2 * Copyright (C) <2003> David A. Schleef <ds@schleef.org>
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
22 * @short_description: Structure describing sets of media formats
23 * @see_also: #GstStructure
25 * Caps (capabilities) are lighweight refcounted objects describing media types.
26 * They are composed of an array of #GstStructure.
28 * Caps are exposed on #GstPadTemplate to describe all possible types a
29 * given pad can handle. They are also stored in the #GstRegistry along with
30 * a description of the #GstElement.
32 * Caps are exposed on the element pads using the gst_pad_get_caps() pad
33 * function. This function describes the possible types that the pad can
34 * handle or produce at runtime.
36 * Caps are also attached to buffers to describe to content of the data
37 * pointed to by the buffer with gst_buffer_set_caps(). Caps attached to
38 * a #GstBuffer allow for format negotiation upstream and downstream.
40 * A #GstCaps can be constructed with the following code fragment:
43 * <title>Creating caps</title>
46 * caps = gst_caps_new_simple ("video/x-raw-yuv",
47 * "format", GST_TYPE_FOURCC, GST_MAKE_FOURCC ('I', '4', '2', '0'),
48 * "framerate", GST_TYPE_FRACTION, 25, 1,
49 * "pixel-aspect-ratio", GST_TYPE_FRACTION, 1, 1,
50 * "width", G_TYPE_INT, 320,
51 * "height", G_TYPE_INT, 240,
56 * A #GstCaps is fixed when it has no properties with ranges or lists. Use
57 * gst_caps_is_fixed() to test for fixed caps. Only fixed caps can be
58 * set on a #GstPad or #GstBuffer.
60 * Various methods exist to work with the media types such as subtracting
63 * Last reviewed on 2007-02-13 (0.10.10)
72 #include "gst_private.h"
74 #include <gobject/gvaluecollector.h>
76 #define DEBUG_REFCOUNT
78 #define CAPS_POISON(caps) G_STMT_START{ \
80 GstCaps *_newcaps = gst_caps_copy (caps); \
81 gst_caps_unref(caps); \
85 #define STRUCTURE_POISON(structure) G_STMT_START{ \
87 GstStructure *_newstruct = gst_structure_copy (structure); \
88 gst_structure_free(structure); \
89 structure = _newstruct; \
92 #define IS_WRITABLE(caps) \
93 (g_atomic_int_get (&(caps)->refcount) == 1)
95 /* same as gst_caps_is_any () */
96 #define CAPS_IS_ANY(caps) \
97 ((caps)->flags & GST_CAPS_FLAGS_ANY)
99 /* same as gst_caps_is_empty () */
100 #define CAPS_IS_EMPTY(caps) \
101 (!CAPS_IS_ANY(caps) && CAPS_IS_EMPTY_SIMPLE(caps))
103 #define CAPS_IS_EMPTY_SIMPLE(caps) \
104 (((caps)->structs == NULL) || ((caps)->structs->len == 0))
106 /* quick way to get a caps structure at an index without doing a type or array
108 #define gst_caps_get_structure_unchecked(caps, index) \
109 ((GstStructure *)g_ptr_array_index ((caps)->structs, (index)))
110 /* quick way to append a structure without checking the args */
111 #define gst_caps_append_structure_unchecked(caps, structure) G_STMT_START{\
112 GstStructure *__s=structure; \
113 gst_structure_set_parent_refcount (__s, &caps->refcount); \
114 g_ptr_array_add (caps->structs, __s); \
117 /* lock to protect multiple invocations of static caps to caps conversion */
118 G_LOCK_DEFINE_STATIC (static_caps_lock);
120 static void gst_caps_transform_to_string (const GValue * src_value,
121 GValue * dest_value);
122 static gboolean gst_caps_from_string_inplace (GstCaps * caps,
123 const gchar * string);
124 static GstCaps *gst_caps_copy_conditional (GstCaps * src);
127 gst_caps_get_type (void)
129 static GType gst_caps_type = 0;
131 if (G_UNLIKELY (gst_caps_type == 0)) {
132 gst_caps_type = g_boxed_type_register_static ("GstCaps",
133 (GBoxedCopyFunc) gst_caps_copy_conditional,
134 (GBoxedFreeFunc) gst_caps_unref);
136 g_value_register_transform_func (gst_caps_type,
137 G_TYPE_STRING, gst_caps_transform_to_string);
140 return gst_caps_type;
143 /* creation/deletion */
146 * gst_caps_new_empty:
148 * Creates a new #GstCaps that is empty. That is, the returned
149 * #GstCaps contains no media formats.
150 * Caller is responsible for unreffing the returned caps.
152 * Returns: the new #GstCaps
155 gst_caps_new_empty (void)
157 GstCaps *caps = g_slice_new (GstCaps);
159 caps->type = GST_TYPE_CAPS;
162 caps->structs = g_ptr_array_new ();
163 /* the 32 has been determined by logging caps sizes in _gst_caps_free
164 * but g_ptr_array uses 16 anyway if it expands once, so this does not help
166 * caps->structs = g_ptr_array_sized_new (32);
169 #ifdef DEBUG_REFCOUNT
170 GST_CAT_LOG (GST_CAT_CAPS, "created caps %p", caps);
179 * Creates a new #GstCaps that indicates that it is compatible with
182 * Returns: the new #GstCaps
185 gst_caps_new_any (void)
187 GstCaps *caps = gst_caps_new_empty ();
189 caps->flags = GST_CAPS_FLAGS_ANY;
195 * gst_caps_new_simple:
196 * @media_type: the media type of the structure
197 * @fieldname: first field to set
198 * @...: additional arguments
200 * Creates a new #GstCaps that contains one #GstStructure. The
201 * structure is defined by the arguments, which have the same format
202 * as gst_structure_new().
203 * Caller is responsible for unreffing the returned caps.
205 * Returns: the new #GstCaps
208 gst_caps_new_simple (const char *media_type, const char *fieldname, ...)
211 GstStructure *structure;
214 caps = gst_caps_new_empty ();
216 va_start (var_args, fieldname);
217 structure = gst_structure_new_valist (media_type, fieldname, var_args);
220 gst_caps_append_structure_unchecked (caps, structure);
227 * @struct1: the first structure to add
228 * @...: additional structures to add
230 * Creates a new #GstCaps and adds all the structures listed as
231 * arguments. The list must be NULL-terminated. The structures
232 * are not copied; the returned #GstCaps owns the structures.
