 g_ptr_array_free (caps->structs, TRUE);
306 memset (caps, 0xff, sizeof (GstCaps));
309 #ifdef DEBUG_REFCOUNT
310 GST_CAT_LOG (GST_CAT_CAPS, "freeing caps %p", caps);
316 * gst_caps_make_writable:
317 * @caps: the #GstCaps to make writable
319 * Returns a writable copy of @caps.
321 * If there is only one reference count on @caps, the caller must be the owner,
322 * and so this function will return the caps object unchanged. If on the other
323 * hand there is more than one reference on the object, a new caps object will
324 * be returned. The caller's reference on @caps will be removed, and instead the
325 * caller will own a reference to the returned object.
327 * In short, this function unrefs the caps in the argument and refs the caps
328 * that it returns. Don't access the argument after calling this function. See
329 * also: gst_caps_ref().
331 * Returns: the same #GstCaps object.
334 gst_caps_make_writable (GstCaps * caps)
338 g_return_val_if_fail (caps != NULL, NULL);
340 /* we are the only instance reffing this caps */
341 if (g_atomic_int_get (&caps->refcount) == 1)
345 copy = gst_caps_copy (caps);
346 gst_caps_unref (caps);
353 * @caps: the #GstCaps to reference
355 * Add a reference to a #GstCaps object.
357 * From this point on, until the caller calls gst_caps_unref() or
358 * gst_caps_make_writable(), it is guaranteed that the caps object will not
359 * change. This means its structures won't change, etc. To use a #GstCaps
360 * object, you must always have a refcount on it -- either the one made
361 * implicitly by gst_caps_new(), or via taking one explicitly with this
364 * Returns: the same #GstCaps object.
367 gst_caps_ref (GstCaps * caps)
369 g_return_val_if_fail (caps != NULL, NULL);
371 #ifdef DEBUG_REFCOUNT
372 GST_CAT_LOG (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
373 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) + 1);
375 g_return_val_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0, NULL);
377 g_atomic_int_inc (&caps->refcount);
384 * @caps: the #GstCaps to unref
386 * Unref a #GstCaps and and free all its structures and the
387 * structures' values when the refcount reaches 0.
390 gst_caps_unref (GstCaps * caps)
392 g_return_if_fail (caps != NULL);
394 #ifdef DEBUG_REFCOUNT
395 GST_CAT_LOG (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
396 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) - 1);
399 g_return_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0);
401 /* if we ended up with the refcount at zero, free the caps */
402 if (G_UNLIKELY (g_atomic_int_dec_and_test (&caps->refcount)))
403 _gst_caps_free (caps);
407 gst_static_caps_get_type (void)
409 static GType staticcaps_type = 0;
411 if (G_UNLIKELY (staticcaps_type == 0)) {
412 staticcaps_type = g_pointer_type_register_static ("GstStaticCaps");
414 return staticcaps_type;
419 * gst_static_caps_get:
420 * @static_caps: the #GstStaticCaps to convert
422 * Converts a #GstStaticCaps to a #GstCaps.
424 * Returns: A pointer to the #GstCaps. Unref after usage. Since the
425 * core holds an additional ref to the returned caps,
426 * use gst_caps_make_writable() on the returned caps to modify it.
