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 static void gst_caps_transform_to_string (const GValue * src_value,
103 GValue * dest_value);
104 static gboolean gst_caps_from_string_inplace (GstCaps * caps,
105 const gchar * string);
106 static GstCaps *gst_caps_copy_conditional (GstCaps * src);
109 gst_caps_get_type (void)
111 static GType gst_caps_type = 0;
113 if (G_UNLIKELY (gst_caps_type == 0)) {
114 gst_caps_type = g_boxed_type_register_static ("GstCaps",
115 (GBoxedCopyFunc) gst_caps_copy_conditional,
116 (GBoxedFreeFunc) gst_caps_unref);
118 g_value_register_transform_func (gst_caps_type,
119 G_TYPE_STRING, gst_caps_transform_to_string);
122 return gst_caps_type;
125 /* creation/deletion */
128 * gst_caps_new_empty:
130 * Creates a new #GstCaps that is empty. That is, the returned
131 * #GstCaps contains no media formats.
132 * Caller is responsible for unreffing the returned caps.
134 * Returns: the new #GstCaps
137 gst_caps_new_empty (void)
139 GstCaps *caps = ALLOC_CAPS ();
141 caps->type = GST_TYPE_CAPS;
144 caps->structs = g_ptr_array_new ();
146 #ifdef DEBUG_REFCOUNT
147 GST_CAT_LOG (GST_CAT_CAPS, "created caps %p", caps);
156 * Creates a new #GstCaps that indicates that it is compatible with
159 * Returns: the new #GstCaps
162 gst_caps_new_any (void)
164 GstCaps *caps = gst_caps_new_empty ();
166 caps->flags = GST_CAPS_FLAGS_ANY;
172 * gst_caps_new_simple:
173 * @media_type: the media type of the structure
174 * @fieldname: first field to set
175 * @...: additional arguments
177 * Creates a new #GstCaps that contains one #GstStructure. The
178 * structure is defined by the arguments, which have the same format
179 * as gst_structure_new().
180 * Caller is responsible for unreffing the returned caps.
182 * Returns: the new #GstCaps
185 gst_caps_new_simple (const char *media_type, const char *fieldname, ...)
188 GstStructure *structure;
191 caps = gst_caps_new_empty ();
193 va_start (var_args, fieldname);
194 structure = gst_structure_new_valist (media_type, fieldname, var_args);
197 gst_caps_append_structure (caps, structure);
204 * @struct1: the first structure to add
205 * @...: additional structures to add
207 * Creates a new #GstCaps and adds all the structures listed as
208 * arguments. The list must be NULL-terminated. The structures
209 * are not copied; the returned #GstCaps owns the structures.
211 * Returns: the new #GstCaps
214 gst_caps_new_full (GstStructure * struct1, ...)
219 va_start (var_args, struct1);
220 caps = gst_caps_new_full_valist (struct1, var_args);
227 * gst_caps_new_full_valist:
228 * @structure: the first structure to add
229 * @var_args: additional structures to add
231 * Creates a new #GstCaps and adds all the structures listed as
232 * arguments. The list must be NULL-terminated. The structures
233 * are not copied; the returned #GstCaps owns the structures.
235 * Returns: the new #GstCaps
238 gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
242 caps = gst_caps_new_empty ();
245 gst_caps_append_structure (caps, structure);
246 structure = va_arg (var_args, GstStructure *);
254 * @caps: the #GstCaps to copy
256 * Creates a new #GstCaps as a copy of the old @caps. The new caps will have a
257 * refcount of 1, owned by the caller. The structures are copied as well.
259 * Note that this function is the semantic equivalent of a gst_caps_ref()
260 * followed by a gst_caps_make_writable(). If you only want to hold on to a
261 * reference to the data, you should use gst_caps_ref().
263 * When you are finished with the caps, call gst_caps_unref() on it.
265 * Returns: the new #GstCaps
268 gst_caps_copy (const GstCaps * caps)
271 GstStructure *structure;
274 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
276 newcaps = gst_caps_new_empty ();
277 newcaps->flags = caps->flags;
279 for (i = 0; i < caps->structs->len; i++) {
280 structure = gst_caps_get_structure (caps, i);
281 gst_caps_append_structure (newcaps, gst_structure_copy (structure));
288 _gst_caps_free (GstCaps * caps)
290 GstStructure *structure;
293 /* The refcount must be 0, but since we're only called by gst_caps_unref,
294 * don't bother testing. */
296 for (i = 0; i < caps->structs->len; i++) {
297 structure = (GstStructure *) gst_caps_get_structure (caps, i);
298 gst_structure_set_parent_refcount (structure, NULL);
299 gst_structure_free (structure);
301 g_ptr_array_free (caps->structs, TRUE);
303 memset (caps, 0xff, sizeof (GstCaps));
309 * gst_caps_make_writable:
310 * @caps: the #GstCaps to make writable
312 * Returns a writable copy of @caps.
