2 * Copyright (C) <2003> David A. Schleef <ds@schleef.org>
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
22 * @short_description: Structure describing sets of media formats
23 * @see_also: #GstStructure
25 * Caps (capabilities) are lighweight refcounted objects describing media types.
26 * They are composed of an array of #GstStructure.
28 * Caps are exposed on #GstPadTemplate to describe all possible types a
29 * given pad can handle. They are also stored in the registry along with
30 * a description of the element.
32 * Caps are exposed on the element pads using the gst_pad_get_caps() pad
33 * function. This function describes the possible types that the pad can
34 * handle or produce at runtime.
36 * Caps are also attached to buffers to describe to content of the data
37 * pointed to by the buffer with gst_buffer_set_caps(). Caps attached to
38 * a #GstBuffer allow for format negotiation upstream and downstream.
40 * A #GstCaps can be constructed with the following code fragment:
43 * <title>Creating caps</title>
46 * caps = gst_caps_new_simple ("video/x-raw-yuv",
47 * "format", GST_TYPE_FOURCC, GST_MAKE_FOURCC ('I', '4', '2', '0'),
48 * "framerate", G_TYPE_DOUBLE, 25.0,
49 * "pixel-aspect-ratio", GST_TYPE_FRACTION, 1, 1,
50 * "width", G_TYPE_INT, 320,
51 * "height", G_TYPE_INT, 240,
56 * A #GstCaps is fixed when it has no properties with ranges or lists. Use
57 * gst_caps_is_fixed() to test for fixed caps. Only fixed caps can be
58 * set on a #GstPad or #GstBuffer.
60 * Various methods exist to work with the media types such as subtracting
63 * Last reviewed on 2005-11-23 (0.9.5)
72 #include "gst_private.h"
75 #define DEBUG_REFCOUNT
77 #define CAPS_POISON(caps) G_STMT_START{ \
79 GstCaps *_newcaps = gst_caps_copy (caps); \
80 gst_caps_unref(caps); \
84 #define STRUCTURE_POISON(structure) G_STMT_START{ \
86 GstStructure *_newstruct = gst_structure_copy (structure); \
87 gst_structure_free(structure); \
88 structure = _newstruct; \
91 #define IS_WRITABLE(caps) \
92 (g_atomic_int_get (&(caps)->refcount) == 1)
94 #if GLIB_CHECK_VERSION (2, 10, 0)
95 #define ALLOC_CAPS() g_slice_new (GstCaps)
96 #define FREE_CAPS(caps) g_slice_free (GstCaps, caps)
98 #define ALLOC_CAPS() g_new (GstCaps, 1)
99 #define FREE_CAPS(caps) g_free (caps)
102 static void gst_caps_transform_to_string (const GValue * src_value,
103 GValue * dest_value);
104 static gboolean gst_caps_from_string_inplace (GstCaps * caps,
105 const gchar * string);
106 static GstCaps *gst_caps_copy_conditional (GstCaps * src);
109 gst_caps_get_type (void)
111 static GType gst_caps_type = 0;
113 if (G_UNLIKELY (gst_caps_type == 0)) {
114 gst_caps_type = g_boxed_type_register_static ("GstCaps",
115 (GBoxedCopyFunc) gst_caps_copy_conditional,
116 (GBoxedFreeFunc) gst_caps_unref);
118 g_value_register_transform_func (gst_caps_type,
119 G_TYPE_STRING, gst_caps_transform_to_string);
122 return gst_caps_type;
125 /* creation/deletion */
128 * gst_caps_new_empty:
130 * Creates a new #GstCaps that is empty. That is, the returned
131 * #GstCaps contains no media formats.
132 * Caller is responsible for unreffing the returned caps.
134 * Returns: the new #GstCaps
137 gst_caps_new_empty (void)
139 GstCaps *caps = ALLOC_CAPS ();
141 caps->type = GST_TYPE_CAPS;
144 caps->structs = g_ptr_array_new ();
146 #ifdef DEBUG_REFCOUNT
147 GST_CAT_LOG (GST_CAT_CAPS, "created caps %p", caps);
156 * Creates a new #GstCaps that indicates that it is compatible with
159 * Returns: the new #GstCaps
162 gst_caps_new_any (void)
164 GstCaps *caps = gst_caps_new_empty ();
166 caps->flags = GST_CAPS_FLAGS_ANY;
172 * gst_caps_new_simple:
173 * @media_type: the media type of the structure
174 * @fieldname: first field to set
175 * @...: additional arguments
177 * Creates a new #GstCaps that contains one #GstStructure. The
178 * structure is defined by the arguments, which have the same format
179 * as gst_structure_new().
180 * Caller is responsible for unreffing the returned caps.