429 gst_static_caps_get (GstStaticCaps * static_caps)
433 g_return_val_if_fail (static_caps != NULL, NULL);
435 caps = (GstCaps *) static_caps;
437 /* refcount is 0 when we need to convert */
438 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount) == 0)) {
442 G_LOCK (static_caps_lock);
443 /* check if other thread already updated */
444 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount) > 0))
447 string = static_caps->string;
449 if (G_UNLIKELY (string == NULL))
452 GST_CAT_LOG (GST_CAT_CAPS, "creating %p", static_caps);
454 /* we construct the caps on the stack, then copy over the struct into our
455 * real caps, refcount last. We do this because we must leave the refcount
456 * of the result caps to 0 so that other threads don't run away with the
457 * caps while we are constructing it. */
458 temp.type = GST_TYPE_CAPS;
459 temp.structs = g_ptr_array_new ();
461 /* initialize the caps to a refcount of 1 so the caps can be writable for
462 * the next statement */
463 gst_atomic_int_set (&temp.refcount, 1);
465 /* convert to string */
466 if (G_UNLIKELY (!gst_caps_from_string_inplace (&temp, string)))
467 g_critical ("Could not convert static caps \"%s\"", string);
469 /* now copy stuff over to the real caps. */
470 caps->type = temp.type;
471 caps->flags = temp.flags;
472 caps->structs = temp.structs;
473 /* and bump the refcount so other threads can now read */
474 gst_atomic_int_set (&caps->refcount, 1);
476 GST_CAT_LOG (GST_CAT_CAPS, "created %p", static_caps);
478 G_UNLOCK (static_caps_lock);
480 /* ref the caps, makes it not writable */
488 G_UNLOCK (static_caps_lock);
489 g_warning ("static caps %p string is NULL", static_caps);
495 static GstStructure *
496 gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
498 /* don't use index_fast, gst_caps_do_simplify relies on the order */
499 GstStructure *s = g_ptr_array_remove_index (caps->structs, idx);
501 gst_structure_set_parent_refcount (s, NULL);
506 gst_structure_is_equal_foreach (GQuark field_id, const GValue * val2,
509 GstStructure *struct1 = (GstStructure *) data;
510 const GValue *val1 = gst_structure_id_get_value (struct1, field_id);
514 if (gst_value_compare (val1, val2) == GST_VALUE_EQUAL) {
522 gst_caps_structure_is_subset_field (GQuark field_id, const GValue * value,
525 GstStructure *subtract_from = user_data;
526 GValue subtraction = { 0, };
530 other = gst_structure_id_get_value (subtract_from, field_id);
532 /* field is missing in one set */
539 if (!gst_value_subtract (&subtraction, other, value)) {
540 /* empty result -> values are the same, or first was a value and
542 * verify that result is empty by swapping args */
543 if (!gst_value_subtract (&subtraction, value, other)) {
546 g_value_unset (&subtraction);
550 res = gst_value_compare (&subtraction, other);
551 g_value_unset (&subtraction);
553 if (res == GST_VALUE_EQUAL) {
554 /* value was empty ? */
562 gst_caps_structure_is_subset (const GstStructure * minuend,
563 const GstStructure * subtrahend)
565 if ((minuend->name != subtrahend->name) ||
566 (gst_structure_n_fields (minuend) !=
567 gst_structure_n_fields (subtrahend))) {
571 return gst_structure_foreach ((GstStructure *) subtrahend,
572 gst_caps_structure_is_subset_field, (gpointer) minuend);
577 * @caps1: the #GstCaps that will be appended to
578 * @caps2: the #GstCaps to append
580 * Appends the structures contained in @caps2 to @caps1. The structures in
581 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
582 * freed. If either caps is ANY, the resulting caps will be ANY.
585 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
587 GstStructure *structure;
590 g_return_if_fail (GST_IS_CAPS (caps1));
591 g_return_if_fail (GST_IS_CAPS (caps2));
592 g_return_if_fail (IS_WRITABLE (caps1));
593 g_return_if_fail (IS_WRITABLE (caps2));
598 if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2)) {
599 /* FIXME: this leaks */
600 caps1->flags |= GST_CAPS_FLAGS_ANY;
601 for (i = caps2->structs->len - 1; i >= 0; i--) {
602 structure = gst_caps_remove_and_get_structure (caps2, i);
603 gst_structure_free (structure);
606 int len = caps2->structs->len;
608 for (i = 0; i < len; i++) {
609 structure = gst_caps_remove_and_get_structure (caps2, 0);
610 gst_caps_append_structure (caps1, structure);
613 gst_caps_unref (caps2); /* guaranteed to free it */
618 * @caps1: the #GstCaps that will take the new entries
619 * @caps2: the #GstCaps to merge in
621 * Appends the structures contained in @caps2 to @caps1 if they are not yet
622 * expressed by @caps1. The structures in @caps2 are not copied -- they are
623 * transferred to @caps1, and then @caps2 is freed.
624 * If either caps is ANY, the resulting caps will be ANY.
