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"
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;
460 temp.structs = g_ptr_array_new ();
462 /* initialize the caps to a refcount of 1 so the caps can be writable for
463 * the next statement */
464 gst_atomic_int_set (&temp.refcount, 1);
466 /* convert to string */
467 if (G_UNLIKELY (!gst_caps_from_string_inplace (&temp, string)))
468 g_critical ("Could not convert static caps \"%s\"", string);
470 /* now copy stuff over to the real caps. */
471 caps->type = temp.type;
472 caps->flags = temp.flags;
473 caps->structs = temp.structs;
474 /* and bump the refcount so other threads can now read */
475 gst_atomic_int_set (&caps->refcount, 1);
477 GST_CAT_LOG (GST_CAT_CAPS, "created %p", static_caps);
479 G_UNLOCK (static_caps_lock);
481 /* ref the caps, makes it not writable */
489 G_UNLOCK (static_caps_lock);
490 g_warning ("static caps %p string is NULL", static_caps);
496 static GstStructure *
497 gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
499 /* don't use index_fast, gst_caps_do_simplify relies on the order */
500 GstStructure *s = g_ptr_array_remove_index (caps->structs, idx);
502 gst_structure_set_parent_refcount (s, NULL);
507 gst_structure_is_equal_foreach (GQuark field_id, const GValue * val2,
510 GstStructure *struct1 = (GstStructure *) data;
511 const GValue *val1 = gst_structure_id_get_value (struct1, field_id);
515 if (gst_value_compare (val1, val2) == GST_VALUE_EQUAL) {
523 gst_caps_structure_is_subset_field (GQuark field_id, const GValue * value,
526 GstStructure *subtract_from = user_data;
527 GValue subtraction = { 0, };
531 other = gst_structure_id_get_value (subtract_from, field_id);
533 /* field is missing in one set */
540 if (!gst_value_subtract (&subtraction, other, value)) {
541 /* empty result -> values are the same, or first was a value and
543 * verify that result is empty by swapping args */
544 if (!gst_value_subtract (&subtraction, value, other)) {
547 g_value_unset (&subtraction);
551 res = gst_value_compare (&subtraction, other);
552 g_value_unset (&subtraction);
554 if (res == GST_VALUE_EQUAL) {
555 /* value was empty ? */
563 gst_caps_structure_is_subset (const GstStructure * minuend,
564 const GstStructure * subtrahend)
566 if ((minuend->name != subtrahend->name) ||
567 (gst_structure_n_fields (minuend) !=
568 gst_structure_n_fields (subtrahend))) {
572 return gst_structure_foreach ((GstStructure *) subtrahend,
573 gst_caps_structure_is_subset_field, (gpointer) minuend);
578 * @caps1: the #GstCaps that will be appended to
579 * @caps2: the #GstCaps to append
581 * Appends the structures contained in @caps2 to @caps1. The structures in
582 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
583 * freed. If either caps is ANY, the resulting caps will be ANY.
586 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
588 GstStructure *structure;
591 g_return_if_fail (GST_IS_CAPS (caps1));
592 g_return_if_fail (GST_IS_CAPS (caps2));
593 g_return_if_fail (IS_WRITABLE (caps1));
594 g_return_if_fail (IS_WRITABLE (caps2));
599 if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2)) {
600 /* FIXME: this leaks */
601 caps1->flags |= GST_CAPS_FLAGS_ANY;
602 for (i = caps2->structs->len - 1; i >= 0; i--) {
603 structure = gst_caps_remove_and_get_structure (caps2, i);
604 gst_structure_free (structure);
607 int len = caps2->structs->len;
609 for (i = 0; i < len; i++) {
610 structure = gst_caps_remove_and_get_structure (caps2, 0);
611 gst_caps_append_structure (caps1, structure);
614 gst_caps_unref (caps2); /* guaranteed to free it */
619 * @caps1: the #GstCaps that will take the new entries
620 * @caps2: the #GstCaps to merge in
622 * Appends the structures contained in @caps2 to @caps1 if they are not yet
623 * expressed by @caps1. The structures in @caps2 are not copied -- they are
624 * transferred to @caps1, and then @caps2 is freed.