182 * Returns: the new #GstCaps
185 gst_caps_new_simple (const char *media_type, const char *fieldname, ...)
188 GstStructure *structure;
191 caps = gst_caps_new_empty ();
193 va_start (var_args, fieldname);
194 structure = gst_structure_new_valist (media_type, fieldname, var_args);
197 gst_caps_append_structure (caps, structure);
204 * @struct1: the first structure to add
205 * @...: additional structures to add
207 * Creates a new #GstCaps and adds all the structures listed as
208 * arguments. The list must be NULL-terminated. The structures
209 * are not copied; the returned #GstCaps owns the structures.
211 * Returns: the new #GstCaps
214 gst_caps_new_full (GstStructure * struct1, ...)
219 va_start (var_args, struct1);
220 caps = gst_caps_new_full_valist (struct1, var_args);
227 * gst_caps_new_full_valist:
228 * @structure: the first structure to add
229 * @var_args: additional structures to add
231 * Creates a new #GstCaps and adds all the structures listed as
232 * arguments. The list must be NULL-terminated. The structures
233 * are not copied; the returned #GstCaps owns the structures.
235 * Returns: the new #GstCaps
238 gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
242 caps = gst_caps_new_empty ();
245 gst_caps_append_structure (caps, structure);
246 structure = va_arg (var_args, GstStructure *);
254 * @caps: the #GstCaps to copy
256 * Creates a new #GstCaps as a copy of the old @caps. The new caps will have a
257 * refcount of 1, owned by the caller. The structures are copied as well.
259 * Note that this function is the semantic equivalent of a gst_caps_ref()
260 * followed by a gst_caps_make_writable(). If you only want to hold on to a
261 * reference to the data, you should use gst_caps_ref().
263 * When you are finished with the caps, call gst_caps_unref() on it.
265 * Returns: the new #GstCaps
268 gst_caps_copy (const GstCaps * caps)
271 GstStructure *structure;
274 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
276 newcaps = gst_caps_new_empty ();
277 newcaps->flags = caps->flags;
279 for (i = 0; i < caps->structs->len; i++) {
280 structure = gst_caps_get_structure (caps, i);
281 gst_caps_append_structure (newcaps, gst_structure_copy (structure));
288 _gst_caps_free (GstCaps * caps)
290 GstStructure *structure;
293 /* The refcount must be 0, but since we're only called by gst_caps_unref,
294 * don't bother testing. */
296 for (i = 0; i < caps->structs->len; i++) {
297 structure = (GstStructure *) gst_caps_get_structure (caps, i);
298 gst_structure_set_parent_refcount (structure, NULL);
299 gst_structure_free (structure);
301 g_ptr_array_free (caps->structs, TRUE);
303 memset (caps, 0xff, sizeof (GstCaps));
309 * gst_caps_make_writable:
310 * @caps: the #GstCaps to make writable
312 * Returns a writable copy of @caps.
314 * If there is only one reference count on @caps, the caller must be the owner,
315 * and so this function will return the caps object unchanged. If on the other
316 * hand there is more than one reference on the object, a new caps object will
317 * be returned. The caller's reference on @caps will be removed, and instead the
318 * caller will own a reference to the returned object.
320 * In short, this function unrefs the caps in the argument and refs the caps
321 * that it returns. Don't access the argument after calling this function. See
322 * also: gst_caps_ref().
324 * Returns: the same #GstCaps object.
327 gst_caps_make_writable (GstCaps * caps)
331 g_return_val_if_fail (caps != NULL, NULL);
333 /* we are the only instance reffing this caps */
334 if (g_atomic_int_get (&caps->refcount) == 1)
338 copy = gst_caps_copy (caps);
339 gst_caps_unref (caps);
346 * @caps: the #GstCaps to reference
348 * Add a reference to a #GstCaps object.
350 * From this point on, until the caller calls gst_caps_unref() or
351 * gst_caps_make_writable(), it is guaranteed that the caps object will not
352 * change. This means its structures won't change, etc. To use a #GstCaps
353 * object, you must always have a refcount on it -- either the one made
354 * implicitly by gst_caps_new(), or via taking one explicitly with this
357 * Returns: the same #GstCaps object.
360 gst_caps_ref (GstCaps * caps)
362 g_return_val_if_fail (caps != NULL, NULL);
364 #ifdef DEBUG_REFCOUNT
365 GST_CAT_LOG (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
366 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) + 1);
368 g_return_val_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0, NULL);
370 g_atomic_int_inc (&caps->refcount);
377 * @caps: the #GstCaps to unref
379 * Unref a #GstCaps and and free all its structures and the
380 * structures' values when the refcount reaches 0.