629 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
631 GstStructure *structure;
634 g_return_if_fail (GST_IS_CAPS (caps1));
635 g_return_if_fail (GST_IS_CAPS (caps2));
636 g_return_if_fail (IS_WRITABLE (caps1));
637 g_return_if_fail (IS_WRITABLE (caps2));
642 if (gst_caps_is_any (caps1)) {
643 for (i = caps2->structs->len - 1; i >= 0; i--) {
644 structure = gst_caps_remove_and_get_structure (caps2, i);
645 gst_structure_free (structure);
647 } else if (gst_caps_is_any (caps2)) {
648 caps1->flags |= GST_CAPS_FLAGS_ANY;
649 for (i = caps1->structs->len - 1; i >= 0; i--) {
650 structure = gst_caps_remove_and_get_structure (caps1, i);
651 gst_structure_free (structure);
654 int len = caps2->structs->len;
656 for (i = 0; i < len; i++) {
657 structure = gst_caps_remove_and_get_structure (caps2, 0);
658 gst_caps_merge_structure (caps1, structure);
661 GstCaps *com = gst_caps_intersect (caps1, caps2);
662 GstCaps *add = gst_caps_subtract (caps2, com);
664 GST_DEBUG ("common : %d", gst_caps_get_size (com));
665 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
666 gst_caps_append (caps1, add);
667 gst_caps_unref (com);
670 gst_caps_unref (caps2); /* guaranteed to free it */
674 * gst_caps_append_structure:
675 * @caps: the #GstCaps that will be appended to
676 * @structure: the #GstStructure to append
678 * Appends @structure to @caps. The structure is not copied; @caps
679 * becomes the owner of @structure.
682 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
684 g_return_if_fail (GST_IS_CAPS (caps));
685 g_return_if_fail (IS_WRITABLE (caps));
687 if (G_LIKELY (structure)) {
688 g_return_if_fail (structure->parent_refcount == NULL);
691 STRUCTURE_POISON (structure);
694 gst_structure_set_parent_refcount (structure, &caps->refcount);
695 g_ptr_array_add (caps->structs, structure);
700 * gst_caps_remove_structure:
701 * @caps: the #GstCaps to remove from
702 * @idx: Index of the structure to remove
704 * removes the stucture with the given index from the list of structures
705 * contained in @caps.
708 gst_caps_remove_structure (GstCaps * caps, guint idx)
710 GstStructure *structure;
712 g_return_if_fail (caps != NULL);
713 g_return_if_fail (idx <= gst_caps_get_size (caps));
714 g_return_if_fail (IS_WRITABLE (caps));
716 structure = gst_caps_remove_and_get_structure (caps, idx);
717 gst_structure_free (structure);
721 * gst_caps_merge_structure:
722 * @caps: the #GstCaps that will the the new structure
723 * @structure: the #GstStructure to merge
725 * Appends @structure to @caps if its not already expressed by @caps. The
726 * structure is not copied; @caps becomes the owner of @structure.
729 gst_caps_merge_structure (GstCaps * caps, GstStructure * structure)
731 g_return_if_fail (GST_IS_CAPS (caps));
732 g_return_if_fail (IS_WRITABLE (caps));
734 if (G_LIKELY (structure)) {
735 GstStructure *structure1;
737 gboolean unique = TRUE;
739 g_return_if_fail (structure->parent_refcount == NULL);
742 STRUCTURE_POISON (structure);
745 /* check each structure */
746 for (i = caps->structs->len - 1; i >= 0; i--) {
747 structure1 = gst_caps_get_structure (caps, i);
748 /* if structure is a subset of structure1, then skip it */
749 if (gst_caps_structure_is_subset (structure1, structure)) {
755 gst_structure_set_parent_refcount (structure, &caps->refcount);
756 g_ptr_array_add (caps->structs, structure);
758 gst_structure_free (structure);
768 * Gets the number of structures contained in @caps.
770 * Returns: the number of structures that @caps contains
773 gst_caps_get_size (const GstCaps * caps)
775 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
777 return caps->structs->len;
781 * gst_caps_get_structure:
783 * @index: the index of the structure
785 * Finds the structure in @caps that has the index @index, and
788 * WARNING: This function takes a const GstCaps *, but returns a
789 * non-const GstStructure *. This is for programming convenience --
790 * the caller should be aware that structures inside a constant
791 * #GstCaps should not be modified.
793 * Returns: a pointer to the #GstStructure corresponding to @index
796 gst_caps_get_structure (const GstCaps * caps, guint index)
798 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
799 g_return_val_if_fail (index < caps->structs->len, NULL);
801 return g_ptr_array_index (caps->structs, index);
806 * @caps: the #GstCaps to copy
807 * @nth: the nth structure to copy
809 * Creates a new #GstCaps and appends a copy of the nth structure
810 * contained in @caps.
812 * Returns: the new #GstCaps
815 gst_caps_copy_nth (const GstCaps * caps, guint nth)
818 GstStructure *structure;
820 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
822 newcaps = gst_caps_new_empty ();
823 newcaps->flags = caps->flags;
825 if (caps->structs->len > nth) {
826 structure = gst_caps_get_structure (caps, nth);
827 gst_caps_append_structure (newcaps, gst_structure_copy (structure));
835 * @caps: the #GstCaps to truncate
837 * Destructively discard all but the first structure from @caps. Useful when
838 * fixating. @caps must be writable.
