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_LOG (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) > 0, 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_LOG (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) > 0);
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) > 0))
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_structure_is_equal_foreach (GQuark field_id, const GValue * val2,
536 GstStructure *struct1 = (GstStructure *) data;
537 const GValue *val1 = gst_structure_id_get_value (struct1, field_id);
539 if (G_UNLIKELY (val1 == NULL))
541 if (gst_value_compare (val1, val2) == GST_VALUE_EQUAL) {
549 gst_caps_structure_is_subset_field (GQuark field_id, const GValue * value,
552 GstStructure *subtract_from = user_data;
553 GValue subtraction = { 0, };
556 if (!(other = gst_structure_id_get_value (subtract_from, field_id)))
557 /* field is missing in one set */
560 /* equal values are subset */
561 if (gst_value_compare (other, value) == GST_VALUE_EQUAL)
569 * -> 1 - [1,2] = empty
573 * -> [1,2] - [1,3] = empty
577 * -> {1,3} - {1,2} = 3
580 * First caps subtraction needs to return a non-empty set, second
581 * subtractions needs to give en empty set.
583 if (gst_value_subtract (&subtraction, other, value)) {
584 g_value_unset (&subtraction);
585 /* !empty result, swapping must be empty */
586 if (!gst_value_subtract (&subtraction, value, other))
589 g_value_unset (&subtraction);
595 gst_caps_structure_is_subset (const GstStructure * minuend,
596 const GstStructure * subtrahend)
598 if ((minuend->name != subtrahend->name) ||
599 (gst_structure_n_fields (minuend) !=
600 gst_structure_n_fields (subtrahend))) {
604 return gst_structure_foreach ((GstStructure *) subtrahend,
605 gst_caps_structure_is_subset_field, (gpointer) minuend);
610 * @caps1: the #GstCaps that will be appended to
611 * @caps2: the #GstCaps to append
613 * Appends the structures contained in @caps2 to @caps1. The structures in
614 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
615 * freed. If either caps is ANY, the resulting caps will be ANY.
618 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
620 GstStructure *structure;
623 g_return_if_fail (GST_IS_CAPS (caps1));
624 g_return_if_fail (GST_IS_CAPS (caps2));
625 g_return_if_fail (IS_WRITABLE (caps1));
626 g_return_if_fail (IS_WRITABLE (caps2));
631 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))) {
632 /* FIXME: this leaks */
633 caps1->flags |= GST_CAPS_FLAGS_ANY;
634 for (i = caps2->structs->len - 1; i >= 0; i--) {
635 structure = gst_caps_remove_and_get_structure (caps2, i);
636 gst_structure_free (structure);
639 for (i = caps2->structs->len; i; i--) {
640 structure = gst_caps_remove_and_get_structure (caps2, 0);
641 gst_caps_append_structure_unchecked (caps1, structure);
644 gst_caps_unref (caps2); /* guaranteed to free it */
649 * @caps1: the #GstCaps that will take the new entries
650 * @caps2: the #GstCaps to merge in
652 * Appends the structures contained in @caps2 to @caps1 if they are not yet
653 * expressed by @caps1. The structures in @caps2 are not copied -- they are
654 * transferred to @caps1, and then @caps2 is freed.
655 * If either caps is ANY, the resulting caps will be ANY.
660 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
662 GstStructure *structure;
665 g_return_if_fail (GST_IS_CAPS (caps1));
666 g_return_if_fail (GST_IS_CAPS (caps2));
667 g_return_if_fail (IS_WRITABLE (caps1));
668 g_return_if_fail (IS_WRITABLE (caps2));
673 if (G_UNLIKELY (CAPS_IS_ANY (caps1))) {
674 for (i = caps2->structs->len - 1; i >= 0; i--) {
675 structure = gst_caps_remove_and_get_structure (caps2, i);
676 gst_structure_free (structure);
678 } else if (G_UNLIKELY (CAPS_IS_ANY (caps2))) {
679 caps1->flags |= GST_CAPS_FLAGS_ANY;
680 for (i = caps1->structs->len - 1; i >= 0; i--) {
681 structure = gst_caps_remove_and_get_structure (caps1, i);
682 gst_structure_free (structure);
685 for (i = caps2->structs->len; i; i--) {
686 structure = gst_caps_remove_and_get_structure (caps2, 0);
687 gst_caps_merge_structure (caps1, structure);
690 GstCaps *com = gst_caps_intersect (caps1, caps2);
691 GstCaps *add = gst_caps_subtract (caps2, com);
693 GST_DEBUG ("common : %d", gst_caps_get_size (com));
694 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
695 gst_caps_append (caps1, add);
696 gst_caps_unref (com);
699 gst_caps_unref (caps2); /* guaranteed to free it */
703 * gst_caps_append_structure:
704 * @caps: the #GstCaps that will be appended to
705 * @structure: the #GstStructure to append
707 * Appends @structure to @caps. The structure is not copied; @caps
708 * becomes the owner of @structure.
