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 /* lock to protect multiple invocations of static caps to caps conversion */
95 G_LOCK_DEFINE_STATIC (static_caps_lock);
97 static void gst_caps_transform_to_string (const GValue * src_value,
99 static gboolean gst_caps_from_string_inplace (GstCaps * caps,
100 const gchar * string);
101 static GstCaps *gst_caps_copy_conditional (GstCaps * src);
104 gst_caps_get_type (void)
106 static GType gst_caps_type = 0;
108 if (G_UNLIKELY (gst_caps_type == 0)) {
109 gst_caps_type = g_boxed_type_register_static ("GstCaps",
110 (GBoxedCopyFunc) gst_caps_copy_conditional,
111 (GBoxedFreeFunc) gst_caps_unref);
113 g_value_register_transform_func (gst_caps_type,
114 G_TYPE_STRING, gst_caps_transform_to_string);
117 return gst_caps_type;
120 /* creation/deletion */
123 * gst_caps_new_empty:
125 * Creates a new #GstCaps that is empty. That is, the returned
126 * #GstCaps contains no media formats.
127 * Caller is responsible for unreffing the returned caps.
129 * Returns: the new #GstCaps
132 gst_caps_new_empty (void)
134 GstCaps *caps = g_slice_new (GstCaps);
136 caps->type = GST_TYPE_CAPS;
139 caps->structs = g_ptr_array_new ();
141 #ifdef DEBUG_REFCOUNT
142 GST_CAT_LOG (GST_CAT_CAPS, "created caps %p", caps);
151 * Creates a new #GstCaps that indicates that it is compatible with
154 * Returns: the new #GstCaps
157 gst_caps_new_any (void)
159 GstCaps *caps = gst_caps_new_empty ();
161 caps->flags = GST_CAPS_FLAGS_ANY;
167 * gst_caps_new_simple:
168 * @media_type: the media type of the structure
169 * @fieldname: first field to set
170 * @...: additional arguments
172 * Creates a new #GstCaps that contains one #GstStructure. The
173 * structure is defined by the arguments, which have the same format
174 * as gst_structure_new().
175 * Caller is responsible for unreffing the returned caps.
177 * Returns: the new #GstCaps
180 gst_caps_new_simple (const char *media_type, const char *fieldname, ...)
183 GstStructure *structure;
186 caps = gst_caps_new_empty ();
188 va_start (var_args, fieldname);
189 structure = gst_structure_new_valist (media_type, fieldname, var_args);
192 gst_caps_append_structure (caps, structure);
199 * @struct1: the first structure to add
200 * @...: additional structures to add
202 * Creates a new #GstCaps and adds all the structures listed as
203 * arguments. The list must be NULL-terminated. The structures
204 * are not copied; the returned #GstCaps owns the structures.
206 * Returns: the new #GstCaps
209 gst_caps_new_full (GstStructure * struct1, ...)
214 va_start (var_args, struct1);
215 caps = gst_caps_new_full_valist (struct1, var_args);
222 * gst_caps_new_full_valist:
223 * @structure: the first structure to add
224 * @var_args: additional structures to add
226 * Creates a new #GstCaps and adds all the structures listed as
227 * arguments. The list must be NULL-terminated. The structures
228 * are not copied; the returned #GstCaps owns the structures.
230 * Returns: the new #GstCaps
233 gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
237 caps = gst_caps_new_empty ();
240 gst_caps_append_structure (caps, structure);
241 structure = va_arg (var_args, GstStructure *);
249 * @caps: the #GstCaps to copy
251 * Creates a new #GstCaps as a copy of the old @caps. The new caps will have a
252 * refcount of 1, owned by the caller. The structures are copied as well.
254 * Note that this function is the semantic equivalent of a gst_caps_ref()
255 * followed by a gst_caps_make_writable(). If you only want to hold on to a
256 * reference to the data, you should use gst_caps_ref().
258 * When you are finished with the caps, call gst_caps_unref() on it.
260 * Returns: the new #GstCaps
263 gst_caps_copy (const GstCaps * caps)
266 GstStructure *structure;
269 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
271 newcaps = gst_caps_new_empty ();
272 newcaps->flags = caps->flags;
274 for (i = 0; i < caps->structs->len; i++) {
275 structure = gst_caps_get_structure (caps, i);
276 gst_caps_append_structure (newcaps, gst_structure_copy (structure));
283 _gst_caps_free (GstCaps * caps)
285 GstStructure *structure;
288 /* The refcount must be 0, but since we're only called by gst_caps_unref,
289 * don't bother testing. */
291 for (i = 0; i < caps->structs->len; i++) {
292 structure = (GstStructure *) gst_caps_get_structure (caps, i);
293 gst_structure_set_parent_refcount (structure, NULL);
294 gst_structure_free (structure);
296 g_ptr_array_free (caps->structs, TRUE);
298 memset (caps, 0xff, sizeof (GstCaps));
301 #ifdef DEBUG_REFCOUNT
302 GST_CAT_LOG (GST_CAT_CAPS, "freeing caps %p", caps);
304 g_slice_free (GstCaps, caps);
308 * gst_caps_make_writable:
309 * @caps: the #GstCaps to make writable
311 * Returns a writable copy of @caps.
