X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=gobject%2Fgvalue.c;h=5277b777ec0b6a828f9b54315af55773acb84928;hb=9da85c7262325478e8730ae9f3e76bd0528a9a8c;hp=b7eaded96007d396702b4c57487891fdc4aeae9e;hpb=f0b9abe801c2e0cccb7930421a81bb77031e3251;p=platform%2Fupstream%2Fglib.git
diff --git a/gobject/gvalue.c b/gobject/gvalue.c
index b7eaded..5277b77 100644
--- a/gobject/gvalue.c
+++ b/gobject/gvalue.c
@@ -1,5 +1,5 @@
/* GObject - GLib Type, Object, Parameter and Signal Library
- * Copyright (C) 1997, 1998, 1999, 2000 Tim Janik and Red Hat, Inc.
+ * Copyright (C) 1997-1999, 2000-2001 Tim Janik and Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
@@ -12,79 +12,276 @@
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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.
+ * Public License along with this library; if not, see .
*/
/*
* FIXME: MT-safety
*/
+#include "config.h"
+
#include
#include "gvalue.h"
#include "gvaluecollector.h"
+#include "gbsearcharray.h"
+#include "gtype-private.h"
+
+
+/**
+ * SECTION:generic_values
+ * @short_description: A polymorphic type that can hold values of any
+ * other type
+ * @see_also: The fundamental types which all support #GValue
+ * operations and thus can be used as a type initializer for
+ * g_value_init() are defined by a separate interface. See the
+ * [standard values API][gobject-Standard-Parameter-and-Value-Types]
+ * for details
+ * @title: Generic values
+ *
+ * The #GValue structure is basically a variable container that consists
+ * of a type identifier and a specific value of that type.
+ * The type identifier within a #GValue structure always determines the
+ * type of the associated value.
+ * To create a undefined #GValue structure, simply create a zero-filled
+ * #GValue structure. To initialize the #GValue, use the g_value_init()
+ * function. A #GValue cannot be used until it is initialized.
+ * The basic type operations (such as freeing and copying) are determined
+ * by the #GTypeValueTable associated with the type ID stored in the #GValue.
+ * Other #GValue operations (such as converting values between types) are
+ * provided by this interface.
+ *
+ * The code in the example program below demonstrates #GValue's
+ * features.
+ *
+ * |[
+ * #include
+ *
+ * static void
+ * int2string (const GValue *src_value,
+ * GValue *dest_value)
+ * {
+ * if (g_value_get_int (src_value) == 42)
+ * g_value_set_static_string (dest_value, "An important number");
+ * else
+ * g_value_set_static_string (dest_value, "What's that?");
+ * }
+ *
+ * int
+ * main (int argc,
+ * char *argv[])
+ * {
+ * // GValues must be initialized
+ * GValue a = G_VALUE_INIT;
+ * GValue b = G_VALUE_INIT;
+ * const gchar *message;
+ *
+ * // The GValue starts empty
+ * g_assert (!G_VALUE_HOLDS_STRING (&a));
+ *
+ * // Put a string in it
+ * g_value_init (&a, G_TYPE_STRING);
+ * g_assert (G_VALUE_HOLDS_STRING (&a));
+ * g_value_set_static_string (&a, "Hello, world!");
+ * g_printf ("%s\n", g_value_get_string (&a));
+ *
+ * // Reset it to its pristine state
+ * g_value_unset (&a);
+ *
+ * // It can then be reused for another type
+ * g_value_init (&a, G_TYPE_INT);
+ * g_value_set_int (&a, 42);
+ *
+ * // Attempt to transform it into a GValue of type STRING
+ * g_value_init (&b, G_TYPE_STRING);
+ *
+ * // An INT is transformable to a STRING
