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gstcaps.c
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/* GStreamer
* Copyright (C) <2003> David A. Schleef <ds@schleef.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:gstcaps
* @short_description: Structure describing sets of media formats
* @see_also: #GstStructure
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <signal.h>
#include "gst_private.h"
#include <gst/gst.h>
#define DEBUG_REFCOUNT
#define CAPS_POISON(caps) G_STMT_START{ \
if (caps) { \
GstCaps *_newcaps = gst_caps_copy (caps); \
gst_caps_unref(caps); \
caps = _newcaps; \
} \
} G_STMT_END
#define STRUCTURE_POISON(structure) G_STMT_START{ \
if (structure) { \
GstStructure *_newstruct = gst_structure_copy (structure); \
gst_structure_free(structure); \
structure = _newstruct; \
} \
} G_STMT_END
#define IS_WRITABLE(caps) \
(g_atomic_int_get (&(caps)->refcount) == 1)
static void gst_caps_transform_to_string (const GValue * src_value,
GValue * dest_value);
static gboolean gst_caps_from_string_inplace (GstCaps * caps,
const gchar * string);
static GstCaps *gst_caps_copy_conditional (GstCaps * src);
GType
gst_caps_get_type (void)
{
static GType gst_caps_type = 0;
if (!gst_caps_type) {
gst_caps_type = g_boxed_type_register_static ("GstCaps",
(GBoxedCopyFunc) gst_caps_copy_conditional,
(GBoxedFreeFunc) gst_caps_unref);
g_value_register_transform_func (gst_caps_type,
G_TYPE_STRING, gst_caps_transform_to_string);
}
return gst_caps_type;
}
/* creation/deletion */
/**
* gst_caps_new_empty:
*
* Creates a new #GstCaps that is empty. That is, the returned
* #GstCaps contains no media formats.
* Caller is responsible for unreffing the returned caps.
*
* Returns: the new #GstCaps
*/
GstCaps *
gst_caps_new_empty (void)
{
GstCaps *caps = g_new0 (GstCaps, 1);
g_atomic_int_inc (&caps->refcount);
caps->type = GST_TYPE_CAPS;
caps->structs = g_ptr_array_new ();
#ifdef DEBUG_REFCOUNT
GST_CAT_LOG (GST_CAT_CAPS, "created caps %p", caps);
#endif
return caps;
}
/**
* gst_caps_new_any:
*
* Creates a new #GstCaps that indicates that it is compatible with
* any media format.
*
* Returns: the new #GstCaps
*/
GstCaps *
gst_caps_new_any (void)
{
GstCaps *caps = gst_caps_new_empty ();
caps->flags = GST_CAPS_FLAGS_ANY;
return caps;
}
/**
* gst_caps_new_simple:
* @media_type: the media type of the structure
* @fieldname: first field to set
* @...: additional arguments
*
* Creates a new #GstCaps that contains one #GstStructure. The
* structure is defined by the arguments, which have the same format
* as @gst_structure_new().
* Caller is responsible for unreffing the returned caps.
*
* Returns: the new #GstCaps
*/
GstCaps *
gst_caps_new_simple (const char *media_type, const char *fieldname, ...)
{
GstCaps *caps;
GstStructure *structure;
va_list var_args;
caps = gst_caps_new_empty ();
va_start (var_args, fieldname);
structure = gst_structure_new_valist (media_type, fieldname, var_args);
va_end (var_args);
gst_caps_append_structure (caps, structure);
return caps;
}
/**
* gst_caps_new_full:
* @struct1: the first structure to add
* @...: additional structures to add
*
* Creates a new #GstCaps and adds all the structures listed as
* arguments. The list must be NULL-terminated. The structures
* are not copied; the returned #GstCaps owns the structures.
*
* Returns: the new #GstCaps
*/
GstCaps *
gst_caps_new_full (GstStructure * struct1, ...)
{
GstCaps *caps;
va_list var_args;
va_start (var_args, struct1);
caps = gst_caps_new_full_valist (struct1, var_args);
va_end (var_args);
return caps;
}
/**
* gst_caps_new_full_valist:
* @structure: the first structure to add
* @var_args: additional structures to add
*
* Creates a new #GstCaps and adds all the structures listed as
* arguments. The list must be NULL-terminated. The structures
* are not copied; the returned #GstCaps owns the structures.