383 gst_caps_unref (GstCaps * caps)
385 g_return_if_fail (caps != NULL);
387 #ifdef DEBUG_REFCOUNT
388 GST_CAT_LOG (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
389 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) - 1);
392 g_return_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0);
394 /* if we ended up with the refcount at zero, free the caps */
395 if (G_UNLIKELY (g_atomic_int_dec_and_test (&caps->refcount)))
396 _gst_caps_free (caps);
400 gst_static_caps_get_type (void)
402 static GType staticcaps_type = 0;
404 if (G_UNLIKELY (staticcaps_type == 0)) {
405 staticcaps_type = g_pointer_type_register_static ("GstStaticCaps");
407 return staticcaps_type;
412 * gst_static_caps_get:
413 * @static_caps: the #GstStaticCaps to convert
415 * Converts a #GstStaticCaps to a #GstCaps.
417 * Returns: A pointer to the #GstCaps. Unref after usage. Since the
418 * core holds an additional ref to the returned caps,
419 * use gst_caps_make_writable() on the returned caps to modify it.
422 gst_static_caps_get (GstStaticCaps * static_caps)
426 g_return_val_if_fail (static_caps != NULL, NULL);
428 caps = (GstCaps *) static_caps;
430 if (caps->type == 0) {
431 if (G_UNLIKELY (static_caps->string == NULL))
434 caps->type = GST_TYPE_CAPS;
435 /* initialize the caps to a refcount of 1 so the caps can be writable... */
436 gst_atomic_int_set (&caps->refcount, 1);
437 caps->structs = g_ptr_array_new ();
439 /* convert to string */
440 if (G_UNLIKELY (!gst_caps_from_string_inplace (caps, static_caps->string)))
441 g_critical ("Could not convert static caps \"%s\"", static_caps->string);
443 /* ref the caps, makes it not writable */
451 g_warning ("static caps string is NULL");
457 static GstStructure *
458 gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
460 /* don't use index_fast, gst_caps_do_simplify relies on the order */
461 GstStructure *s = g_ptr_array_remove_index (caps->structs, idx);
463 gst_structure_set_parent_refcount (s, NULL);
469 * @caps1: the #GstCaps that will be appended to
470 * @caps2: the #GstCaps to append
472 * Appends the structures contained in @caps2 to @caps1. The structures in
473 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
474 * freed. If either caps is ANY, the resulting caps will be ANY.
477 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
479 GstStructure *structure;
482 g_return_if_fail (GST_IS_CAPS (caps1));
483 g_return_if_fail (GST_IS_CAPS (caps2));
484 g_return_if_fail (IS_WRITABLE (caps1));
485 g_return_if_fail (IS_WRITABLE (caps2));
490 if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2)) {
491 /* FIXME: this leaks */
492 caps1->flags |= GST_CAPS_FLAGS_ANY;
493 for (i = caps2->structs->len - 1; i >= 0; i--) {
494 structure = gst_caps_remove_and_get_structure (caps2, i);
495 gst_structure_free (structure);
498 int len = caps2->structs->len;
500 for (i = 0; i < len; i++) {
501 structure = gst_caps_remove_and_get_structure (caps2, 0);
502 gst_caps_append_structure (caps1, structure);
505 gst_caps_unref (caps2); /* guaranteed to free it */
509 * gst_caps_append_structure:
510 * @caps: the #GstCaps that will be appended to
511 * @structure: the #GstStructure to append
513 * Appends @structure to @caps. The structure is not copied; @caps
514 * becomes the owner of @structure.
517 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
519 g_return_if_fail (GST_IS_CAPS (caps));
520 g_return_if_fail (IS_WRITABLE (caps));
522 if (G_LIKELY (structure)) {
523 g_return_if_fail (structure->parent_refcount == NULL);
526 STRUCTURE_POISON (structure);
529 gst_structure_set_parent_refcount (structure, &caps->refcount);
530 g_ptr_array_add (caps->structs, structure);
535 * gst_caps_remove_structure:
536 * @caps: the #GstCaps to remove from
537 * @idx: Index of the structure to remove
539 * removes the stucture with the given index from the list of structures
540 * contained in @caps.
543 gst_caps_remove_structure (GstCaps * caps, guint idx)
545 GstStructure *structure;
547 g_return_if_fail (caps != NULL);
548 g_return_if_fail (idx <= gst_caps_get_size (caps));
549 g_return_if_fail (IS_WRITABLE (caps));
551 structure = gst_caps_remove_and_get_structure (caps, idx);
552 gst_structure_free (structure);
556 * gst_caps_split_one:
559 * This function is not implemented.
564 gst_caps_split_one (GstCaps * caps)
567 g_critical ("unimplemented");
576 * Gets the number of structures contained in @caps.