625 * If either caps is ANY, the resulting caps will be ANY.
630 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
632 GstStructure *structure;
635 g_return_if_fail (GST_IS_CAPS (caps1));
636 g_return_if_fail (GST_IS_CAPS (caps2));
637 g_return_if_fail (IS_WRITABLE (caps1));
638 g_return_if_fail (IS_WRITABLE (caps2));
643 if (gst_caps_is_any (caps1)) {
644 for (i = caps2->structs->len - 1; i >= 0; i--) {
645 structure = gst_caps_remove_and_get_structure (caps2, i);
646 gst_structure_free (structure);
648 } else if (gst_caps_is_any (caps2)) {
649 caps1->flags |= GST_CAPS_FLAGS_ANY;
650 for (i = caps1->structs->len - 1; i >= 0; i--) {
651 structure = gst_caps_remove_and_get_structure (caps1, i);
652 gst_structure_free (structure);
655 int len = caps2->structs->len;
657 for (i = 0; i < len; i++) {
658 structure = gst_caps_remove_and_get_structure (caps2, 0);
659 gst_caps_merge_structure (caps1, structure);
662 GstCaps *com = gst_caps_intersect (caps1, caps2);
663 GstCaps *add = gst_caps_subtract (caps2, com);
665 GST_DEBUG ("common : %d", gst_caps_get_size (com));
666 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
667 gst_caps_append (caps1, add);
668 gst_caps_unref (com);
671 gst_caps_unref (caps2); /* guaranteed to free it */
675 * gst_caps_append_structure:
676 * @caps: the #GstCaps that will be appended to
677 * @structure: the #GstStructure to append
679 * Appends @structure to @caps. The structure is not copied; @caps
680 * becomes the owner of @structure.
683 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
685 g_return_if_fail (GST_IS_CAPS (caps));
686 g_return_if_fail (IS_WRITABLE (caps));
688 if (G_LIKELY (structure)) {
689 g_return_if_fail (structure->parent_refcount == NULL);
692 STRUCTURE_POISON (structure);
695 gst_structure_set_parent_refcount (structure, &caps->refcount);
696 g_ptr_array_add (caps->structs, structure);
701 * gst_caps_remove_structure:
702 * @caps: the #GstCaps to remove from
703 * @idx: Index of the structure to remove
705 * removes the stucture with the given index from the list of structures
706 * contained in @caps.
709 gst_caps_remove_structure (GstCaps * caps, guint idx)
711 GstStructure *structure;
713 g_return_if_fail (caps != NULL);
714 g_return_if_fail (idx <= gst_caps_get_size (caps));
715 g_return_if_fail (IS_WRITABLE (caps));
717 structure = gst_caps_remove_and_get_structure (caps, idx);
718 gst_structure_free (structure);
722 * gst_caps_merge_structure:
723 * @caps: the #GstCaps that will the the new structure
724 * @structure: the #GstStructure to merge
726 * Appends @structure to @caps if its not already expressed by @caps. The
727 * structure is not copied; @caps becomes the owner of @structure.
730 gst_caps_merge_structure (GstCaps * caps, GstStructure * structure)
732 g_return_if_fail (GST_IS_CAPS (caps));
733 g_return_if_fail (IS_WRITABLE (caps));
735 if (G_LIKELY (structure)) {
736 GstStructure *structure1;
738 gboolean unique = TRUE;
740 g_return_if_fail (structure->parent_refcount == NULL);
743 STRUCTURE_POISON (structure);
746 /* check each structure */
747 for (i = caps->structs->len - 1; i >= 0; i--) {
748 structure1 = gst_caps_get_structure (caps, i);
749 /* if structure is a subset of structure1, then skip it */
750 if (gst_caps_structure_is_subset (structure1, structure)) {
756 gst_structure_set_parent_refcount (structure, &caps->refcount);
757 g_ptr_array_add (caps->structs, structure);
759 gst_structure_free (structure);
769 * Gets the number of structures contained in @caps.