314 * If there is only one reference count on @caps, the caller must be the owner,
315 * and so this function will return the caps object unchanged. If on the other
316 * hand there is more than one reference on the object, a new caps object will
317 * be returned. The caller's reference on @caps will be removed, and instead the
318 * caller will own a reference to the returned object.
320 * In short, this function unrefs the caps in the argument and refs the caps
321 * that it returns. Don't access the argument after calling this function. See
322 * also: gst_caps_ref().
324 * Returns: the same #GstCaps object.
327 gst_caps_make_writable (GstCaps * caps)
331 g_return_val_if_fail (caps != NULL, NULL);
333 /* we are the only instance reffing this caps */
334 if (g_atomic_int_get (&caps->refcount) == 1)
338 copy = gst_caps_copy (caps);
339 gst_caps_unref (caps);
346 * @caps: the #GstCaps to reference
348 * Add a reference to a #GstCaps object.
350 * From this point on, until the caller calls gst_caps_unref() or
351 * gst_caps_make_writable(), it is guaranteed that the caps object will not
352 * change. This means its structures won't change, etc. To use a #GstCaps
353 * object, you must always have a refcount on it -- either the one made
354 * implicitly by gst_caps_new(), or via taking one explicitly with this
357 * Returns: the same #GstCaps object.
360 gst_caps_ref (GstCaps * caps)
362 g_return_val_if_fail (caps != NULL, NULL);
364 #ifdef DEBUG_REFCOUNT
365 GST_CAT_LOG (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
366 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) + 1);
368 g_return_val_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0, NULL);
370 g_atomic_int_inc (&caps->refcount);
377 * @caps: the #GstCaps to unref
379 * Unref a #GstCaps and and free all its structures and the
380 * structures' values when the refcount reaches 0.
383 gst_caps_unref (GstCaps * caps)
385 g_return_if_fail (caps != NULL);
387 #ifdef DEBUG_REFCOUNT
388 GST_CAT_LOG (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
389 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) - 1);
392 g_return_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0);
394 /* if we ended up with the refcount at zero, free the caps */
395 if (G_UNLIKELY (g_atomic_int_dec_and_test (&caps->refcount)))
396 _gst_caps_free (caps);
400 gst_static_caps_get_type (void)
402 static GType staticcaps_type = 0;
404 if (G_UNLIKELY (staticcaps_type == 0)) {
405 staticcaps_type = g_pointer_type_register_static ("GstStaticCaps");
407 return staticcaps_type;
412 * gst_static_caps_get:
413 * @static_caps: the #GstStaticCaps to convert
415 * Converts a #GstStaticCaps to a #GstCaps.
417 * Returns: A pointer to the #GstCaps. Unref after usage. Since the
418 * core holds an additional ref to the returned caps,
419 * use gst_caps_make_writable() on the returned caps to modify it.
422 gst_static_caps_get (GstStaticCaps * static_caps)
426 g_return_val_if_fail (static_caps != NULL, NULL);
428 caps = (GstCaps *) static_caps;
430 if (caps->type == 0) {
431 if (G_UNLIKELY (static_caps->string == NULL))
434 caps->type = GST_TYPE_CAPS;
435 /* initialize the caps to a refcount of 1 so the caps can be writable... */
436 gst_atomic_int_set (&caps->refcount, 1);
437 caps->structs = g_ptr_array_new ();
439 /* convert to string */
440 if (G_UNLIKELY (!gst_caps_from_string_inplace (caps, static_caps->string)))
441 g_critical ("Could not convert static caps \"%s\"", static_caps->string);
443 /* ref the caps, makes it not writable */
451 g_warning ("static caps string is NULL");
457 static GstStructure *
458 gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
460 /* don't use index_fast, gst_caps_do_simplify relies on the order */
461 GstStructure *s = g_ptr_array_remove_index (caps->structs, idx);
463 gst_structure_set_parent_refcount (s, NULL);
468 gst_structure_is_equal_foreach (GQuark field_id, const GValue * val2,
471 GstStructure *struct1 = (GstStructure *) data;
472 const GValue *val1 = gst_structure_id_get_value (struct1, field_id);
476 if (gst_value_compare (val1, val2) == GST_VALUE_EQUAL) {
485 * @caps1: the #GstCaps that will be appended to
486 * @caps2: the #GstCaps to append
488 * Appends the structures contained in @caps2 to @caps1. The structures in
489 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
490 * freed. If either caps is ANY, the resulting caps will be ANY.