*
* Returns: the new #GstCaps
*/
GstCaps *
gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
{
GstCaps *caps;
caps = gst_caps_new_empty ();
while (structure) {
gst_caps_append_structure (caps, structure);
structure = va_arg (var_args, GstStructure *);
}
return caps;
}
/**
* gst_caps_copy:
* @caps: the #GstCaps to copy
*
* Creates a new #GstCaps as a copy of the old @caps. The new caps will have a
* refcount of 1, owned by the caller. The structures are copied as well.
*
* Note that this function is the semantic equivalent of a gst_caps_ref()
* followed by a gst_caps_make_writable(). If you only want to hold on to a
* reference to the data, you should use gst_caps_ref().
*
* When you are finished with the caps, call gst_caps_unref() on it.
*
* Returns: the new #GstCaps
*/
GstCaps *
gst_caps_copy (const GstCaps * caps)
{
GstCaps *newcaps;
GstStructure *structure;
guint i;
g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
newcaps = gst_caps_new_empty ();
newcaps->flags = caps->flags;
for (i = 0; i < caps->structs->len; i++) {
structure = gst_caps_get_structure (caps, i);
gst_caps_append_structure (newcaps, gst_structure_copy (structure));
}
return newcaps;
}
static void
_gst_caps_free (GstCaps * caps)
{
GstStructure *structure;
guint i;
/* The refcount must be 0, but since we're only called by gst_caps_unref,
* don't bother testing. */
for (i = 0; i < caps->structs->len; i++) {
structure = (GstStructure *) gst_caps_get_structure (caps, i);
gst_structure_set_parent_refcount (structure, NULL);
gst_structure_free (structure);
}
g_ptr_array_free (caps->structs, TRUE);
#ifdef USE_POISONING
memset (caps, 0xff, sizeof (GstCaps));
#endif
g_free (caps);
}
/**
* gst_caps_make_writable:
* @caps: the #GstCaps to make writable
*
* Returns a writable copy of @caps.
*
* If there is only one reference count on @caps, the caller must be the owner,
* and so this function will return the caps object unchanged. If on the other
* hand there is more than one reference on the object, a new caps object will
* be returned. The caller's reference on @caps will be removed, and instead the
* caller will own a reference to the returned object.
*
* In short, this function unrefs the caps in the argument and refs the caps
* that it returns. Don't access the argument after calling this function. See
* also: gst_caps_ref().
*
* Returns: the same #GstCaps object.
*/
GstCaps *
gst_caps_make_writable (GstCaps * caps)
{
GstCaps *copy;
g_return_val_if_fail (caps != NULL, NULL);
/* we are the only instance reffing this caps */
if (g_atomic_int_get (&caps->refcount) == 1)
return caps;
/* else copy */
copy = gst_caps_copy (caps);
gst_caps_unref (caps);
return copy;
}
/**
* gst_caps_ref:
* @caps: the #GstCaps to reference
*
* Add a reference to a #GstCaps object.
*
* From this point on, until the caller calls gst_caps_unref() or
* gst_caps_make_writable(), it is guaranteed that the caps object will not
* change. This means its structures won't change, etc. To use a #GstCaps
* object, you must always have a refcount on it -- either the one made
* implicitly by gst_caps_new(), or via taking one explicitly with this
* function.
*
* Returns: the same #GstCaps object.
*/
GstCaps *
gst_caps_ref (GstCaps * caps)
{
g_return_val_if_fail (caps != NULL, NULL);
#ifdef DEBUG_REFCOUNT
GST_CAT_LOG (GST_CAT_CAPS, "%p %d->%d", caps,
GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) + 1);
#endif
g_return_val_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0, NULL);
g_atomic_int_inc (&caps->refcount);
return caps;
}
/**
* gst_caps_unref:
* @caps: the #GstCaps to unref
*
* Unref a #GstCaps and and free all its structures and the
* structures' values when the refcount reaches 0.
