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) > 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_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) > 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_caps_append_structure_unchecked (caps, structure);
785 gst_structure_free (structure);
794 * Gets the number of structures contained in @caps.
796 * Returns: the number of structures that @caps contains
799 gst_caps_get_size (const GstCaps * caps)
801 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
803 return caps->structs->len;
807 * gst_caps_get_structure:
809 * @index: the index of the structure
811 * Finds the structure in @caps that has the index @index, and
814 * WARNING: This function takes a const GstCaps *, but returns a
815 * non-const GstStructure *. This is for programming convenience --
816 * the caller should be aware that structures inside a constant
817 * #GstCaps should not be modified. However, if you know the caps
818 * are writable, either because you have just copied them or made
819 * them writable with gst_caps_make_writable(), you may modify the
820 * structure returned in the usual way, e.g. with functions like
821 * gst_structure_set().
823 * You do not need to free or unref the structure returned, it
824 * belongs to the #GstCaps.
826 * Returns: a pointer to the #GstStructure corresponding to @index
829 gst_caps_get_structure (const GstCaps * caps, guint index)
831 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
832 g_return_val_if_fail (index < caps->structs->len, NULL);
834 return gst_caps_get_structure_unchecked (caps, index);
839 * @caps: the #GstCaps to copy
840 * @nth: the nth structure to copy
842 * Creates a new #GstCaps and appends a copy of the nth structure
843 * contained in @caps.
845 * Returns: the new #GstCaps
848 gst_caps_copy_nth (const GstCaps * caps, guint nth)
851 GstStructure *structure;
853 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
855 newcaps = gst_caps_new_empty ();
856 newcaps->flags = caps->flags;
858 if (G_LIKELY (caps->structs->len > nth)) {
859 structure = gst_caps_get_structure_unchecked (caps, nth);
860 gst_caps_append_structure_unchecked (newcaps,
861 gst_structure_copy (structure));
869 * @caps: the #GstCaps to truncate
871 * Destructively discard all but the first structure from @caps. Useful when
872 * fixating. @caps must be writable.
875 gst_caps_truncate (GstCaps * caps)
879 g_return_if_fail (GST_IS_CAPS (caps));
880 g_return_if_fail (IS_WRITABLE (caps));
882 i = caps->structs->len - 1;
885 gst_caps_remove_structure (caps, i--);
889 * gst_caps_set_value:
890 * @caps: a writable caps
891 * @field: name of the field to set
892 * @value: value to set the field to
894 * Sets the given @field on all structures of @caps to the given @value.
895 * This is a convenience function for calling gst_structure_set_value() on
896 * all structures of @caps.
901 gst_caps_set_value (GstCaps * caps, const char *field, const GValue * value)
905 g_return_if_fail (GST_IS_CAPS (caps));
906 g_return_if_fail (IS_WRITABLE (caps));
907 g_return_if_fail (field != NULL);
908 g_return_if_fail (G_IS_VALUE (value));
910 len = caps->structs->len;
911 for (i = 0; i < len; i++) {
912 GstStructure *structure = gst_caps_get_structure_unchecked (caps, i);
913 gst_structure_set_value (structure, field, value);
918 * gst_caps_set_simple_valist:
919 * @caps: the #GstCaps to set
920 * @field: first field to set
921 * @varargs: additional parameters
923 * Sets fields in a #GstCaps. The arguments must be passed in the same
924 * manner as gst_structure_set(), and be NULL-terminated.
925 * <note>Prior to GStreamer version 0.10.26, this function failed when
926 * @caps was not simple. If your code needs to work with those versions
927 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
928 * is %TRUE for @caps.</note>
931 gst_caps_set_simple_valist (GstCaps * caps, const char *field, va_list varargs)
933 GValue value = { 0, };
935 g_return_if_fail (GST_IS_CAPS (caps));
936 g_return_if_fail (IS_WRITABLE (caps));
942 type = va_arg (varargs, GType);
944 if (G_UNLIKELY (type == G_TYPE_DATE)) {
945 g_warning ("Don't use G_TYPE_DATE, use GST_TYPE_DATE instead\n");
946 type = GST_TYPE_DATE;
948 #if GLIB_CHECK_VERSION(2,23,3)
949 G_VALUE_COLLECT_INIT (&value, type, varargs, 0, &err);
951 g_value_init (&value, type);
952 G_VALUE_COLLECT (&value, varargs, 0, &err);
954 if (G_UNLIKELY (err)) {
955 g_critical ("%s", err);
959 gst_caps_set_value (caps, field, &value);
961 g_value_unset (&value);
963 field = va_arg (varargs, const gchar *);
968 * gst_caps_set_simple:
969 * @caps: the #GstCaps to set
970 * @field: first field to set
971 * @...: additional parameters
973 * Sets fields in a #GstCaps. The arguments must be passed in the same
974 * manner as gst_structure_set(), and be NULL-terminated.