+ * g_assert (g_value_type_transformable (G_TYPE_INT, G_TYPE_STRING));
+ *
+ * g_value_transform (&a, &b);
+ * g_printf ("%s\n", g_value_get_string (&b));
+ *
+ * // Attempt to transform it again using a custom transform function
+ * g_value_register_transform_func (G_TYPE_INT, G_TYPE_STRING, int2string);
+ * g_value_transform (&a, &b);
+ * g_printf ("%s\n", g_value_get_string (&b));
+ * return 0;
+ * }
+ * ]|
+ */
/* --- typedefs & structures --- */
-typedef struct
-{
- GType value_type1;
- GType value_type2;
- GValueExchange func;
- GType first_type;
-} ExchangeEntry;
+typedef struct {
+ GType src_type;
+ GType dest_type;
+ GValueTransform func;
+} TransformEntry;
+
+
+/* --- prototypes --- */
+static gint transform_entries_cmp (gconstpointer bsearch_node1,
+ gconstpointer bsearch_node2);
/* --- variables --- */
-static GHashTable *param_exchange_ht = NULL;
+static GBSearchArray *transform_array = NULL;
+static GBSearchConfig transform_bconfig = {
+ sizeof (TransformEntry),
+ transform_entries_cmp,
+ G_BSEARCH_ARRAY_ALIGN_POWER2,
+};
/* --- functions --- */
void
+_g_value_c_init (void)
+{
+ transform_array = g_bsearch_array_create (&transform_bconfig);
+}
+
+static inline void /* keep this function in sync with gvaluecollector.h and gboxed.c */
+value_meminit (GValue *value,
+ GType value_type)
+{
+ value->g_type = value_type;
+ memset (value->data, 0, sizeof (value->data));
+}
+
+/**
+ * g_value_init:
+ * @value: A zero-filled (uninitialized) #GValue structure.
+ * @g_type: Type the #GValue should hold values of.
+ *
+ * Initializes @value with the default value of @type.
+ *
+ * Returns: (transfer none): the #GValue structure that has been passed in
+ */
+GValue*
g_value_init (GValue *value,
GType g_type)
{
- GTypeValueTable *value_table = g_type_value_table_peek (g_type);
-
- g_return_if_fail (value != NULL);
- g_return_if_fail (G_VALUE_TYPE (value) == 0);
-
- if (value_table)
+ /* g_return_val_if_fail (G_TYPE_IS_VALUE (g_type), NULL); be more elaborate below */
+ g_return_val_if_fail (value != NULL, NULL);
+ /* g_return_val_if_fail (G_VALUE_TYPE (value) == 0, NULL); be more elaborate below */
+
+ if (G_TYPE_IS_VALUE (g_type) && G_VALUE_TYPE (value) == 0)
{
- memset (value, 0, sizeof (*value));
- value->g_type = g_type;
+ GTypeValueTable *value_table = g_type_value_table_peek (g_type);
+
+ /* setup and init */
+ value_meminit (value, g_type);
value_table->value_init (value);
}
- else
- g_warning (G_STRLOC ": cannot initialize value of type `%s' which has no GTypeValueTable",
- g_type_name (g_type));
+ else if (G_VALUE_TYPE (value))
+ g_warning ("%s: cannot initialize GValue with type '%s', the value has already been initialized as '%s'",
+ G_STRLOC,
+ g_type_name (g_type),
+ g_type_name (G_VALUE_TYPE (value)));
+ else /* !G_TYPE_IS_VALUE (g_type) */
+ g_warning ("%s: cannot initialize GValue with type '%s', %s",
+ G_STRLOC,
+ g_type_name (g_type),
+ g_type_value_table_peek (g_type) ?
+ "this type is abstract with regards to GValue use, use a more specific (derived) type" :
+ "this type has no GTypeValueTable implementation");
+ return value;
}
+/**
+ * g_value_copy:
+ * @src_value: An initialized #GValue structure.
+ * @dest_value: An initialized #GValue structure of the same type as @src_value.
+ *
+ * Copies the value of @src_value into @dest_value.