493 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
495 GstStructure *structure;
498 g_return_if_fail (GST_IS_CAPS (caps1));
499 g_return_if_fail (GST_IS_CAPS (caps2));
500 g_return_if_fail (IS_WRITABLE (caps1));
501 g_return_if_fail (IS_WRITABLE (caps2));
506 if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2)) {
507 /* FIXME: this leaks */
508 caps1->flags |= GST_CAPS_FLAGS_ANY;
509 for (i = caps2->structs->len - 1; i >= 0; i--) {
510 structure = gst_caps_remove_and_get_structure (caps2, i);
511 gst_structure_free (structure);
514 int len = caps2->structs->len;
516 for (i = 0; i < len; i++) {
517 structure = gst_caps_remove_and_get_structure (caps2, 0);
518 gst_caps_append_structure (caps1, structure);
521 gst_caps_unref (caps2); /* guaranteed to free it */
526 * @caps1: the #GstCaps that will take the new entries
527 * @caps2: the #GstCaps to merge in
529 * Appends the structures contained in @caps2 to @caps1 if they are not yet in
530 * @caps1. The structures in @caps2 are not copied -- they are transferred to
531 * @caps1, and then @caps2 is freed.
532 * If either caps is ANY, the resulting caps will be ANY.
535 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
537 GstStructure *structure;
540 g_return_if_fail (GST_IS_CAPS (caps1));
541 g_return_if_fail (GST_IS_CAPS (caps2));
542 g_return_if_fail (IS_WRITABLE (caps1));
543 g_return_if_fail (IS_WRITABLE (caps2));
548 if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2)) {
549 /* FIXME: this leaks */
550 caps1->flags |= GST_CAPS_FLAGS_ANY;
551 for (i = caps2->structs->len - 1; i >= 0; i--) {
552 structure = gst_caps_remove_and_get_structure (caps2, i);
553 gst_structure_free (structure);
556 GstCaps *com = gst_caps_intersect (caps1, caps2);
557 GstCaps *add = gst_caps_subtract (caps2, com);
560 GST_DEBUG ("common : %d", gst_caps_get_size (com));
561 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
563 gst_caps_append (caps1, add);
564 gst_caps_unref (com);
566 gst_caps_unref (caps2); /* guaranteed to free it */
570 * gst_caps_append_structure:
571 * @caps: the #GstCaps that will be appended to
572 * @structure: the #GstStructure to append
574 * Appends @structure to @caps. The structure is not copied; @caps
575 * becomes the owner of @structure.
578 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
580 g_return_if_fail (GST_IS_CAPS (caps));
581 g_return_if_fail (IS_WRITABLE (caps));
583 if (G_LIKELY (structure)) {
584 g_return_if_fail (structure->parent_refcount == NULL);
587 STRUCTURE_POISON (structure);
590 gst_structure_set_parent_refcount (structure, &caps->refcount);
591 g_ptr_array_add (caps->structs, structure);
596 * gst_caps_remove_structure:
597 * @caps: the #GstCaps to remove from
598 * @idx: Index of the structure to remove
600 * removes the stucture with the given index from the list of structures
601 * contained in @caps.
604 gst_caps_remove_structure (GstCaps * caps, guint idx)
606 GstStructure *structure;
608 g_return_if_fail (caps != NULL);
609 g_return_if_fail (idx <= gst_caps_get_size (caps));
610 g_return_if_fail (IS_WRITABLE (caps));
612 structure = gst_caps_remove_and_get_structure (caps, idx);
613 gst_structure_free (structure);
620 * Gets the number of structures contained in @caps.
622 * Returns: the number of structures that @caps contains
625 gst_caps_get_size (const GstCaps * caps)
627 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
629 return caps->structs->len;
633 * gst_caps_get_structure:
635 * @index: the index of the structure
637 * Finds the structure in @caps that has the index @index, and
640 * WARNING: This function takes a const GstCaps *, but returns a
641 * non-const GstStructure *. This is for programming convenience --
642 * the caller should be aware that structures inside a constant
643 * #GstCaps should not be modified.