711 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
713 g_return_if_fail (GST_IS_CAPS (caps));
714 g_return_if_fail (IS_WRITABLE (caps));
716 if (G_LIKELY (structure)) {
717 g_return_if_fail (structure->parent_refcount == NULL);
720 STRUCTURE_POISON (structure);
723 gst_caps_append_structure_unchecked (caps, structure);
728 * gst_caps_remove_structure:
729 * @caps: the #GstCaps to remove from
730 * @idx: Index of the structure to remove
732 * removes the stucture with the given index from the list of structures
733 * contained in @caps.
736 gst_caps_remove_structure (GstCaps * caps, guint idx)
738 GstStructure *structure;
740 g_return_if_fail (caps != NULL);
741 g_return_if_fail (idx <= gst_caps_get_size (caps));
742 g_return_if_fail (IS_WRITABLE (caps));
744 structure = gst_caps_remove_and_get_structure (caps, idx);
745 gst_structure_free (structure);
749 * gst_caps_merge_structure:
750 * @caps: the #GstCaps that will the the new structure
751 * @structure: the #GstStructure to merge
753 * Appends @structure to @caps if its not already expressed by @caps. The
754 * structure is not copied; @caps becomes the owner of @structure.
757 gst_caps_merge_structure (GstCaps * caps, GstStructure * structure)
759 g_return_if_fail (GST_IS_CAPS (caps));
760 g_return_if_fail (IS_WRITABLE (caps));
762 if (G_LIKELY (structure)) {
763 GstStructure *structure1;
765 gboolean unique = TRUE;
767 g_return_if_fail (structure->parent_refcount == NULL);
770 STRUCTURE_POISON (structure);
773 /* check each structure */
774 for (i = caps->structs->len - 1; i >= 0; i--) {
775 structure1 = gst_caps_get_structure_unchecked (caps, i);
776 /* if structure is a subset of structure1, then skip it */
777 if (gst_caps_structure_is_subset (structure1, structure)) {
783 gst_structure_set_parent_refcount (structure, &caps->refcount);
784 g_ptr_array_add (caps->structs, structure);
786 gst_structure_free (structure);
795 * Gets the number of structures contained in @caps.
797 * Returns: the number of structures that @caps contains
800 gst_caps_get_size (const GstCaps * caps)
802 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
804 return caps->structs->len;
808 * gst_caps_get_structure:
810 * @index: the index of the structure
812 * Finds the structure in @caps that has the index @index, and
815 * WARNING: This function takes a const GstCaps *, but returns a
816 * non-const GstStructure *. This is for programming convenience --
817 * the caller should be aware that structures inside a constant
818 * #GstCaps should not be modified. However, if you know the caps
819 * are writable, either because you have just copied them or made
820 * them writable with gst_caps_make_writable(), you may modify the
821 * structure returned in the usual way, e.g. with functions like
822 * gst_structure_set().
824 * You do not need to free or unref the structure returned, it
825 * belongs to the #GstCaps.
827 * Returns: a pointer to the #GstStructure corresponding to @index
830 gst_caps_get_structure (const GstCaps * caps, guint index)
832 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
833 g_return_val_if_fail (index < caps->structs->len, NULL);
835 return gst_caps_get_structure_unchecked (caps, index);
840 * @caps: the #GstCaps to copy
841 * @nth: the nth structure to copy
843 * Creates a new #GstCaps and appends a copy of the nth structure
844 * contained in @caps.
846 * Returns: the new #GstCaps
849 gst_caps_copy_nth (const GstCaps * caps, guint nth)
852 GstStructure *structure;
854 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
856 newcaps = gst_caps_new_empty ();
857 newcaps->flags = caps->flags;
859 if (G_LIKELY (caps->structs->len > nth)) {
860 structure = gst_caps_get_structure_unchecked (caps, nth);
861 gst_caps_append_structure_unchecked (newcaps,
862 gst_structure_copy (structure));
870 * @caps: the #GstCaps to truncate
872 * Destructively discard all but the first structure from @caps. Useful when
873 * fixating. @caps must be writable.
876 gst_caps_truncate (GstCaps * caps)
880 g_return_if_fail (GST_IS_CAPS (caps));
881 g_return_if_fail (IS_WRITABLE (caps));
883 i = caps->structs->len - 1;
886 gst_caps_remove_structure (caps, i--);
890 * gst_caps_set_value:
891 * @caps: a writable caps
892 * @field: name of the field to set
893 * @value: value to set the field to
895 * Sets the given @field on all structures of @caps to the given @value.