578 * Returns: the number of structures that @caps contains
581 gst_caps_get_size (const GstCaps * caps)
583 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
585 return caps->structs->len;
589 * gst_caps_get_structure:
591 * @index: the index of the structure
593 * Finds the structure in @caps that has the index @index, and
596 * WARNING: This function takes a const GstCaps *, but returns a
597 * non-const GstStructure *. This is for programming convenience --
598 * the caller should be aware that structures inside a constant
599 * #GstCaps should not be modified.
601 * Returns: a pointer to the #GstStructure corresponding to @index
604 gst_caps_get_structure (const GstCaps * caps, guint index)
606 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
607 g_return_val_if_fail (index < caps->structs->len, NULL);
609 return g_ptr_array_index (caps->structs, index);
614 * @caps: the #GstCaps to copy
615 * @nth: the nth structure to copy
617 * Creates a new #GstCaps and appends a copy of the nth structure
618 * contained in @caps.
620 * Returns: the new #GstCaps
623 gst_caps_copy_nth (const GstCaps * caps, guint nth)
626 GstStructure *structure;
628 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
630 newcaps = gst_caps_new_empty ();
631 newcaps->flags = caps->flags;
633 if (caps->structs->len > nth) {
634 structure = gst_caps_get_structure (caps, nth);
635 gst_caps_append_structure (newcaps, gst_structure_copy (structure));
643 * @caps: the #GstCaps to truncate
645 * Destructively discard all but the first structure from @caps. Useful when
646 * fixating. @caps must be writable.
649 gst_caps_truncate (GstCaps * caps)
653 g_return_if_fail (GST_IS_CAPS (caps));
654 g_return_if_fail (IS_WRITABLE (caps));
656 i = caps->structs->len - 1;
659 gst_caps_remove_structure (caps, i--);
663 * gst_caps_set_simple:
664 * @caps: the #GstCaps to set
665 * @field: first field to set
666 * @...: additional parameters
668 * Sets fields in a simple #GstCaps. A simple #GstCaps is one that
669 * only has one structure. The arguments must be passed in the same
670 * manner as gst_structure_set(), and be NULL-terminated.
673 gst_caps_set_simple (GstCaps * caps, char *field, ...)
675 GstStructure *structure;
678 g_return_if_fail (GST_IS_CAPS (caps));
679 g_return_if_fail (caps->structs->len == 1);
680 g_return_if_fail (IS_WRITABLE (caps));
682 structure = gst_caps_get_structure (caps, 0);
684 va_start (var_args, field);
685 gst_structure_set_valist (structure, field, var_args);
690 * gst_caps_set_simple_valist:
691 * @caps: the #GstCaps to copy
692 * @field: first field to set
693 * @varargs: additional parameters
695 * Sets fields in a simple #GstCaps. A simple #GstCaps is one that
696 * only has one structure. The arguments must be passed in the same
697 * manner as gst_structure_set(), and be NULL-terminated.
700 gst_caps_set_simple_valist (GstCaps * caps, char *field, va_list varargs)
702 GstStructure *structure;
704 g_return_if_fail (GST_IS_CAPS (caps));
705 g_return_if_fail (caps->structs->len != 1);
706 g_return_if_fail (IS_WRITABLE (caps));
708 structure = gst_caps_get_structure (caps, 0);
710 gst_structure_set_valist (structure, field, varargs);
717 * @caps: the #GstCaps to test
719 * Determines if @caps represents any media format.
721 * Returns: TRUE if @caps represents any format.
724 gst_caps_is_any (const GstCaps * caps)
726 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
728 return (caps->flags & GST_CAPS_FLAGS_ANY);
733 * @caps: the #GstCaps to test
735 * Determines if @caps represents no media formats.
737 * Returns: TRUE if @caps represents no formats.
740 gst_caps_is_empty (const GstCaps * caps)
742 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
744 if (caps->flags & GST_CAPS_FLAGS_ANY)
747 return (caps->structs == NULL) || (caps->structs->len == 0);
751 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
754 return gst_value_is_fixed (value);
759 * @caps: the #GstCaps to test
761 * Fixed #GstCaps describe exactly one format, that is, they have exactly
762 * one structure, and each field in the structure describes a fixed type.