234 * Returns: the new #GstCaps
237 gst_caps_new_full (GstStructure * struct1, ...)
242 va_start (var_args, struct1);
243 caps = gst_caps_new_full_valist (struct1, var_args);
250 * gst_caps_new_full_valist:
251 * @structure: the first structure to add
252 * @var_args: additional structures to add
254 * Creates a new #GstCaps and adds all the structures listed as
255 * arguments. The list must be NULL-terminated. The structures
256 * are not copied; the returned #GstCaps owns the structures.
258 * Returns: the new #GstCaps
261 gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
265 caps = gst_caps_new_empty ();
268 gst_caps_append_structure_unchecked (caps, structure);
269 structure = va_arg (var_args, GstStructure *);
277 * @caps: the #GstCaps to copy
279 * Creates a new #GstCaps as a copy of the old @caps. The new caps will have a
280 * refcount of 1, owned by the caller. The structures are copied as well.
282 * Note that this function is the semantic equivalent of a gst_caps_ref()
283 * followed by a gst_caps_make_writable(). If you only want to hold on to a
284 * reference to the data, you should use gst_caps_ref().
286 * When you are finished with the caps, call gst_caps_unref() on it.
288 * Returns: the new #GstCaps
291 gst_caps_copy (const GstCaps * caps)
294 GstStructure *structure;
297 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
299 newcaps = gst_caps_new_empty ();
300 newcaps->flags = caps->flags;
301 n = caps->structs->len;
303 for (i = 0; i < n; i++) {
304 structure = gst_caps_get_structure_unchecked (caps, i);
305 gst_caps_append_structure_unchecked (newcaps,
306 gst_structure_copy (structure));
313 _gst_caps_free (GstCaps * caps)
315 GstStructure *structure;
318 /* The refcount must be 0, but since we're only called by gst_caps_unref,
319 * don't bother testing. */
320 len = caps->structs->len;
321 /* This can be used to get statistics about caps sizes */
322 /*GST_CAT_INFO (GST_CAT_CAPS, "caps size: %d", len); */
323 for (i = 0; i < len; i++) {
324 structure = (GstStructure *) gst_caps_get_structure_unchecked (caps, i);
325 gst_structure_set_parent_refcount (structure, NULL);
326 gst_structure_free (structure);
328 g_ptr_array_free (caps->structs, TRUE);
330 memset (caps, 0xff, sizeof (GstCaps));
333 #ifdef DEBUG_REFCOUNT
334 GST_CAT_LOG (GST_CAT_CAPS, "freeing caps %p", caps);
336 g_slice_free (GstCaps, caps);
340 * gst_caps_make_writable:
341 * @caps: the #GstCaps to make writable
343 * Returns a writable copy of @caps.
345 * If there is only one reference count on @caps, the caller must be the owner,
346 * and so this function will return the caps object unchanged. If on the other
347 * hand there is more than one reference on the object, a new caps object will
348 * be returned. The caller's reference on @caps will be removed, and instead the
349 * caller will own a reference to the returned object.
351 * In short, this function unrefs the caps in the argument and refs the caps
352 * that it returns. Don't access the argument after calling this function. See
353 * also: gst_caps_ref().
355 * Returns: the same #GstCaps object.
358 gst_caps_make_writable (GstCaps * caps)
362 g_return_val_if_fail (caps != NULL, NULL);
364 /* we are the only instance reffing this caps */
365 if (IS_WRITABLE (caps))
369 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy caps");
370 copy = gst_caps_copy (caps);
371 gst_caps_unref (caps);
378 * @caps: the #GstCaps to reference
380 * Add a reference to a #GstCaps object.
382 * From this point on, until the caller calls gst_caps_unref() or
383 * gst_caps_make_writable(), it is guaranteed that the caps object will not
384 * change. This means its structures won't change, etc. To use a #GstCaps
385 * object, you must always have a refcount on it -- either the one made
386 * implicitly by e.g. gst_caps_new_simple(), or via taking one explicitly with
389 * Returns: the same #GstCaps object.
392 gst_caps_ref (GstCaps * caps)
394 g_return_val_if_fail (caps != NULL, NULL);
396 #ifdef DEBUG_REFCOUNT
397 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
398 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) + 1);
400 g_return_val_if_fail (GST_CAPS_REFCOUNT_VALUE (caps), NULL);
402 g_atomic_int_inc (&caps->refcount);
409 * @caps: the #GstCaps to unref
411 * Unref a #GstCaps and and free all its structures and the
412 * structures' values when the refcount reaches 0.
415 gst_caps_unref (GstCaps * caps)
417 g_return_if_fail (caps != NULL);
419 #ifdef DEBUG_REFCOUNT
420 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
421 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) - 1);
424 g_return_if_fail (GST_CAPS_REFCOUNT_VALUE (caps));
426 /* if we ended up with the refcount at zero, free the caps */
427 if (G_UNLIKELY (g_atomic_int_dec_and_test (&caps->refcount)))
428 _gst_caps_free (caps);
432 gst_static_caps_get_type (void)
434 static GType staticcaps_type = 0;
436 if (G_UNLIKELY (staticcaps_type == 0)) {
437 staticcaps_type = g_pointer_type_register_static ("GstStaticCaps");
439 return staticcaps_type;
444 * gst_static_caps_get:
445 * @static_caps: the #GstStaticCaps to convert
447 * Converts a #GstStaticCaps to a #GstCaps.
449 * Returns: A pointer to the #GstCaps. Unref after usage. Since the
450 * core holds an additional ref to the returned caps,
451 * use gst_caps_make_writable() on the returned caps to modify it.