975 * <note>Prior to GStreamer version 0.10.26, this function failed when
976 * @caps was not simple. If your code needs to work with those versions
977 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
978 * is %TRUE for @caps.</note>
981 gst_caps_set_simple (GstCaps * caps, const char *field, ...)
985 g_return_if_fail (GST_IS_CAPS (caps));
986 g_return_if_fail (IS_WRITABLE (caps));
988 va_start (var_args, field);
989 gst_caps_set_simple_valist (caps, field, var_args);
997 * @caps: the #GstCaps to test
999 * Determines if @caps represents any media format.
1001 * Returns: TRUE if @caps represents any format.
1004 gst_caps_is_any (const GstCaps * caps)
1006 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1008 return (CAPS_IS_ANY (caps));
1012 * gst_caps_is_empty:
1013 * @caps: the #GstCaps to test
1015 * Determines if @caps represents no media formats.
1017 * Returns: TRUE if @caps represents no formats.
1020 gst_caps_is_empty (const GstCaps * caps)
1022 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1024 if (CAPS_IS_ANY (caps))
1027 return CAPS_IS_EMPTY_SIMPLE (caps);
1031 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
1034 return gst_value_is_fixed (value);
1038 * gst_caps_is_fixed:
1039 * @caps: the #GstCaps to test
1041 * Fixed #GstCaps describe exactly one format, that is, they have exactly
1042 * one structure, and each field in the structure describes a fixed type.
1043 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
1045 * Returns: TRUE if @caps is fixed
1048 gst_caps_is_fixed (const GstCaps * caps)
1050 GstStructure *structure;
1052 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1054 if (caps->structs->len != 1)
1057 structure = gst_caps_get_structure_unchecked (caps, 0);
1059 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
1063 * gst_caps_is_equal_fixed:
1064 * @caps1: the #GstCaps to test
1065 * @caps2: the #GstCaps to test
1067 * Tests if two #GstCaps are equal. This function only works on fixed
1070 * Returns: TRUE if the arguments represent the same format
1073 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
1075 GstStructure *struct1, *struct2;
1077 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
1078 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
1080 struct1 = gst_caps_get_structure_unchecked (caps1, 0);
1081 struct2 = gst_caps_get_structure_unchecked (caps2, 0);
1083 if (struct1->name != struct2->name) {
1086 if (struct1->fields->len != struct2->fields->len) {
1090 return gst_structure_foreach (struct1, gst_structure_is_equal_foreach,
1095 * gst_caps_is_always_compatible:
1096 * @caps1: the #GstCaps to test
1097 * @caps2: the #GstCaps to test
1099 * A given #GstCaps structure is always compatible with another if
1100 * every media format that is in the first is also contained in the
1101 * second. That is, @caps1 is a subset of @caps2.
1103 * Returns: TRUE if @caps1 is a subset of @caps2.
1106 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
1108 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1109 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1111 return gst_caps_is_subset (caps1, caps2);
1115 * gst_caps_is_subset:
1116 * @subset: a #GstCaps
1117 * @superset: a potentially greater #GstCaps
1119 * Checks if all caps represented by @subset are also represented by @superset.
1120 * <note>This function does not work reliably if optional properties for caps
1121 * are included on one caps and omitted on the other.</note>
1123 * Returns: %TRUE if @subset is a subset of @superset
1126 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
1131 g_return_val_if_fail (subset != NULL, FALSE);
1132 g_return_val_if_fail (superset != NULL, FALSE);
1134 if (CAPS_IS_EMPTY (subset) || CAPS_IS_ANY (superset))
1136 if (CAPS_IS_ANY (subset) || CAPS_IS_EMPTY (superset))
1139 caps = gst_caps_subtract (subset, superset);
1140 ret = CAPS_IS_EMPTY_SIMPLE (caps);
1141 gst_caps_unref (caps);
1146 * gst_caps_is_equal:
1147 * @caps1: a #GstCaps
1148 * @caps2: another #GstCaps
1150 * Checks if the given caps represent the same set of caps.