771 * Returns: the number of structures that @caps contains
774 gst_caps_get_size (const GstCaps * caps)
776 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
778 return caps->structs->len;
782 * gst_caps_get_structure:
784 * @index: the index of the structure
786 * Finds the structure in @caps that has the index @index, and
789 * WARNING: This function takes a const GstCaps *, but returns a
790 * non-const GstStructure *. This is for programming convenience --
791 * the caller should be aware that structures inside a constant
792 * #GstCaps should not be modified.
794 * Returns: a pointer to the #GstStructure corresponding to @index
797 gst_caps_get_structure (const GstCaps * caps, guint index)
799 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
800 g_return_val_if_fail (index < caps->structs->len, NULL);
802 return g_ptr_array_index (caps->structs, index);
807 * @caps: the #GstCaps to copy
808 * @nth: the nth structure to copy
810 * Creates a new #GstCaps and appends a copy of the nth structure
811 * contained in @caps.
813 * Returns: the new #GstCaps
816 gst_caps_copy_nth (const GstCaps * caps, guint nth)
819 GstStructure *structure;
821 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
823 newcaps = gst_caps_new_empty ();
824 newcaps->flags = caps->flags;
826 if (caps->structs->len > nth) {
827 structure = gst_caps_get_structure (caps, nth);
828 gst_caps_append_structure (newcaps, gst_structure_copy (structure));
836 * @caps: the #GstCaps to truncate
838 * Destructively discard all but the first structure from @caps. Useful when
839 * fixating. @caps must be writable.
842 gst_caps_truncate (GstCaps * caps)
846 g_return_if_fail (GST_IS_CAPS (caps));
847 g_return_if_fail (IS_WRITABLE (caps));
849 i = caps->structs->len - 1;
852 gst_caps_remove_structure (caps, i--);
856 * gst_caps_set_simple:
857 * @caps: the #GstCaps to set
858 * @field: first field to set
859 * @...: additional parameters
861 * Sets fields in a simple #GstCaps. A simple #GstCaps is one that
862 * only has one structure. The arguments must be passed in the same
863 * manner as gst_structure_set(), and be NULL-terminated.
866 gst_caps_set_simple (GstCaps * caps, char *field, ...)
868 GstStructure *structure;
871 g_return_if_fail (GST_IS_CAPS (caps));
872 g_return_if_fail (caps->structs->len == 1);
873 g_return_if_fail (IS_WRITABLE (caps));
875 structure = gst_caps_get_structure (caps, 0);
877 va_start (var_args, field);
878 gst_structure_set_valist (structure, field, var_args);
883 * gst_caps_set_simple_valist:
884 * @caps: the #GstCaps to copy
885 * @field: first field to set
886 * @varargs: additional parameters
888 * Sets fields in a simple #GstCaps. A simple #GstCaps is one that
889 * only has one structure. The arguments must be passed in the same
890 * manner as gst_structure_set(), and be NULL-terminated.
893 gst_caps_set_simple_valist (GstCaps * caps, char *field, va_list varargs)
895 GstStructure *structure;
897 g_return_if_fail (GST_IS_CAPS (caps));
898 g_return_if_fail (caps->structs->len == 1);
899 g_return_if_fail (IS_WRITABLE (caps));
901 structure = gst_caps_get_structure (caps, 0);
903 gst_structure_set_valist (structure, field, varargs);
910 * @caps: the #GstCaps to test
912 * Determines if @caps represents any media format.
914 * Returns: TRUE if @caps represents any format.
917 gst_caps_is_any (const GstCaps * caps)
919 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
921 return (caps->flags & GST_CAPS_FLAGS_ANY);
926 * @caps: the #GstCaps to test
928 * Determines if @caps represents no media formats.
930 * Returns: TRUE if @caps represents no formats.