454 gst_static_caps_get (GstStaticCaps * static_caps)
458 g_return_val_if_fail (static_caps != NULL, NULL);
460 caps = (GstCaps *) static_caps;
462 /* refcount is 0 when we need to convert */
463 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount) == 0)) {
467 G_LOCK (static_caps_lock);
468 /* check if other thread already updated */
469 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount)))
472 string = static_caps->string;
474 if (G_UNLIKELY (string == NULL))
477 GST_CAT_LOG (GST_CAT_CAPS, "creating %p", static_caps);
479 /* we construct the caps on the stack, then copy over the struct into our
480 * real caps, refcount last. We do this because we must leave the refcount
481 * of the result caps to 0 so that other threads don't run away with the
482 * caps while we are constructing it. */
483 temp.type = GST_TYPE_CAPS;
485 temp.structs = g_ptr_array_new ();
487 /* initialize the caps to a refcount of 1 so the caps can be writable for
488 * the next statement */
491 /* convert to string */
492 if (G_UNLIKELY (!gst_caps_from_string_inplace (&temp, string)))
493 g_critical ("Could not convert static caps \"%s\"", string);
495 /* now copy stuff over to the real caps. */
496 caps->type = temp.type;
497 caps->flags = temp.flags;
498 caps->structs = temp.structs;
499 /* and bump the refcount so other threads can now read */
500 g_atomic_int_set (&caps->refcount, 1);
502 GST_CAT_LOG (GST_CAT_CAPS, "created %p", static_caps);
504 G_UNLOCK (static_caps_lock);
506 /* ref the caps, makes it not writable */
514 G_UNLOCK (static_caps_lock);
515 g_warning ("static caps %p string is NULL", static_caps);
522 static GstStructure *
523 gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
525 /* don't use index_fast, gst_caps_do_simplify relies on the order */
526 GstStructure *s = g_ptr_array_remove_index (caps->structs, idx);
528 gst_structure_set_parent_refcount (s, NULL);
533 * gst_caps_steal_structure:
534 * @caps: the #GstCaps to retrieve from
535 * @index: Index of the structure to retrieve
537 * Retrieves the stucture with the given index from the list of structures
538 * contained in @caps. The caller becomes the owner of the returned structure.
540 * Returns: a pointer to the #GstStructure corresponding to @index.
545 gst_caps_steal_structure (GstCaps * caps, guint index)
547 g_return_val_if_fail (caps != NULL, NULL);
548 g_return_val_if_fail (IS_WRITABLE (caps), NULL);
550 if (G_UNLIKELY (index >= caps->structs->len))
553 return gst_caps_remove_and_get_structure (caps, index);
557 gst_structure_is_equal_foreach (GQuark field_id, const GValue * val2,
560 GstStructure *struct1 = (GstStructure *) data;
561 const GValue *val1 = gst_structure_id_get_value (struct1, field_id);
563 if (G_UNLIKELY (val1 == NULL))
565 if (gst_value_compare (val1, val2) == GST_VALUE_EQUAL) {
573 gst_caps_structure_is_subset_field (GQuark field_id, const GValue * value,
576 GstStructure *subtract_from = user_data;
577 GValue subtraction = { 0, };
580 if (!(other = gst_structure_id_get_value (subtract_from, field_id)))
581 /* field is missing in one set */
584 /* equal values are subset */
585 if (gst_value_compare (other, value) == GST_VALUE_EQUAL)
593 * -> 1 - [1,2] = empty
597 * -> [1,2] - [1,3] = empty
601 * -> {1,3} - {1,2} = 3
604 * First caps subtraction needs to return a non-empty set, second
605 * subtractions needs to give en empty set.
607 if (gst_value_subtract (&subtraction, other, value)) {
608 g_value_unset (&subtraction);
609 /* !empty result, swapping must be empty */
610 if (!gst_value_subtract (&subtraction, value, other))
613 g_value_unset (&subtraction);
619 gst_caps_structure_is_subset (const GstStructure * minuend,
620 const GstStructure * subtrahend)
622 if ((minuend->name != subtrahend->name) ||
623 (gst_structure_n_fields (minuend) !=
624 gst_structure_n_fields (subtrahend))) {
628 return gst_structure_foreach ((GstStructure *) subtrahend,
629 gst_caps_structure_is_subset_field, (gpointer) minuend);
634 * @caps1: the #GstCaps that will be appended to
635 * @caps2: the #GstCaps to append
637 * Appends the structures contained in @caps2 to @caps1. The structures in
638 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
639 * freed. If either caps is ANY, the resulting caps will be ANY.
642 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
644 GstStructure *structure;
647 g_return_if_fail (GST_IS_CAPS (caps1));
648 g_return_if_fail (GST_IS_CAPS (caps2));
649 g_return_if_fail (IS_WRITABLE (caps1));
650 g_return_if_fail (IS_WRITABLE (caps2));
655 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))) {
656 /* FIXME: this leaks */
657 caps1->flags |= GST_CAPS_FLAGS_ANY;
658 for (i = caps2->structs->len - 1; i >= 0; i--) {
659 structure = gst_caps_remove_and_get_structure (caps2, i);
660 gst_structure_free (structure);
663 for (i = caps2->structs->len; i; i--) {
664 structure = gst_caps_remove_and_get_structure (caps2, 0);
665 gst_caps_append_structure_unchecked (caps1, structure);
668 gst_caps_unref (caps2); /* guaranteed to free it */
673 * @caps1: the #GstCaps that will take the new entries
674 * @caps2: the #GstCaps to merge in
676 * Appends the structures contained in @caps2 to @caps1 if they are not yet
677 * expressed by @caps1. The structures in @caps2 are not copied -- they are
678 * transferred to @caps1, and then @caps2 is freed.
679 * If either caps is ANY, the resulting caps will be ANY.
684 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
686 GstStructure *structure;
689 g_return_if_fail (GST_IS_CAPS (caps1));
690 g_return_if_fail (GST_IS_CAPS (caps2));
691 g_return_if_fail (IS_WRITABLE (caps1));
692 g_return_if_fail (IS_WRITABLE (caps2));
697 if (G_UNLIKELY (CAPS_IS_ANY (caps1))) {
698 for (i = caps2->structs->len - 1; i >= 0; i--) {
699 structure = gst_caps_remove_and_get_structure (caps2, i);
700 gst_structure_free (structure);
702 } else if (G_UNLIKELY (CAPS_IS_ANY (caps2))) {
703 caps1->flags |= GST_CAPS_FLAGS_ANY;
704 for (i = caps1->structs->len - 1; i >= 0; i--) {
705 structure = gst_caps_remove_and_get_structure (caps1, i);
706 gst_structure_free (structure);
709 for (i = caps2->structs->len; i; i--) {
710 structure = gst_caps_remove_and_get_structure (caps2, 0);
711 gst_caps_merge_structure (caps1, structure);
714 GstCaps *com = gst_caps_intersect (caps1, caps2);
715 GstCaps *add = gst_caps_subtract (caps2, com);
717 GST_DEBUG ("common : %d", gst_caps_get_size (com));
718 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
719 gst_caps_append (caps1, add);
720 gst_caps_unref (com);
723 gst_caps_unref (caps2); /* guaranteed to free it */
727 * gst_caps_append_structure:
728 * @caps: the #GstCaps that will be appended to
729 * @structure: the #GstStructure to append
731 * Appends @structure to @caps. The structure is not copied; @caps
732 * becomes the owner of @structure.