841 gst_caps_truncate (GstCaps * caps)
845 g_return_if_fail (GST_IS_CAPS (caps));
846 g_return_if_fail (IS_WRITABLE (caps));
848 i = caps->structs->len - 1;
851 gst_caps_remove_structure (caps, i--);
855 * gst_caps_set_simple:
856 * @caps: the #GstCaps to set
857 * @field: first field to set
858 * @...: additional parameters
860 * Sets fields in a simple #GstCaps. A simple #GstCaps is one that
861 * only has one structure. The arguments must be passed in the same
862 * manner as gst_structure_set(), and be NULL-terminated.
865 gst_caps_set_simple (GstCaps * caps, char *field, ...)
867 GstStructure *structure;
870 g_return_if_fail (GST_IS_CAPS (caps));
871 g_return_if_fail (caps->structs->len == 1);
872 g_return_if_fail (IS_WRITABLE (caps));
874 structure = gst_caps_get_structure (caps, 0);
876 va_start (var_args, field);
877 gst_structure_set_valist (structure, field, var_args);
882 * gst_caps_set_simple_valist:
883 * @caps: the #GstCaps to copy
884 * @field: first field to set
885 * @varargs: additional parameters
887 * Sets fields in a simple #GstCaps. A simple #GstCaps is one that
888 * only has one structure. The arguments must be passed in the same
889 * manner as gst_structure_set(), and be NULL-terminated.
892 gst_caps_set_simple_valist (GstCaps * caps, char *field, va_list varargs)
894 GstStructure *structure;
896 g_return_if_fail (GST_IS_CAPS (caps));
897 g_return_if_fail (caps->structs->len != 1);
898 g_return_if_fail (IS_WRITABLE (caps));
900 structure = gst_caps_get_structure (caps, 0);
902 gst_structure_set_valist (structure, field, varargs);
909 * @caps: the #GstCaps to test
911 * Determines if @caps represents any media format.
913 * Returns: TRUE if @caps represents any format.
916 gst_caps_is_any (const GstCaps * caps)
918 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
920 return (caps->flags & GST_CAPS_FLAGS_ANY);
925 * @caps: the #GstCaps to test
927 * Determines if @caps represents no media formats.
929 * Returns: TRUE if @caps represents no formats.
932 gst_caps_is_empty (const GstCaps * caps)
934 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
936 if (caps->flags & GST_CAPS_FLAGS_ANY)
939 return (caps->structs == NULL) || (caps->structs->len == 0);
943 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
946 return gst_value_is_fixed (value);
951 * @caps: the #GstCaps to test
953 * Fixed #GstCaps describe exactly one format, that is, they have exactly
954 * one structure, and each field in the structure describes a fixed type.
955 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
957 * Returns: TRUE if @caps is fixed
960 gst_caps_is_fixed (const GstCaps * caps)
962 GstStructure *structure;
964 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
966 if (caps->structs->len != 1)
969 structure = gst_caps_get_structure (caps, 0);
971 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
975 * gst_caps_is_equal_fixed:
976 * @caps1: the #GstCaps to test
977 * @caps2: the #GstCaps to test
979 * Tests if two #GstCaps are equal. This function only works on fixed
982 * Returns: TRUE if the arguments represent the same format
985 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
987 GstStructure *struct1, *struct2;
989 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
990 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
992 struct1 = gst_caps_get_structure (caps1, 0);
993 struct2 = gst_caps_get_structure (caps2, 0);
995 if (struct1->name != struct2->name) {
998 if (struct1->fields->len != struct2->fields->len) {
1002 return gst_structure_foreach (struct1, gst_structure_is_equal_foreach,
1007 * gst_caps_is_always_compatible:
1008 * @caps1: the #GstCaps to test
1009 * @caps2: the #GstCaps to test
1011 * A given #GstCaps structure is always compatible with another if
1012 * every media format that is in the first is also contained in the
1013 * second. That is, @caps1 is a subset of @caps2.
1015 * Returns: TRUE if @caps1 is a subset of @caps2.