763 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
765 * Returns: TRUE if @caps is fixed
768 gst_caps_is_fixed (const GstCaps * caps)
770 GstStructure *structure;
772 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
774 if (caps->structs->len != 1)
777 structure = gst_caps_get_structure (caps, 0);
779 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
783 gst_structure_is_equal_foreach (GQuark field_id, const GValue * val2,
786 GstStructure *struct1 = (GstStructure *) data;
787 const GValue *val1 = gst_structure_id_get_value (struct1, field_id);
791 if (gst_value_compare (val1, val2) == GST_VALUE_EQUAL) {
799 * gst_caps_is_equal_fixed:
800 * @caps1: the #GstCaps to test
801 * @caps2: the #GstCaps to test
803 * Tests if two #GstCaps are equal. This function only works on fixed
806 * Returns: TRUE if the arguments represent the same format
809 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
811 GstStructure *struct1, *struct2;
813 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
814 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
816 struct1 = gst_caps_get_structure (caps1, 0);
817 struct2 = gst_caps_get_structure (caps2, 0);
819 if (struct1->name != struct2->name) {
822 if (struct1->fields->len != struct2->fields->len) {
826 return gst_structure_foreach (struct1, gst_structure_is_equal_foreach,
831 * gst_caps_is_always_compatible:
832 * @caps1: the #GstCaps to test
833 * @caps2: the #GstCaps to test
835 * A given #GstCaps structure is always compatible with another if
836 * every media format that is in the first is also contained in the
837 * second. That is, @caps1 is a subset of @caps2.
839 * Returns: TRUE if @caps1 is a subset of @caps2.
842 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
844 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
845 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
847 return gst_caps_is_subset (caps1, caps2);
851 * gst_caps_is_subset:
852 * @subset: a #GstCaps
853 * @superset: a potentially greater #GstCaps
855 * Checks if all caps represented by @subset are also represented by @superset
856 * <note>This function does not work reliably if optional properties for caps
857 * are included on one caps and omitted on the other.</note>
859 * Returns: TRUE if @subset is a subset of @superset
862 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
867 g_return_val_if_fail (subset != NULL, FALSE);
868 g_return_val_if_fail (superset != NULL, FALSE);
870 if (gst_caps_is_empty (subset) || gst_caps_is_any (superset))
872 if (gst_caps_is_any (subset) || gst_caps_is_empty (superset))
875 caps = gst_caps_subtract (subset, superset);
876 ret = gst_caps_is_empty (caps);
877 gst_caps_unref (caps);
884 * @caps2: another #GstCaps
886 * Checks if the given caps represent the same set of caps.
887 * <note>This function does not work reliably if optional properties for caps
888 * are included on one caps and omitted on the other.</note>
890 * This function deals correctly with passing NULL for any of the caps.
892 * Returns: TRUE if both caps are equal.
895 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
897 /* NULL <-> NULL is allowed here */
901 /* one of them NULL => they are different (can't be both NULL because
902 * we checked that above) */
903 if (caps1 == NULL || caps2 == NULL)
906 if (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2))
907 return gst_caps_is_equal_fixed (caps1, caps2);
909 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
915 const GstStructure *intersect;
921 gst_caps_structure_intersect_field (GQuark id, const GValue * val1,
924 IntersectData *idata = (IntersectData *) data;
925 GValue dest_value = { 0 };
926 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
929 gst_structure_id_set_value (idata->dest, id, val1);
930 } else if (idata->first_run) {
931 if (gst_value_intersect (&dest_value, val1, val2)) {
932 gst_structure_id_set_value (idata->dest, id, &dest_value);
933 g_value_unset (&dest_value);
942 static GstStructure *
943 gst_caps_structure_intersect (const GstStructure * struct1,
944 const GstStructure * struct2)
948 g_return_val_if_fail (struct1 != NULL, NULL);
949 g_return_val_if_fail (struct2 != NULL, NULL);
951 if (struct1->name != struct2->name)
954 data.dest = gst_structure_id_empty_new (struct1->name);
955 data.intersect = struct2;
956 data.first_run = TRUE;
957 if (!gst_structure_foreach ((GstStructure *) struct1,
958 gst_caps_structure_intersect_field, &data))
961 data.intersect = struct1;
962 data.first_run = FALSE;
963 if (!gst_structure_foreach ((GstStructure *) struct2,
964 gst_caps_structure_intersect_field, &data))
970 gst_structure_free (data.dest);
975 static GstStructure *
976 gst_caps_structure_union (const GstStructure * struct1,
977 const GstStructure * struct2)
981 const GstStructureField *field1;
982 const GstStructureField *field2;
985 /* FIXME this doesn't actually work */
987 if (struct1->name != struct2->name)
990 dest = gst_structure_id_empty_new (struct1->name);
992 for (i = 0; i < struct1->fields->len; i++) {
993 GValue dest_value = { 0 };
995 field1 = GST_STRUCTURE_FIELD (struct1, i);
996 field2 = gst_structure_id_get_field (struct2, field1->name);
998 if (field2 == NULL) {
1001 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1002 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1005 ret = gst_value_compare (&field1->value, &field2->value);
1017 * gst_caps_intersect:
1018 * @caps1: a #GstCaps to intersect
1019 * @caps2: a #GstCaps to intersect
1021 * Creates a new #GstCaps that contains all the formats that are common
1022 * to both @caps1 and @caps2.