645 * Returns: a pointer to the #GstStructure corresponding to @index
648 gst_caps_get_structure (const GstCaps * caps, guint index)
650 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
651 g_return_val_if_fail (index < caps->structs->len, NULL);
653 return g_ptr_array_index (caps->structs, index);
658 * @caps: the #GstCaps to copy
659 * @nth: the nth structure to copy
661 * Creates a new #GstCaps and appends a copy of the nth structure
662 * contained in @caps.
664 * Returns: the new #GstCaps
667 gst_caps_copy_nth (const GstCaps * caps, guint nth)
670 GstStructure *structure;
672 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
674 newcaps = gst_caps_new_empty ();
675 newcaps->flags = caps->flags;
677 if (caps->structs->len > nth) {
678 structure = gst_caps_get_structure (caps, nth);
679 gst_caps_append_structure (newcaps, gst_structure_copy (structure));
687 * @caps: the #GstCaps to truncate
689 * Destructively discard all but the first structure from @caps. Useful when
690 * fixating. @caps must be writable.
693 gst_caps_truncate (GstCaps * caps)
697 g_return_if_fail (GST_IS_CAPS (caps));
698 g_return_if_fail (IS_WRITABLE (caps));
700 i = caps->structs->len - 1;
703 gst_caps_remove_structure (caps, i--);
707 * gst_caps_set_simple:
708 * @caps: the #GstCaps to set
709 * @field: first field to set
710 * @...: additional parameters
712 * Sets fields in a simple #GstCaps. A simple #GstCaps is one that
713 * only has one structure. The arguments must be passed in the same
714 * manner as gst_structure_set(), and be NULL-terminated.
717 gst_caps_set_simple (GstCaps * caps, char *field, ...)
719 GstStructure *structure;
722 g_return_if_fail (GST_IS_CAPS (caps));
723 g_return_if_fail (caps->structs->len == 1);
724 g_return_if_fail (IS_WRITABLE (caps));
726 structure = gst_caps_get_structure (caps, 0);
728 va_start (var_args, field);
729 gst_structure_set_valist (structure, field, var_args);
734 * gst_caps_set_simple_valist:
735 * @caps: the #GstCaps to copy
736 * @field: first field to set
737 * @varargs: additional parameters
739 * Sets fields in a simple #GstCaps. A simple #GstCaps is one that
740 * only has one structure. The arguments must be passed in the same
741 * manner as gst_structure_set(), and be NULL-terminated.
744 gst_caps_set_simple_valist (GstCaps * caps, char *field, va_list varargs)
746 GstStructure *structure;
748 g_return_if_fail (GST_IS_CAPS (caps));
749 g_return_if_fail (caps->structs->len != 1);
750 g_return_if_fail (IS_WRITABLE (caps));
752 structure = gst_caps_get_structure (caps, 0);
754 gst_structure_set_valist (structure, field, varargs);
761 * @caps: the #GstCaps to test
763 * Determines if @caps represents any media format.
765 * Returns: TRUE if @caps represents any format.
768 gst_caps_is_any (const GstCaps * caps)
770 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
772 return (caps->flags & GST_CAPS_FLAGS_ANY);
777 * @caps: the #GstCaps to test
779 * Determines if @caps represents no media formats.
781 * Returns: TRUE if @caps represents no formats.
784 gst_caps_is_empty (const GstCaps * caps)
786 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
788 if (caps->flags & GST_CAPS_FLAGS_ANY)
791 return (caps->structs == NULL) || (caps->structs->len == 0);
795 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
798 return gst_value_is_fixed (value);
803 * @caps: the #GstCaps to test
805 * Fixed #GstCaps describe exactly one format, that is, they have exactly
806 * one structure, and each field in the structure describes a fixed type.
807 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
809 * Returns: TRUE if @caps is fixed
812 gst_caps_is_fixed (const GstCaps * caps)
814 GstStructure *structure;
816 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
818 if (caps->structs->len != 1)
821 structure = gst_caps_get_structure (caps, 0);
823 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
827 * gst_caps_is_equal_fixed:
828 * @caps1: the #GstCaps to test
829 * @caps2: the #GstCaps to test
831 * Tests if two #GstCaps are equal. This function only works on fixed
834 * Returns: TRUE if the arguments represent the same format
837 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
839 GstStructure *struct1, *struct2;
841 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
842 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
844 struct1 = gst_caps_get_structure (caps1, 0);
845 struct2 = gst_caps_get_structure (caps2, 0);
847 if (struct1->name != struct2->name) {
850 if (struct1->fields->len != struct2->fields->len) {
854 return gst_structure_foreach (struct1, gst_structure_is_equal_foreach,
859 * gst_caps_is_always_compatible:
860 * @caps1: the #GstCaps to test
861 * @caps2: the #GstCaps to test
863 * A given #GstCaps structure is always compatible with another if
864 * every media format that is in the first is also contained in the
865 * second. That is, @caps1 is a subset of @caps2.