*/
void
gst_caps_unref (GstCaps * caps)
{
g_return_if_fail (caps != NULL);
#ifdef DEBUG_REFCOUNT
GST_CAT_LOG (GST_CAT_CAPS, "%p %d->%d", caps,
GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) - 1);
#endif
g_return_if_fail (GST_CAPS_REFCOUNT_VALUE (caps) > 0);
/* if we ended up with the refcount at zero, free the caps */
if (g_atomic_int_dec_and_test (&caps->refcount)) {
_gst_caps_free (caps);
}
}
/**
* gst_static_caps_get:
* @static_caps: the #GstStaticCaps to convert
*
* Converts a #GstStaticCaps to a #GstCaps.
*
* Returns: A pointer to the #GstCaps. Unref after usage. Since the
* core holds an additional ref to the returned caps,
* use gst_caps_make_writable() on the returned caps to modify it.
*/
GstCaps *
gst_static_caps_get (GstStaticCaps * static_caps)
{
GstCaps *caps = (GstCaps *) static_caps;
gboolean ret;
if (caps->type == 0) {
if (static_caps->string == NULL) {
g_warning ("static caps is NULL");
return NULL;
}
caps->type = GST_TYPE_CAPS;
/* initialize the caps to a refcount of 1 so the caps can be writable... */
gst_atomic_int_set (&caps->refcount, 1);
caps->structs = g_ptr_array_new ();
ret = gst_caps_from_string_inplace (caps, static_caps->string);
if (!ret) {
g_critical ("Could not convert static caps \"%s\"", static_caps->string);
}
}
/* ref the caps, makes it not writable */
gst_caps_ref (caps);
return caps;
}
/* manipulation */
static GstStructure *
gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
{
/* don't use index_fast, gst_caps_simplify relies on the order */
GstStructure *s = g_ptr_array_remove_index (caps->structs, idx);
gst_structure_set_parent_refcount (s, NULL);
return s;
}
/**
* gst_caps_append:
* @caps1: the #GstCaps that will be appended to
* @caps2: the #GstCaps to append
*
* Appends the structures contained in @caps2 to @caps1. The structures in
* @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
* freed. If either caps is ANY, the resulting caps will be ANY.
*/
void
gst_caps_append (GstCaps * caps1, GstCaps * caps2)
{
GstStructure *structure;
int i;
g_return_if_fail (GST_IS_CAPS (caps1));
g_return_if_fail (GST_IS_CAPS (caps2));
g_return_if_fail (IS_WRITABLE (caps1));
g_return_if_fail (IS_WRITABLE (caps2));
#ifdef USE_POISONING
CAPS_POISON (caps2);
#endif
if (gst_caps_is_any (caps1) || gst_caps_is_any (caps2)) {
/* FIXME: this leaks */
caps1->flags |= GST_CAPS_FLAGS_ANY;
for (i = caps2->structs->len - 1; i >= 0; i--) {
structure = gst_caps_remove_and_get_structure (caps2, i);
gst_structure_free (structure);
}
} else {
int len = caps2->structs->len;
for (i = 0; i < len; i++) {
structure = gst_caps_remove_and_get_structure (caps2, 0);
gst_caps_append_structure (caps1, structure);
}
}
gst_caps_unref (caps2); /* guaranteed to free it */
}
/**
* gst_caps_append_structure:
* @caps: the #GstCaps that will be appended to
* @structure: the #GstStructure to append
*
* Appends @structure to @caps. The structure is not copied; @caps
* becomes the owner of @structure.
*/
void
gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
{
g_return_if_fail (GST_IS_CAPS (caps));
g_return_if_fail (IS_WRITABLE (caps));
if (structure) {
g_return_if_fail (structure->parent_refcount == NULL);
#if 0
#ifdef USE_POISONING
STRUCTURE_POISON (structure);
#endif
#endif
gst_structure_set_parent_refcount (structure, &caps->refcount);
g_ptr_array_add (caps->structs, structure);
}
}
/*
* gst_caps_remove_structure:
* @caps: the #GstCaps to remove from
* @idx: Index of the structure to remove
*
* removes the stucture with the given index from the list of structures
* contained in @caps.