735 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
737 g_return_if_fail (GST_IS_CAPS (caps));
738 g_return_if_fail (IS_WRITABLE (caps));
740 if (G_LIKELY (structure)) {
741 g_return_if_fail (structure->parent_refcount == NULL);
744 STRUCTURE_POISON (structure);
747 gst_caps_append_structure_unchecked (caps, structure);
752 * gst_caps_remove_structure:
753 * @caps: the #GstCaps to remove from
754 * @idx: Index of the structure to remove
756 * removes the stucture with the given index from the list of structures
757 * contained in @caps.
760 gst_caps_remove_structure (GstCaps * caps, guint idx)
762 GstStructure *structure;
764 g_return_if_fail (caps != NULL);
765 g_return_if_fail (idx <= gst_caps_get_size (caps));
766 g_return_if_fail (IS_WRITABLE (caps));
768 structure = gst_caps_remove_and_get_structure (caps, idx);
769 gst_structure_free (structure);
773 * gst_caps_merge_structure:
774 * @caps: the #GstCaps that will the the new structure
775 * @structure: the #GstStructure to merge
777 * Appends @structure to @caps if its not already expressed by @caps. The
778 * structure is not copied; @caps becomes the owner of @structure.
781 gst_caps_merge_structure (GstCaps * caps, GstStructure * structure)
783 g_return_if_fail (GST_IS_CAPS (caps));
784 g_return_if_fail (IS_WRITABLE (caps));
786 if (G_LIKELY (structure)) {
787 GstStructure *structure1;
789 gboolean unique = TRUE;
791 g_return_if_fail (structure->parent_refcount == NULL);
794 STRUCTURE_POISON (structure);
797 /* check each structure */
798 for (i = caps->structs->len - 1; i >= 0; i--) {
799 structure1 = gst_caps_get_structure_unchecked (caps, i);
800 /* if structure is a subset of structure1, then skip it */
801 if (gst_caps_structure_is_subset (structure1, structure)) {
807 gst_caps_append_structure_unchecked (caps, structure);
809 gst_structure_free (structure);
818 * Gets the number of structures contained in @caps.
820 * Returns: the number of structures that @caps contains
823 gst_caps_get_size (const GstCaps * caps)
825 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
827 return caps->structs->len;
831 * gst_caps_get_structure:
833 * @index: the index of the structure
835 * Finds the structure in @caps that has the index @index, and
838 * WARNING: This function takes a const GstCaps *, but returns a
839 * non-const GstStructure *. This is for programming convenience --
840 * the caller should be aware that structures inside a constant
841 * #GstCaps should not be modified. However, if you know the caps
842 * are writable, either because you have just copied them or made
843 * them writable with gst_caps_make_writable(), you may modify the
844 * structure returned in the usual way, e.g. with functions like
845 * gst_structure_set().
847 * You do not need to free or unref the structure returned, it
848 * belongs to the #GstCaps.
850 * Returns: a pointer to the #GstStructure corresponding to @index
853 gst_caps_get_structure (const GstCaps * caps, guint index)
855 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
856 g_return_val_if_fail (index < caps->structs->len, NULL);
858 return gst_caps_get_structure_unchecked (caps, index);
863 * @caps: the #GstCaps to copy
864 * @nth: the nth structure to copy
866 * Creates a new #GstCaps and appends a copy of the nth structure
867 * contained in @caps.
869 * Returns: the new #GstCaps
872 gst_caps_copy_nth (const GstCaps * caps, guint nth)
875 GstStructure *structure;
877 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
879 newcaps = gst_caps_new_empty ();
880 newcaps->flags = caps->flags;
882 if (G_LIKELY (caps->structs->len > nth)) {
883 structure = gst_caps_get_structure_unchecked (caps, nth);
884 gst_caps_append_structure_unchecked (newcaps,
885 gst_structure_copy (structure));
893 * @caps: the #GstCaps to truncate
895 * Destructively discard all but the first structure from @caps. Useful when
896 * fixating. @caps must be writable.
899 gst_caps_truncate (GstCaps * caps)
903 g_return_if_fail (GST_IS_CAPS (caps));
904 g_return_if_fail (IS_WRITABLE (caps));
906 i = caps->structs->len - 1;
909 gst_caps_remove_structure (caps, i--);
913 * gst_caps_set_value:
914 * @caps: a writable caps
915 * @field: name of the field to set
916 * @value: value to set the field to
918 * Sets the given @field on all structures of @caps to the given @value.
919 * This is a convenience function for calling gst_structure_set_value() on
920 * all structures of @caps.
925 gst_caps_set_value (GstCaps * caps, const char *field, const GValue * value)
929 g_return_if_fail (GST_IS_CAPS (caps));
930 g_return_if_fail (IS_WRITABLE (caps));
931 g_return_if_fail (field != NULL);
932 g_return_if_fail (G_IS_VALUE (value));
934 len = caps->structs->len;
935 for (i = 0; i < len; i++) {
936 GstStructure *structure = gst_caps_get_structure_unchecked (caps, i);
937 gst_structure_set_value (structure, field, value);
942 * gst_caps_set_simple_valist:
943 * @caps: the #GstCaps to set
944 * @field: first field to set
945 * @varargs: additional parameters
947 * Sets fields in a #GstCaps. The arguments must be passed in the same
948 * manner as gst_structure_set(), and be NULL-terminated.
949 * <note>Prior to GStreamer version 0.10.26, this function failed when
950 * @caps was not simple. If your code needs to work with those versions
951 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
952 * is %TRUE for @caps.</note>
955 gst_caps_set_simple_valist (GstCaps * caps, const char *field, va_list varargs)
957 GValue value = { 0, };
959 g_return_if_fail (GST_IS_CAPS (caps));
960 g_return_if_fail (IS_WRITABLE (caps));
966 type = va_arg (varargs, GType);
968 if (G_UNLIKELY (type == G_TYPE_DATE)) {
969 g_warning ("Don't use G_TYPE_DATE, use GST_TYPE_DATE instead\n");
970 type = GST_TYPE_DATE;
972 #if GLIB_CHECK_VERSION(2,23,3)
973 G_VALUE_COLLECT_INIT (&value, type, varargs, 0, &err);
975 g_value_init (&value, type);
976 G_VALUE_COLLECT (&value, varargs, 0, &err);
978 if (G_UNLIKELY (err)) {
979 g_critical ("%s", err);
983 gst_caps_set_value (caps, field, &value);
985 g_value_unset (&value);
987 field = va_arg (varargs, const gchar *);
992 * gst_caps_set_simple:
993 * @caps: the #GstCaps to set
994 * @field: first field to set
995 * @...: additional parameters
997 * Sets fields in a #GstCaps. The arguments must be passed in the same
998 * manner as gst_structure_set(), and be NULL-terminated.