+ */
void
g_value_copy (const GValue *src_value,
GValue *dest_value)
{
- GTypeValueTable *value_table;
-
g_return_if_fail (G_IS_VALUE (src_value));
g_return_if_fail (G_IS_VALUE (dest_value));
- g_return_if_fail (g_type_is_a (G_VALUE_TYPE (src_value), G_VALUE_TYPE (dest_value)));
-
- value_table = g_type_value_table_peek (G_VALUE_TYPE (dest_value));
- if (!value_table)
- g_return_if_fail (g_type_value_table_peek (G_VALUE_TYPE (dest_value)) != NULL);
+ g_return_if_fail (g_value_type_compatible (G_VALUE_TYPE (src_value), G_VALUE_TYPE (dest_value)));
if (src_value != dest_value)
{
- /* make sure dest_value's value is free()d and zero initialized */
- g_value_reset (dest_value);
-
+ GType dest_type = G_VALUE_TYPE (dest_value);
+ GTypeValueTable *value_table = g_type_value_table_peek (dest_type);
+
+ /* make sure dest_value's value is free()d */
+ if (value_table->value_free)
+ value_table->value_free (dest_value);
+
+ /* setup and copy */
+ value_meminit (dest_value, dest_type);
value_table->value_copy (src_value, dest_value);
}
}
+/**
+ * g_value_reset:
+ * @value: An initialized #GValue structure.
+ *
+ * Clears the current value in @value and resets it to the default value
+ * (as if the value had just been initialized).
+ *
+ * Returns: the #GValue structure that has been passed in
+ */
+GValue*
+g_value_reset (GValue *value)
+{
+ GTypeValueTable *value_table;
+ GType g_type;
+
+ g_return_val_if_fail (G_IS_VALUE (value), NULL);
+
+ g_type = G_VALUE_TYPE (value);
+ value_table = g_type_value_table_peek (g_type);
+
+ /* make sure value's value is free()d */
+ if (value_table->value_free)
+ value_table->value_free (value);
+
+ /* setup and init */
+ value_meminit (value, g_type);
+ value_table->value_init (value);
+
+ return value;
+}
+
+/**
+ * g_value_unset:
+ * @value: An initialized #GValue structure.
+ *
+ * Clears the current value in @value and "unsets" the type,
+ * this releases all resources associated with this GValue.
+ * An unset value is the same as an uninitialized (zero-filled)
+ * #GValue structure.
+ */
+void
+g_value_unset (GValue *value)
+{
+ GTypeValueTable *value_table;
+
+ g_return_if_fail (G_IS_VALUE (value));
+
+ value_table = g_type_value_table_peek (G_VALUE_TYPE (value));
+
+ if (value_table->value_free)
+ value_table->value_free (value);
+ memset (value, 0, sizeof (*value));
+}
+
+/**
+ * g_value_fits_pointer:
+ * @value: An initialized #GValue structure.
+ *
+ * Determines if @value will fit inside the size of a pointer value.
+ * This is an internal function introduced mainly for C marshallers.
+ *
+ * Returns: %TRUE if @value will fit inside a pointer value.
+ */
gboolean
g_value_fits_pointer (const GValue *value)
{
@@ -93,269 +290,330 @@ g_value_fits_pointer (const GValue *value)
g_return_val_if_fail (G_IS_VALUE (value), FALSE);
value_table = g_type_value_table_peek (G_VALUE_TYPE (value));
- if (!value_table)
- g_return_val_if_fail (g_type_value_table_peek (G_VALUE_TYPE (value)) != NULL, FALSE);
return value_table->value_peek_pointer != NULL;
}
+/**
+ * g_value_peek_pointer:
+ * @value: An initialized #GValue structure
+ *
+ * Returns the value contents as pointer. This function asserts that
+ * g_value_fits_pointer() returned %TRUE for the passed in value.
+ * This is an internal function introduced mainly for C marshallers.
+ *
+ * Returns: (transfer none): the value contents as pointer
+ */
gpointer
-g_value_get_as_pointer (const GValue *value)
+g_value_peek_pointer (const GValue *value)
{
GTypeValueTable *value_table;
g_return_val_if_fail (G_IS_VALUE (value), NULL);
value_table = g_type_value_table_peek (G_VALUE_TYPE (value));
- if (!value_table)
- g_return_val_if_fail (g_type_value_table_peek (G_VALUE_TYPE (value)) != NULL, NULL);
if (!value_table->value_peek_pointer)
- g_return_val_if_fail (g_value_fits_pointer (value) == TRUE, NULL);
+ {
+ g_return_val_if_fail (g_value_fits_pointer (value) == TRUE, NULL);
+ return NULL;
+ }
return value_table->value_peek_pointer (value);
}
+/**
+ * g_value_set_instance:
+ * @value: An initialized #GValue structure.