933 gst_caps_is_empty (const GstCaps * caps)
935 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
937 if (caps->flags & GST_CAPS_FLAGS_ANY)
940 return (caps->structs == NULL) || (caps->structs->len == 0);
944 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
947 return gst_value_is_fixed (value);
952 * @caps: the #GstCaps to test
954 * Fixed #GstCaps describe exactly one format, that is, they have exactly
955 * one structure, and each field in the structure describes a fixed type.
956 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
958 * Returns: TRUE if @caps is fixed
961 gst_caps_is_fixed (const GstCaps * caps)
963 GstStructure *structure;
965 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
967 if (caps->structs->len != 1)
970 structure = gst_caps_get_structure (caps, 0);
972 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
976 * gst_caps_is_equal_fixed:
977 * @caps1: the #GstCaps to test
978 * @caps2: the #GstCaps to test
980 * Tests if two #GstCaps are equal. This function only works on fixed
983 * Returns: TRUE if the arguments represent the same format
986 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
988 GstStructure *struct1, *struct2;
990 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
991 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
993 struct1 = gst_caps_get_structure (caps1, 0);
994 struct2 = gst_caps_get_structure (caps2, 0);
996 if (struct1->name != struct2->name) {
999 if (struct1->fields->len != struct2->fields->len) {
1003 return gst_structure_foreach (struct1, gst_structure_is_equal_foreach,
1008 * gst_caps_is_always_compatible:
1009 * @caps1: the #GstCaps to test
1010 * @caps2: the #GstCaps to test
1012 * A given #GstCaps structure is always compatible with another if
1013 * every media format that is in the first is also contained in the
1014 * second. That is, @caps1 is a subset of @caps2.
1016 * Returns: TRUE if @caps1 is a subset of @caps2.
1019 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
1021 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1022 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1024 return gst_caps_is_subset (caps1, caps2);
1028 * gst_caps_is_subset:
1029 * @subset: a #GstCaps
1030 * @superset: a potentially greater #GstCaps
1032 * Checks if all caps represented by @subset are also represented by @superset.
1033 * <note>This function does not work reliably if optional properties for caps
1034 * are included on one caps and omitted on the other.</note>
1036 * Returns: %TRUE if @subset is a subset of @superset
1039 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
1044 g_return_val_if_fail (subset != NULL, FALSE);
1045 g_return_val_if_fail (superset != NULL, FALSE);
1047 if (gst_caps_is_empty (subset) || gst_caps_is_any (superset))
1049 if (gst_caps_is_any (subset) || gst_caps_is_empty (superset))
1052 caps = gst_caps_subtract (subset, superset);
1053 ret = gst_caps_is_empty (caps);
1054 gst_caps_unref (caps);
1059 * gst_caps_is_equal:
1060 * @caps1: a #GstCaps
1061 * @caps2: another #GstCaps
1063 * Checks if the given caps represent the same set of caps.
1064 * <note>This function does not work reliably if optional properties for caps
1065 * are included on one caps and omitted on the other.</note>
1067 * This function deals correctly with passing NULL for any of the caps.
1069 * Returns: TRUE if both caps are equal.
