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Diffstat (limited to 'include/glib/gobject/gvaluecollector.h')
| -rw-r--r-- | include/glib/gobject/gvaluecollector.h | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/include/glib/gobject/gvaluecollector.h b/include/glib/gobject/gvaluecollector.h new file mode 100644 index 0000000000..177aa3dfae --- /dev/null +++ b/include/glib/gobject/gvaluecollector.h @@ -0,0 +1,261 @@ +/* GObject - GLib Type, Object, Parameter and Signal Library + * Copyright (C) 1998-1999, 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 + * License as published by the Free Software Foundation; either + * version 2.1 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 + * 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, see <http://www.gnu.org/licenses/>. + * + * gvaluecollector.h: GValue varargs stubs + */ +/** + * SECTION:value_collection + * @Short_description: Converting varargs to generic values + * @Title: Varargs Value Collection + * + * The macros in this section provide the varargs parsing support needed + * in variadic GObject functions such as g_object_new() or g_object_set(). + * They currently support the collection of integral types, floating point + * types and pointers. + */ +#ifndef __G_VALUE_COLLECTOR_H__ +#define __G_VALUE_COLLECTOR_H__ + +#include <glib-object.h> + +G_BEGIN_DECLS + +/* we may want to add aggregate types here some day, if requested + * by users. the basic C types are covered already, everything + * smaller than an int is promoted to an integer and floats are + * always promoted to doubles for varargs call constructions. + */ +enum /*< skip >*/ +{ + G_VALUE_COLLECT_INT = 'i', + G_VALUE_COLLECT_LONG = 'l', + G_VALUE_COLLECT_INT64 = 'q', + G_VALUE_COLLECT_DOUBLE = 'd', + G_VALUE_COLLECT_POINTER = 'p' +}; + + +/* vararg union holding actual values collected + */ +/** + * GTypeCValue: + * @v_int: the field for holding integer values + * @v_long: the field for holding long integer values + * @v_int64: the field for holding 64 bit integer values + * @v_double: the field for holding floating point values + * @v_pointer: the field for holding pointers + * + * A union holding one collected value. + */ +union _GTypeCValue +{ + gint v_int; + glong v_long; + gint64 v_int64; + gdouble v_double; + gpointer v_pointer; +}; + +/** + * G_VALUE_COLLECT_INIT: + * @value: a #GValue return location. @value must contain only 0 bytes. + * @_value_type: the #GType to use for @value. + * @var_args: the va_list variable; it may be evaluated multiple times + * @flags: flags which are passed on to the collect_value() function of + * the #GTypeValueTable of @value. + * @__error: a #gchar** variable that will be modified to hold a g_new() + * allocated error messages if something fails + * + * Collects a variable argument value from a va_list. We have to + * implement the varargs collection as a macro, because on some systems + * va_list variables cannot be passed by reference. + * + * Since: 2.24 + */ +#define G_VALUE_COLLECT_INIT(value, _value_type, var_args, flags, __error) \ +G_STMT_START { \ + GValue *g_vci_val = (value); \ + guint g_vci_flags = (flags); \ + GTypeValueTable *g_vci_vtab = g_type_value_table_peek (_value_type); \ + const gchar *g_vci_collect_format = g_vci_vtab->collect_format; \ + GTypeCValue g_vci_cvalues[G_VALUE_COLLECT_FORMAT_MAX_LENGTH] = { { 0, }, }; \ + guint g_vci_n_values = 0; \ + \ + g_vci_val->g_type = _value_type; /* value_meminit() from gvalue.c */ \ + while (*g_vci_collect_format) \ + { \ + GTypeCValue *g_vci_cvalue = g_vci_cvalues + g_vci_n_values++; \ + \ + switch (*g_vci_collect_format++) \ + { \ + case G_VALUE_COLLECT_INT: \ + g_vci_cvalue->v_int = va_arg ((var_args), gint); \ + break; \ + case G_VALUE_COLLECT_LONG: \ + g_vci_cvalue->v_long = va_arg ((var_args), glong); \ + break; \ + case G_VALUE_COLLECT_INT64: \ + g_vci_cvalue->v_int64 = va_arg ((var_args), gint64); \ + break; \ + case G_VALUE_COLLECT_DOUBLE: \ + g_vci_cvalue->v_double = va_arg ((var_args), gdouble); \ + break; \ + case G_VALUE_COLLECT_POINTER: \ + g_vci_cvalue->v_pointer = va_arg ((var_args), gpointer); \ + break; \ + default: \ + g_assert_not_reached (); \ + } \ + } \ + *(__error) = g_vci_vtab->collect_value (g_vci_val, \ + g_vci_n_values, \ + g_vci_cvalues, \ + g_vci_flags); \ +} G_STMT_END + +/** + * G_VALUE_COLLECT: + * @value: a #GValue return location. @value is supposed to be initialized + * according to the value type to be collected + * @var_args: the va_list variable; it may be evaluated multiple times + * @flags: flags which are passed on to the collect_value() function of + * the #GTypeValueTable of @value. + * @__error: a #gchar** variable that will be modified to hold a g_new() + * allocated error messages if something fails + * + * Collects a variable argument value from a va_list. We have to + * implement the varargs collection as a macro, because on some systems + * va_list variables cannot be passed by reference. + * + * Note: If you are creating the @value argument just before calling this macro, + * you should use the #G_VALUE_COLLECT_INIT variant and pass the unitialized + * #GValue. That variant is faster than #G_VALUE_COLLECT. + */ +#define G_VALUE_COLLECT(value, var_args, flags, __error) G_STMT_START { \ + GValue *g_vc_value = (value); \ + GType g_vc_value_type = G_VALUE_TYPE (g_vc_value); \ + GTypeValueTable *g_vc_vtable = g_type_value_table_peek (g_vc_value_type); \ + \ + if (g_vc_vtable->value_free) \ + g_vc_vtable->value_free (g_vc_value); \ + memset (g_vc_value->data, 0, sizeof (g_vc_value->data)); \ + \ + G_VALUE_COLLECT_INIT(value, g_vc_value_type, var_args, flags, __error); \ +} G_STMT_END + +/** + * G_VALUE_COLLECT_SKIP: + * @_value_type: the #GType of the value to skip + * @var_args: the va_list variable; it may be evaluated multiple times + * + * Skip an argument of type @_value_type from @var_args. + */ +#define G_VALUE_COLLECT_SKIP(_value_type, var_args) \ +G_STMT_START { \ + GTypeValueTable *g_vcs_vtable = g_type_value_table_peek (_value_type); \ + const gchar *g_vcs_collect_format = g_vcs_vtable->collect_format; \ + \ + while (*g_vcs_collect_format) \ + { \ + switch (*g_vcs_collect_format++) \ + { \ + case G_VALUE_COLLECT_INT: \ + va_arg ((var_args), gint); \ + break; \ + case G_VALUE_COLLECT_LONG: \ + va_arg ((var_args), glong); \ + break; \ + case G_VALUE_COLLECT_INT64: \ + va_arg ((var_args), gint64); \ + break; \ + case G_VALUE_COLLECT_DOUBLE: \ + va_arg ((var_args), gdouble); \ + break; \ + case G_VALUE_COLLECT_POINTER: \ + va_arg ((var_args), gpointer); \ + break; \ + default: \ + g_assert_not_reached (); \ + } \ + } \ +} G_STMT_END + +/** + * G_VALUE_LCOPY: + * @value: a #GValue to store into the @var_args; this must be initialized + * and set + * @var_args: the va_list variable; it may be evaluated multiple times + * @flags: flags which are passed on to the lcopy_value() function of + * the #GTypeValueTable of @value. + * @__error: a #gchar** variable that will be modified to hold a g_new() + * allocated error message if something fails + * + * Stores a value’s value into one or more argument locations from a va_list. + * This is the inverse of G_VALUE_COLLECT(). + */ +#define G_VALUE_LCOPY(value, var_args, flags, __error) \ +G_STMT_START { \ + const GValue *g_vl_value = (value); \ + guint g_vl_flags = (flags); \ + GType g_vl_value_type = G_VALUE_TYPE (g_vl_value); \ + GTypeValueTable *g_vl_vtable = g_type_value_table_peek (g_vl_value_type); \ + const gchar *g_vl_lcopy_format = g_vl_vtable->lcopy_format; \ + GTypeCValue g_vl_cvalues[G_VALUE_COLLECT_FORMAT_MAX_LENGTH] = { { 0, }, }; \ + guint g_vl_n_values = 0; \ + \ + while (*g_vl_lcopy_format) \ + { \ + GTypeCValue *g_vl_cvalue = g_vl_cvalues + g_vl_n_values++; \ + \ + switch (*g_vl_lcopy_format++) \ + { \ + case G_VALUE_COLLECT_INT: \ + g_vl_cvalue->v_int = va_arg ((var_args), gint); \ + break; \ + case G_VALUE_COLLECT_LONG: \ + g_vl_cvalue->v_long = va_arg ((var_args), glong); \ + break; \ + case G_VALUE_COLLECT_INT64: \ + g_vl_cvalue->v_int64 = va_arg ((var_args), gint64); \ + break; \ + case G_VALUE_COLLECT_DOUBLE: \ + g_vl_cvalue->v_double = va_arg ((var_args), gdouble); \ + break; \ + case G_VALUE_COLLECT_POINTER: \ + g_vl_cvalue->v_pointer = va_arg ((var_args), gpointer); \ + break; \ + default: \ + g_assert_not_reached (); \ + } \ + } \ + *(__error) = g_vl_vtable->lcopy_value (g_vl_value, \ + g_vl_n_values, \ + g_vl_cvalues, \ + g_vl_flags); \ +} G_STMT_END + + +/** + * G_VALUE_COLLECT_FORMAT_MAX_LENGTH: + * + * The maximal number of #GTypeCValues which can be collected for a + * single #GValue. + */ +#define G_VALUE_COLLECT_FORMAT_MAX_LENGTH (8) + +G_END_DECLS + +#endif /* __G_VALUE_COLLECTOR_H__ */ |