1151 * <note>This function does not work reliably if optional properties for caps
1152 * are included on one caps and omitted on the other.</note>
1154 * This function deals correctly with passing NULL for any of the caps.
1156 * Returns: TRUE if both caps are equal.
1159 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1161 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1162 * So there should be an assertion that caps1 and caps2 != NULL */
1164 /* NULL <-> NULL is allowed here */
1165 if (G_UNLIKELY (caps1 == caps2))
1168 /* one of them NULL => they are different (can't be both NULL because
1169 * we checked that above) */
1170 if (G_UNLIKELY (caps1 == NULL || caps2 == NULL))
1173 if (G_UNLIKELY (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2)))
1174 return gst_caps_is_equal_fixed (caps1, caps2);
1176 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1179 /* intersect operation */
1184 const GstStructure *intersect;
1189 gst_caps_structure_intersect_field1 (GQuark id, const GValue * val1,
1192 IntersectData *idata = (IntersectData *) data;
1193 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1195 if (G_UNLIKELY (val2 == NULL)) {
1196 gst_structure_id_set_value (idata->dest, id, val1);
1198 GValue dest_value = { 0 };
1199 if (gst_value_intersect (&dest_value, val1, val2)) {
1200 gst_structure_id_set_value (idata->dest, id, &dest_value);
1201 g_value_unset (&dest_value);
1210 gst_caps_structure_intersect_field2 (GQuark id, const GValue * val1,
1213 IntersectData *idata = (IntersectData *) data;
1214 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1216 if (G_UNLIKELY (val2 == NULL)) {
1217 gst_structure_id_set_value (idata->dest, id, val1);
1222 static GstStructure *
1223 gst_caps_structure_intersect (const GstStructure * struct1,
1224 const GstStructure * struct2)
1228 g_assert (struct1 != NULL);
1229 g_assert (struct2 != NULL);
1231 if (G_UNLIKELY (struct1->name != struct2->name))
1234 /* copy fields from struct1 which we have not in struct2 to target
1235 * intersect if we have the field in both */
1236 data.dest = gst_structure_id_empty_new (struct1->name);
1237 data.intersect = struct2;
1238 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1239 gst_caps_structure_intersect_field1, &data)))
1242 /* copy fields from struct2 which we have not in struct1 to target */
1243 data.intersect = struct1;
1244 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct2,
1245 gst_caps_structure_intersect_field2, &data)))
1251 gst_structure_free (data.dest);
1256 gst_caps_structure_can_intersect_field (GQuark id, const GValue * val1,
1259 GstStructure *other = (GstStructure *) data;
1260 const GValue *val2 = gst_structure_id_get_value (other, id);
1262 if (G_LIKELY (val2)) {
1263 if (!gst_value_can_intersect (val1, val2)) {
1266 gint eq = gst_value_compare (val1, val2);
1268 if (eq == GST_VALUE_UNORDERED) {
1269 /* we need to try interseting */
1270 GValue dest_value = { 0 };
1271 if (gst_value_intersect (&dest_value, val1, val2)) {
1272 g_value_unset (&dest_value);
1276 } else if (eq != GST_VALUE_EQUAL) {
1285 gst_caps_structure_can_intersect (const GstStructure * struct1,
1286 const GstStructure * struct2)
1288 g_assert (struct1 != NULL);
1289 g_assert (struct2 != NULL);
1291 if (G_UNLIKELY (struct1->name != struct2->name))
1294 /* tries to intersect if we have the field in both */
1295 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1296 gst_caps_structure_can_intersect_field, (gpointer) struct2)))
1303 * gst_caps_can_intersect:
1304 * @caps1: a #GstCaps to intersect
1305 * @caps2: a #GstCaps to intersect
1307 * Tries intersecting @caps1 and @caps2 and reports wheter the result would not
1310 * Returns: %TRUE if intersection would be not empty
1315 gst_caps_can_intersect (const GstCaps * caps1, const GstCaps * caps2)
1317 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1318 guint j, k, len1, len2;
1319 GstStructure *struct1;
1320 GstStructure *struct2;
1322 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1323 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1325 /* caps are exactly the same pointers */
1326 if (G_UNLIKELY (caps1 == caps2))
1329 /* empty caps on either side, return empty */
1330 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1333 /* one of the caps is any */
1334 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2)))
1337 /* run zigzag on top line then right line, this preserves the caps order
1338 * much better than a simple loop.