1024 * Returns: the new #GstCaps
1027 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1029 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1032 GstStructure *struct1;
1033 GstStructure *struct2;
1035 GstStructure *istruct;
1037 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1038 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1040 if (gst_caps_is_empty (caps1) || gst_caps_is_empty (caps2)) {
1041 return gst_caps_new_empty ();
1043 if (gst_caps_is_any (caps1))
1044 return gst_caps_copy (caps2);
1045 if (gst_caps_is_any (caps2))
1046 return gst_caps_copy (caps1);
1048 dest = gst_caps_new_empty ();
1050 /* run zigzag on top line then right line, this preserves the caps order
1051 * much better than a simple loop.
1053 * This algorithm zigzags over the caps structures as demonstrated in
1054 * the folowing matrix:
1062 * First we iterate over the caps1 structures (top line) intersecting
1063 * the structures diagonally down, then we iterate over the caps2
1066 for (i = 0; i < caps1->structs->len + caps2->structs->len - 1; i++) {
1067 /* caps1 index goes from 0 to caps1->structs->len-1 */
1068 j = MIN (i, caps1->structs->len - 1);
1069 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1070 * up from 1 to caps2->structs->len - 1 */
1073 /* now run the diagonal line, end condition is the left or bottom
1075 while (k < caps2->structs->len) {
1076 struct1 = gst_caps_get_structure (caps1, j);
1077 struct2 = gst_caps_get_structure (caps2, k);
1079 istruct = gst_caps_structure_intersect (struct1, struct2);
1081 gst_caps_append_structure (dest, istruct);
1082 /* move down left */
1085 break; /* so we don't roll back to G_MAXUINT */
1094 const GstStructure *subtract_from;
1101 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1104 SubtractionEntry *e = user_data;
1105 GValue subtraction = { 0, };
1106 const GValue *other;
1107 GstStructure *structure;
1109 other = gst_structure_id_get_value (e->subtract_from, field_id);
1113 if (!gst_value_subtract (&subtraction, other, value))
1115 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1116 g_value_unset (&subtraction);
1119 structure = gst_structure_copy (e->subtract_from);
1120 gst_structure_id_set_value (structure, field_id, &subtraction);
1121 g_value_unset (&subtraction);
1122 e->put_into = g_slist_prepend (e->put_into, structure);
1128 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1129 const GstStructure * subtrahend)
1134 e.subtract_from = minuend;
1137 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1138 gst_caps_structure_subtract_field, &e);
1144 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1145 gst_structure_free (walk->data);
1147 g_slist_free (e.put_into);
1153 * gst_caps_subtract:
1154 * @minuend: #GstCaps to substract from
1155 * @subtrahend: #GstCaps to substract
1157 * Subtracts the @subtrahend from the @minuend.
1158 * <note>This function does not work reliably if optional properties for caps
1159 * are included on one caps and omitted on the other.</note>
1161 * Returns: the resulting caps
1164 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1169 GstCaps *dest = NULL, *src;
1171 g_return_val_if_fail (minuend != NULL, NULL);
1172 g_return_val_if_fail (subtrahend != NULL, NULL);
1174 if (gst_caps_is_empty (minuend) || gst_caps_is_any (subtrahend)) {
1175 return gst_caps_new_empty ();
1177 if (gst_caps_is_empty (subtrahend))
1178 return gst_caps_copy (minuend);
1180 /* FIXME: Do we want this here or above?
1181 The reason we need this is that there is no definition about what
1182 ANY means for specific types, so it's not possible to reduce ANY partially
1183 You can only remove everything or nothing and that is done above.
1184 Note: there's a test that checks this behaviour. */
1185 g_return_val_if_fail (!gst_caps_is_any (minuend), NULL);
1186 g_assert (subtrahend->structs->len > 0);
1188 src = gst_caps_copy (minuend);
1189 for (i = 0; i < subtrahend->structs->len; i++) {
1190 sub = gst_caps_get_structure (subtrahend, i);
1192 gst_caps_unref (src);
1195 dest = gst_caps_new_empty ();
1196 for (j = 0; j < src->structs->len; j++) {
1197 min = gst_caps_get_structure (src, j);
1198 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1201 if (gst_caps_structure_subtract (&list, min, sub)) {
1204 for (walk = list; walk; walk = g_slist_next (walk)) {
1205 gst_caps_append_structure (dest, (GstStructure *) walk->data);
1207 g_slist_free (list);
1209 gst_caps_append_structure (dest, gst_structure_copy (min));
1212 gst_caps_append_structure (dest, gst_structure_copy (min));
1215 if (gst_caps_is_empty (dest)) {
1216 gst_caps_unref (src);
1221 gst_caps_unref (src);
1222 gst_caps_do_simplify (dest);
1228 * @caps1: a #GstCaps to union
1229 * @caps2: a #GstCaps to union
1231 * Creates a new #GstCaps that contains all the formats that are in
1232 * either @caps1 and @caps2.