1072 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1074 /* NULL <-> NULL is allowed here */
1078 /* one of them NULL => they are different (can't be both NULL because
1079 * we checked that above) */
1080 if (caps1 == NULL || caps2 == NULL)
1083 if (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2))
1084 return gst_caps_is_equal_fixed (caps1, caps2);
1086 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1092 const GstStructure *intersect;
1098 gst_caps_structure_intersect_field (GQuark id, const GValue * val1,
1101 IntersectData *idata = (IntersectData *) data;
1102 GValue dest_value = { 0 };
1103 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1106 gst_structure_id_set_value (idata->dest, id, val1);
1107 } else if (idata->first_run) {
1108 if (gst_value_intersect (&dest_value, val1, val2)) {
1109 gst_structure_id_set_value (idata->dest, id, &dest_value);
1110 g_value_unset (&dest_value);
1119 static GstStructure *
1120 gst_caps_structure_intersect (const GstStructure * struct1,
1121 const GstStructure * struct2)
1125 g_return_val_if_fail (struct1 != NULL, NULL);
1126 g_return_val_if_fail (struct2 != NULL, NULL);
1128 if (struct1->name != struct2->name)
1131 data.dest = gst_structure_id_empty_new (struct1->name);
1132 data.intersect = struct2;
1133 data.first_run = TRUE;
1134 if (!gst_structure_foreach ((GstStructure *) struct1,
1135 gst_caps_structure_intersect_field, &data))
1138 data.intersect = struct1;
1139 data.first_run = FALSE;
1140 if (!gst_structure_foreach ((GstStructure *) struct2,
1141 gst_caps_structure_intersect_field, &data))
1147 gst_structure_free (data.dest);
1152 static GstStructure *
1153 gst_caps_structure_union (const GstStructure * struct1,
1154 const GstStructure * struct2)
1158 const GstStructureField *field1;
1159 const GstStructureField *field2;
1162 /* FIXME this doesn't actually work */
1164 if (struct1->name != struct2->name)
1167 dest = gst_structure_id_empty_new (struct1->name);
1169 for (i = 0; i < struct1->fields->len; i++) {
1170 GValue dest_value = { 0 };
1172 field1 = GST_STRUCTURE_FIELD (struct1, i);
1173 field2 = gst_structure_id_get_field (struct2, field1->name);
1175 if (field2 == NULL) {
1178 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1179 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1182 ret = gst_value_compare (&field1->value, &field2->value);
1194 * gst_caps_intersect:
1195 * @caps1: a #GstCaps to intersect
1196 * @caps2: a #GstCaps to intersect
1198 * Creates a new #GstCaps that contains all the formats that are common
1199 * to both @caps1 and @caps2.
1201 * Returns: the new #GstCaps
1204 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1206 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1209 GstStructure *struct1;
1210 GstStructure *struct2;
1212 GstStructure *istruct;
1214 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1215 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1217 /* caps are exactly the same pointers, just copy one caps */
1219 return gst_caps_copy (caps1);
1221 /* empty caps on either side, return empty */
1222 if (gst_caps_is_empty (caps1) || gst_caps_is_empty (caps2))
1223 return gst_caps_new_empty ();
1225 /* one of the caps is any, just copy the other caps */
1226 if (gst_caps_is_any (caps1))
1227 return gst_caps_copy (caps2);
1228 if (gst_caps_is_any (caps2))
1229 return gst_caps_copy (caps1);
1231 dest = gst_caps_new_empty ();
1233 /* run zigzag on top line then right line, this preserves the caps order
1234 * much better than a simple loop.
1236 * This algorithm zigzags over the caps structures as demonstrated in
1237 * the folowing matrix:
1245 * First we iterate over the caps1 structures (top line) intersecting
1246 * the structures diagonally down, then we iterate over the caps2
1249 for (i = 0; i < caps1->structs->len + caps2->structs->len - 1; i++) {
1250 /* caps1 index goes from 0 to caps1->structs->len-1 */
1251 j = MIN (i, caps1->structs->len - 1);
1252 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1253 * up from 1 to caps2->structs->len - 1 */
1256 /* now run the diagonal line, end condition is the left or bottom
1258 while (k < caps2->structs->len) {
1259 struct1 = gst_caps_get_structure (caps1, j);
1260 struct2 = gst_caps_get_structure (caps2, k);
1262 istruct = gst_caps_structure_intersect (struct1, struct2);
1264 gst_caps_append_structure (dest, istruct);
1265 /* move down left */
1268 break; /* so we don't roll back to G_MAXUINT */
1277 const GstStructure *subtract_from;
1284 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1287 SubtractionEntry *e = user_data;
1288 GValue subtraction = { 0, };
1289 const GValue *other;
1290 GstStructure *structure;
1292 other = gst_structure_id_get_value (e->subtract_from, field_id);
1296 if (!gst_value_subtract (&subtraction, other, value))
1298 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1299 g_value_unset (&subtraction);
1302 structure = gst_structure_copy (e->subtract_from);
1303 gst_structure_id_set_value (structure, field_id, &subtraction);
1304 g_value_unset (&subtraction);
1305 e->put_into = g_slist_prepend (e->put_into, structure);
1311 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1312 const GstStructure * subtrahend)
1317 e.subtract_from = minuend;
1320 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1321 gst_caps_structure_subtract_field, &e);
1327 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1328 gst_structure_free (walk->data);
1330 g_slist_free (e.put_into);
1336 * gst_caps_subtract:
1337 * @minuend: #GstCaps to substract from
1338 * @subtrahend: #GstCaps to substract
1340 * Subtracts the @subtrahend from the @minuend.