1340 * This algorithm zigzags over the caps structures as demonstrated in
1341 * the folowing matrix:
1349 * First we iterate over the caps1 structures (top line) intersecting
1350 * the structures diagonally down, then we iterate over the caps2
1353 len1 = caps1->structs->len;
1354 len2 = caps2->structs->len;
1355 for (i = 0; i < len1 + len2 - 1; i++) {
1356 /* superset index goes from 0 to sgst_caps_structure_intersectuperset->structs->len-1 */
1357 j = MIN (i, len1 - 1);
1358 /* subset index stays 0 until i reaches superset->structs->len, then it
1359 * counts up from 1 to subset->structs->len - 1 */
1362 /* now run the diagonal line, end condition is the left or bottom
1365 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1366 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1368 if (gst_caps_structure_can_intersect (struct1, struct2)) {
1371 /* move down left */
1373 if (G_UNLIKELY (j == 0))
1374 break; /* so we don't roll back to G_MAXUINT */
1382 * gst_caps_intersect:
1383 * @caps1: a #GstCaps to intersect
1384 * @caps2: a #GstCaps to intersect
1386 * Creates a new #GstCaps that contains all the formats that are common
1387 * to both @caps1 and @caps2.
1389 * Returns: the new #GstCaps
1392 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1394 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1395 guint j, k, len1, len2;
1397 GstStructure *struct1;
1398 GstStructure *struct2;
1400 GstStructure *istruct;
1402 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1403 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1405 /* caps are exactly the same pointers, just copy one caps */
1406 if (G_UNLIKELY (caps1 == caps2))
1407 return gst_caps_copy (caps1);
1409 /* empty caps on either side, return empty */
1410 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1411 return gst_caps_new_empty ();
1413 /* one of the caps is any, just copy the other caps */
1414 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1415 return gst_caps_copy (caps2);
1416 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1417 return gst_caps_copy (caps1);
1419 dest = gst_caps_new_empty ();
1421 /* run zigzag on top line then right line, this preserves the caps order
1422 * much better than a simple loop.
1424 * This algorithm zigzags over the caps structures as demonstrated in
1425 * the folowing matrix:
1433 * First we iterate over the caps1 structures (top line) intersecting
1434 * the structures diagonally down, then we iterate over the caps2
1437 len1 = caps1->structs->len;
1438 len2 = caps2->structs->len;
1439 for (i = 0; i < len1 + len2 - 1; i++) {
1440 /* caps1 index goes from 0 to caps1->structs->len-1 */
1441 j = MIN (i, len1 - 1);
1442 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1443 * up from 1 to caps2->structs->len - 1 */
1446 /* now run the diagonal line, end condition is the left or bottom
1449 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1450 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1452 istruct = gst_caps_structure_intersect (struct1, struct2);
1454 gst_caps_append_structure (dest, istruct);
1455 /* move down left */
1457 if (G_UNLIKELY (j == 0))
1458 break; /* so we don't roll back to G_MAXUINT */
1465 /* subtract operation */
1469 const GstStructure *subtract_from;
1475 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1478 SubtractionEntry *e = user_data;
1479 GValue subtraction = { 0, };
1480 const GValue *other;
1481 GstStructure *structure;
1483 other = gst_structure_id_get_value (e->subtract_from, field_id);
1487 if (!gst_value_subtract (&subtraction, other, value))
1489 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1490 g_value_unset (&subtraction);
1493 structure = gst_structure_copy (e->subtract_from);
1494 gst_structure_id_set_value (structure, field_id, &subtraction);
1495 g_value_unset (&subtraction);
1496 e->put_into = g_slist_prepend (e->put_into, structure);
1502 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1503 const GstStructure * subtrahend)
1508 e.subtract_from = minuend;
1511 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1512 gst_caps_structure_subtract_field, &e);
1518 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1519 gst_structure_free (walk->data);
1521 g_slist_free (e.put_into);
1527 * gst_caps_subtract:
1528 * @minuend: #GstCaps to substract from
1529 * @subtrahend: #GstCaps to substract
1531 * Subtracts the @subtrahend from the @minuend.