*/
void
gst_caps_remove_structure (GstCaps * caps, guint idx)
{
GstStructure *structure;
g_return_if_fail (caps != NULL);
g_return_if_fail (idx <= gst_caps_get_size (caps));
g_return_if_fail (IS_WRITABLE (caps));
structure = gst_caps_remove_and_get_structure (caps, idx);
gst_structure_free (structure);
}
/**
* gst_caps_split_one:
* @caps: a #GstCaps
*
* This function is not implemented.
*
* Returns: NULL
*/
GstCaps *
gst_caps_split_one (GstCaps * caps)
{
/* FIXME */
g_critical ("unimplemented");
return NULL;
}
/**
* gst_caps_get_size:
* @caps: a #GstCaps
*
* Gets the number of structures contained in @caps.
*
* Returns: the number of structures that @caps contains
*/
guint
gst_caps_get_size (const GstCaps * caps)
{
g_return_val_if_fail (GST_IS_CAPS (caps), 0);
return caps->structs->len;
}
/**
* gst_caps_get_structure:
* @caps: a #GstCaps
* @index: the index of the structure
*
* Finds the structure in @caps that has the index @index, and
* returns it.
*
* WARNING: This function takes a const GstCaps *, but returns a
* non-const GstStructure *. This is for programming convenience --
* the caller should be aware that structures inside a constant
* @GstCaps should not be modified.
*
* Returns: a pointer to the #GstStructure corresponding to @index
*/
GstStructure *
gst_caps_get_structure (const GstCaps * caps, guint index)
{
g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
g_return_val_if_fail (index >= 0, NULL);
g_return_val_if_fail (index < caps->structs->len, NULL);
return g_ptr_array_index (caps->structs, index);
}
/**
* gst_caps_copy_nth:
* @caps: the @GstCaps to copy
* @nth: the nth structure to copy
*
* Creates a new @GstCaps and appends a copy of the nth structure
* contained in @caps.
*
* Returns: the new @GstCaps
*/
GstCaps *
gst_caps_copy_nth (const GstCaps * caps, guint nth)
{
GstCaps *newcaps;
GstStructure *structure;
g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
newcaps = gst_caps_new_empty ();
newcaps->flags = caps->flags;
if (caps->structs->len > nth) {
structure = gst_caps_get_structure (caps, nth);
gst_caps_append_structure (newcaps, gst_structure_copy (structure));
}
return newcaps;
}
/**
* gst_caps_truncate:
* @caps: the @GstCaps to truncate
*
* Destructively discard all but the first structure from @caps. Useful when
* fixating. @caps must be writable.
*/
void
gst_caps_truncate (GstCaps * caps)
{
gint i;
g_return_if_fail (GST_IS_CAPS (caps));
g_return_if_fail (IS_WRITABLE (caps));
i = caps->structs->len - 1;
while (i > 0)
gst_caps_remove_structure (caps, i--);
}
/**
* gst_caps_set_simple:
* @caps: the @GstCaps to set
* @field: first field to set
* @...: additional parameters
*
* Sets fields in a simple #GstCaps. A simple #GstCaps is one that
* only has one structure. The arguments must be passed in the same
* manner as @gst_structure_set(), and be NULL-terminated.
*/
void
gst_caps_set_simple (GstCaps * caps, char *field, ...)
{
GstStructure *structure;
va_list var_args;
g_return_if_fail (GST_IS_CAPS (caps));
g_return_if_fail (caps->structs->len == 1);
g_return_if_fail (IS_WRITABLE (caps));
structure = gst_caps_get_structure (caps, 0);
va_start (var_args, field);
gst_structure_set_valist (structure, field, var_args);
va_end (var_args);
}
/**
* gst_caps_set_simple_valist:
* @caps: the @GstCaps to copy
* @field: first field to set
* @varargs: additional parameters
*
* Sets fields in a simple #GstCaps. A simple #GstCaps is one that
* only has one structure. The arguments must be passed in the same
* manner as @gst_structure_set(), and be NULL-terminated.
*/
void
gst_caps_set_simple_valist (GstCaps * caps, char *field, va_list varargs)
{
GstStructure *structure;
g_return_if_fail (GST_IS_CAPS (caps));
g_return_if_fail (caps->structs->len != 1);
g_return_if_fail (IS_WRITABLE (caps));
structure = gst_caps_get_structure (caps, 0);
gst_structure_set_valist (structure, field, varargs);
}
/* tests */
/**
* gst_caps_is_any:
* @caps: the @GstCaps to test
*
* Determines if @caps represents any media format.