896 * This is a convenience function for calling gst_structure_set_value() on
897 * all structures of @caps.
902 gst_caps_set_value (GstCaps * caps, const char *field, const GValue * value)
906 g_return_if_fail (GST_IS_CAPS (caps));
907 g_return_if_fail (IS_WRITABLE (caps));
908 g_return_if_fail (field != NULL);
909 g_return_if_fail (G_IS_VALUE (value));
911 len = caps->structs->len;
912 for (i = 0; i < len; i++) {
913 GstStructure *structure = gst_caps_get_structure_unchecked (caps, i);
914 gst_structure_set_value (structure, field, value);
919 * gst_caps_set_simple_valist:
920 * @caps: the #GstCaps to set
921 * @field: first field to set
922 * @varargs: additional parameters
924 * Sets fields in a #GstCaps. The arguments must be passed in the same
925 * manner as gst_structure_set(), and be NULL-terminated.
926 * <note>Prior to GStreamer version 0.10.26, this function failed when
927 * @caps was not simple. If your code needs to work with those versions
928 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
929 * is %TRUE for @caps.</note>
932 gst_caps_set_simple_valist (GstCaps * caps, const char *field, va_list varargs)
934 GValue value = { 0, };
936 g_return_if_fail (GST_IS_CAPS (caps));
937 g_return_if_fail (IS_WRITABLE (caps));
943 type = va_arg (varargs, GType);
945 if (G_UNLIKELY (type == G_TYPE_DATE)) {
946 g_warning ("Don't use G_TYPE_DATE, use GST_TYPE_DATE instead\n");
947 type = GST_TYPE_DATE;
949 #if GLIB_CHECK_VERSION(2,23,3)
950 G_VALUE_COLLECT_INIT (&value, type, varargs, 0, &err);
952 g_value_init (&value, type);
953 G_VALUE_COLLECT (&value, varargs, 0, &err);
955 if (G_UNLIKELY (err)) {
956 g_critical ("%s", err);
960 gst_caps_set_value (caps, field, &value);
962 g_value_unset (&value);
964 field = va_arg (varargs, const gchar *);
969 * gst_caps_set_simple:
970 * @caps: the #GstCaps to set
971 * @field: first field to set
972 * @...: additional parameters
974 * Sets fields in a #GstCaps. The arguments must be passed in the same
975 * manner as gst_structure_set(), and be NULL-terminated.
976 * <note>Prior to GStreamer version 0.10.26, this function failed when
977 * @caps was not simple. If your code needs to work with those versions
978 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
979 * is %TRUE for @caps.</note>
982 gst_caps_set_simple (GstCaps * caps, const char *field, ...)
986 g_return_if_fail (GST_IS_CAPS (caps));
987 g_return_if_fail (IS_WRITABLE (caps));
989 va_start (var_args, field);
990 gst_caps_set_simple_valist (caps, field, var_args);
998 * @caps: the #GstCaps to test
1000 * Determines if @caps represents any media format.
1002 * Returns: TRUE if @caps represents any format.
1005 gst_caps_is_any (const GstCaps * caps)
1007 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1009 return (CAPS_IS_ANY (caps));
1013 * gst_caps_is_empty:
1014 * @caps: the #GstCaps to test
1016 * Determines if @caps represents no media formats.
1018 * Returns: TRUE if @caps represents no formats.
1021 gst_caps_is_empty (const GstCaps * caps)
1023 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1025 if (CAPS_IS_ANY (caps))
1028 return CAPS_IS_EMPTY_SIMPLE (caps);
1032 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
1035 return gst_value_is_fixed (value);
1039 * gst_caps_is_fixed:
1040 * @caps: the #GstCaps to test
1042 * Fixed #GstCaps describe exactly one format, that is, they have exactly
1043 * one structure, and each field in the structure describes a fixed type.
1044 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
1046 * Returns: TRUE if @caps is fixed
1049 gst_caps_is_fixed (const GstCaps * caps)
1051 GstStructure *structure;
1053 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1055 if (caps->structs->len != 1)
1058 structure = gst_caps_get_structure_unchecked (caps, 0);
1060 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
1064 * gst_caps_is_equal_fixed:
1065 * @caps1: the #GstCaps to test
1066 * @caps2: the #GstCaps to test
1068 * Tests if two #GstCaps are equal. This function only works on fixed
1071 * Returns: TRUE if the arguments represent the same format
1074 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
1076 GstStructure *struct1, *struct2;
1078 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
1079 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
1081 struct1 = gst_caps_get_structure_unchecked (caps1, 0);
1082 struct2 = gst_caps_get_structure_unchecked (caps2, 0);
1084 if (struct1->name != struct2->name) {
1087 if (struct1->fields->len != struct2->fields->len) {
1091 return gst_structure_foreach (struct1, gst_structure_is_equal_foreach,
1096 * gst_caps_is_always_compatible:
1097 * @caps1: the #GstCaps to test
1098 * @caps2: the #GstCaps to test
1100 * A given #GstCaps structure is always compatible with another if
1101 * every media format that is in the first is also contained in the
1102 * second. That is, @caps1 is a subset of @caps2.