313 * If there is only one reference count on @caps, the caller must be the owner,
314 * and so this function will return the caps object unchanged. If on the other
315 * hand there is more than one reference on the object, a new caps object will
316 * be returned. The caller's reference on @caps will be removed, and instead the
317 * caller will own a reference to the returned object.
319 * In short, this function unrefs the caps in the argument and refs the caps
320 * that it returns. Don't access the argument after calling this function. See
321 * also: gst_caps_ref().
323 * Returns: the same #GstCaps object.
326 gst_caps_make_writable (GstCaps * caps)
330 g_return_val_if_fail (caps != NULL, NULL);
332 /* we are the only instance reffing this caps */
333 if (g_atomic_int_get (&caps->refcount) == 1)
337 copy = gst_caps_copy (caps);
338 gst_caps_unref (caps);
345 * @caps: the #GstCaps to reference
347 * Add a reference to a #GstCaps object.
349 * From this point on, until the caller calls gst_caps_unref() or
350 * gst_caps_make_writable(), it is guaranteed that the caps object will not
351 * change. This means its structures won't change, etc. To use a #GstCaps
352 * object, you must always have a refcount on it -- either the one made
353 * implicitly by gst_caps_new(), or via taking one explicitly with this
356 * Returns: the same #GstCaps object.
359 gst_caps_ref (GstCaps * caps)
361 g_return_val_if_fail (caps != NULL, NULL);
363 #ifdef DEBUG_REFCOUNT
364 GST_CAT_LOG (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
365 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) + 1);
367 g_return_val_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0, NULL);
369 g_atomic_int_inc (&caps->refcount);
376 * @caps: the #GstCaps to unref
378 * Unref a #GstCaps and and free all its structures and the
379 * structures' values when the refcount reaches 0.
382 gst_caps_unref (GstCaps * caps)
384 g_return_if_fail (caps != NULL);
386 #ifdef DEBUG_REFCOUNT
387 GST_CAT_LOG (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
388 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) - 1);
391 g_return_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0);
393 /* if we ended up with the refcount at zero, free the caps */
394 if (G_UNLIKELY (g_atomic_int_dec_and_test (&caps->refcount)))
395 _gst_caps_free (caps);
399 gst_static_caps_get_type (void)
401 static GType staticcaps_type = 0;
403 if (G_UNLIKELY (staticcaps_type == 0)) {
404 staticcaps_type = g_pointer_type_register_static ("GstStaticCaps");
406 return staticcaps_type;
411 * gst_static_caps_get:
412 * @static_caps: the #GstStaticCaps to convert
414 * Converts a #GstStaticCaps to a #GstCaps.
416 * Returns: A pointer to the #GstCaps. Unref after usage. Since the
417 * core holds an additional ref to the returned caps,
418 * use gst_caps_make_writable() on the returned caps to modify it.
421 gst_static_caps_get (GstStaticCaps * static_caps)
425 g_return_val_if_fail (static_caps != NULL, NULL);
427 caps = (GstCaps *) static_caps;
429 /* refcount is 0 when we need to convert */
430 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount) == 0)) {
434 G_LOCK (static_caps_lock);
435 /* check if other thread already updated */
436 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount) > 0))
439 string = static_caps->string;
441 if (G_UNLIKELY (string == NULL))
444 GST_CAT_LOG (GST_CAT_CAPS, "creating %p", static_caps);
446 /* we construct the caps on the stack, then copy over the struct into our
447 * real caps, refcount last. We do this because we must leave the refcount
448 * of the result caps to 0 so that other threads don't run away with the
449 * caps while we are constructing it. */
450 temp.type = GST_TYPE_CAPS;
452 temp.structs = g_ptr_array_new ();
454 /* initialize the caps to a refcount of 1 so the caps can be writable for
455 * the next statement */
458 /* convert to string */
459 if (G_UNLIKELY (!gst_caps_from_string_inplace (&temp, string)))
460 g_critical ("Could not convert static caps \"%s\"", string);
462 /* now copy stuff over to the real caps. */
463 caps->type = temp.type;
464 caps->flags = temp.flags;
465 caps->structs = temp.structs;
466 /* and bump the refcount so other threads can now read */
467 g_atomic_int_set (&caps->refcount, 1);
469 GST_CAT_LOG (GST_CAT_CAPS, "created %p", static_caps);
471 G_UNLOCK (static_caps_lock);
473 /* ref the caps, makes it not writable */
481 G_UNLOCK (static_caps_lock);
482 g_warning ("static caps %p string is NULL", static_caps);
488 static GstStructure *
489 gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
491 /* don't use index_fast, gst_caps_do_simplify relies on the order */
492 GstStructure *s = g_ptr_array_remove_index (caps->structs, idx);
494 gst_structure_set_parent_refcount (s, NULL);
499 gst_structure_is_equal_foreach (GQuark field_id, const GValue * val2,
502 GstStructure *struct1 = (GstStructure *) data;
503 const GValue *val1 = gst_structure_id_get_value (struct1, field_id);
507 if (gst_value_compare (val1, val2) == GST_VALUE_EQUAL) {
515 gst_caps_structure_is_subset_field (GQuark field_id, const GValue * value,
518 GstStructure *subtract_from = user_data;
519 GValue subtraction = { 0, };
522 if (!(other = gst_structure_id_get_value (subtract_from, field_id)))
523 /* field is missing in one set */
526 /* equal values are subset */
527 if (gst_value_compare (other, value) == GST_VALUE_EQUAL)
535 * -> 1 - [1,2] = empty
539 * -> [1,2] - [1,3] = empty
543 * -> {1,3} - {1,2} = 3
546 * First caps subtraction needs to return a non-empty set, second
547 * subtractions needs to give en empty set.