1532 * <note>This function does not work reliably if optional properties for caps
1533 * are included on one caps and omitted on the other.</note>
1535 * Returns: the resulting caps
1538 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1543 GstCaps *dest = NULL, *src;
1545 g_return_val_if_fail (minuend != NULL, NULL);
1546 g_return_val_if_fail (subtrahend != NULL, NULL);
1548 if (CAPS_IS_EMPTY (minuend) || CAPS_IS_ANY (subtrahend)) {
1549 return gst_caps_new_empty ();
1551 if (CAPS_IS_EMPTY_SIMPLE (subtrahend))
1552 return gst_caps_copy (minuend);
1554 /* FIXME: Do we want this here or above?
1555 The reason we need this is that there is no definition about what
1556 ANY means for specific types, so it's not possible to reduce ANY partially
1557 You can only remove everything or nothing and that is done above.
1558 Note: there's a test that checks this behaviour. */
1559 g_return_val_if_fail (!CAPS_IS_ANY (minuend), NULL);
1560 sublen = subtrahend->structs->len;
1561 g_assert (sublen > 0);
1563 src = gst_caps_copy (minuend);
1564 for (i = 0; i < sublen; i++) {
1567 sub = gst_caps_get_structure_unchecked (subtrahend, i);
1569 gst_caps_unref (src);
1572 dest = gst_caps_new_empty ();
1573 srclen = src->structs->len;
1574 for (j = 0; j < srclen; j++) {
1575 min = gst_caps_get_structure_unchecked (src, j);
1576 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1579 if (gst_caps_structure_subtract (&list, min, sub)) {
1582 for (walk = list; walk; walk = g_slist_next (walk)) {
1583 gst_caps_append_structure_unchecked (dest,
1584 (GstStructure *) walk->data);
1586 g_slist_free (list);
1588 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1591 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1594 if (CAPS_IS_EMPTY_SIMPLE (dest)) {
1595 gst_caps_unref (src);
1600 gst_caps_unref (src);
1601 gst_caps_do_simplify (dest);
1605 /* union operation */
1608 static GstStructure *
1609 gst_caps_structure_union (const GstStructure * struct1,
1610 const GstStructure * struct2)
1614 const GstStructureField *field1;
1615 const GstStructureField *field2;
1618 /* FIXME this doesn't actually work */
1620 if (struct1->name != struct2->name)
1623 dest = gst_structure_id_empty_new (struct1->name);
1625 for (i = 0; i < struct1->fields->len; i++) {
1626 GValue dest_value = { 0 };
1628 field1 = GST_STRUCTURE_FIELD (struct1, i);
1629 field2 = gst_structure_id_get_field (struct2, field1->name);
1631 if (field2 == NULL) {
1634 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1635 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1638 ret = gst_value_compare (&field1->value, &field2->value);
1649 * @caps1: a #GstCaps to union
1650 * @caps2: a #GstCaps to union
1652 * Creates a new #GstCaps that contains all the formats that are in
1653 * either @caps1 and @caps2.
1655 * Returns: the new #GstCaps
1658 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1663 /* NULL pointers are no correct GstCaps */
1664 g_return_val_if_fail (caps1 != NULL, NULL);
1665 g_return_val_if_fail (caps2 != NULL, NULL);
1667 if (CAPS_IS_EMPTY (caps1))
1668 return gst_caps_copy (caps2);
1670 if (CAPS_IS_EMPTY (caps2))
1671 return gst_caps_copy (caps1);
1673 if (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))
1674 return gst_caps_new_any ();
1676 dest1 = gst_caps_copy (caps1);
1677 dest2 = gst_caps_copy (caps2);
1678 gst_caps_append (dest1, dest2);
1680 gst_caps_do_simplify (dest1);
1684 /* normalize/simplify operations */
1686 typedef struct _NormalizeForeach
1689 GstStructure *structure;
1694 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1696 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1700 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1701 guint len = gst_value_list_get_size (value);
1702 for (i = 1; i < len; i++) {
1703 const GValue *v = gst_value_list_get_value (value, i);
1704 GstStructure *structure = gst_structure_copy (nf->structure);
1706 gst_structure_id_set_value (structure, field_id, v);
1707 gst_caps_append_structure_unchecked (nf->caps, structure);
1710 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1711 gst_structure_id_set_value (nf->structure, field_id, &val);
1712 g_value_unset (&val);
1720 * gst_caps_normalize:
1721 * @caps: a #GstCaps to normalize
1723 * Creates a new #GstCaps that represents the same set of formats as
1724 * @caps, but contains no lists. Each list is expanded into separate
1727 * Returns: the new #GstCaps
1730 gst_caps_normalize (const GstCaps * caps)
1732 NormalizeForeach nf;
1736 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1738 newcaps = gst_caps_copy (caps);