*
* Returns: TRUE if @caps represents any format.
*/
gboolean
gst_caps_is_any (const GstCaps * caps)
{
g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
return (caps->flags & GST_CAPS_FLAGS_ANY);
}
/**
* gst_caps_is_empty:
* @caps: the @GstCaps to test
*
* Determines if @caps represents no media formats.
*
* Returns: TRUE if @caps represents no formats.
*/
gboolean
gst_caps_is_empty (const GstCaps * caps)
{
g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
if (caps->flags & GST_CAPS_FLAGS_ANY)
return FALSE;
return (caps->structs == NULL) || (caps->structs->len == 0);
}
static gboolean
gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
gpointer unused)
{
return gst_value_is_fixed (value);
}
/**
* gst_caps_is_fixed:
* @caps: the @GstCaps to test
*
* Fixed @GstCaps describe exactly one format, that is, they have exactly
* one structure, and each field in the structure describes a fixed type.
* Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
*
* Returns: TRUE if @caps is fixed
*/
gboolean
gst_caps_is_fixed (const GstCaps * caps)
{
GstStructure *structure;
g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
if (caps->structs->len != 1)
return FALSE;
structure = gst_caps_get_structure (caps, 0);
return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
}
static gboolean
gst_structure_is_equal_foreach (GQuark field_id, const GValue * val2,
gpointer data)
{
GstStructure *struct1 = (GstStructure *) data;
const GValue *val1 = gst_structure_id_get_value (struct1, field_id);
if (val1 == NULL)
return FALSE;
if (gst_value_compare (val1, val2) == GST_VALUE_EQUAL) {
return TRUE;
}
return FALSE;
}
/**
* gst_caps_is_equal_fixed:
* @caps1: the #GstCaps to test
* @caps2: the #GstCaps to test
*
* Tests if two #GstCaps are equal. This function only works on fixed
* #GstCaps.
*
* Returns: TRUE if the arguments represent the same format
*/
gboolean
gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
{
GstStructure *struct1, *struct2;
g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
struct1 = gst_caps_get_structure (caps1, 0);
struct2 = gst_caps_get_structure (caps2, 0);
if (struct1->name != struct2->name) {
return FALSE;
}
if (struct1->fields->len != struct2->fields->len) {
return FALSE;
}
return gst_structure_foreach (struct1, gst_structure_is_equal_foreach,
struct2);
}
/**
* gst_caps_is_always_compatible:
* @caps1: the #GstCaps to test
* @caps2: the #GstCaps to test
*
* A given #GstCaps structure is always compatible with another if
* every media format that is in the first is also contained in the
* second. That is, @caps1 is a subset of @caps2.
*
* Returns: TRUE if @caps1 is a subset of @caps2.
*/
gboolean
gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
{
g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
return gst_caps_is_subset (caps1, caps2);
}
/**
* gst_caps_is_subset:
* @subset: a #GstCaps
* @superset: a potentially greater #GstCaps
*
* Checks if all caps represented by @subset are also represented by @superset
* <note>This function does not work reliably if optional properties for caps
* are included on one caps and omitted on the other.</note>
*
* Returns: TRUE if @subset is a subset of @superset
*/
gboolean
gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
{
GstCaps *caps;
gboolean ret;
g_return_val_if_fail (subset != NULL, FALSE);
g_return_val_if_fail (superset != NULL, FALSE);
if (gst_caps_is_empty (subset) || gst_caps_is_any (superset))
return TRUE;
if (gst_caps_is_any (subset) || gst_caps_is_empty (superset))
return FALSE;
caps = gst_caps_subtract (subset, superset);
ret = gst_caps_is_empty (caps);
gst_caps_unref (caps);
return ret;
}
/**
* gst_caps_is_equal:
* @caps1: a #GstCaps
* @caps2: another #GstCaps
*
* Checks if the given caps represent the same set of caps.