549 if (gst_value_subtract (&subtraction, other, value)) {
550 g_value_unset (&subtraction);
551 /* !empty result, swapping must be empty */
552 if (!gst_value_subtract (&subtraction, value, other))
555 g_value_unset (&subtraction);
561 gst_caps_structure_is_subset (const GstStructure * minuend,
562 const GstStructure * subtrahend)
564 if ((minuend->name != subtrahend->name) ||
565 (gst_structure_n_fields (minuend) !=
566 gst_structure_n_fields (subtrahend))) {
570 return gst_structure_foreach ((GstStructure *) subtrahend,
571 gst_caps_structure_is_subset_field, (gpointer) minuend);
576 * @caps1: the #GstCaps that will be appended to
577 * @caps2: the #GstCaps to append
579 * Appends the structures contained in @caps2 to @caps1. The structures in
580 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
581 * freed. If either caps is ANY, the resulting caps will be ANY.
584 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
586 GstStructure *structure;
589 g_return_if_fail (GST_IS_CAPS (caps1));
590 g_return_if_fail (GST_IS_CAPS (caps2));
591 g_return_if_fail (IS_WRITABLE (caps1));
592 g_return_if_fail (IS_WRITABLE (caps2));
597 if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2)) {
598 /* FIXME: this leaks */
599 caps1->flags |= GST_CAPS_FLAGS_ANY;
600 for (i = caps2->structs->len - 1; i >= 0; i--) {
601 structure = gst_caps_remove_and_get_structure (caps2, i);
602 gst_structure_free (structure);
605 int len = caps2->structs->len;
607 for (i = 0; i < len; i++) {
608 structure = gst_caps_remove_and_get_structure (caps2, 0);
609 gst_caps_append_structure (caps1, structure);
612 gst_caps_unref (caps2); /* guaranteed to free it */
617 * @caps1: the #GstCaps that will take the new entries
618 * @caps2: the #GstCaps to merge in
620 * Appends the structures contained in @caps2 to @caps1 if they are not yet
621 * expressed by @caps1. The structures in @caps2 are not copied -- they are
622 * transferred to @caps1, and then @caps2 is freed.
623 * If either caps is ANY, the resulting caps will be ANY.
628 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
630 GstStructure *structure;
633 g_return_if_fail (GST_IS_CAPS (caps1));
634 g_return_if_fail (GST_IS_CAPS (caps2));
635 g_return_if_fail (IS_WRITABLE (caps1));
636 g_return_if_fail (IS_WRITABLE (caps2));
641 if (gst_caps_is_any (caps1)) {
642 for (i = caps2->structs->len - 1; i >= 0; i--) {
643 structure = gst_caps_remove_and_get_structure (caps2, i);
644 gst_structure_free (structure);
646 } else if (gst_caps_is_any (caps2)) {
647 caps1->flags |= GST_CAPS_FLAGS_ANY;
648 for (i = caps1->structs->len - 1; i >= 0; i--) {
649 structure = gst_caps_remove_and_get_structure (caps1, i);
650 gst_structure_free (structure);
653 int len = caps2->structs->len;
655 for (i = 0; i < len; i++) {
656 structure = gst_caps_remove_and_get_structure (caps2, 0);
657 gst_caps_merge_structure (caps1, structure);
660 GstCaps *com = gst_caps_intersect (caps1, caps2);
661 GstCaps *add = gst_caps_subtract (caps2, com);
663 GST_DEBUG ("common : %d", gst_caps_get_size (com));
664 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
665 gst_caps_append (caps1, add);
666 gst_caps_unref (com);
669 gst_caps_unref (caps2); /* guaranteed to free it */
673 * gst_caps_append_structure:
674 * @caps: the #GstCaps that will be appended to
675 * @structure: the #GstStructure to append
677 * Appends @structure to @caps. The structure is not copied; @caps
678 * becomes the owner of @structure.
681 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
683 g_return_if_fail (GST_IS_CAPS (caps));
684 g_return_if_fail (IS_WRITABLE (caps));
686 if (G_LIKELY (structure)) {
687 g_return_if_fail (structure->parent_refcount == NULL);
690 STRUCTURE_POISON (structure);
693 gst_structure_set_parent_refcount (structure, &caps->refcount);
694 g_ptr_array_add (caps->structs, structure);
699 * gst_caps_remove_structure:
700 * @caps: the #GstCaps to remove from
701 * @idx: Index of the structure to remove
703 * removes the stucture with the given index from the list of structures
704 * contained in @caps.