867 * Returns: TRUE if @caps1 is a subset of @caps2.
870 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
872 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
873 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
875 return gst_caps_is_subset (caps1, caps2);
879 * gst_caps_is_subset:
880 * @subset: a #GstCaps
881 * @superset: a potentially greater #GstCaps
883 * Checks if all caps represented by @subset are also represented by @superset
884 * <note>This function does not work reliably if optional properties for caps
885 * are included on one caps and omitted on the other.</note>
887 * Returns: TRUE if @subset is a subset of @superset
890 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
895 g_return_val_if_fail (subset != NULL, FALSE);
896 g_return_val_if_fail (superset != NULL, FALSE);
898 if (gst_caps_is_empty (subset) || gst_caps_is_any (superset))
900 if (gst_caps_is_any (subset) || gst_caps_is_empty (superset))
903 caps = gst_caps_subtract (subset, superset);
904 ret = gst_caps_is_empty (caps);
905 gst_caps_unref (caps);
912 * @caps2: another #GstCaps
914 * Checks if the given caps represent the same set of caps.
915 * <note>This function does not work reliably if optional properties for caps
916 * are included on one caps and omitted on the other.</note>
918 * This function deals correctly with passing NULL for any of the caps.
920 * Returns: TRUE if both caps are equal.
923 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
925 /* NULL <-> NULL is allowed here */
929 /* one of them NULL => they are different (can't be both NULL because
930 * we checked that above) */
931 if (caps1 == NULL || caps2 == NULL)
934 if (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2))
935 return gst_caps_is_equal_fixed (caps1, caps2);
937 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
943 const GstStructure *intersect;
949 gst_caps_structure_intersect_field (GQuark id, const GValue * val1,
952 IntersectData *idata = (IntersectData *) data;
953 GValue dest_value = { 0 };
954 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
957 gst_structure_id_set_value (idata->dest, id, val1);
958 } else if (idata->first_run) {
959 if (gst_value_intersect (&dest_value, val1, val2)) {
960 gst_structure_id_set_value (idata->dest, id, &dest_value);
961 g_value_unset (&dest_value);
970 static GstStructure *
971 gst_caps_structure_intersect (const GstStructure * struct1,
972 const GstStructure * struct2)
976 g_return_val_if_fail (struct1 != NULL, NULL);
977 g_return_val_if_fail (struct2 != NULL, NULL);
979 if (struct1->name != struct2->name)
982 data.dest = gst_structure_id_empty_new (struct1->name);
983 data.intersect = struct2;
984 data.first_run = TRUE;
985 if (!gst_structure_foreach ((GstStructure *) struct1,
986 gst_caps_structure_intersect_field, &data))
989 data.intersect = struct1;
990 data.first_run = FALSE;
991 if (!gst_structure_foreach ((GstStructure *) struct2,
992 gst_caps_structure_intersect_field, &data))
998 gst_structure_free (data.dest);
1003 static GstStructure *
1004 gst_caps_structure_union (const GstStructure * struct1,
1005 const GstStructure * struct2)
1009 const GstStructureField *field1;
1010 const GstStructureField *field2;
1013 /* FIXME this doesn't actually work */
1015 if (struct1->name != struct2->name)
1018 dest = gst_structure_id_empty_new (struct1->name);
1020 for (i = 0; i < struct1->fields->len; i++) {
1021 GValue dest_value = { 0 };
1023 field1 = GST_STRUCTURE_FIELD (struct1, i);
1024 field2 = gst_structure_id_get_field (struct2, field1->name);
1026 if (field2 == NULL) {
1029 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1030 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1033 ret = gst_value_compare (&field1->value, &field2->value);
1045 * gst_caps_intersect:
1046 * @caps1: a #GstCaps to intersect
1047 * @caps2: a #GstCaps to intersect
1049 * Creates a new #GstCaps that contains all the formats that are common
1050 * to both @caps1 and @caps2.
1052 * Returns: the new #GstCaps
1055 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1057 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1060 GstStructure *struct1;
1061 GstStructure *struct2;
1063 GstStructure *istruct;
1065 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1066 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1068 if (gst_caps_is_empty (caps1) || gst_caps_is_empty (caps2)) {
1069 return gst_caps_new_empty ();
1071 if (gst_caps_is_any (caps1))
1072 return gst_caps_copy (caps2);
1073 if (gst_caps_is_any (caps2))
1074 return gst_caps_copy (caps1);
1076 dest = gst_caps_new_empty ();
1078 /* run zigzag on top line then right line, this preserves the caps order
1079 * much better than a simple loop.