999 * <note>Prior to GStreamer version 0.10.26, this function failed when
1000 * @caps was not simple. If your code needs to work with those versions
1001 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
1002 * is %TRUE for @caps.</note>
1005 gst_caps_set_simple (GstCaps * caps, const char *field, ...)
1009 g_return_if_fail (GST_IS_CAPS (caps));
1010 g_return_if_fail (IS_WRITABLE (caps));
1012 va_start (var_args, field);
1013 gst_caps_set_simple_valist (caps, field, var_args);
1021 * @caps: the #GstCaps to test
1023 * Determines if @caps represents any media format.
1025 * Returns: TRUE if @caps represents any format.
1028 gst_caps_is_any (const GstCaps * caps)
1030 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1032 return (CAPS_IS_ANY (caps));
1036 * gst_caps_is_empty:
1037 * @caps: the #GstCaps to test
1039 * Determines if @caps represents no media formats.
1041 * Returns: TRUE if @caps represents no formats.
1044 gst_caps_is_empty (const GstCaps * caps)
1046 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1048 if (CAPS_IS_ANY (caps))
1051 return CAPS_IS_EMPTY_SIMPLE (caps);
1055 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
1058 return gst_value_is_fixed (value);
1062 * gst_caps_is_fixed:
1063 * @caps: the #GstCaps to test
1065 * Fixed #GstCaps describe exactly one format, that is, they have exactly
1066 * one structure, and each field in the structure describes a fixed type.
1067 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
1069 * Returns: TRUE if @caps is fixed
1072 gst_caps_is_fixed (const GstCaps * caps)
1074 GstStructure *structure;
1076 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1078 if (caps->structs->len != 1)
1081 structure = gst_caps_get_structure_unchecked (caps, 0);
1083 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
1087 * gst_caps_is_equal_fixed:
1088 * @caps1: the #GstCaps to test
1089 * @caps2: the #GstCaps to test
1091 * Tests if two #GstCaps are equal. This function only works on fixed
1094 * Returns: TRUE if the arguments represent the same format
1097 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
1099 GstStructure *struct1, *struct2;
1101 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
1102 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
1104 struct1 = gst_caps_get_structure_unchecked (caps1, 0);
1105 struct2 = gst_caps_get_structure_unchecked (caps2, 0);
1107 if (struct1->name != struct2->name) {
1110 if (struct1->fields->len != struct2->fields->len) {
1114 return gst_structure_foreach (struct1, gst_structure_is_equal_foreach,
1119 * gst_caps_is_always_compatible:
1120 * @caps1: the #GstCaps to test
1121 * @caps2: the #GstCaps to test
1123 * A given #GstCaps structure is always compatible with another if
1124 * every media format that is in the first is also contained in the
1125 * second. That is, @caps1 is a subset of @caps2.
1127 * Returns: TRUE if @caps1 is a subset of @caps2.
1130 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
1132 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1133 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1135 return gst_caps_is_subset (caps1, caps2);
1139 * gst_caps_is_subset:
1140 * @subset: a #GstCaps
1141 * @superset: a potentially greater #GstCaps
1143 * Checks if all caps represented by @subset are also represented by @superset.
1144 * <note>This function does not work reliably if optional properties for caps
1145 * are included on one caps and omitted on the other.</note>
1147 * Returns: %TRUE if @subset is a subset of @superset
1150 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
1155 g_return_val_if_fail (subset != NULL, FALSE);
1156 g_return_val_if_fail (superset != NULL, FALSE);
1158 if (CAPS_IS_EMPTY (subset) || CAPS_IS_ANY (superset))
1160 if (CAPS_IS_ANY (subset) || CAPS_IS_EMPTY (superset))
1163 caps = gst_caps_subtract (subset, superset);
1164 ret = CAPS_IS_EMPTY_SIMPLE (caps);
1165 gst_caps_unref (caps);
1170 * gst_caps_is_equal:
1171 * @caps1: a #GstCaps
1172 * @caps2: another #GstCaps
1174 * Checks if the given caps represent the same set of caps.
1175 * <note>This function does not work reliably if optional properties for caps
1176 * are included on one caps and omitted on the other.</note>
1178 * This function deals correctly with passing NULL for any of the caps.
1180 * Returns: TRUE if both caps are equal.