707 gst_caps_remove_structure (GstCaps * caps, guint idx)
709 GstStructure *structure;
711 g_return_if_fail (caps != NULL);
712 g_return_if_fail (idx <= gst_caps_get_size (caps));
713 g_return_if_fail (IS_WRITABLE (caps));
715 structure = gst_caps_remove_and_get_structure (caps, idx);
716 gst_structure_free (structure);
720 * gst_caps_merge_structure:
721 * @caps: the #GstCaps that will the the new structure
722 * @structure: the #GstStructure to merge
724 * Appends @structure to @caps if its not already expressed by @caps. The
725 * structure is not copied; @caps becomes the owner of @structure.
728 gst_caps_merge_structure (GstCaps * caps, GstStructure * structure)
730 g_return_if_fail (GST_IS_CAPS (caps));
731 g_return_if_fail (IS_WRITABLE (caps));
733 if (G_LIKELY (structure)) {
734 GstStructure *structure1;
736 gboolean unique = TRUE;
738 g_return_if_fail (structure->parent_refcount == NULL);
741 STRUCTURE_POISON (structure);
744 /* check each structure */
745 for (i = caps->structs->len - 1; i >= 0; i--) {
746 structure1 = gst_caps_get_structure (caps, i);
747 /* if structure is a subset of structure1, then skip it */
748 if (gst_caps_structure_is_subset (structure1, structure)) {
754 gst_structure_set_parent_refcount (structure, &caps->refcount);
755 g_ptr_array_add (caps->structs, structure);
757 gst_structure_free (structure);
767 * Gets the number of structures contained in @caps.
769 * Returns: the number of structures that @caps contains
772 gst_caps_get_size (const GstCaps * caps)
774 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
776 return caps->structs->len;
780 * gst_caps_get_structure:
782 * @index: the index of the structure
784 * Finds the structure in @caps that has the index @index, and
787 * WARNING: This function takes a const GstCaps *, but returns a
788 * non-const GstStructure *. This is for programming convenience --
789 * the caller should be aware that structures inside a constant
790 * #GstCaps should not be modified.
792 * Returns: a pointer to the #GstStructure corresponding to @index
795 gst_caps_get_structure (const GstCaps * caps, guint index)
797 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
798 g_return_val_if_fail (index < caps->structs->len, NULL);
800 return g_ptr_array_index (caps->structs, index);
805 * @caps: the #GstCaps to copy
806 * @nth: the nth structure to copy
808 * Creates a new #GstCaps and appends a copy of the nth structure
809 * contained in @caps.
811 * Returns: the new #GstCaps
814 gst_caps_copy_nth (const GstCaps * caps, guint nth)
817 GstStructure *structure;
819 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
821 newcaps = gst_caps_new_empty ();
822 newcaps->flags = caps->flags;
824 if (caps->structs->len > nth) {
825 structure = gst_caps_get_structure (caps, nth);
826 gst_caps_append_structure (newcaps, gst_structure_copy (structure));
834 * @caps: the #GstCaps to truncate
836 * Destructively discard all but the first structure from @caps. Useful when
837 * fixating. @caps must be writable.
840 gst_caps_truncate (GstCaps * caps)
844 g_return_if_fail (GST_IS_CAPS (caps));
845 g_return_if_fail (IS_WRITABLE (caps));
847 i = caps->structs->len - 1;
850 gst_caps_remove_structure (caps, i--);
854 * gst_caps_set_simple:
855 * @caps: the #GstCaps to set
856 * @field: first field to set
857 * @...: additional parameters
859 * Sets fields in a simple #GstCaps. A simple #GstCaps is one that
860 * only has one structure. The arguments must be passed in the same
861 * manner as gst_structure_set(), and be NULL-terminated.
864 gst_caps_set_simple (GstCaps * caps, const char *field, ...)
866 GstStructure *structure;
869 g_return_if_fail (GST_IS_CAPS (caps));
870 g_return_if_fail (caps->structs->len == 1);
871 g_return_if_fail (IS_WRITABLE (caps));
873 structure = gst_caps_get_structure (caps, 0);
875 va_start (var_args, field);
876 gst_structure_set_valist (structure, field, var_args);
881 * gst_caps_set_simple_valist:
882 * @caps: the #GstCaps to copy
883 * @field: first field to set
884 * @varargs: additional parameters
886 * Sets fields in a simple #GstCaps. A simple #GstCaps is one that
887 * only has one structure. The arguments must be passed in the same
888 * manner as gst_structure_set(), and be NULL-terminated.
891 gst_caps_set_simple_valist (GstCaps * caps, const char *field, va_list varargs)
893 GstStructure *structure;
895 g_return_if_fail (GST_IS_CAPS (caps));
896 g_return_if_fail (caps->structs->len == 1);
897 g_return_if_fail (IS_WRITABLE (caps));
899 structure = gst_caps_get_structure (caps, 0);
901 gst_structure_set_valist (structure, field, varargs);
908 * @caps: the #GstCaps to test
910 * Determines if @caps represents any media format.
912 * Returns: TRUE if @caps represents any format.
915 gst_caps_is_any (const GstCaps * caps)
917 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
919 return (caps->flags & GST_CAPS_FLAGS_ANY);
924 * @caps: the #GstCaps to test
926 * Determines if @caps represents no media formats.
928 * Returns: TRUE if @caps represents no formats.