1104 * Returns: TRUE if @caps1 is a subset of @caps2.
1107 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
1109 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1110 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1112 return gst_caps_is_subset (caps1, caps2);
1116 * gst_caps_is_subset:
1117 * @subset: a #GstCaps
1118 * @superset: a potentially greater #GstCaps
1120 * Checks if all caps represented by @subset are also represented by @superset.
1121 * <note>This function does not work reliably if optional properties for caps
1122 * are included on one caps and omitted on the other.</note>
1124 * Returns: %TRUE if @subset is a subset of @superset
1127 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
1132 g_return_val_if_fail (subset != NULL, FALSE);
1133 g_return_val_if_fail (superset != NULL, FALSE);
1135 if (CAPS_IS_EMPTY (subset) || CAPS_IS_ANY (superset))
1137 if (CAPS_IS_ANY (subset) || CAPS_IS_EMPTY (superset))
1140 caps = gst_caps_subtract (subset, superset);
1141 ret = CAPS_IS_EMPTY_SIMPLE (caps);
1142 gst_caps_unref (caps);
1147 * gst_caps_is_equal:
1148 * @caps1: a #GstCaps
1149 * @caps2: another #GstCaps
1151 * Checks if the given caps represent the same set of caps.
1152 * <note>This function does not work reliably if optional properties for caps
1153 * are included on one caps and omitted on the other.</note>
1155 * This function deals correctly with passing NULL for any of the caps.
1157 * Returns: TRUE if both caps are equal.
1160 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1162 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1163 * So there should be an assertion that caps1 and caps2 != NULL */
1165 /* NULL <-> NULL is allowed here */
1166 if (G_UNLIKELY (caps1 == caps2))
1169 /* one of them NULL => they are different (can't be both NULL because
1170 * we checked that above) */
1171 if (G_UNLIKELY (caps1 == NULL || caps2 == NULL))
1174 if (G_UNLIKELY (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2)))
1175 return gst_caps_is_equal_fixed (caps1, caps2);
1177 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1180 /* intersect operation */
1185 const GstStructure *intersect;
1190 gst_caps_structure_intersect_field1 (GQuark id, const GValue * val1,
1193 IntersectData *idata = (IntersectData *) data;
1194 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1196 if (G_UNLIKELY (val2 == NULL)) {
1197 gst_structure_id_set_value (idata->dest, id, val1);
1199 GValue dest_value = { 0 };
1200 if (gst_value_intersect (&dest_value, val1, val2)) {
1201 gst_structure_id_set_value (idata->dest, id, &dest_value);
1202 g_value_unset (&dest_value);
1211 gst_caps_structure_intersect_field2 (GQuark id, const GValue * val1,
1214 IntersectData *idata = (IntersectData *) data;
1215 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1217 if (G_UNLIKELY (val2 == NULL)) {
1218 gst_structure_id_set_value (idata->dest, id, val1);
1223 static GstStructure *
1224 gst_caps_structure_intersect (const GstStructure * struct1,
1225 const GstStructure * struct2)
1229 g_assert (struct1 != NULL);
1230 g_assert (struct2 != NULL);
1232 if (G_UNLIKELY (struct1->name != struct2->name))
1235 /* copy fields from struct1 which we have not in struct2 to target
1236 * intersect if we have the field in both */
1237 data.dest = gst_structure_id_empty_new (struct1->name);
1238 data.intersect = struct2;
1239 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1240 gst_caps_structure_intersect_field1, &data)))
1243 /* copy fields from struct2 which we have not in struct1 to target */
1244 data.intersect = struct1;
1245 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct2,
1246 gst_caps_structure_intersect_field2, &data)))
1252 gst_structure_free (data.dest);
1257 gst_caps_structure_can_intersect_field (GQuark id, const GValue * val1,
1260 GstStructure *other = (GstStructure *) data;
1261 const GValue *val2 = gst_structure_id_get_value (other, id);
1263 if (G_LIKELY (val2)) {
1264 if (!gst_value_can_intersect (val1, val2)) {
1267 gint eq = gst_value_compare (val1, val2);
1269 if (eq == GST_VALUE_UNORDERED) {
1270 /* we need to try interseting */
1271 GValue dest_value = { 0 };
1272 if (gst_value_intersect (&dest_value, val1, val2)) {
1273 g_value_unset (&dest_value);
1277 } else if (eq != GST_VALUE_EQUAL) {
1286 gst_caps_structure_can_intersect (const GstStructure * struct1,
1287 const GstStructure * struct2)
1289 g_assert (struct1 != NULL);
1290 g_assert (struct2 != NULL);
1292 if (G_UNLIKELY (struct1->name != struct2->name))
1295 /* tries to intersect if we have the field in both */
1296 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1297 gst_caps_structure_can_intersect_field, (gpointer) struct2)))
1304 * gst_caps_can_intersect:
1305 * @caps1: a #GstCaps to intersect
1306 * @caps2: a #GstCaps to intersect
1308 * Tries intersecting @caps1 and @caps2 and reports wheter the result would not
1311 * Returns: %TRUE if intersection would be not empty
1316 gst_caps_can_intersect (const GstCaps * caps1, const GstCaps * caps2)