1183 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1185 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1186 * So there should be an assertion that caps1 and caps2 != NULL */
1188 /* NULL <-> NULL is allowed here */
1189 if (G_UNLIKELY (caps1 == caps2))
1192 /* one of them NULL => they are different (can't be both NULL because
1193 * we checked that above) */
1194 if (G_UNLIKELY (caps1 == NULL || caps2 == NULL))
1197 if (G_UNLIKELY (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2)))
1198 return gst_caps_is_equal_fixed (caps1, caps2);
1200 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1203 /* intersect operation */
1208 const GstStructure *intersect;
1213 gst_caps_structure_intersect_field1 (GQuark id, const GValue * val1,
1216 IntersectData *idata = (IntersectData *) data;
1217 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1219 if (G_UNLIKELY (val2 == NULL)) {
1220 gst_structure_id_set_value (idata->dest, id, val1);
1222 GValue dest_value = { 0 };
1223 if (gst_value_intersect (&dest_value, val1, val2)) {
1224 gst_structure_id_set_value (idata->dest, id, &dest_value);
1225 g_value_unset (&dest_value);
1234 gst_caps_structure_intersect_field2 (GQuark id, const GValue * val1,
1237 IntersectData *idata = (IntersectData *) data;
1238 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1240 if (G_UNLIKELY (val2 == NULL)) {
1241 gst_structure_id_set_value (idata->dest, id, val1);
1246 static GstStructure *
1247 gst_caps_structure_intersect (const GstStructure * struct1,
1248 const GstStructure * struct2)
1252 g_assert (struct1 != NULL);
1253 g_assert (struct2 != NULL);
1255 if (G_UNLIKELY (struct1->name != struct2->name))
1258 /* copy fields from struct1 which we have not in struct2 to target
1259 * intersect if we have the field in both */
1260 data.dest = gst_structure_id_empty_new (struct1->name);
1261 data.intersect = struct2;
1262 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1263 gst_caps_structure_intersect_field1, &data)))
1266 /* copy fields from struct2 which we have not in struct1 to target */
1267 data.intersect = struct1;
1268 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct2,
1269 gst_caps_structure_intersect_field2, &data)))
1275 gst_structure_free (data.dest);
1280 gst_caps_structure_can_intersect_field (GQuark id, const GValue * val1,
1283 GstStructure *other = (GstStructure *) data;
1284 const GValue *val2 = gst_structure_id_get_value (other, id);
1286 if (G_LIKELY (val2)) {
1287 if (!gst_value_can_intersect (val1, val2)) {
1290 gint eq = gst_value_compare (val1, val2);
1292 if (eq == GST_VALUE_UNORDERED) {
1293 /* we need to try interseting */
1294 GValue dest_value = { 0 };
1295 if (gst_value_intersect (&dest_value, val1, val2)) {
1296 g_value_unset (&dest_value);
1300 } else if (eq != GST_VALUE_EQUAL) {
1309 gst_caps_structure_can_intersect (const GstStructure * struct1,
1310 const GstStructure * struct2)
1312 g_assert (struct1 != NULL);
1313 g_assert (struct2 != NULL);
1315 if (G_UNLIKELY (struct1->name != struct2->name))
1318 /* tries to intersect if we have the field in both */
1319 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1320 gst_caps_structure_can_intersect_field, (gpointer) struct2)))
1327 * gst_caps_can_intersect:
1328 * @caps1: a #GstCaps to intersect
1329 * @caps2: a #GstCaps to intersect
1331 * Tries intersecting @caps1 and @caps2 and reports whether the result would not
1334 * Returns: %TRUE if intersection would be not empty
1339 gst_caps_can_intersect (const GstCaps * caps1, const GstCaps * caps2)
1341 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1342 guint j, k, len1, len2;
1343 GstStructure *struct1;
1344 GstStructure *struct2;
1346 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1347 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1349 /* caps are exactly the same pointers */
1350 if (G_UNLIKELY (caps1 == caps2))
1353 /* empty caps on either side, return empty */
1354 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1357 /* one of the caps is any */
1358 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2)))
1361 /* run zigzag on top line then right line, this preserves the caps order
1362 * much better than a simple loop.
1364 * This algorithm zigzags over the caps structures as demonstrated in
1365 * the folowing matrix:
1368 * +------------- total distance: +-------------
1369 * | 1 2 4 7 0 | 0 1 2 3
1370 * caps2 | 3 5 8 10 1 | 1 2 3 4
1371 * | 6 9 11 12 2 | 2 3 4 5
1373 * First we iterate over the caps1 structures (top line) intersecting
1374 * the structures diagonally down, then we iterate over the caps2
1375 * structures. The result is that the intersections are ordered based on the
1376 * sum of the indexes in the list.
1378 len1 = caps1->structs->len;
1379 len2 = caps2->structs->len;
1380 for (i = 0; i < len1 + len2 - 1; i++) {
1381 /* superset index goes from 0 to sgst_caps_structure_intersectuperset->structs->len-1 */
1382 j = MIN (i, len1 - 1);
1383 /* subset index stays 0 until i reaches superset->structs->len, then it
1384 * counts up from 1 to subset->structs->len - 1 */
1387 /* now run the diagonal line, end condition is the left or bottom
1390 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1391 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1393 if (gst_caps_structure_can_intersect (struct1, struct2)) {
1396 /* move down left */
1398 if (G_UNLIKELY (j == 0))
1399 break; /* so we don't roll back to G_MAXUINT */
1407 * gst_caps_intersect:
1408 * @caps1: a #GstCaps to intersect
1409 * @caps2: a #GstCaps to intersect
1411 * Creates a new #GstCaps that contains all the formats that are common
1412 * to both @caps1 and @caps2.
1414 * Returns: the new #GstCaps
1417 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1419 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1420 guint j, k, len1, len2;
1422 GstStructure *struct1;
1423 GstStructure *struct2;
1425 GstStructure *istruct;
1427 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1428 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1430 /* caps are exactly the same pointers, just copy one caps */
1431 if (G_UNLIKELY (caps1 == caps2))
1432 return gst_caps_copy (caps1);
1434 /* empty caps on either side, return empty */
1435 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1436 return gst_caps_new_empty ();
1438 /* one of the caps is any, just copy the other caps */
1439 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1440 return gst_caps_copy (caps2);
1441 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1442 return gst_caps_copy (caps1);
1444 dest = gst_caps_new_empty ();
1446 /* run zigzag on top line then right line, this preserves the caps order
1447 * much better than a simple loop.
1449 * This algorithm zigzags over the caps structures as demonstrated in
1450 * the folowing matrix:
1458 * First we iterate over the caps1 structures (top line) intersecting
1459 * the structures diagonally down, then we iterate over the caps2
1462 len1 = caps1->structs->len;
1463 len2 = caps2->structs->len;
1464 for (i = 0; i < len1 + len2 - 1; i++) {
1465 /* caps1 index goes from 0 to caps1->structs->len-1 */
1466 j = MIN (i, len1 - 1);
1467 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1468 * up from 1 to caps2->structs->len - 1 */
1471 /* now run the diagonal line, end condition is the left or bottom
1474 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1475 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1477 istruct = gst_caps_structure_intersect (struct1, struct2);
1479 gst_caps_append_structure (dest, istruct);
1480 /* move down left */
1482 if (G_UNLIKELY (j == 0))
1483 break; /* so we don't roll back to G_MAXUINT */
1490 /* subtract operation */
1494 const GstStructure *subtract_from;
1500 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1503 SubtractionEntry *e = user_data;
1504 GValue subtraction = { 0, };
1505 const GValue *other;
1506 GstStructure *structure;
1508 other = gst_structure_id_get_value (e->subtract_from, field_id);
1512 if (!gst_value_subtract (&subtraction, other, value))
1514 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1515 g_value_unset (&subtraction);
1518 structure = gst_structure_copy (e->subtract_from);
1519 gst_structure_id_set_value (structure, field_id, &subtraction);
1520 g_value_unset (&subtraction);
1521 e->put_into = g_slist_prepend (e->put_into, structure);
1527 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1528 const GstStructure * subtrahend)
1533 e.subtract_from = minuend;
1536 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1537 gst_caps_structure_subtract_field, &e);
1543 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1544 gst_structure_free (walk->data);
1546 g_slist_free (e.put_into);
1552 * gst_caps_subtract:
1553 * @minuend: #GstCaps to substract from
1554 * @subtrahend: #GstCaps to substract
1556 * Subtracts the @subtrahend from the @minuend.