+ * @instance: (allow-none): the instance
+ *
+ * Sets @value from an instantiatable type via the
+ * value_table's collect_value() function.
+ */
void
g_value_set_instance (GValue *value,
gpointer instance)
{
- g_return_if_fail (G_IS_VALUE (value));
+ GType g_type;
+ GTypeValueTable *value_table;
+ GTypeCValue cvalue;
+ gchar *error_msg;
- g_value_reset (value);
+ g_return_if_fail (G_IS_VALUE (value));
if (instance)
{
- GType g_type = G_VALUE_TYPE (value);
- GTypeValueTable *value_table = g_type_value_table_peek (g_type);
- GTypeCValue cvalue = { 0, };
- guint nth_value = 0;
- guint collect_type = value_table->collect_type;
- gchar *error_msg;
-
g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
- g_return_if_fail (g_type_is_a (G_TYPE_FROM_INSTANCE (instance), G_VALUE_TYPE (value)));
- g_return_if_fail (value_table->collect_type == G_VALUE_COLLECT_POINTER);
-
- cvalue.v_pointer = instance;
- error_msg = value_table->collect_value (value, nth_value++, &collect_type, &cvalue);
-
- /* this shouldn't be triggered, instance types should collect just one pointer,
- * but since we have to follow the calling conventions for collect_value(),
- * we can attempt to feed them with 0s if they insist on extra args.
- */
- while (collect_type && !error_msg)
- {
- memset (&cvalue, 0, sizeof (cvalue));
- error_msg = value_table->collect_value (value, nth_value++, &collect_type, &cvalue);
- }
-
- if (error_msg)
- {
- g_warning ("%s: %s", G_STRLOC, error_msg);
- g_free (error_msg);
-
- /* we purposely leak the value here, it might not be
- * in a sane state if an error condition occoured
- */
- memset (value, 0, sizeof (*value));
- value->g_type = g_type;
- value_table->value_init (value);
- }
+ g_return_if_fail (g_value_type_compatible (G_TYPE_FROM_INSTANCE (instance), G_VALUE_TYPE (value)));
}
-}
-
-void
-g_value_unset (GValue *value)
-{
- GTypeValueTable *value_table = g_type_value_table_peek (G_VALUE_TYPE (value));
-
- g_return_if_fail (G_IS_VALUE (value));
- if (!value_table)
- g_return_if_fail (g_type_value_table_peek (G_VALUE_TYPE (value)) != NULL);
- if (value_table->value_free)
- value_table->value_free (value);
- memset (value, 0, sizeof (*value));
-}
-
-void
-g_value_reset (GValue *value)
-{
- GTypeValueTable *value_table;
- GType g_type;
+ g_type = G_VALUE_TYPE (value);
+ value_table = g_type_value_table_peek (g_type);
- g_return_if_fail (G_IS_VALUE (value));
+ g_return_if_fail (strcmp (value_table->collect_format, "p") == 0);
- value_table = g_type_value_table_peek (G_VALUE_TYPE (value));
- g_type = G_VALUE_TYPE (value);
+ memset (&cvalue, 0, sizeof (cvalue));
+ cvalue.v_pointer = instance;
+ /* make sure value's value is free()d */
if (value_table->value_free)
value_table->value_free (value);
- memset (value, 0, sizeof (*value));
-
- value->g_type = g_type;
- value_table->value_init (value);
-}
-static gboolean
-exchange_entries_equal (gconstpointer v1,
- gconstpointer v2)
-{
- const ExchangeEntry *entry1 = v1;
- const ExchangeEntry *entry2 = v2;
-
- return (entry1->value_type1 == entry2->value_type1 &&
- entry1->value_type2 == entry2->value_type2);
+ /* setup and collect */
+ value_meminit (value, g_type);
+ error_msg = value_table->collect_value (value, 1, &cvalue, 0);
+ if (error_msg)
+ {
+ g_warning ("%s: %s", G_STRLOC, error_msg);
+ g_free (error_msg);
+
+ /* we purposely leak the value here, it might not be
+ * in a sane state if an error condition occoured
+ */
+ value_meminit (value, g_type);
+ value_table->value_init (value);
+ }
}
-static guint
-exchange_entry_hash (gconstpointer key)
+/**
+ * g_value_init_from_instance:
+ * @value: An uninitialized #GValue structure.