1318 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1319 guint j, k, len1, len2;
1320 GstStructure *struct1;
1321 GstStructure *struct2;
1323 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1324 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1326 /* caps are exactly the same pointers */
1327 if (G_UNLIKELY (caps1 == caps2))
1330 /* empty caps on either side, return empty */
1331 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1334 /* one of the caps is any */
1335 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2)))
1338 /* run zigzag on top line then right line, this preserves the caps order
1339 * much better than a simple loop.
1341 * This algorithm zigzags over the caps structures as demonstrated in
1342 * the folowing matrix:
1350 * First we iterate over the caps1 structures (top line) intersecting
1351 * the structures diagonally down, then we iterate over the caps2
1354 len1 = caps1->structs->len;
1355 len2 = caps2->structs->len;
1356 for (i = 0; i < len1 + len2 - 1; i++) {
1357 /* superset index goes from 0 to sgst_caps_structure_intersectuperset->structs->len-1 */
1358 j = MIN (i, len1 - 1);
1359 /* subset index stays 0 until i reaches superset->structs->len, then it
1360 * counts up from 1 to subset->structs->len - 1 */
1363 /* now run the diagonal line, end condition is the left or bottom
1366 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1367 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1369 if (gst_caps_structure_can_intersect (struct1, struct2)) {
1372 /* move down left */
1374 if (G_UNLIKELY (j == 0))
1375 break; /* so we don't roll back to G_MAXUINT */
1383 * gst_caps_intersect:
1384 * @caps1: a #GstCaps to intersect
1385 * @caps2: a #GstCaps to intersect
1387 * Creates a new #GstCaps that contains all the formats that are common
1388 * to both @caps1 and @caps2.
1390 * Returns: the new #GstCaps
1393 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1395 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1396 guint j, k, len1, len2;
1398 GstStructure *struct1;
1399 GstStructure *struct2;
1401 GstStructure *istruct;
1403 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1404 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1406 /* caps are exactly the same pointers, just copy one caps */
1407 if (G_UNLIKELY (caps1 == caps2))
1408 return gst_caps_copy (caps1);
1410 /* empty caps on either side, return empty */
1411 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1412 return gst_caps_new_empty ();
1414 /* one of the caps is any, just copy the other caps */
1415 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1416 return gst_caps_copy (caps2);
1417 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1418 return gst_caps_copy (caps1);
1420 dest = gst_caps_new_empty ();
1422 /* run zigzag on top line then right line, this preserves the caps order
1423 * much better than a simple loop.
1425 * This algorithm zigzags over the caps structures as demonstrated in
1426 * the folowing matrix:
1434 * First we iterate over the caps1 structures (top line) intersecting
1435 * the structures diagonally down, then we iterate over the caps2
1438 len1 = caps1->structs->len;
1439 len2 = caps2->structs->len;
1440 for (i = 0; i < len1 + len2 - 1; i++) {
1441 /* caps1 index goes from 0 to caps1->structs->len-1 */
1442 j = MIN (i, len1 - 1);
1443 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1444 * up from 1 to caps2->structs->len - 1 */
1447 /* now run the diagonal line, end condition is the left or bottom
1450 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1451 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1453 istruct = gst_caps_structure_intersect (struct1, struct2);
1455 gst_caps_append_structure (dest, istruct);
1456 /* move down left */
1458 if (G_UNLIKELY (j == 0))
1459 break; /* so we don't roll back to G_MAXUINT */
1466 /* subtract operation */
1470 const GstStructure *subtract_from;
1476 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1479 SubtractionEntry *e = user_data;
1480 GValue subtraction = { 0, };
1481 const GValue *other;
1482 GstStructure *structure;
1484 other = gst_structure_id_get_value (e->subtract_from, field_id);
1488 if (!gst_value_subtract (&subtraction, other, value))
1490 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1491 g_value_unset (&subtraction);
1494 structure = gst_structure_copy (e->subtract_from);
1495 gst_structure_id_set_value (structure, field_id, &subtraction);
1496 g_value_unset (&subtraction);
1497 e->put_into = g_slist_prepend (e->put_into, structure);
1503 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1504 const GstStructure * subtrahend)
1509 e.subtract_from = minuend;
1512 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1513 gst_caps_structure_subtract_field, &e);
1519 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1520 gst_structure_free (walk->data);
1522 g_slist_free (e.put_into);
1528 * gst_caps_subtract:
1529 * @minuend: #GstCaps to substract from
1530 * @subtrahend: #GstCaps to substract
1532 * Subtracts the @subtrahend from the @minuend.