1341 * <note>This function does not work reliably if optional properties for caps
1342 * are included on one caps and omitted on the other.</note>
1344 * Returns: the resulting caps
1347 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1352 GstCaps *dest = NULL, *src;
1354 g_return_val_if_fail (minuend != NULL, NULL);
1355 g_return_val_if_fail (subtrahend != NULL, NULL);
1357 if (gst_caps_is_empty (minuend) || gst_caps_is_any (subtrahend)) {
1358 return gst_caps_new_empty ();
1360 if (gst_caps_is_empty (subtrahend))
1361 return gst_caps_copy (minuend);
1363 /* FIXME: Do we want this here or above?
1364 The reason we need this is that there is no definition about what
1365 ANY means for specific types, so it's not possible to reduce ANY partially
1366 You can only remove everything or nothing and that is done above.
1367 Note: there's a test that checks this behaviour. */
1368 g_return_val_if_fail (!gst_caps_is_any (minuend), NULL);
1369 g_assert (subtrahend->structs->len > 0);
1371 src = gst_caps_copy (minuend);
1372 for (i = 0; i < subtrahend->structs->len; i++) {
1373 sub = gst_caps_get_structure (subtrahend, i);
1375 gst_caps_unref (src);
1378 dest = gst_caps_new_empty ();
1379 for (j = 0; j < src->structs->len; j++) {
1380 min = gst_caps_get_structure (src, j);
1381 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1384 if (gst_caps_structure_subtract (&list, min, sub)) {
1387 for (walk = list; walk; walk = g_slist_next (walk)) {
1388 gst_caps_append_structure (dest, (GstStructure *) walk->data);
1390 g_slist_free (list);
1392 gst_caps_append_structure (dest, gst_structure_copy (min));
1395 gst_caps_append_structure (dest, gst_structure_copy (min));
1398 if (gst_caps_is_empty (dest)) {
1399 gst_caps_unref (src);
1404 gst_caps_unref (src);
1405 gst_caps_do_simplify (dest);
1411 * @caps1: a #GstCaps to union
1412 * @caps2: a #GstCaps to union
1414 * Creates a new #GstCaps that contains all the formats that are in
1415 * either @caps1 and @caps2.
1417 * Returns: the new #GstCaps
1420 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1425 if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2))
1426 return gst_caps_new_any ();
1428 dest1 = gst_caps_copy (caps1);
1429 dest2 = gst_caps_copy (caps2);
1430 gst_caps_append (dest1, dest2);
1432 gst_caps_do_simplify (dest1);
1436 typedef struct _NormalizeForeach
1439 GstStructure *structure;
1444 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1446 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1450 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1451 for (i = 1; i < gst_value_list_get_size (value); i++) {
1452 const GValue *v = gst_value_list_get_value (value, i);
1453 GstStructure *structure = gst_structure_copy (nf->structure);
1455 gst_structure_id_set_value (structure, field_id, v);
1456 gst_caps_append_structure (nf->caps, structure);
1459 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1460 gst_structure_id_set_value (nf->structure, field_id, &val);
1461 g_value_unset (&val);
1469 * gst_caps_normalize:
1470 * @caps: a #GstCaps to normalize
1472 * Creates a new #GstCaps that represents the same set of formats as
1473 * @caps, but contains no lists. Each list is expanded into separate
1476 * Returns: the new #GstCaps
1479 gst_caps_normalize (const GstCaps * caps)
1481 NormalizeForeach nf;
1485 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1487 newcaps = gst_caps_copy (caps);
1490 for (i = 0; i < newcaps->structs->len; i++) {
1491 nf.structure = gst_caps_get_structure (newcaps, i);
1493 while (!gst_structure_foreach (nf.structure,
1494 gst_caps_normalize_foreach, &nf));
1501 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1504 const GstStructure *struct1 = *((const GstStructure **) one);
1505 const GstStructure *struct2 = *((const GstStructure **) two);
1507 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1508 So what's the best way? */
1509 ret = strcmp (gst_structure_get_name (struct1),
1510 gst_structure_get_name (struct2));