931 gst_caps_is_empty (const GstCaps * caps)
933 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
935 if (caps->flags & GST_CAPS_FLAGS_ANY)
938 return (caps->structs == NULL) || (caps->structs->len == 0);
942 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
945 return gst_value_is_fixed (value);
950 * @caps: the #GstCaps to test
952 * Fixed #GstCaps describe exactly one format, that is, they have exactly
953 * one structure, and each field in the structure describes a fixed type.
954 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
956 * Returns: TRUE if @caps is fixed
959 gst_caps_is_fixed (const GstCaps * caps)
961 GstStructure *structure;
963 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
965 if (caps->structs->len != 1)
968 structure = gst_caps_get_structure (caps, 0);
970 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
974 * gst_caps_is_equal_fixed:
975 * @caps1: the #GstCaps to test
976 * @caps2: the #GstCaps to test
978 * Tests if two #GstCaps are equal. This function only works on fixed
981 * Returns: TRUE if the arguments represent the same format
984 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
986 GstStructure *struct1, *struct2;
988 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
989 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
991 struct1 = gst_caps_get_structure (caps1, 0);
992 struct2 = gst_caps_get_structure (caps2, 0);
994 if (struct1->name != struct2->name) {
997 if (struct1->fields->len != struct2->fields->len) {
1001 return gst_structure_foreach (struct1, gst_structure_is_equal_foreach,
1006 * gst_caps_is_always_compatible:
1007 * @caps1: the #GstCaps to test
1008 * @caps2: the #GstCaps to test
1010 * A given #GstCaps structure is always compatible with another if
1011 * every media format that is in the first is also contained in the
1012 * second. That is, @caps1 is a subset of @caps2.
1014 * Returns: TRUE if @caps1 is a subset of @caps2.
1017 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
1019 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1020 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1022 return gst_caps_is_subset (caps1, caps2);
1026 * gst_caps_is_subset:
1027 * @subset: a #GstCaps
1028 * @superset: a potentially greater #GstCaps
1030 * Checks if all caps represented by @subset are also represented by @superset.
1031 * <note>This function does not work reliably if optional properties for caps
1032 * are included on one caps and omitted on the other.</note>
1034 * Returns: %TRUE if @subset is a subset of @superset
1037 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
1042 g_return_val_if_fail (subset != NULL, FALSE);
1043 g_return_val_if_fail (superset != NULL, FALSE);
1045 if (gst_caps_is_empty (subset) || gst_caps_is_any (superset))
1047 if (gst_caps_is_any (subset) || gst_caps_is_empty (superset))
1050 caps = gst_caps_subtract (subset, superset);
1051 ret = gst_caps_is_empty (caps);
1052 gst_caps_unref (caps);
1057 * gst_caps_is_equal:
1058 * @caps1: a #GstCaps
1059 * @caps2: another #GstCaps
1061 * Checks if the given caps represent the same set of caps.
1062 * <note>This function does not work reliably if optional properties for caps
1063 * are included on one caps and omitted on the other.</note>
1065 * This function deals correctly with passing NULL for any of the caps.
1067 * Returns: TRUE if both caps are equal.
1070 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1072 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1073 * So there should be an assertion that caps1 and caps2 != NULL */
1075 /* NULL <-> NULL is allowed here */
1079 /* one of them NULL => they are different (can't be both NULL because
1080 * we checked that above) */
1081 if (caps1 == NULL || caps2 == NULL)
1084 if (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2))
1085 return gst_caps_is_equal_fixed (caps1, caps2);
1087 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1093 const GstStructure *intersect;
1099 gst_caps_structure_intersect_field (GQuark id, const GValue * val1,
1102 IntersectData *idata = (IntersectData *) data;
1103 GValue dest_value = { 0 };
1104 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1107 gst_structure_id_set_value (idata->dest, id, val1);
1108 } else if (idata->first_run) {
1109 if (gst_value_intersect (&dest_value, val1, val2)) {
1110 gst_structure_id_set_value (idata->dest, id, &dest_value);
1111 g_value_unset (&dest_value);
1120 static GstStructure *
1121 gst_caps_structure_intersect (const GstStructure * struct1,
1122 const GstStructure * struct2)
1126 g_return_val_if_fail (struct1 != NULL, NULL);
1127 g_return_val_if_fail (struct2 != NULL, NULL);
1129 if (struct1->name != struct2->name)
1132 data.dest = gst_structure_id_empty_new (struct1->name);
1133 data.intersect = struct2;
1134 data.first_run = TRUE;
1135 if (!gst_structure_foreach ((GstStructure *) struct1,
1136 gst_caps_structure_intersect_field, &data))
1139 data.intersect = struct1;
1140 data.first_run = FALSE;
1141 if (!gst_structure_foreach ((GstStructure *) struct2,
1142 gst_caps_structure_intersect_field, &data))
1148 gst_structure_free (data.dest);
1153 static GstStructure *
1154 gst_caps_structure_union (const GstStructure * struct1,
1155 const GstStructure * struct2)
1159 const GstStructureField *field1;
1160 const GstStructureField *field2;
1163 /* FIXME this doesn't actually work */
1165 if (struct1->name != struct2->name)
1168 dest = gst_structure_id_empty_new (struct1->name);
1170 for (i = 0; i < struct1->fields->len; i++) {
1171 GValue dest_value = { 0 };
1173 field1 = GST_STRUCTURE_FIELD (struct1, i);
1174 field2 = gst_structure_id_get_field (struct2, field1->name);
1176 if (field2 == NULL) {
1179 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1180 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1183 ret = gst_value_compare (&field1->value, &field2->value);
1195 * gst_caps_intersect:
1196 * @caps1: a #GstCaps to intersect
1197 * @caps2: a #GstCaps to intersect
1199 * Creates a new #GstCaps that contains all the formats that are common
1200 * to both @caps1 and @caps2.