1557 * <note>This function does not work reliably if optional properties for caps
1558 * are included on one caps and omitted on the other.</note>
1560 * Returns: the resulting caps
1563 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1568 GstCaps *dest = NULL, *src;
1570 g_return_val_if_fail (minuend != NULL, NULL);
1571 g_return_val_if_fail (subtrahend != NULL, NULL);
1573 if (CAPS_IS_EMPTY (minuend) || CAPS_IS_ANY (subtrahend)) {
1574 return gst_caps_new_empty ();
1576 if (CAPS_IS_EMPTY_SIMPLE (subtrahend))
1577 return gst_caps_copy (minuend);
1579 /* FIXME: Do we want this here or above?
1580 The reason we need this is that there is no definition about what
1581 ANY means for specific types, so it's not possible to reduce ANY partially
1582 You can only remove everything or nothing and that is done above.
1583 Note: there's a test that checks this behaviour. */
1584 g_return_val_if_fail (!CAPS_IS_ANY (minuend), NULL);
1585 sublen = subtrahend->structs->len;
1588 src = gst_caps_copy (minuend);
1589 for (i = 0; i < sublen; i++) {
1592 sub = gst_caps_get_structure_unchecked (subtrahend, i);
1594 gst_caps_unref (src);
1597 dest = gst_caps_new_empty ();
1598 srclen = src->structs->len;
1599 for (j = 0; j < srclen; j++) {
1600 min = gst_caps_get_structure_unchecked (src, j);
1601 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1604 if (gst_caps_structure_subtract (&list, min, sub)) {
1607 for (walk = list; walk; walk = g_slist_next (walk)) {
1608 gst_caps_append_structure_unchecked (dest,
1609 (GstStructure *) walk->data);
1611 g_slist_free (list);
1613 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1616 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1619 if (CAPS_IS_EMPTY_SIMPLE (dest)) {
1620 gst_caps_unref (src);
1625 gst_caps_unref (src);
1626 gst_caps_do_simplify (dest);
1630 /* union operation */
1633 static GstStructure *
1634 gst_caps_structure_union (const GstStructure * struct1,
1635 const GstStructure * struct2)
1639 const GstStructureField *field1;
1640 const GstStructureField *field2;
1643 /* FIXME this doesn't actually work */
1645 if (struct1->name != struct2->name)
1648 dest = gst_structure_id_empty_new (struct1->name);
1650 for (i = 0; i < struct1->fields->len; i++) {
1651 GValue dest_value = { 0 };
1653 field1 = GST_STRUCTURE_FIELD (struct1, i);
1654 field2 = gst_structure_id_get_field (struct2, field1->name);
1656 if (field2 == NULL) {
1659 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1660 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1663 ret = gst_value_compare (&field1->value, &field2->value);
1674 * @caps1: a #GstCaps to union
1675 * @caps2: a #GstCaps to union
1677 * Creates a new #GstCaps that contains all the formats that are in
1678 * either @caps1 and @caps2.
1680 * Returns: the new #GstCaps
1683 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1688 /* NULL pointers are no correct GstCaps */
1689 g_return_val_if_fail (caps1 != NULL, NULL);
1690 g_return_val_if_fail (caps2 != NULL, NULL);
1692 if (CAPS_IS_EMPTY (caps1))
1693 return gst_caps_copy (caps2);
1695 if (CAPS_IS_EMPTY (caps2))
1696 return gst_caps_copy (caps1);
1698 if (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))
1699 return gst_caps_new_any ();
1701 dest1 = gst_caps_copy (caps1);
1702 dest2 = gst_caps_copy (caps2);
1703 gst_caps_append (dest1, dest2);
1705 gst_caps_do_simplify (dest1);
1709 /* normalize/simplify operations */
1711 typedef struct _NormalizeForeach
1714 GstStructure *structure;
1719 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1721 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1725 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1726 guint len = gst_value_list_get_size (value);
1727 for (i = 1; i < len; i++) {
1728 const GValue *v = gst_value_list_get_value (value, i);
1729 GstStructure *structure = gst_structure_copy (nf->structure);
1731 gst_structure_id_set_value (structure, field_id, v);
1732 gst_caps_append_structure_unchecked (nf->caps, structure);
1735 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1736 gst_structure_id_set_value (nf->structure, field_id, &val);
1737 g_value_unset (&val);
1745 * gst_caps_normalize:
1746 * @caps: a #GstCaps to normalize
1748 * Creates a new #GstCaps that represents the same set of formats as
1749 * @caps, but contains no lists. Each list is expanded into separate
1752 * Returns: the new #GstCaps
1755 gst_caps_normalize (const GstCaps * caps)
1757 NormalizeForeach nf;
1761 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1763 newcaps = gst_caps_copy (caps);
1766 for (i = 0; i < gst_caps_get_size (newcaps); i++) {
1767 nf.structure = gst_caps_get_structure_unchecked (newcaps, i);
1769 while (!gst_structure_foreach (nf.structure,
1770 gst_caps_normalize_foreach, &nf));
1777 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1780 const GstStructure *struct1 = *((const GstStructure **) one);
1781 const GstStructure *struct2 = *((const GstStructure **) two);
1783 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1784 So what's the best way? */
1785 ret = strcmp (gst_structure_get_name (struct1),
1786 gst_structure_get_name (struct2));
1790 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1797 GstStructure *compare;
1802 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1805 UnionField *u = user_data;
1806 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1810 g_value_unset (&u->value);
1813 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1816 g_value_unset (&u->value);
1820 gst_value_union (&u->value, val, value);
1825 gst_caps_structure_simplify (GstStructure ** result,
1826 const GstStructure * simplify, GstStructure * compare)
1829 UnionField field = { 0, {0,}, NULL };
1831 /* try to subtract to get a real subset */
1832 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1833 if (list == NULL) { /* no result */
1836 } else if (list->next == NULL) { /* one result */
1837 *result = list->data;
1838 g_slist_free (list);
1840 } else { /* multiple results */
1841 g_slist_foreach (list, (GFunc) gst_structure_free, NULL);
1842 g_slist_free (list);
1847 /* try to union both structs */
1848 field.compare = compare;
1849 if (gst_structure_foreach ((GstStructure *) simplify,
1850 gst_caps_structure_figure_out_union, &field)) {
1851 gboolean ret = FALSE;
1853 /* now we know all of simplify's fields are the same in compare
1854 * but at most one field: field.name */
1855 if (G_IS_VALUE (&field.value)) {
1856 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1857 gst_structure_id_set_value (compare, field.name, &field.value);
1861 g_value_unset (&field.value);
1862 } else if (gst_structure_n_fields (simplify) <=
1863 gst_structure_n_fields (compare)) {
1864 /* compare is just more specific, will be optimized away later */
1865 /* FIXME: do this here? */
1866 GST_LOG ("found a case that will be optimized later.");
1868 gchar *one = gst_structure_to_string (simplify);
1869 gchar *two = gst_structure_to_string (compare);
1872 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1884 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1885 GstStructure * new, gint i)
1887 gst_structure_set_parent_refcount (old, NULL);
1888 gst_structure_free (old);
1889 gst_structure_set_parent_refcount (new, &caps->refcount);
1890 g_ptr_array_index (caps->structs, i) = new;
1894 * gst_caps_do_simplify:
1895 * @caps: a #GstCaps to simplify
1897 * Modifies the given @caps inplace into a representation that represents the
1898 * same set of formats, but in a simpler form. Component structures that are
1899 * identical are merged. Component structures that have values that can be
1900 * merged are also merged.