1018 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
1020 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1021 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1023 return gst_caps_is_subset (caps1, caps2);
1027 * gst_caps_is_subset:
1028 * @subset: a #GstCaps
1029 * @superset: a potentially greater #GstCaps
1031 * Checks if all caps represented by @subset are also represented by @superset
1032 * <note>This function does not work reliably if optional properties for caps
1033 * are included on one caps and omitted on the other.</note>
1035 * Returns: TRUE if @subset is a subset of @superset
1038 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
1043 g_return_val_if_fail (subset != NULL, FALSE);
1044 g_return_val_if_fail (superset != NULL, FALSE);
1046 if (gst_caps_is_empty (subset) || gst_caps_is_any (superset))
1048 if (gst_caps_is_any (subset) || gst_caps_is_empty (superset))
1051 caps = gst_caps_subtract (subset, superset);
1052 ret = gst_caps_is_empty (caps);
1053 gst_caps_unref (caps);
1058 * gst_caps_is_equal:
1059 * @caps1: a #GstCaps
1060 * @caps2: another #GstCaps
1062 * Checks if the given caps represent the same set of caps.
1063 * <note>This function does not work reliably if optional properties for caps
1064 * are included on one caps and omitted on the other.</note>
1066 * This function deals correctly with passing NULL for any of the caps.
1068 * Returns: TRUE if both caps are equal.
1071 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1073 /* NULL <-> NULL is allowed here */
1077 /* one of them NULL => they are different (can't be both NULL because
1078 * we checked that above) */
1079 if (caps1 == NULL || caps2 == NULL)
1082 if (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2))
1083 return gst_caps_is_equal_fixed (caps1, caps2);
1085 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1091 const GstStructure *intersect;
1097 gst_caps_structure_intersect_field (GQuark id, const GValue * val1,
1100 IntersectData *idata = (IntersectData *) data;
1101 GValue dest_value = { 0 };
1102 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1105 gst_structure_id_set_value (idata->dest, id, val1);
1106 } else if (idata->first_run) {
1107 if (gst_value_intersect (&dest_value, val1, val2)) {
1108 gst_structure_id_set_value (idata->dest, id, &dest_value);
1109 g_value_unset (&dest_value);
1118 static GstStructure *
1119 gst_caps_structure_intersect (const GstStructure * struct1,
1120 const GstStructure * struct2)
1124 g_return_val_if_fail (struct1 != NULL, NULL);
1125 g_return_val_if_fail (struct2 != NULL, NULL);
1127 if (struct1->name != struct2->name)
1130 data.dest = gst_structure_id_empty_new (struct1->name);
1131 data.intersect = struct2;
1132 data.first_run = TRUE;
1133 if (!gst_structure_foreach ((GstStructure *) struct1,
1134 gst_caps_structure_intersect_field, &data))
1137 data.intersect = struct1;
1138 data.first_run = FALSE;
1139 if (!gst_structure_foreach ((GstStructure *) struct2,
1140 gst_caps_structure_intersect_field, &data))
1146 gst_structure_free (data.dest);
1151 static GstStructure *
1152 gst_caps_structure_union (const GstStructure * struct1,
1153 const GstStructure * struct2)
1157 const GstStructureField *field1;
1158 const GstStructureField *field2;
1161 /* FIXME this doesn't actually work */
1163 if (struct1->name != struct2->name)
1166 dest = gst_structure_id_empty_new (struct1->name);
1168 for (i = 0; i < struct1->fields->len; i++) {
1169 GValue dest_value = { 0 };
1171 field1 = GST_STRUCTURE_FIELD (struct1, i);
1172 field2 = gst_structure_id_get_field (struct2, field1->name);
1174 if (field2 == NULL) {
1177 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1178 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1181 ret = gst_value_compare (&field1->value, &field2->value);
1193 * gst_caps_intersect:
1194 * @caps1: a #GstCaps to intersect
1195 * @caps2: a #GstCaps to intersect
1197 * Creates a new #GstCaps that contains all the formats that are common
1198 * to both @caps1 and @caps2.
1200 * Returns: the new #GstCaps
1203 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1205 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1208 GstStructure *struct1;
1209 GstStructure *struct2;
1211 GstStructure *istruct;
1213 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1214 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1216 if (gst_caps_is_empty (caps1) || gst_caps_is_empty (caps2)) {
1217 return gst_caps_new_empty ();
1219 if (gst_caps_is_any (caps1))
1220 return gst_caps_copy (caps2);
1221 if (gst_caps_is_any (caps2))
1222 return gst_caps_copy (caps1);
1224 dest = gst_caps_new_empty ();
1226 /* run zigzag on top line then right line, this preserves the caps order
1227 * much better than a simple loop.