1234 * Returns: the new #GstCaps
1237 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1242 if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2))
1243 return gst_caps_new_any ();
1245 dest1 = gst_caps_copy (caps1);
1246 dest2 = gst_caps_copy (caps2);
1247 gst_caps_append (dest1, dest2);
1249 gst_caps_do_simplify (dest1);
1253 typedef struct _NormalizeForeach
1256 GstStructure *structure;
1261 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1263 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1267 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1268 for (i = 1; i < gst_value_list_get_size (value); i++) {
1269 const GValue *v = gst_value_list_get_value (value, i);
1270 GstStructure *structure = gst_structure_copy (nf->structure);
1272 gst_structure_id_set_value (structure, field_id, v);
1273 gst_caps_append_structure (nf->caps, structure);
1276 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1277 gst_structure_id_set_value (nf->structure, field_id, &val);
1278 g_value_unset (&val);
1286 * gst_caps_normalize:
1287 * @caps: a #GstCaps to normalize
1289 * Creates a new #GstCaps that represents the same set of formats as
1290 * @caps, but contains no lists. Each list is expanded into separate
1293 * Returns: the new #GstCaps
1296 gst_caps_normalize (const GstCaps * caps)
1298 NormalizeForeach nf;
1302 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1304 newcaps = gst_caps_copy (caps);
1307 for (i = 0; i < newcaps->structs->len; i++) {
1308 nf.structure = gst_caps_get_structure (newcaps, i);
1310 while (!gst_structure_foreach (nf.structure,
1311 gst_caps_normalize_foreach, &nf));
1318 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1321 const GstStructure *struct1 = *((const GstStructure **) one);
1322 const GstStructure *struct2 = *((const GstStructure **) two);
1324 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1325 So what's the best way? */
1326 ret = strcmp (gst_structure_get_name (struct1),
1327 gst_structure_get_name (struct2));
1331 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1338 GstStructure *compare;
1343 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1346 UnionField *u = user_data;
1347 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1351 g_value_unset (&u->value);
1354 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1357 g_value_unset (&u->value);
1361 gst_value_union (&u->value, val, value);
1366 gst_caps_structure_simplify (GstStructure ** result,
1367 const GstStructure * simplify, GstStructure * compare)
1370 UnionField field = { 0, {0,}, NULL };
1372 /* try to subtract to get a real subset */
1373 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1374 switch (g_slist_length (list)) {
1379 *result = list->data;
1380 g_slist_free (list);
1386 for (walk = list; walk; walk = g_slist_next (walk)) {
1387 gst_structure_free (walk->data);
1389 g_slist_free (list);
1395 /* try to union both structs */
1396 field.compare = compare;
1397 if (gst_structure_foreach ((GstStructure *) simplify,
1398 gst_caps_structure_figure_out_union, &field)) {
1399 gboolean ret = FALSE;
1401 /* now we know all of simplify's fields are the same in compare
1402 * but at most one field: field.name */
1403 if (G_IS_VALUE (&field.value)) {
1404 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1405 gst_structure_id_set_value (compare, field.name, &field.value);
1409 g_value_unset (&field.value);
1410 } else if (gst_structure_n_fields (simplify) <=
1411 gst_structure_n_fields (compare)) {
1412 /* compare is just more specific, will be optimized away later */
1413 /* FIXME: do this here? */
1414 GST_LOG ("found a case that will be optimized later.");
1416 gchar *one = gst_structure_to_string (simplify);
1417 gchar *two = gst_structure_to_string (compare);
1420 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1432 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1433 GstStructure * new, gint i)
1435 gst_structure_set_parent_refcount (old, NULL);
1436 gst_structure_free (old);
1437 gst_structure_set_parent_refcount (new, &caps->refcount);
1438 g_ptr_array_index (caps->structs, i) = new;
1442 * gst_caps_do_simplify:
1443 * @caps: a #GstCaps to simplify
1445 * Modifies the given @caps inplace into a representation that represents the
1446 * same set of formats, but in a simpler form. Component structures that are
1447 * identical are merged. Component structures that have values that can be
1448 * merged are also merged.