1514 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1521 GstStructure *compare;
1526 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1529 UnionField *u = user_data;
1530 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1534 g_value_unset (&u->value);
1537 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1540 g_value_unset (&u->value);
1544 gst_value_union (&u->value, val, value);
1549 gst_caps_structure_simplify (GstStructure ** result,
1550 const GstStructure * simplify, GstStructure * compare)
1553 UnionField field = { 0, {0,}, NULL };
1555 /* try to subtract to get a real subset */
1556 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1557 switch (g_slist_length (list)) {
1562 *result = list->data;
1563 g_slist_free (list);
1569 for (walk = list; walk; walk = g_slist_next (walk)) {
1570 gst_structure_free (walk->data);
1572 g_slist_free (list);
1578 /* try to union both structs */
1579 field.compare = compare;
1580 if (gst_structure_foreach ((GstStructure *) simplify,
1581 gst_caps_structure_figure_out_union, &field)) {
1582 gboolean ret = FALSE;
1584 /* now we know all of simplify's fields are the same in compare
1585 * but at most one field: field.name */
1586 if (G_IS_VALUE (&field.value)) {
1587 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1588 gst_structure_id_set_value (compare, field.name, &field.value);
1592 g_value_unset (&field.value);
1593 } else if (gst_structure_n_fields (simplify) <=
1594 gst_structure_n_fields (compare)) {
1595 /* compare is just more specific, will be optimized away later */
1596 /* FIXME: do this here? */
1597 GST_LOG ("found a case that will be optimized later.");
1599 gchar *one = gst_structure_to_string (simplify);
1600 gchar *two = gst_structure_to_string (compare);
1603 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1615 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1616 GstStructure * new, gint i)
1618 gst_structure_set_parent_refcount (old, NULL);
1619 gst_structure_free (old);
1620 gst_structure_set_parent_refcount (new, &caps->refcount);
1621 g_ptr_array_index (caps->structs, i) = new;
1625 * gst_caps_do_simplify:
1626 * @caps: a #GstCaps to simplify
1628 * Modifies the given @caps inplace into a representation that represents the
1629 * same set of formats, but in a simpler form. Component structures that are
1630 * identical are merged. Component structures that have values that can be
1631 * merged are also merged.
1633 * Returns: TRUE, if the caps could be simplified
1636 gst_caps_do_simplify (GstCaps * caps)
1638 GstStructure *simplify, *compare, *result = NULL;
1640 gboolean changed = FALSE;
1642 g_return_val_if_fail (caps != NULL, FALSE);
1643 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1645 if (gst_caps_get_size (caps) < 2)
1648 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1650 start = caps->structs->len - 1;
1651 for (i = caps->structs->len - 1; i >= 0; i--) {
1652 simplify = gst_caps_get_structure (caps, i);
1653 if (gst_structure_get_name_id (simplify) !=
1654 gst_structure_get_name_id (gst_caps_get_structure (caps, start)))
1656 for (j = start; j >= 0; j--) {
1659 compare = gst_caps_get_structure (caps, j);
1660 if (gst_structure_get_name_id (simplify) !=
1661 gst_structure_get_name_id (compare)) {
1664 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1666 gst_caps_switch_structures (caps, simplify, result, i);
1669 gst_caps_remove_structure (caps, i);
1681 /* gst_caps_do_simplify (caps); */
1685 #ifndef GST_DISABLE_LOADSAVE
1687 * gst_caps_save_thyself:
1688 * @caps: a #GstCaps structure
1689 * @parent: a XML parent node
1691 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
1693 * Returns: a XML node pointer
1696 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
1698 char *s = gst_caps_to_string (caps);
1700 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
1706 * gst_caps_load_thyself:
1707 * @parent: a XML node
1709 * Creates a #GstCaps from its XML serialization.