1081 * This algorithm zigzags over the caps structures as demonstrated in
1082 * the folowing matrix:
1090 * First we iterate over the caps1 structures (top line) intersecting
1091 * the structures diagonally down, then we iterate over the caps2
1094 for (i = 0; i < caps1->structs->len + caps2->structs->len - 1; i++) {
1095 /* caps1 index goes from 0 to caps1->structs->len-1 */
1096 j = MIN (i, caps1->structs->len - 1);
1097 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1098 * up from 1 to caps2->structs->len - 1 */
1101 /* now run the diagonal line, end condition is the left or bottom
1103 while (k < caps2->structs->len) {
1104 struct1 = gst_caps_get_structure (caps1, j);
1105 struct2 = gst_caps_get_structure (caps2, k);
1107 istruct = gst_caps_structure_intersect (struct1, struct2);
1109 gst_caps_append_structure (dest, istruct);
1110 /* move down left */
1113 break; /* so we don't roll back to G_MAXUINT */
1122 const GstStructure *subtract_from;
1129 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1132 SubtractionEntry *e = user_data;
1133 GValue subtraction = { 0, };
1134 const GValue *other;
1135 GstStructure *structure;
1137 other = gst_structure_id_get_value (e->subtract_from, field_id);
1141 if (!gst_value_subtract (&subtraction, other, value))
1143 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1144 g_value_unset (&subtraction);
1147 structure = gst_structure_copy (e->subtract_from);
1148 gst_structure_id_set_value (structure, field_id, &subtraction);
1149 g_value_unset (&subtraction);
1150 e->put_into = g_slist_prepend (e->put_into, structure);
1156 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1157 const GstStructure * subtrahend)
1162 e.subtract_from = minuend;
1165 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1166 gst_caps_structure_subtract_field, &e);
1172 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1173 gst_structure_free (walk->data);
1175 g_slist_free (e.put_into);
1181 * gst_caps_subtract:
1182 * @minuend: #GstCaps to substract from
1183 * @subtrahend: #GstCaps to substract
1185 * Subtracts the @subtrahend from the @minuend.
1186 * <note>This function does not work reliably if optional properties for caps
1187 * are included on one caps and omitted on the other.</note>
1189 * Returns: the resulting caps
1192 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1197 GstCaps *dest = NULL, *src;
1199 g_return_val_if_fail (minuend != NULL, NULL);
1200 g_return_val_if_fail (subtrahend != NULL, NULL);
1202 if (gst_caps_is_empty (minuend) || gst_caps_is_any (subtrahend)) {
1203 return gst_caps_new_empty ();
1205 if (gst_caps_is_empty (subtrahend))
1206 return gst_caps_copy (minuend);
1208 /* FIXME: Do we want this here or above?
1209 The reason we need this is that there is no definition about what
1210 ANY means for specific types, so it's not possible to reduce ANY partially
1211 You can only remove everything or nothing and that is done above.
1212 Note: there's a test that checks this behaviour. */
1213 g_return_val_if_fail (!gst_caps_is_any (minuend), NULL);
1214 g_assert (subtrahend->structs->len > 0);
1216 src = gst_caps_copy (minuend);
1217 for (i = 0; i < subtrahend->structs->len; i++) {
1218 sub = gst_caps_get_structure (subtrahend, i);
1220 gst_caps_unref (src);
1223 dest = gst_caps_new_empty ();
1224 for (j = 0; j < src->structs->len; j++) {
1225 min = gst_caps_get_structure (src, j);
1226 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1229 if (gst_caps_structure_subtract (&list, min, sub)) {
1232 for (walk = list; walk; walk = g_slist_next (walk)) {
1233 gst_caps_append_structure (dest, (GstStructure *) walk->data);
1235 g_slist_free (list);
1237 gst_caps_append_structure (dest, gst_structure_copy (min));
1240 gst_caps_append_structure (dest, gst_structure_copy (min));
1243 if (gst_caps_is_empty (dest)) {
1244 gst_caps_unref (src);
1249 gst_caps_unref (src);
1250 gst_caps_do_simplify (dest);
1256 * @caps1: a #GstCaps to union
1257 * @caps2: a #GstCaps to union
1259 * Creates a new #GstCaps that contains all the formats that are in
1260 * either @caps1 and @caps2.