1533 * <note>This function does not work reliably if optional properties for caps
1534 * are included on one caps and omitted on the other.</note>
1536 * Returns: the resulting caps
1539 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1544 GstCaps *dest = NULL, *src;
1546 g_return_val_if_fail (minuend != NULL, NULL);
1547 g_return_val_if_fail (subtrahend != NULL, NULL);
1549 if (CAPS_IS_EMPTY (minuend) || CAPS_IS_ANY (subtrahend)) {
1550 return gst_caps_new_empty ();
1552 if (CAPS_IS_EMPTY_SIMPLE (subtrahend))
1553 return gst_caps_copy (minuend);
1555 /* FIXME: Do we want this here or above?
1556 The reason we need this is that there is no definition about what
1557 ANY means for specific types, so it's not possible to reduce ANY partially
1558 You can only remove everything or nothing and that is done above.
1559 Note: there's a test that checks this behaviour. */
1560 g_return_val_if_fail (!CAPS_IS_ANY (minuend), NULL);
1561 sublen = subtrahend->structs->len;
1562 g_assert (sublen > 0);
1564 src = gst_caps_copy (minuend);
1565 for (i = 0; i < sublen; i++) {
1568 sub = gst_caps_get_structure_unchecked (subtrahend, i);
1570 gst_caps_unref (src);
1573 dest = gst_caps_new_empty ();
1574 srclen = src->structs->len;
1575 for (j = 0; j < srclen; j++) {
1576 min = gst_caps_get_structure_unchecked (src, j);
1577 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1580 if (gst_caps_structure_subtract (&list, min, sub)) {
1583 for (walk = list; walk; walk = g_slist_next (walk)) {
1584 gst_caps_append_structure_unchecked (dest,
1585 (GstStructure *) walk->data);
1587 g_slist_free (list);
1589 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1592 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1595 if (CAPS_IS_EMPTY_SIMPLE (dest)) {
1596 gst_caps_unref (src);
1601 gst_caps_unref (src);
1602 gst_caps_do_simplify (dest);
1606 /* union operation */
1609 static GstStructure *
1610 gst_caps_structure_union (const GstStructure * struct1,
1611 const GstStructure * struct2)
1615 const GstStructureField *field1;
1616 const GstStructureField *field2;
1619 /* FIXME this doesn't actually work */
1621 if (struct1->name != struct2->name)
1624 dest = gst_structure_id_empty_new (struct1->name);
1626 for (i = 0; i < struct1->fields->len; i++) {
1627 GValue dest_value = { 0 };
1629 field1 = GST_STRUCTURE_FIELD (struct1, i);
1630 field2 = gst_structure_id_get_field (struct2, field1->name);
1632 if (field2 == NULL) {
1635 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1636 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1639 ret = gst_value_compare (&field1->value, &field2->value);
1650 * @caps1: a #GstCaps to union
1651 * @caps2: a #GstCaps to union
1653 * Creates a new #GstCaps that contains all the formats that are in
1654 * either @caps1 and @caps2.