+ * @instance: the instance
+ *
+ * Initializes and sets @value from an instantiatable type via the
+ * value_table's collect_value() function.
+ *
+ * Note: The @value will be initialised with the exact type of
+ * @instance. If you wish to set the @value's type to a different GType
+ * (such as a parent class GType), you need to manually call
+ * g_value_init() and g_value_set_instance().
+ *
+ * Since: 2.42
+ */
+void
+g_value_init_from_instance (GValue *value,
+ gpointer instance)
{
- const ExchangeEntry *entry = key;
-
- return entry->value_type1 ^ entry->value_type2;
-}
+ g_return_if_fail (value != NULL && G_VALUE_TYPE(value) == 0);
-static void
-value_exchange_memcpy (GValue *value1,
- GValue *value2)
-{
- GValue tmp_value;
-
- memcpy (&tmp_value.data, &value1->data, sizeof (value1->data));
- memcpy (&value1->data, &value2->data, sizeof (value1->data));
- memcpy (&value2->data, &tmp_value.data, sizeof (value2->data));
+ if (G_IS_OBJECT (instance))
+ {
+ /* Fast-path.
+ * If G_IS_OBJECT() succeeds we know:
+ * * that instance is present and valid
+ * * that it is a GObject, and therefore we can directly
+ * use the collect implementation (g_object_ref) */
+ value_meminit (value, G_TYPE_FROM_INSTANCE (instance));
+ value->data[0].v_pointer = g_object_ref (instance);
+ }
+ else
+ {
+ GType g_type;
+ GTypeValueTable *value_table;
+ GTypeCValue cvalue;
+ gchar *error_msg;
+
+ g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
+
+ g_type = G_TYPE_FROM_INSTANCE (instance);
+ value_table = g_type_value_table_peek (g_type);
+ g_return_if_fail (strcmp (value_table->collect_format, "p") == 0);
+
+ memset (&cvalue, 0, sizeof (cvalue));
+ cvalue.v_pointer = instance;
+
+ /* setup and collect */
+ value_meminit (value, g_type);
+ value_table->value_init (value);
+ error_msg = value_table->collect_value (value, 1, &cvalue, 0);
+ if (error_msg)
+ {
+ g_warning ("%s: %s", G_STRLOC, error_msg);
+ g_free (error_msg);
+
+ /* we purposely leak the value here, it might not be
+ * in a sane state if an error condition occoured
+ */
+ value_meminit (value, g_type);
+ value_table->value_init (value);
+ }
+ }
}
-static inline GValueExchange
-exchange_func_lookup (GType value_type1,
- GType value_type2,
- gboolean *need_swap)
+static GValueTransform
+transform_func_lookup (GType src_type,
+ GType dest_type)
{
- if (value_type1 == value_type2)
- return value_exchange_memcpy;
- else
+ TransformEntry entry;
+
+ entry.src_type = src_type;
+ do
{
- GType type1 = value_type1;
-
+ entry.dest_type = dest_type;
do
{
- GType type2 = value_type2;
+ TransformEntry *e;
- do
+ e = g_bsearch_array_lookup (transform_array, &transform_bconfig, &entry);
+ if (e)
{
- ExchangeEntry entry, *ret;
-
- entry.value_type1 = MIN (type1, type2);
- entry.value_type2 = MAX (type1, type2);
- ret = g_hash_table_lookup (param_exchange_ht, &entry);
- if (ret)
- {
- if (need_swap)
- *need_swap = ret->first_type == type2;
-
- return ret->func;
- }
-
- type2 = g_type_parent (type2);
+ /* need to check that there hasn't been a change in value handling */
+ if (g_type_value_table_peek (entry.dest_type) == g_type_value_table_peek (dest_type) &&
+ g_type_value_table_peek (entry.src_type) == g_type_value_table_peek (src_type))
+ return e->func;
}
- while (type2);