1229 * This algorithm zigzags over the caps structures as demonstrated in
1230 * the folowing matrix:
1238 * First we iterate over the caps1 structures (top line) intersecting
1239 * the structures diagonally down, then we iterate over the caps2
1242 for (i = 0; i < caps1->structs->len + caps2->structs->len - 1; i++) {
1243 /* caps1 index goes from 0 to caps1->structs->len-1 */
1244 j = MIN (i, caps1->structs->len - 1);
1245 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1246 * up from 1 to caps2->structs->len - 1 */
1249 /* now run the diagonal line, end condition is the left or bottom
1251 while (k < caps2->structs->len) {
1252 struct1 = gst_caps_get_structure (caps1, j);
1253 struct2 = gst_caps_get_structure (caps2, k);
1255 istruct = gst_caps_structure_intersect (struct1, struct2);
1257 gst_caps_append_structure (dest, istruct);
1258 /* move down left */
1261 break; /* so we don't roll back to G_MAXUINT */
1270 const GstStructure *subtract_from;
1277 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1280 SubtractionEntry *e = user_data;
1281 GValue subtraction = { 0, };
1282 const GValue *other;
1283 GstStructure *structure;
1285 other = gst_structure_id_get_value (e->subtract_from, field_id);
1289 if (!gst_value_subtract (&subtraction, other, value))
1291 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1292 g_value_unset (&subtraction);
1295 structure = gst_structure_copy (e->subtract_from);
1296 gst_structure_id_set_value (structure, field_id, &subtraction);
1297 g_value_unset (&subtraction);
1298 e->put_into = g_slist_prepend (e->put_into, structure);
1304 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1305 const GstStructure * subtrahend)
1310 e.subtract_from = minuend;
1313 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1314 gst_caps_structure_subtract_field, &e);
1320 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1321 gst_structure_free (walk->data);
1323 g_slist_free (e.put_into);
1329 * gst_caps_subtract:
1330 * @minuend: #GstCaps to substract from
1331 * @subtrahend: #GstCaps to substract
1333 * Subtracts the @subtrahend from the @minuend.
1334 * <note>This function does not work reliably if optional properties for caps
1335 * are included on one caps and omitted on the other.</note>
1337 * Returns: the resulting caps
1340 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1345 GstCaps *dest = NULL, *src;
1347 g_return_val_if_fail (minuend != NULL, NULL);
1348 g_return_val_if_fail (subtrahend != NULL, NULL);
1350 if (gst_caps_is_empty (minuend) || gst_caps_is_any (subtrahend)) {
1351 return gst_caps_new_empty ();
1353 if (gst_caps_is_empty (subtrahend))
1354 return gst_caps_copy (minuend);
1356 /* FIXME: Do we want this here or above?
1357 The reason we need this is that there is no definition about what
1358 ANY means for specific types, so it's not possible to reduce ANY partially
1359 You can only remove everything or nothing and that is done above.
1360 Note: there's a test that checks this behaviour. */
1361 g_return_val_if_fail (!gst_caps_is_any (minuend), NULL);
1362 g_assert (subtrahend->structs->len > 0);
1364 src = gst_caps_copy (minuend);
1365 for (i = 0; i < subtrahend->structs->len; i++) {
1366 sub = gst_caps_get_structure (subtrahend, i);
1368 gst_caps_unref (src);
1371 dest = gst_caps_new_empty ();
1372 for (j = 0; j < src->structs->len; j++) {
1373 min = gst_caps_get_structure (src, j);
1374 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1377 if (gst_caps_structure_subtract (&list, min, sub)) {
1380 for (walk = list; walk; walk = g_slist_next (walk)) {
1381 gst_caps_append_structure (dest, (GstStructure *) walk->data);
1383 g_slist_free (list);
1385 gst_caps_append_structure (dest, gst_structure_copy (min));
1388 gst_caps_append_structure (dest, gst_structure_copy (min));
1391 if (gst_caps_is_empty (dest)) {
1392 gst_caps_unref (src);
1397 gst_caps_unref (src);
1398 gst_caps_do_simplify (dest);
1404 * @caps1: a #GstCaps to union
1405 * @caps2: a #GstCaps to union
1407 * Creates a new #GstCaps that contains all the formats that are in
1408 * either @caps1 and @caps2.