1656 * Returns: the new #GstCaps
1659 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1664 /* NULL pointers are no correct GstCaps */
1665 g_return_val_if_fail (caps1 != NULL, NULL);
1666 g_return_val_if_fail (caps2 != NULL, NULL);
1668 if (CAPS_IS_EMPTY (caps1))
1669 return gst_caps_copy (caps2);
1671 if (CAPS_IS_EMPTY (caps2))
1672 return gst_caps_copy (caps1);
1674 if (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))
1675 return gst_caps_new_any ();
1677 dest1 = gst_caps_copy (caps1);
1678 dest2 = gst_caps_copy (caps2);
1679 gst_caps_append (dest1, dest2);
1681 gst_caps_do_simplify (dest1);
1685 /* normalize/simplify operations */
1687 typedef struct _NormalizeForeach
1690 GstStructure *structure;
1695 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1697 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1701 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1702 guint len = gst_value_list_get_size (value);
1703 for (i = 1; i < len; i++) {
1704 const GValue *v = gst_value_list_get_value (value, i);
1705 GstStructure *structure = gst_structure_copy (nf->structure);
1707 gst_structure_id_set_value (structure, field_id, v);
1708 gst_caps_append_structure_unchecked (nf->caps, structure);
1711 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1712 gst_structure_id_set_value (nf->structure, field_id, &val);
1713 g_value_unset (&val);
1721 * gst_caps_normalize:
1722 * @caps: a #GstCaps to normalize
1724 * Creates a new #GstCaps that represents the same set of formats as
1725 * @caps, but contains no lists. Each list is expanded into separate
1728 * Returns: the new #GstCaps
1731 gst_caps_normalize (const GstCaps * caps)
1733 NormalizeForeach nf;
1737 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1739 newcaps = gst_caps_copy (caps);
1741 nlen = newcaps->structs->len;
1743 for (i = 0; i < nlen; i++) {
1744 nf.structure = gst_caps_get_structure_unchecked (newcaps, i);
1746 while (!gst_structure_foreach (nf.structure,
1747 gst_caps_normalize_foreach, &nf));
1754 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1757 const GstStructure *struct1 = *((const GstStructure **) one);
1758 const GstStructure *struct2 = *((const GstStructure **) two);
1760 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1761 So what's the best way? */
1762 ret = strcmp (gst_structure_get_name (struct1),
1763 gst_structure_get_name (struct2));
1767 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1774 GstStructure *compare;
1779 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1782 UnionField *u = user_data;
1783 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1787 g_value_unset (&u->value);
1790 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1793 g_value_unset (&u->value);
1797 gst_value_union (&u->value, val, value);
1802 gst_caps_structure_simplify (GstStructure ** result,
1803 const GstStructure * simplify, GstStructure * compare)
1806 UnionField field = { 0, {0,}, NULL };
1808 /* try to subtract to get a real subset */
1809 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1810 switch (g_slist_length (list)) {
1815 *result = list->data;
1816 g_slist_free (list);
1822 for (walk = list; walk; walk = g_slist_next (walk)) {
1823 gst_structure_free (walk->data);
1825 g_slist_free (list);
1831 /* try to union both structs */
1832 field.compare = compare;
1833 if (gst_structure_foreach ((GstStructure *) simplify,
1834 gst_caps_structure_figure_out_union, &field)) {
1835 gboolean ret = FALSE;
1837 /* now we know all of simplify's fields are the same in compare
1838 * but at most one field: field.name */
1839 if (G_IS_VALUE (&field.value)) {
1840 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1841 gst_structure_id_set_value (compare, field.name, &field.value);
1845 g_value_unset (&field.value);
1846 } else if (gst_structure_n_fields (simplify) <=
1847 gst_structure_n_fields (compare)) {
1848 /* compare is just more specific, will be optimized away later */
1849 /* FIXME: do this here? */
1850 GST_LOG ("found a case that will be optimized later.");
1852 gchar *one = gst_structure_to_string (simplify);
1853 gchar *two = gst_structure_to_string (compare);
1856 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1868 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1869 GstStructure * new, gint i)
1871 gst_structure_set_parent_refcount (old, NULL);
1872 gst_structure_free (old);
1873 gst_structure_set_parent_refcount (new, &caps->refcount);
1874 g_ptr_array_index (caps->structs, i) = new;
1878 * gst_caps_do_simplify:
1879 * @caps: a #GstCaps to simplify
1881 * Modifies the given @caps inplace into a representation that represents the
1882 * same set of formats, but in a simpler form. Component structures that are
1883 * identical are merged. Component structures that have values that can be
1884 * merged are also merged.
1886 * Returns: TRUE, if the caps could be simplified
1889 gst_caps_do_simplify (GstCaps * caps)
1891 GstStructure *simplify, *compare, *result = NULL;
1893 gboolean changed = FALSE;
1895 g_return_val_if_fail (caps != NULL, FALSE);
1896 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1898 if (gst_caps_get_size (caps) < 2)
1901 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1903 start = caps->structs->len - 1;
1904 for (i = caps->structs->len - 1; i >= 0; i--) {
1905 simplify = gst_caps_get_structure_unchecked (caps, i);
1906 if (gst_structure_get_name_id (simplify) !=
1907 gst_structure_get_name_id (gst_caps_get_structure_unchecked (caps,
1910 for (j = start; j >= 0; j--) {
1913 compare = gst_caps_get_structure_unchecked (caps, j);
1914 if (gst_structure_get_name_id (simplify) !=
1915 gst_structure_get_name_id (compare)) {
1918 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1920 gst_caps_switch_structures (caps, simplify, result, i);
1923 gst_caps_remove_structure (caps, i);
1935 /* gst_caps_do_simplify (caps); */
1941 #ifndef GST_DISABLE_LOADSAVE
1943 * gst_caps_save_thyself:
1944 * @caps: a #GstCaps structure
1945 * @parent: a XML parent node
1947 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
1949 * Returns: a XML node pointer
1952 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
1954 char *s = gst_caps_to_string (caps);
1956 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
1962 * gst_caps_load_thyself:
1963 * @parent: a XML node
1965 * Creates a #GstCaps from its XML serialization.