1202 * Returns: the new #GstCaps
1205 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1207 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1210 GstStructure *struct1;
1211 GstStructure *struct2;
1213 GstStructure *istruct;
1215 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1216 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1218 /* caps are exactly the same pointers, just copy one caps */
1220 return gst_caps_copy (caps1);
1222 /* empty caps on either side, return empty */
1223 if (gst_caps_is_empty (caps1) || gst_caps_is_empty (caps2))
1224 return gst_caps_new_empty ();
1226 /* one of the caps is any, just copy the other caps */
1227 if (gst_caps_is_any (caps1))
1228 return gst_caps_copy (caps2);
1229 if (gst_caps_is_any (caps2))
1230 return gst_caps_copy (caps1);
1232 dest = gst_caps_new_empty ();
1234 /* run zigzag on top line then right line, this preserves the caps order
1235 * much better than a simple loop.
1237 * This algorithm zigzags over the caps structures as demonstrated in
1238 * the folowing matrix:
1246 * First we iterate over the caps1 structures (top line) intersecting
1247 * the structures diagonally down, then we iterate over the caps2
1250 for (i = 0; i < caps1->structs->len + caps2->structs->len - 1; i++) {
1251 /* caps1 index goes from 0 to caps1->structs->len-1 */
1252 j = MIN (i, caps1->structs->len - 1);
1253 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1254 * up from 1 to caps2->structs->len - 1 */
1257 /* now run the diagonal line, end condition is the left or bottom
1259 while (k < caps2->structs->len) {
1260 struct1 = gst_caps_get_structure (caps1, j);
1261 struct2 = gst_caps_get_structure (caps2, k);
1263 istruct = gst_caps_structure_intersect (struct1, struct2);
1265 gst_caps_append_structure (dest, istruct);
1266 /* move down left */
1269 break; /* so we don't roll back to G_MAXUINT */
1278 const GstStructure *subtract_from;
1285 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1288 SubtractionEntry *e = user_data;
1289 GValue subtraction = { 0, };
1290 const GValue *other;
1291 GstStructure *structure;
1293 other = gst_structure_id_get_value (e->subtract_from, field_id);
1297 if (!gst_value_subtract (&subtraction, other, value))
1299 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1300 g_value_unset (&subtraction);
1303 structure = gst_structure_copy (e->subtract_from);
1304 gst_structure_id_set_value (structure, field_id, &subtraction);
1305 g_value_unset (&subtraction);
1306 e->put_into = g_slist_prepend (e->put_into, structure);
1312 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1313 const GstStructure * subtrahend)
1318 e.subtract_from = minuend;
1321 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1322 gst_caps_structure_subtract_field, &e);
1328 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1329 gst_structure_free (walk->data);
1331 g_slist_free (e.put_into);
1337 * gst_caps_subtract:
1338 * @minuend: #GstCaps to substract from
1339 * @subtrahend: #GstCaps to substract
1341 * Subtracts the @subtrahend from the @minuend.
1342 * <note>This function does not work reliably if optional properties for caps
1343 * are included on one caps and omitted on the other.</note>
1345 * Returns: the resulting caps
1348 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1353 GstCaps *dest = NULL, *src;
1355 g_return_val_if_fail (minuend != NULL, NULL);
1356 g_return_val_if_fail (subtrahend != NULL, NULL);
1358 if (gst_caps_is_empty (minuend) || gst_caps_is_any (subtrahend)) {
1359 return gst_caps_new_empty ();
1361 if (gst_caps_is_empty (subtrahend))
1362 return gst_caps_copy (minuend);
1364 /* FIXME: Do we want this here or above?
1365 The reason we need this is that there is no definition about what
1366 ANY means for specific types, so it's not possible to reduce ANY partially
1367 You can only remove everything or nothing and that is done above.
1368 Note: there's a test that checks this behaviour. */
1369 g_return_val_if_fail (!gst_caps_is_any (minuend), NULL);
1370 g_assert (subtrahend->structs->len > 0);
1372 src = gst_caps_copy (minuend);
1373 for (i = 0; i < subtrahend->structs->len; i++) {
1374 sub = gst_caps_get_structure (subtrahend, i);
1376 gst_caps_unref (src);
1379 dest = gst_caps_new_empty ();
1380 for (j = 0; j < src->structs->len; j++) {
1381 min = gst_caps_get_structure (src, j);
1382 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1385 if (gst_caps_structure_subtract (&list, min, sub)) {
1388 for (walk = list; walk; walk = g_slist_next (walk)) {
1389 gst_caps_append_structure (dest, (GstStructure *) walk->data);
1391 g_slist_free (list);
1393 gst_caps_append_structure (dest, gst_structure_copy (min));
1396 gst_caps_append_structure (dest, gst_structure_copy (min));
1399 if (gst_caps_is_empty (dest)) {
1400 gst_caps_unref (src);
1405 gst_caps_unref (src);
1406 gst_caps_do_simplify (dest);
1412 * @caps1: a #GstCaps to union
1413 * @caps2: a #GstCaps to union
1415 * Creates a new #GstCaps that contains all the formats that are in
1416 * either @caps1 and @caps2.