1450 * Returns: TRUE, if the caps could be simplified
1453 gst_caps_do_simplify (GstCaps * caps)
1455 GstStructure *simplify, *compare, *result = NULL;
1457 gboolean changed = FALSE;
1459 g_return_val_if_fail (caps != NULL, FALSE);
1460 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1462 if (gst_caps_get_size (caps) < 2)
1465 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1467 start = caps->structs->len - 1;
1468 for (i = caps->structs->len - 1; i >= 0; i--) {
1469 simplify = gst_caps_get_structure (caps, i);
1470 if (gst_structure_get_name_id (simplify) !=
1471 gst_structure_get_name_id (gst_caps_get_structure (caps, start)))
1473 for (j = start; j >= 0; j--) {
1476 compare = gst_caps_get_structure (caps, j);
1477 if (gst_structure_get_name_id (simplify) !=
1478 gst_structure_get_name_id (compare)) {
1481 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1483 gst_caps_switch_structures (caps, simplify, result, i);
1486 gst_caps_remove_structure (caps, i);
1498 /* gst_caps_do_simplify (caps); */
1502 #ifndef GST_DISABLE_LOADSAVE
1504 * gst_caps_save_thyself:
1505 * @caps: a #GstCaps structure
1506 * @parent: a XML parent node
1508 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
1510 * Returns: a XML node pointer
1513 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
1515 char *s = gst_caps_to_string (caps);
1517 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
1523 * gst_caps_load_thyself:
1524 * @parent: a XML node
1526 * Creates a #GstCaps from its XML serialization.
1528 * Returns: a new #GstCaps structure
1531 gst_caps_load_thyself (xmlNodePtr parent)
1533 if (strcmp ("caps", (char *) parent->name) == 0) {
1534 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
1545 * @caps: a pointer to #GstCaps
1546 * @newcaps: a #GstCaps to replace *caps
1548 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
1549 * pointed to by @caps, if applicable, then modifies @caps to point to
1550 * @newcaps. An additional ref on @newcaps is taken.
1552 * This function does not take any locks so you might want to lock
1553 * the object owning @caps pointer.
1556 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
1560 g_return_if_fail (caps != NULL);
1564 if (newcaps != oldcaps) {
1566 gst_caps_ref (newcaps);
1571 gst_caps_unref (oldcaps);
1576 * gst_caps_to_string:
1579 * Converts @caps to a string representation. This string representation
1580 * can be converted back to a #GstCaps by gst_caps_from_string().
1582 * For debugging purposes its easier to do something like this:
1584 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
1586 * This prints the caps in human readble form.
1588 * Returns: a newly allocated string representing @caps.
1591 gst_caps_to_string (const GstCaps * caps)
1596 /* NOTE: This function is potentially called by the debug system,
1597 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
1598 * should be careful to avoid recursion. This includes any functions
1599 * called by gst_caps_to_string. In particular, calls should
1600 * not use the GST_PTR_FORMAT extension. */
1603 return g_strdup ("NULL");
1605 if (gst_caps_is_any (caps)) {
1606 return g_strdup ("ANY");
1608 if (gst_caps_is_empty (caps)) {
1609 return g_strdup ("EMPTY");
1612 s = g_string_new ("");
1613 for (i = 0; i < caps->structs->len; i++) {
1614 GstStructure *structure;
1618 g_string_append (s, "; ");
1620 structure = gst_caps_get_structure (caps, i);
1621 sstr = gst_structure_to_string (structure);
1622 g_string_append (s, sstr);
1626 return g_string_free (s, FALSE);
1630 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
1632 GstStructure *structure;
1635 g_return_val_if_fail (string, FALSE);
1636 if (strcmp ("ANY", string) == 0) {
1637 caps->flags = GST_CAPS_FLAGS_ANY;
1640 if (strcmp ("EMPTY", string) == 0) {
1644 structure = gst_structure_from_string (string, &s);
1645 if (structure == NULL) {
1648 gst_caps_append_structure (caps, structure);
1652 while (g_ascii_isspace (*s))
1654 structure = gst_structure_from_string (s, &s);
1655 if (structure == NULL) {
1658 gst_caps_append_structure (caps, structure);
1659 while (g_ascii_isspace (*s))
1671 * gst_caps_from_string:
1672 * @string: a string to convert to #GstCaps
1674 * Converts @caps from a string representation.
1676 * Returns: a newly allocated #GstCaps
1679 gst_caps_from_string (const gchar * string)
1683 caps = gst_caps_new_empty ();
1684 if (gst_caps_from_string_inplace (caps, string)) {
1687 gst_caps_unref (caps);
1693 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
1695 g_return_if_fail (G_IS_VALUE (src_value));
1696 g_return_if_fail (G_IS_VALUE (dest_value));
1697 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
1698 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
1699 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
1701 dest_value->data[0].v_pointer =
1702 gst_caps_to_string (src_value->data[0].v_pointer);
1706 gst_caps_copy_conditional (GstCaps * src)
1709 return gst_caps_ref (src);