1262 * Returns: the new #GstCaps
1265 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1270 if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2))
1271 return gst_caps_new_any ();
1273 dest1 = gst_caps_copy (caps1);
1274 dest2 = gst_caps_copy (caps2);
1275 gst_caps_append (dest1, dest2);
1277 gst_caps_do_simplify (dest1);
1281 typedef struct _NormalizeForeach
1284 GstStructure *structure;
1289 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1291 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1295 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1296 for (i = 1; i < gst_value_list_get_size (value); i++) {
1297 const GValue *v = gst_value_list_get_value (value, i);
1298 GstStructure *structure = gst_structure_copy (nf->structure);
1300 gst_structure_id_set_value (structure, field_id, v);
1301 gst_caps_append_structure (nf->caps, structure);
1304 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1305 gst_structure_id_set_value (nf->structure, field_id, &val);
1306 g_value_unset (&val);
1314 * gst_caps_normalize:
1315 * @caps: a #GstCaps to normalize
1317 * Creates a new #GstCaps that represents the same set of formats as
1318 * @caps, but contains no lists. Each list is expanded into separate
1321 * Returns: the new #GstCaps
1324 gst_caps_normalize (const GstCaps * caps)
1326 NormalizeForeach nf;
1330 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1332 newcaps = gst_caps_copy (caps);
1335 for (i = 0; i < newcaps->structs->len; i++) {
1336 nf.structure = gst_caps_get_structure (newcaps, i);
1338 while (!gst_structure_foreach (nf.structure,
1339 gst_caps_normalize_foreach, &nf));
1346 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1349 const GstStructure *struct1 = *((const GstStructure **) one);
1350 const GstStructure *struct2 = *((const GstStructure **) two);
1352 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1353 So what's the best way? */
1354 ret = strcmp (gst_structure_get_name (struct1),
1355 gst_structure_get_name (struct2));
1359 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1366 GstStructure *compare;
1371 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1374 UnionField *u = user_data;
1375 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1379 g_value_unset (&u->value);
1382 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1385 g_value_unset (&u->value);
1389 gst_value_union (&u->value, val, value);
1394 gst_caps_structure_simplify (GstStructure ** result,
1395 const GstStructure * simplify, GstStructure * compare)
1398 UnionField field = { 0, {0,}, NULL };
1400 /* try to subtract to get a real subset */
1401 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1402 switch (g_slist_length (list)) {
1407 *result = list->data;
1408 g_slist_free (list);
1414 for (walk = list; walk; walk = g_slist_next (walk)) {
1415 gst_structure_free (walk->data);
1417 g_slist_free (list);
1423 /* try to union both structs */
1424 field.compare = compare;
1425 if (gst_structure_foreach ((GstStructure *) simplify,
1426 gst_caps_structure_figure_out_union, &field)) {
1427 gboolean ret = FALSE;
1429 /* now we know all of simplify's fields are the same in compare
1430 * but at most one field: field.name */
1431 if (G_IS_VALUE (&field.value)) {
1432 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1433 gst_structure_id_set_value (compare, field.name, &field.value);
1437 g_value_unset (&field.value);
1438 } else if (gst_structure_n_fields (simplify) <=
1439 gst_structure_n_fields (compare)) {
1440 /* compare is just more specific, will be optimized away later */
1441 /* FIXME: do this here? */
1442 GST_LOG ("found a case that will be optimized later.");
1444 gchar *one = gst_structure_to_string (simplify);
1445 gchar *two = gst_structure_to_string (compare);
1448 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1460 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1461 GstStructure * new, gint i)
1463 gst_structure_set_parent_refcount (old, NULL);
1464 gst_structure_free (old);
1465 gst_structure_set_parent_refcount (new, &caps->refcount);
1466 g_ptr_array_index (caps->structs, i) = new;
1470 * gst_caps_do_simplify:
1471 * @caps: a #GstCaps to simplify
1473 * Modifies the given @caps inplace into a representation that represents the
1474 * same set of formats, but in a simpler form. Component structures that are
1475 * identical are merged. Component structures that have values that can be
1476 * merged are also merged.