1740 nlen = newcaps->structs->len;
1742 for (i = 0; i < nlen; i++) {
1743 nf.structure = gst_caps_get_structure_unchecked (newcaps, i);
1745 while (!gst_structure_foreach (nf.structure,
1746 gst_caps_normalize_foreach, &nf));
1753 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1756 const GstStructure *struct1 = *((const GstStructure **) one);
1757 const GstStructure *struct2 = *((const GstStructure **) two);
1759 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1760 So what's the best way? */
1761 ret = strcmp (gst_structure_get_name (struct1),
1762 gst_structure_get_name (struct2));
1766 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1773 GstStructure *compare;
1778 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1781 UnionField *u = user_data;
1782 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1786 g_value_unset (&u->value);
1789 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1792 g_value_unset (&u->value);
1796 gst_value_union (&u->value, val, value);
1801 gst_caps_structure_simplify (GstStructure ** result,
1802 const GstStructure * simplify, GstStructure * compare)
1805 UnionField field = { 0, {0,}, NULL };
1807 /* try to subtract to get a real subset */
1808 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1809 switch (g_slist_length (list)) {
1814 *result = list->data;
1815 g_slist_free (list);
1821 for (walk = list; walk; walk = g_slist_next (walk)) {
1822 gst_structure_free (walk->data);
1824 g_slist_free (list);
1830 /* try to union both structs */
1831 field.compare = compare;
1832 if (gst_structure_foreach ((GstStructure *) simplify,
1833 gst_caps_structure_figure_out_union, &field)) {
1834 gboolean ret = FALSE;
1836 /* now we know all of simplify's fields are the same in compare
1837 * but at most one field: field.name */
1838 if (G_IS_VALUE (&field.value)) {
1839 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1840 gst_structure_id_set_value (compare, field.name, &field.value);
1844 g_value_unset (&field.value);
1845 } else if (gst_structure_n_fields (simplify) <=
1846 gst_structure_n_fields (compare)) {
1847 /* compare is just more specific, will be optimized away later */
1848 /* FIXME: do this here? */
1849 GST_LOG ("found a case that will be optimized later.");
1851 gchar *one = gst_structure_to_string (simplify);
1852 gchar *two = gst_structure_to_string (compare);
1855 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1867 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1868 GstStructure * new, gint i)
1870 gst_structure_set_parent_refcount (old, NULL);
1871 gst_structure_free (old);
1872 gst_structure_set_parent_refcount (new, &caps->refcount);
1873 g_ptr_array_index (caps->structs, i) = new;
1877 * gst_caps_do_simplify:
1878 * @caps: a #GstCaps to simplify
1880 * Modifies the given @caps inplace into a representation that represents the
1881 * same set of formats, but in a simpler form. Component structures that are
1882 * identical are merged. Component structures that have values that can be
1883 * merged are also merged.
1885 * Returns: TRUE, if the caps could be simplified
1888 gst_caps_do_simplify (GstCaps * caps)
1890 GstStructure *simplify, *compare, *result = NULL;
1892 gboolean changed = FALSE;
1894 g_return_val_if_fail (caps != NULL, FALSE);
1895 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1897 if (gst_caps_get_size (caps) < 2)
1900 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1902 start = caps->structs->len - 1;
1903 for (i = caps->structs->len - 1; i >= 0; i--) {
1904 simplify = gst_caps_get_structure_unchecked (caps, i);
1905 if (gst_structure_get_name_id (simplify) !=
1906 gst_structure_get_name_id (gst_caps_get_structure_unchecked (caps,
1909 for (j = start; j >= 0; j--) {
1912 compare = gst_caps_get_structure_unchecked (caps, j);
1913 if (gst_structure_get_name_id (simplify) !=
1914 gst_structure_get_name_id (compare)) {
1917 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1919 gst_caps_switch_structures (caps, simplify, result, i);
1922 gst_caps_remove_structure (caps, i);
1934 /* gst_caps_do_simplify (caps); */
1940 #ifndef GST_DISABLE_LOADSAVE
1942 * gst_caps_save_thyself:
1943 * @caps: a #GstCaps structure
1944 * @parent: a XML parent node
1946 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
1948 * Returns: a XML node pointer
1951 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
1953 char *s = gst_caps_to_string (caps);
1955 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
1961 * gst_caps_load_thyself:
1962 * @parent: a XML node
1964 * Creates a #GstCaps from its XML serialization.