1711 * Returns: a new #GstCaps structure
1714 gst_caps_load_thyself (xmlNodePtr parent)
1716 if (strcmp ("caps", (char *) parent->name) == 0) {
1717 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
1728 * @caps: a pointer to #GstCaps
1729 * @newcaps: a #GstCaps to replace *caps
1731 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
1732 * pointed to by @caps, if applicable, then modifies @caps to point to
1733 * @newcaps. An additional ref on @newcaps is taken.
1735 * This function does not take any locks so you might want to lock
1736 * the object owning @caps pointer.
1739 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
1743 g_return_if_fail (caps != NULL);
1747 if (newcaps != oldcaps) {
1749 gst_caps_ref (newcaps);
1754 gst_caps_unref (oldcaps);
1759 * gst_caps_to_string:
1762 * Converts @caps to a string representation. This string representation
1763 * can be converted back to a #GstCaps by gst_caps_from_string().
1765 * For debugging purposes its easier to do something like this:
1767 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
1769 * This prints the caps in human readble form.
1771 * Returns: a newly allocated string representing @caps.
1774 gst_caps_to_string (const GstCaps * caps)
1779 /* NOTE: This function is potentially called by the debug system,
1780 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
1781 * should be careful to avoid recursion. This includes any functions
1782 * called by gst_caps_to_string. In particular, calls should
1783 * not use the GST_PTR_FORMAT extension. */
1786 return g_strdup ("NULL");
1788 if (gst_caps_is_any (caps)) {
1789 return g_strdup ("ANY");
1791 if (gst_caps_is_empty (caps)) {
1792 return g_strdup ("EMPTY");
1795 s = g_string_new ("");
1796 for (i = 0; i < caps->structs->len; i++) {
1797 GstStructure *structure;
1801 /* ';' is now added by gst_structure_to_string */
1802 g_string_append_c (s, ' ');
1805 structure = gst_caps_get_structure (caps, i);
1806 sstr = gst_structure_to_string (structure);
1807 g_string_append (s, sstr);
1810 if (s->len && s->str[s->len - 1] == ';') {
1811 /* remove latest ';' */
1812 s->str[--s->len] = '\0';
1815 return g_string_free (s, FALSE);
1819 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
1821 GstStructure *structure;
1824 g_return_val_if_fail (string, FALSE);
1825 if (strcmp ("ANY", string) == 0) {
1826 caps->flags = GST_CAPS_FLAGS_ANY;
1829 if (strcmp ("EMPTY", string) == 0) {
1833 structure = gst_structure_from_string (string, &s);
1834 if (structure == NULL) {
1837 gst_caps_append_structure (caps, structure);
1841 while (g_ascii_isspace (*s))
1846 structure = gst_structure_from_string (s, &s);
1847 if (structure == NULL) {
1850 gst_caps_append_structure (caps, structure);
1858 * gst_caps_from_string:
1859 * @string: a string to convert to #GstCaps
1861 * Converts @caps from a string representation.
1863 * Returns: a newly allocated #GstCaps
1866 gst_caps_from_string (const gchar * string)
1870 caps = gst_caps_new_empty ();
1871 if (gst_caps_from_string_inplace (caps, string)) {
1874 gst_caps_unref (caps);
1880 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
1882 g_return_if_fail (G_IS_VALUE (src_value));
1883 g_return_if_fail (G_IS_VALUE (dest_value));
1884 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
1885 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
1886 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
1888 dest_value->data[0].v_pointer =
1889 gst_caps_to_string (src_value->data[0].v_pointer);
1893 gst_caps_copy_conditional (GstCaps * src)
1896 return gst_caps_ref (src);