1418 * Returns: the new #GstCaps
1421 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1426 /* NULL pointers are no correct GstCaps */
1427 g_return_val_if_fail (caps1 != NULL, NULL);
1428 g_return_val_if_fail (caps2 != NULL, NULL);
1430 if (gst_caps_is_empty (caps1))
1431 return gst_caps_copy (caps2);
1433 if (gst_caps_is_empty (caps2))
1434 return gst_caps_copy (caps1);
1436 if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2))
1437 return gst_caps_new_any ();
1439 dest1 = gst_caps_copy (caps1);
1440 dest2 = gst_caps_copy (caps2);
1441 gst_caps_append (dest1, dest2);
1443 gst_caps_do_simplify (dest1);
1447 typedef struct _NormalizeForeach
1450 GstStructure *structure;
1455 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1457 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1461 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1462 for (i = 1; i < gst_value_list_get_size (value); i++) {
1463 const GValue *v = gst_value_list_get_value (value, i);
1464 GstStructure *structure = gst_structure_copy (nf->structure);
1466 gst_structure_id_set_value (structure, field_id, v);
1467 gst_caps_append_structure (nf->caps, structure);
1470 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1471 gst_structure_id_set_value (nf->structure, field_id, &val);
1472 g_value_unset (&val);
1480 * gst_caps_normalize:
1481 * @caps: a #GstCaps to normalize
1483 * Creates a new #GstCaps that represents the same set of formats as
1484 * @caps, but contains no lists. Each list is expanded into separate
1487 * Returns: the new #GstCaps
1490 gst_caps_normalize (const GstCaps * caps)
1492 NormalizeForeach nf;
1496 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1498 newcaps = gst_caps_copy (caps);
1501 for (i = 0; i < newcaps->structs->len; i++) {
1502 nf.structure = gst_caps_get_structure (newcaps, i);
1504 while (!gst_structure_foreach (nf.structure,
1505 gst_caps_normalize_foreach, &nf));
1512 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1515 const GstStructure *struct1 = *((const GstStructure **) one);
1516 const GstStructure *struct2 = *((const GstStructure **) two);
1518 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1519 So what's the best way? */
1520 ret = strcmp (gst_structure_get_name (struct1),
1521 gst_structure_get_name (struct2));
1525 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1532 GstStructure *compare;
1537 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1540 UnionField *u = user_data;
1541 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1545 g_value_unset (&u->value);
1548 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1551 g_value_unset (&u->value);
1555 gst_value_union (&u->value, val, value);
1560 gst_caps_structure_simplify (GstStructure ** result,
1561 const GstStructure * simplify, GstStructure * compare)
1564 UnionField field = { 0, {0,}, NULL };
1566 /* try to subtract to get a real subset */
1567 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1568 switch (g_slist_length (list)) {
1573 *result = list->data;
1574 g_slist_free (list);
1580 for (walk = list; walk; walk = g_slist_next (walk)) {
1581 gst_structure_free (walk->data);
1583 g_slist_free (list);
1589 /* try to union both structs */
1590 field.compare = compare;
1591 if (gst_structure_foreach ((GstStructure *) simplify,
1592 gst_caps_structure_figure_out_union, &field)) {
1593 gboolean ret = FALSE;
1595 /* now we know all of simplify's fields are the same in compare
1596 * but at most one field: field.name */
1597 if (G_IS_VALUE (&field.value)) {
1598 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1599 gst_structure_id_set_value (compare, field.name, &field.value);
1603 g_value_unset (&field.value);
1604 } else if (gst_structure_n_fields (simplify) <=
1605 gst_structure_n_fields (compare)) {
1606 /* compare is just more specific, will be optimized away later */
1607 /* FIXME: do this here? */
1608 GST_LOG ("found a case that will be optimized later.");
1610 gchar *one = gst_structure_to_string (simplify);
1611 gchar *two = gst_structure_to_string (compare);
1614 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1626 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1627 GstStructure * new, gint i)
1629 gst_structure_set_parent_refcount (old, NULL);
1630 gst_structure_free (old);
1631 gst_structure_set_parent_refcount (new, &caps->refcount);
1632 g_ptr_array_index (caps->structs, i) = new;
1636 * gst_caps_do_simplify:
1637 * @caps: a #GstCaps to simplify
1639 * Modifies the given @caps inplace into a representation that represents the
1640 * same set of formats, but in a simpler form. Component structures that are
1641 * identical are merged. Component structures that have values that can be
1642 * merged are also merged.