* <note>This function does not work reliably if optional properties for caps
* are included on one caps and omitted on the other.</note>
*
* Returns: TRUE if both caps are equal
*/
gboolean
gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
{
g_return_val_if_fail (caps1 != NULL, FALSE);
g_return_val_if_fail (caps2 != NULL, FALSE);
if (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2))
return gst_caps_is_equal_fixed (caps1, caps2);
return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
}
typedef struct
{
GstStructure *dest;
const GstStructure *intersect;
gboolean first_run;
}
IntersectData;
static gboolean
gst_caps_structure_intersect_field (GQuark id, const GValue * val1,
gpointer data)
{
IntersectData *idata = (IntersectData *) data;
GValue dest_value = { 0 };
const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
if (val2 == NULL) {
gst_structure_id_set_value (idata->dest, id, val1);
} else if (idata->first_run) {
if (gst_value_intersect (&dest_value, val1, val2)) {
gst_structure_id_set_value (idata->dest, id, &dest_value);
g_value_unset (&dest_value);
} else {
return FALSE;
}
}
return TRUE;
}
static GstStructure *
gst_caps_structure_intersect (const GstStructure * struct1,
const GstStructure * struct2)
{
IntersectData data;
g_return_val_if_fail (struct1 != NULL, NULL);
g_return_val_if_fail (struct2 != NULL, NULL);
if (struct1->name != struct2->name)
return NULL;
data.dest = gst_structure_id_empty_new (struct1->name);
data.intersect = struct2;
data.first_run = TRUE;
if (!gst_structure_foreach ((GstStructure *) struct1,
gst_caps_structure_intersect_field, &data))
goto error;
data.intersect = struct1;
data.first_run = FALSE;
if (!gst_structure_foreach ((GstStructure *) struct2,
gst_caps_structure_intersect_field, &data))
goto error;
return data.dest;
error:
gst_structure_free (data.dest);
return NULL;
}
#if 0
static GstStructure *
gst_caps_structure_union (const GstStructure * struct1,
const GstStructure * struct2)
{
int i;
GstStructure *dest;
const GstStructureField *field1;
const GstStructureField *field2;
int ret;
/* FIXME this doesn't actually work */
if (struct1->name != struct2->name)
return NULL;
dest = gst_structure_id_empty_new (struct1->name);
for (i = 0; i < struct1->fields->len; i++) {
GValue dest_value = { 0 };
field1 = GST_STRUCTURE_FIELD (struct1, i);
field2 = gst_structure_id_get_field (struct2, field1->name);
if (field2 == NULL) {
continue;
} else {
if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
gst_structure_set_value (dest, g_quark_to_string (field1->name),
&dest_value);
} else {
ret = gst_value_compare (&field1->value, &field2->value);
}
}
}
return dest;
}
#endif
/* operations */
/**
* gst_caps_intersect:
* @caps1: a #GstCaps to intersect
* @caps2: a #GstCaps to intersect
*
* Creates a new #GstCaps that contains all the formats that are common
* to both @caps1 and @caps2.
*
* Returns: the new #GstCaps
*/
GstCaps *
gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
{
guint64 i; /* index can be up to 2 * G_MAX_UINT */
guint j, k;
GstStructure *struct1;
GstStructure *struct2;
GstCaps *dest;
GstStructure *istruct;
g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
if (gst_caps_is_empty (caps1) || gst_caps_is_empty (caps2)) {
return gst_caps_new_empty ();
}
if (gst_caps_is_any (caps1))
return gst_caps_copy (caps2);
if (gst_caps_is_any (caps2))
return gst_caps_copy (caps1);
dest = gst_caps_new_empty ();
/* run zigzag on top line then right line, this preserves the caps order
* much better than a simple loop.
*
* This algorithm zigzags over the caps structures as demonstrated in
* the folowing matrix:
*
* caps1
* +-------------
* | 1 2 4 7
* caps2 | 3 5 8 10
* | 6 9 11 12
*
* First we iterate over the caps1 structures (top line) intersecting
* the structures diagonally down, then we iterate over the caps2
* structures.
*/
for (i = 0; i < caps1->structs->len + caps2->structs->len - 1; i++) {
/* caps1 index goes from 0 to caps1->structs->len-1 */
j = MIN (i, caps1->structs->len - 1);
/* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
* up from 1 to caps2->structs->len - 1 */
k = MAX (0, i - j);