1902 * Returns: TRUE, if the caps could be simplified
1905 gst_caps_do_simplify (GstCaps * caps)
1907 GstStructure *simplify, *compare, *result = NULL;
1909 gboolean changed = FALSE;
1911 g_return_val_if_fail (caps != NULL, FALSE);
1912 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1914 if (gst_caps_get_size (caps) < 2)
1917 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1919 start = caps->structs->len - 1;
1920 for (i = caps->structs->len - 1; i >= 0; i--) {
1921 simplify = gst_caps_get_structure_unchecked (caps, i);
1922 if (gst_structure_get_name_id (simplify) !=
1923 gst_structure_get_name_id (gst_caps_get_structure_unchecked (caps,
1926 for (j = start; j >= 0; j--) {
1929 compare = gst_caps_get_structure_unchecked (caps, j);
1930 if (gst_structure_get_name_id (simplify) !=
1931 gst_structure_get_name_id (compare)) {
1934 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1936 gst_caps_switch_structures (caps, simplify, result, i);
1939 gst_caps_remove_structure (caps, i);
1951 /* gst_caps_do_simplify (caps); */
1959 * @caps: a pointer to #GstCaps
1960 * @newcaps: a #GstCaps to replace *caps
1962 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
1963 * pointed to by @caps, if applicable, then modifies @caps to point to
1964 * @newcaps. An additional ref on @newcaps is taken.
1966 * This function does not take any locks so you might want to lock
1967 * the object owning @caps pointer.
1970 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
1974 g_return_if_fail (caps != NULL);
1978 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p, %p -> %p", caps, oldcaps, newcaps);
1980 if (newcaps != oldcaps) {
1982 gst_caps_ref (newcaps);
1987 gst_caps_unref (oldcaps);
1992 * gst_caps_to_string:
1995 * Converts @caps to a string representation. This string representation
1996 * can be converted back to a #GstCaps by gst_caps_from_string().
1998 * For debugging purposes its easier to do something like this:
2000 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
2002 * This prints the caps in human readble form.
2004 * Returns: a newly allocated string representing @caps.
2007 gst_caps_to_string (const GstCaps * caps)
2009 guint i, slen, clen;
2012 /* NOTE: This function is potentially called by the debug system,
2013 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
2014 * should be careful to avoid recursion. This includes any functions
2015 * called by gst_caps_to_string. In particular, calls should
2016 * not use the GST_PTR_FORMAT extension. */
2019 return g_strdup ("NULL");
2021 if (CAPS_IS_ANY (caps)) {
2022 return g_strdup ("ANY");
2024 if (CAPS_IS_EMPTY_SIMPLE (caps)) {
2025 return g_strdup ("EMPTY");
2028 /* estimate a rough string length to avoid unnecessary reallocs in GString */
2030 clen = caps->structs->len;
2031 for (i = 0; i < clen; i++) {
2033 STRUCTURE_ESTIMATED_STRING_LEN (gst_caps_get_structure_unchecked (caps,
2037 s = g_string_sized_new (slen);
2038 for (i = 0; i < clen; i++) {
2039 GstStructure *structure;
2042 /* ';' is now added by gst_structure_to_string */
2043 g_string_append_c (s, ' ');
2046 structure = gst_caps_get_structure_unchecked (caps, i);
2047 priv_gst_structure_append_to_gstring (structure, s);
2049 if (s->len && s->str[s->len - 1] == ';') {
2050 /* remove latest ';' */
2051 s->str[--s->len] = '\0';
2053 return g_string_free (s, FALSE);
2057 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
2059 GstStructure *structure;
2062 if (strcmp ("ANY", string) == 0) {
2063 caps->flags = GST_CAPS_FLAGS_ANY;
2066 if (strcmp ("EMPTY", string) == 0) {
2070 structure = gst_structure_from_string (string, &s);
2071 if (structure == NULL) {
2074 gst_caps_append_structure_unchecked (caps, structure);
2078 while (g_ascii_isspace (*s))
2083 structure = gst_structure_from_string (s, &s);
2084 if (structure == NULL) {
2087 gst_caps_append_structure_unchecked (caps, structure);
2095 * gst_caps_from_string:
2096 * @string: a string to convert to #GstCaps
2098 * Converts @caps from a string representation.
2100 * Returns: a newly allocated #GstCaps
2103 gst_caps_from_string (const gchar * string)
2107 g_return_val_if_fail (string, FALSE);
2109 caps = gst_caps_new_empty ();
2110 if (gst_caps_from_string_inplace (caps, string)) {
2113 gst_caps_unref (caps);
2119 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
2121 g_return_if_fail (G_IS_VALUE (src_value));
2122 g_return_if_fail (G_IS_VALUE (dest_value));
2123 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
2124 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
2125 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
2127 dest_value->data[0].v_pointer =
2128 gst_caps_to_string (src_value->data[0].v_pointer);
2132 gst_caps_copy_conditional (GstCaps * src)
2135 return gst_caps_ref (src);