-
- type1 = g_type_parent (type1);
+ entry.dest_type = g_type_parent (entry.dest_type);
}
- while (type1);
+ while (entry.dest_type);
+
+ entry.src_type = g_type_parent (entry.src_type);
}
-
+ while (entry.src_type);
+
return NULL;
}
-void
-g_value_register_exchange_func (GType value_type1,
- GType value_type2,
- GValueExchange func)
+static gint
+transform_entries_cmp (gconstpointer bsearch_node1,
+ gconstpointer bsearch_node2)
{
- ExchangeEntry entry;
-
- g_return_if_fail (g_type_name (value_type1) != NULL);
- g_return_if_fail (g_type_name (value_type2) != NULL);
- g_return_if_fail (func != NULL);
-
- entry.value_type1 = MIN (value_type1, value_type2);
- entry.value_type2 = MAX (value_type1, value_type2);
- if (param_exchange_ht && g_hash_table_lookup (param_exchange_ht, &entry))
- g_warning (G_STRLOC ": cannot re-register param value exchange function "
- "for `%s' and `%s'",
- g_type_name (value_type1),
- g_type_name (value_type2));
+ const TransformEntry *e1 = bsearch_node1;
+ const TransformEntry *e2 = bsearch_node2;
+ gint cmp = G_BSEARCH_ARRAY_CMP (e1->src_type, e2->src_type);
+
+ if (cmp)
+ return cmp;
else
- {
- ExchangeEntry *entry = g_new (ExchangeEntry, 1);
-
- if (!param_exchange_ht)
- param_exchange_ht = g_hash_table_new (exchange_entry_hash, exchange_entries_equal);
- entry->value_type1 = MIN (value_type1, value_type2);
- entry->value_type2 = MAX (value_type1, value_type2);
- entry->func = func;
- entry->first_type = value_type1;
- g_hash_table_insert (param_exchange_ht, entry, entry);
- }
+ return G_BSEARCH_ARRAY_CMP (e1->dest_type, e2->dest_type);
}
+/**
+ * g_value_register_transform_func: (skip)
+ * @src_type: Source type.
+ * @dest_type: Target type.
+ * @transform_func: a function which transforms values of type @src_type
+ * into value of type @dest_type
+ *
+ * Registers a value transformation function for use in g_value_transform().
+ * A previously registered transformation function for @src_type and @dest_type
+ * will be replaced.
+ */
+void
+g_value_register_transform_func (GType src_type,
+ GType dest_type,
+ GValueTransform transform_func)
+{
+ TransformEntry entry;
+
+ /* these checks won't pass for dynamic types.
+ * g_return_if_fail (G_TYPE_HAS_VALUE_TABLE (src_type));
+ * g_return_if_fail (G_TYPE_HAS_VALUE_TABLE (dest_type));
+ */
+ g_return_if_fail (transform_func != NULL);
+
+ entry.src_type = src_type;
+ entry.dest_type = dest_type;
+
+#if 0 /* let transform function replacement be a valid operation */
+ if (g_bsearch_array_lookup (transform_array, &transform_bconfig, &entry))
+ g_warning ("reregistering value transformation function (%p) for '%s' to '%s'",
+ transform_func,
+ g_type_name (src_type),
+ g_type_name (dest_type));
+#endif
+
+ entry.func = transform_func;
+ transform_array = g_bsearch_array_replace (transform_array, &transform_bconfig, &entry);
+}
+
+/**
+ * g_value_type_transformable:
+ * @src_type: Source type.
+ * @dest_type: Target type.
+ *
+ * Check whether g_value_transform() is able to transform values
+ * of type @src_type into values of type @dest_type. Note that for
+ * the types to be transformable, they must be compatible and a
+ * transform function must be registered.
+ *
+ * Returns: %TRUE if the transformation is possible, %FALSE otherwise.