1410 * Returns: the new #GstCaps
1413 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1418 if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2))
1419 return gst_caps_new_any ();
1421 dest1 = gst_caps_copy (caps1);
1422 dest2 = gst_caps_copy (caps2);
1423 gst_caps_append (dest1, dest2);
1425 gst_caps_do_simplify (dest1);
1429 typedef struct _NormalizeForeach
1432 GstStructure *structure;
1437 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1439 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1443 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1444 for (i = 1; i < gst_value_list_get_size (value); i++) {
1445 const GValue *v = gst_value_list_get_value (value, i);
1446 GstStructure *structure = gst_structure_copy (nf->structure);
1448 gst_structure_id_set_value (structure, field_id, v);
1449 gst_caps_append_structure (nf->caps, structure);
1452 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1453 gst_structure_id_set_value (nf->structure, field_id, &val);
1454 g_value_unset (&val);
1462 * gst_caps_normalize:
1463 * @caps: a #GstCaps to normalize
1465 * Creates a new #GstCaps that represents the same set of formats as
1466 * @caps, but contains no lists. Each list is expanded into separate
1469 * Returns: the new #GstCaps
1472 gst_caps_normalize (const GstCaps * caps)
1474 NormalizeForeach nf;
1478 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1480 newcaps = gst_caps_copy (caps);
1483 for (i = 0; i < newcaps->structs->len; i++) {
1484 nf.structure = gst_caps_get_structure (newcaps, i);
1486 while (!gst_structure_foreach (nf.structure,
1487 gst_caps_normalize_foreach, &nf));
1494 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1497 const GstStructure *struct1 = *((const GstStructure **) one);
1498 const GstStructure *struct2 = *((const GstStructure **) two);
1500 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1501 So what's the best way? */
1502 ret = strcmp (gst_structure_get_name (struct1),
1503 gst_structure_get_name (struct2));
1507 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1514 GstStructure *compare;
1519 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1522 UnionField *u = user_data;
1523 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1527 g_value_unset (&u->value);
1530 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1533 g_value_unset (&u->value);
1537 gst_value_union (&u->value, val, value);
1542 gst_caps_structure_simplify (GstStructure ** result,
1543 const GstStructure * simplify, GstStructure * compare)
1546 UnionField field = { 0, {0,}, NULL };
1548 /* try to subtract to get a real subset */
1549 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1550 switch (g_slist_length (list)) {
1555 *result = list->data;
1556 g_slist_free (list);
1562 for (walk = list; walk; walk = g_slist_next (walk)) {
1563 gst_structure_free (walk->data);
1565 g_slist_free (list);
1571 /* try to union both structs */
1572 field.compare = compare;
1573 if (gst_structure_foreach ((GstStructure *) simplify,
1574 gst_caps_structure_figure_out_union, &field)) {
1575 gboolean ret = FALSE;
1577 /* now we know all of simplify's fields are the same in compare
1578 * but at most one field: field.name */
1579 if (G_IS_VALUE (&field.value)) {
1580 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1581 gst_structure_id_set_value (compare, field.name, &field.value);
1585 g_value_unset (&field.value);
1586 } else if (gst_structure_n_fields (simplify) <=
1587 gst_structure_n_fields (compare)) {
1588 /* compare is just more specific, will be optimized away later */
1589 /* FIXME: do this here? */
1590 GST_LOG ("found a case that will be optimized later.");
1592 gchar *one = gst_structure_to_string (simplify);
1593 gchar *two = gst_structure_to_string (compare);
1596 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1608 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1609 GstStructure * new, gint i)
1611 gst_structure_set_parent_refcount (old, NULL);
1612 gst_structure_free (old);
1613 gst_structure_set_parent_refcount (new, &caps->refcount);
1614 g_ptr_array_index (caps->structs, i) = new;
1618 * gst_caps_do_simplify:
1619 * @caps: a #GstCaps to simplify
1621 * Modifies the given @caps inplace into a representation that represents the
1622 * same set of formats, but in a simpler form. Component structures that are
1623 * identical are merged. Component structures that have values that can be
1624 * merged are also merged.