1967 * Returns: a new #GstCaps structure
1970 gst_caps_load_thyself (xmlNodePtr parent)
1972 if (strcmp ("caps", (char *) parent->name) == 0) {
1973 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
1984 * @caps: a pointer to #GstCaps
1985 * @newcaps: a #GstCaps to replace *caps
1987 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
1988 * pointed to by @caps, if applicable, then modifies @caps to point to
1989 * @newcaps. An additional ref on @newcaps is taken.
1991 * This function does not take any locks so you might want to lock
1992 * the object owning @caps pointer.
1995 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
1999 g_return_if_fail (caps != NULL);
2003 GST_CAT_LOG (GST_CAT_REFCOUNTING, "%p, %p -> %p", caps, oldcaps, newcaps);
2005 if (newcaps != oldcaps) {
2007 gst_caps_ref (newcaps);
2012 gst_caps_unref (oldcaps);
2017 * gst_caps_to_string:
2020 * Converts @caps to a string representation. This string representation
2021 * can be converted back to a #GstCaps by gst_caps_from_string().
2023 * For debugging purposes its easier to do something like this:
2025 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
2027 * This prints the caps in human readble form.
2029 * Returns: a newly allocated string representing @caps.
2032 gst_caps_to_string (const GstCaps * caps)
2034 guint i, slen, clen;
2037 /* NOTE: This function is potentially called by the debug system,
2038 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
2039 * should be careful to avoid recursion. This includes any functions
2040 * called by gst_caps_to_string. In particular, calls should
2041 * not use the GST_PTR_FORMAT extension. */
2044 return g_strdup ("NULL");
2046 if (CAPS_IS_ANY (caps)) {
2047 return g_strdup ("ANY");
2049 if (CAPS_IS_EMPTY_SIMPLE (caps)) {
2050 return g_strdup ("EMPTY");
2053 /* estimate a rough string length to avoid unnecessary reallocs in GString */
2055 clen = caps->structs->len;
2056 for (i = 0; i < clen; i++) {
2058 STRUCTURE_ESTIMATED_STRING_LEN (gst_caps_get_structure_unchecked (caps,
2062 s = g_string_sized_new (slen);
2063 for (i = 0; i < clen; i++) {
2064 GstStructure *structure;
2067 /* ';' is now added by gst_structure_to_string */
2068 g_string_append_c (s, ' ');
2071 structure = gst_caps_get_structure_unchecked (caps, i);
2072 priv_gst_structure_append_to_gstring (structure, s);
2074 if (s->len && s->str[s->len - 1] == ';') {
2075 /* remove latest ';' */
2076 s->str[--s->len] = '\0';
2078 return g_string_free (s, FALSE);
2082 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
2084 GstStructure *structure;
2087 if (strcmp ("ANY", string) == 0) {
2088 caps->flags = GST_CAPS_FLAGS_ANY;
2091 if (strcmp ("EMPTY", string) == 0) {
2095 structure = gst_structure_from_string (string, &s);
2096 if (structure == NULL) {
2099 gst_caps_append_structure_unchecked (caps, structure);
2103 while (g_ascii_isspace (*s))
2108 structure = gst_structure_from_string (s, &s);
2109 if (structure == NULL) {
2112 gst_caps_append_structure_unchecked (caps, structure);
2120 * gst_caps_from_string:
2121 * @string: a string to convert to #GstCaps
2123 * Converts @caps from a string representation.
2125 * Returns: a newly allocated #GstCaps
2128 gst_caps_from_string (const gchar * string)
2132 g_return_val_if_fail (string, FALSE);
2134 caps = gst_caps_new_empty ();
2135 if (gst_caps_from_string_inplace (caps, string)) {
2138 gst_caps_unref (caps);
2144 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
2146 g_return_if_fail (G_IS_VALUE (src_value));
2147 g_return_if_fail (G_IS_VALUE (dest_value));
2148 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
2149 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
2150 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
2152 dest_value->data[0].v_pointer =
2153 gst_caps_to_string (src_value->data[0].v_pointer);
2157 gst_caps_copy_conditional (GstCaps * src)
2160 return gst_caps_ref (src);