+ */
gboolean
-g_value_types_exchangable (GType value_type1,
- GType value_type2)
+g_value_type_transformable (GType src_type,
+ GType dest_type)
{
- g_return_val_if_fail (G_TYPE_IS_VALUE (value_type1), FALSE); /* these might bite us, think G_TYPE_ENUM */
- g_return_val_if_fail (G_TYPE_IS_VALUE (value_type2), FALSE);
-
- return exchange_func_lookup (value_type1, value_type2, NULL) != NULL;
+ g_return_val_if_fail (G_TYPE_IS_VALUE (src_type), FALSE);
+ g_return_val_if_fail (G_TYPE_IS_VALUE (dest_type), FALSE);
+
+ return (g_value_type_compatible (src_type, dest_type) ||
+ transform_func_lookup (src_type, dest_type) != NULL);
}
+/**
+ * g_value_type_compatible:
+ * @src_type: source type to be copied.
+ * @dest_type: destination type for copying.
+ *
+ * Returns whether a #GValue of type @src_type can be copied into
+ * a #GValue of type @dest_type.
+ *
+ * Returns: %TRUE if g_value_copy() is possible with @src_type and @dest_type.
+ */
gboolean
-g_values_exchange (GValue *value1,
- GValue *value2)
+g_value_type_compatible (GType src_type,
+ GType dest_type)
{
- g_return_val_if_fail (G_IS_VALUE (value1), FALSE);
- g_return_val_if_fail (G_IS_VALUE (value2), FALSE);
-
- if (value1 != value2)
- {
- gboolean need_swap;
- GValueExchange value_exchange = exchange_func_lookup (G_VALUE_TYPE (value1),
- G_VALUE_TYPE (value2),
- &need_swap);
- if (value_exchange)
- {
- if (need_swap)
- value_exchange (value2, value1);
- else
- value_exchange (value1, value2);
- }
-
- return value_exchange != NULL;
- }
-
- return TRUE;
+ g_return_val_if_fail (G_TYPE_IS_VALUE (src_type), FALSE);
+ g_return_val_if_fail (G_TYPE_IS_VALUE (dest_type), FALSE);
+
+ return (g_type_is_a (src_type, dest_type) &&
+ g_type_value_table_peek (dest_type) == g_type_value_table_peek (src_type));
}
+/**
+ * g_value_transform:
+ * @src_value: Source value.
+ * @dest_value: Target value.
+ *
+ * Tries to cast the contents of @src_value into a type appropriate
+ * to store in @dest_value, e.g. to transform a %G_TYPE_INT value
+ * into a %G_TYPE_FLOAT value. Performing transformations between
+ * value types might incur precision lossage. Especially
+ * transformations into strings might reveal seemingly arbitrary
+ * results and shouldn't be relied upon for production code (such
+ * as rcfile value or object property serialization).
+ *
+ * Returns: Whether a transformation rule was found and could be applied.
+ * Upon failing transformations, @dest_value is left untouched.
+ */
gboolean
-g_value_convert (const GValue *src_value,
- GValue *dest_value)
+g_value_transform (const GValue *src_value,
+ GValue *dest_value)
{
- gboolean success = TRUE;
-
+ GType dest_type;
+
g_return_val_if_fail (G_IS_VALUE (src_value), FALSE);
g_return_val_if_fail (G_IS_VALUE (dest_value), FALSE);
-
- if (src_value != dest_value)
+
+ dest_type = G_VALUE_TYPE (dest_value);
+ if (g_value_type_compatible (G_VALUE_TYPE (src_value), dest_type))
{
- GValue tmp_value = { 0, };
-
- g_value_init (&tmp_value, G_VALUE_TYPE (src_value));
- g_value_copy (src_value, &tmp_value);
+ g_value_copy (src_value, dest_value);
- success = g_values_exchange (&tmp_value, dest_value);
- g_value_unset (&tmp_value);
+ return TRUE;
}
-
- return success;
+ else
+ {
+ GValueTransform transform = transform_func_lookup (G_VALUE_TYPE (src_value), dest_type);
+
+ if (transform)
+ {
+ g_value_unset (dest_value);
+
+ /* setup and transform */
+ value_meminit (dest_value, dest_type);
+ transform (src_value, dest_value);
+
+ return TRUE;
+ }
+ }
+ return FALSE;
}