1626 * Returns: TRUE, if the caps could be simplified
1629 gst_caps_do_simplify (GstCaps * caps)
1631 GstStructure *simplify, *compare, *result = NULL;
1633 gboolean changed = FALSE;
1635 g_return_val_if_fail (caps != NULL, FALSE);
1636 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1638 if (gst_caps_get_size (caps) < 2)
1641 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1643 start = caps->structs->len - 1;
1644 for (i = caps->structs->len - 1; i >= 0; i--) {
1645 simplify = gst_caps_get_structure (caps, i);
1646 if (gst_structure_get_name_id (simplify) !=
1647 gst_structure_get_name_id (gst_caps_get_structure (caps, start)))
1649 for (j = start; j >= 0; j--) {
1652 compare = gst_caps_get_structure (caps, j);
1653 if (gst_structure_get_name_id (simplify) !=
1654 gst_structure_get_name_id (compare)) {
1657 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1659 gst_caps_switch_structures (caps, simplify, result, i);
1662 gst_caps_remove_structure (caps, i);
1674 /* gst_caps_do_simplify (caps); */
1678 #ifndef GST_DISABLE_LOADSAVE
1680 * gst_caps_save_thyself:
1681 * @caps: a #GstCaps structure
1682 * @parent: a XML parent node
1684 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
1686 * Returns: a XML node pointer
1689 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
1691 char *s = gst_caps_to_string (caps);
1693 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
1699 * gst_caps_load_thyself:
1700 * @parent: a XML node
1702 * Creates a #GstCaps from its XML serialization.
1704 * Returns: a new #GstCaps structure
1707 gst_caps_load_thyself (xmlNodePtr parent)
1709 if (strcmp ("caps", (char *) parent->name) == 0) {
1710 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
1721 * @caps: a pointer to #GstCaps
1722 * @newcaps: a #GstCaps to replace *caps
1724 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
1725 * pointed to by @caps, if applicable, then modifies @caps to point to
1726 * @newcaps. An additional ref on @newcaps is taken.
1728 * This function does not take any locks so you might want to lock
1729 * the object owning @caps pointer.
1732 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
1736 g_return_if_fail (caps != NULL);
1740 if (newcaps != oldcaps) {
1742 gst_caps_ref (newcaps);
1747 gst_caps_unref (oldcaps);
1752 * gst_caps_to_string:
1755 * Converts @caps to a string representation. This string representation
1756 * can be converted back to a #GstCaps by gst_caps_from_string().
1758 * For debugging purposes its easier to do something like this:
1760 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
1762 * This prints the caps in human readble form.
1764 * Returns: a newly allocated string representing @caps.
1767 gst_caps_to_string (const GstCaps * caps)
1772 /* NOTE: This function is potentially called by the debug system,
1773 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
1774 * should be careful to avoid recursion. This includes any functions
1775 * called by gst_caps_to_string. In particular, calls should
1776 * not use the GST_PTR_FORMAT extension. */
1779 return g_strdup ("NULL");
1781 if (gst_caps_is_any (caps)) {
1782 return g_strdup ("ANY");
1784 if (gst_caps_is_empty (caps)) {
1785 return g_strdup ("EMPTY");
1788 s = g_string_new ("");
1789 for (i = 0; i < caps->structs->len; i++) {
1790 GstStructure *structure;
1794 g_string_append (s, "; ");
1796 structure = gst_caps_get_structure (caps, i);
1797 sstr = gst_structure_to_string (structure);
1798 g_string_append (s, sstr);
1802 return g_string_free (s, FALSE);
1806 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
1808 GstStructure *structure;
1811 g_return_val_if_fail (string, FALSE);
1812 if (strcmp ("ANY", string) == 0) {
1813 caps->flags = GST_CAPS_FLAGS_ANY;
1816 if (strcmp ("EMPTY", string) == 0) {
1820 structure = gst_structure_from_string (string, &s);
1821 if (structure == NULL) {
1824 gst_caps_append_structure (caps, structure);
1828 while (g_ascii_isspace (*s))
1830 structure = gst_structure_from_string (s, &s);
1831 if (structure == NULL) {
1834 gst_caps_append_structure (caps, structure);
1835 while (g_ascii_isspace (*s))
1847 * gst_caps_from_string:
1848 * @string: a string to convert to #GstCaps
1850 * Converts @caps from a string representation.
1852 * Returns: a newly allocated #GstCaps
1855 gst_caps_from_string (const gchar * string)
1859 caps = gst_caps_new_empty ();
1860 if (gst_caps_from_string_inplace (caps, string)) {
1863 gst_caps_unref (caps);
1869 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
1871 g_return_if_fail (G_IS_VALUE (src_value));
1872 g_return_if_fail (G_IS_VALUE (dest_value));
1873 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
1874 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
1875 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
1877 dest_value->data[0].v_pointer =
1878 gst_caps_to_string (src_value->data[0].v_pointer);
1882 gst_caps_copy_conditional (GstCaps * src)
1885 return gst_caps_ref (src);