1644 * Returns: TRUE, if the caps could be simplified
1647 gst_caps_do_simplify (GstCaps * caps)
1649 GstStructure *simplify, *compare, *result = NULL;
1651 gboolean changed = FALSE;
1653 g_return_val_if_fail (caps != NULL, FALSE);
1654 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1656 if (gst_caps_get_size (caps) < 2)
1659 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1661 start = caps->structs->len - 1;
1662 for (i = caps->structs->len - 1; i >= 0; i--) {
1663 simplify = gst_caps_get_structure (caps, i);
1664 if (gst_structure_get_name_id (simplify) !=
1665 gst_structure_get_name_id (gst_caps_get_structure (caps, start)))
1667 for (j = start; j >= 0; j--) {
1670 compare = gst_caps_get_structure (caps, j);
1671 if (gst_structure_get_name_id (simplify) !=
1672 gst_structure_get_name_id (compare)) {
1675 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1677 gst_caps_switch_structures (caps, simplify, result, i);
1680 gst_caps_remove_structure (caps, i);
1692 /* gst_caps_do_simplify (caps); */
1696 #ifndef GST_DISABLE_LOADSAVE
1698 * gst_caps_save_thyself:
1699 * @caps: a #GstCaps structure
1700 * @parent: a XML parent node
1702 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
1704 * Returns: a XML node pointer
1707 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
1709 char *s = gst_caps_to_string (caps);
1711 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
1717 * gst_caps_load_thyself:
1718 * @parent: a XML node
1720 * Creates a #GstCaps from its XML serialization.
1722 * Returns: a new #GstCaps structure
1725 gst_caps_load_thyself (xmlNodePtr parent)
1727 if (strcmp ("caps", (char *) parent->name) == 0) {
1728 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
1739 * @caps: a pointer to #GstCaps
1740 * @newcaps: a #GstCaps to replace *caps
1742 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
1743 * pointed to by @caps, if applicable, then modifies @caps to point to
1744 * @newcaps. An additional ref on @newcaps is taken.
1746 * This function does not take any locks so you might want to lock
1747 * the object owning @caps pointer.
1750 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
1754 g_return_if_fail (caps != NULL);
1758 if (newcaps != oldcaps) {
1760 gst_caps_ref (newcaps);
1765 gst_caps_unref (oldcaps);
1770 * gst_caps_to_string:
1773 * Converts @caps to a string representation. This string representation
1774 * can be converted back to a #GstCaps by gst_caps_from_string().
1776 * For debugging purposes its easier to do something like this:
1778 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
1780 * This prints the caps in human readble form.
1782 * Returns: a newly allocated string representing @caps.
1785 gst_caps_to_string (const GstCaps * caps)
1790 /* NOTE: This function is potentially called by the debug system,
1791 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
1792 * should be careful to avoid recursion. This includes any functions
1793 * called by gst_caps_to_string. In particular, calls should
1794 * not use the GST_PTR_FORMAT extension. */
1797 return g_strdup ("NULL");
1799 if (gst_caps_is_any (caps)) {
1800 return g_strdup ("ANY");
1802 if (gst_caps_is_empty (caps)) {
1803 return g_strdup ("EMPTY");
1806 /* estimate a rough string length to avoid unnecessary reallocs in GString */
1808 for (i = 0; i < caps->structs->len; i++) {
1809 slen += STRUCTURE_ESTIMATED_STRING_LEN (gst_caps_get_structure (caps, i));
1812 s = g_string_sized_new (slen);
1813 for (i = 0; i < caps->structs->len; i++) {
1814 GstStructure *structure;
1817 /* ';' is now added by gst_structure_to_string */
1818 g_string_append_c (s, ' ');
1821 structure = gst_caps_get_structure (caps, i);
1822 priv_gst_structure_append_to_gstring (structure, s);
1824 if (s->len && s->str[s->len - 1] == ';') {
1825 /* remove latest ';' */
1826 s->str[--s->len] = '\0';
1828 return g_string_free (s, FALSE);
1832 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
1834 GstStructure *structure;
1837 g_return_val_if_fail (string, FALSE);
1838 if (strcmp ("ANY", string) == 0) {
1839 caps->flags = GST_CAPS_FLAGS_ANY;
1842 if (strcmp ("EMPTY", string) == 0) {
1846 structure = gst_structure_from_string (string, &s);
1847 if (structure == NULL) {
1850 gst_caps_append_structure (caps, structure);
1854 while (g_ascii_isspace (*s))
1859 structure = gst_structure_from_string (s, &s);
1860 if (structure == NULL) {
1863 gst_caps_append_structure (caps, structure);
1871 * gst_caps_from_string:
1872 * @string: a string to convert to #GstCaps
1874 * Converts @caps from a string representation.
1876 * Returns: a newly allocated #GstCaps
1879 gst_caps_from_string (const gchar * string)
1883 caps = gst_caps_new_empty ();
1884 if (gst_caps_from_string_inplace (caps, string)) {
1887 gst_caps_unref (caps);
1893 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
1895 g_return_if_fail (G_IS_VALUE (src_value));
1896 g_return_if_fail (G_IS_VALUE (dest_value));
1897 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
1898 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
1899 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
1901 dest_value->data[0].v_pointer =
1902 gst_caps_to_string (src_value->data[0].v_pointer);
1906 gst_caps_copy_conditional (GstCaps * src)
1909 return gst_caps_ref (src);