1966 * Returns: a new #GstCaps structure
1969 gst_caps_load_thyself (xmlNodePtr parent)
1971 if (strcmp ("caps", (char *) parent->name) == 0) {
1972 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
1983 * @caps: a pointer to #GstCaps
1984 * @newcaps: a #GstCaps to replace *caps
1986 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
1987 * pointed to by @caps, if applicable, then modifies @caps to point to
1988 * @newcaps. An additional ref on @newcaps is taken.
1990 * This function does not take any locks so you might want to lock
1991 * the object owning @caps pointer.
1994 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
1998 g_return_if_fail (caps != NULL);
2002 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p, %p -> %p", caps, oldcaps, newcaps);
2004 if (newcaps != oldcaps) {
2006 gst_caps_ref (newcaps);
2011 gst_caps_unref (oldcaps);
2016 * gst_caps_to_string:
2019 * Converts @caps to a string representation. This string representation
2020 * can be converted back to a #GstCaps by gst_caps_from_string().
2022 * For debugging purposes its easier to do something like this:
2024 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
2026 * This prints the caps in human readble form.
2028 * Returns: a newly allocated string representing @caps.
2031 gst_caps_to_string (const GstCaps * caps)
2033 guint i, slen, clen;
2036 /* NOTE: This function is potentially called by the debug system,
2037 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
2038 * should be careful to avoid recursion. This includes any functions
2039 * called by gst_caps_to_string. In particular, calls should
2040 * not use the GST_PTR_FORMAT extension. */
2043 return g_strdup ("NULL");
2045 if (CAPS_IS_ANY (caps)) {
2046 return g_strdup ("ANY");
2048 if (CAPS_IS_EMPTY_SIMPLE (caps)) {
2049 return g_strdup ("EMPTY");
2052 /* estimate a rough string length to avoid unnecessary reallocs in GString */
2054 clen = caps->structs->len;
2055 for (i = 0; i < clen; i++) {
2057 STRUCTURE_ESTIMATED_STRING_LEN (gst_caps_get_structure_unchecked (caps,
2061 s = g_string_sized_new (slen);
2062 for (i = 0; i < clen; i++) {
2063 GstStructure *structure;
2066 /* ';' is now added by gst_structure_to_string */
2067 g_string_append_c (s, ' ');
2070 structure = gst_caps_get_structure_unchecked (caps, i);
2071 priv_gst_structure_append_to_gstring (structure, s);
2073 if (s->len && s->str[s->len - 1] == ';') {
2074 /* remove latest ';' */
2075 s->str[--s->len] = '\0';
2077 return g_string_free (s, FALSE);
2081 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
2083 GstStructure *structure;
2086 if (strcmp ("ANY", string) == 0) {
2087 caps->flags = GST_CAPS_FLAGS_ANY;
2090 if (strcmp ("EMPTY", string) == 0) {
2094 structure = gst_structure_from_string (string, &s);
2095 if (structure == NULL) {
2098 gst_caps_append_structure_unchecked (caps, structure);
2102 while (g_ascii_isspace (*s))
2107 structure = gst_structure_from_string (s, &s);
2108 if (structure == NULL) {
2111 gst_caps_append_structure_unchecked (caps, structure);
2119 * gst_caps_from_string:
2120 * @string: a string to convert to #GstCaps
2122 * Converts @caps from a string representation.
2124 * Returns: a newly allocated #GstCaps
2127 gst_caps_from_string (const gchar * string)
2131 g_return_val_if_fail (string, FALSE);
2133 caps = gst_caps_new_empty ();
2134 if (gst_caps_from_string_inplace (caps, string)) {
2137 gst_caps_unref (caps);
2143 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
2145 g_return_if_fail (G_IS_VALUE (src_value));
2146 g_return_if_fail (G_IS_VALUE (dest_value));
2147 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
2148 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
2149 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
2151 dest_value->data[0].v_pointer =
2152 gst_caps_to_string (src_value->data[0].v_pointer);
2156 gst_caps_copy_conditional (GstCaps * src)
2159 return gst_caps_ref (src);