1478 * Returns: TRUE, if the caps could be simplified
1481 gst_caps_do_simplify (GstCaps * caps)
1483 GstStructure *simplify, *compare, *result = NULL;
1485 gboolean changed = FALSE;
1487 g_return_val_if_fail (caps != NULL, FALSE);
1488 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1490 if (gst_caps_get_size (caps) < 2)
1493 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1495 start = caps->structs->len - 1;
1496 for (i = caps->structs->len - 1; i >= 0; i--) {
1497 simplify = gst_caps_get_structure (caps, i);
1498 if (gst_structure_get_name_id (simplify) !=
1499 gst_structure_get_name_id (gst_caps_get_structure (caps, start)))
1501 for (j = start; j >= 0; j--) {
1504 compare = gst_caps_get_structure (caps, j);
1505 if (gst_structure_get_name_id (simplify) !=
1506 gst_structure_get_name_id (compare)) {
1509 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1511 gst_caps_switch_structures (caps, simplify, result, i);
1514 gst_caps_remove_structure (caps, i);
1526 /* gst_caps_do_simplify (caps); */
1530 #ifndef GST_DISABLE_LOADSAVE
1532 * gst_caps_save_thyself:
1533 * @caps: a #GstCaps structure
1534 * @parent: a XML parent node
1536 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
1538 * Returns: a XML node pointer
1541 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
1543 char *s = gst_caps_to_string (caps);
1545 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
1551 * gst_caps_load_thyself:
1552 * @parent: a XML node
1554 * Creates a #GstCaps from its XML serialization.
1556 * Returns: a new #GstCaps structure
1559 gst_caps_load_thyself (xmlNodePtr parent)
1561 if (strcmp ("caps", (char *) parent->name) == 0) {
1562 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
1573 * @caps: a pointer to #GstCaps
1574 * @newcaps: a #GstCaps to replace *caps
1576 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
1577 * pointed to by @caps, if applicable, then modifies @caps to point to
1578 * @newcaps. An additional ref on @newcaps is taken.
1580 * This function does not take any locks so you might want to lock
1581 * the object owning @caps pointer.
1584 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
1588 g_return_if_fail (caps != NULL);
1592 if (newcaps != oldcaps) {
1594 gst_caps_ref (newcaps);
1599 gst_caps_unref (oldcaps);
1604 * gst_caps_to_string:
1607 * Converts @caps to a string representation. This string representation
1608 * can be converted back to a #GstCaps by gst_caps_from_string().
1610 * For debugging purposes its easier to do something like this:
1612 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
1614 * This prints the caps in human readble form.
1616 * Returns: a newly allocated string representing @caps.
1619 gst_caps_to_string (const GstCaps * caps)
1624 /* NOTE: This function is potentially called by the debug system,
1625 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
1626 * should be careful to avoid recursion. This includes any functions
1627 * called by gst_caps_to_string. In particular, calls should
1628 * not use the GST_PTR_FORMAT extension. */
1631 return g_strdup ("NULL");
1633 if (gst_caps_is_any (caps)) {
1634 return g_strdup ("ANY");
1636 if (gst_caps_is_empty (caps)) {
1637 return g_strdup ("EMPTY");
1640 s = g_string_new ("");
1641 for (i = 0; i < caps->structs->len; i++) {
1642 GstStructure *structure;
1646 g_string_append (s, "; ");
1648 structure = gst_caps_get_structure (caps, i);
1649 sstr = gst_structure_to_string (structure);
1650 g_string_append (s, sstr);
1654 return g_string_free (s, FALSE);
1658 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
1660 GstStructure *structure;
1663 g_return_val_if_fail (string, FALSE);
1664 if (strcmp ("ANY", string) == 0) {
1665 caps->flags = GST_CAPS_FLAGS_ANY;
1668 if (strcmp ("EMPTY", string) == 0) {
1672 structure = gst_structure_from_string (string, &s);
1673 if (structure == NULL) {
1676 gst_caps_append_structure (caps, structure);
1680 while (g_ascii_isspace (*s))
1682 structure = gst_structure_from_string (s, &s);
1683 if (structure == NULL) {
1686 gst_caps_append_structure (caps, structure);
1687 while (g_ascii_isspace (*s))
1699 * gst_caps_from_string:
1700 * @string: a string to convert to #GstCaps
1702 * Converts @caps from a string representation.
1704 * Returns: a newly allocated #GstCaps
1707 gst_caps_from_string (const gchar * string)
1711 caps = gst_caps_new_empty ();
1712 if (gst_caps_from_string_inplace (caps, string)) {
1715 gst_caps_unref (caps);
1721 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
1723 g_return_if_fail (G_IS_VALUE (src_value));
1724 g_return_if_fail (G_IS_VALUE (dest_value));
1725 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
1726 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
1727 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
1729 dest_value->data[0].v_pointer =
1730 gst_caps_to_string (src_value->data[0].v_pointer);
1734 gst_caps_copy_conditional (GstCaps * src)
1737 return gst_caps_ref (src);