gobject/gvaluecollector.h

   1 /* GObject - GLib Type, Object, Parameter and Signal Library
   2  * Copyright (C) 1998-1999, 2000-2001 Tim Janik and Red Hat, Inc.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser 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.
   8  *
   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  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General
  15  * Public 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.
  18  *
  19  * gvaluecollector.h: GValue varargs stubs
  20  */
  21 #ifndef __G_VALUE_COLLECTOR_H__
  22 #define __G_VALUE_COLLECTOR_H__
  23
  24
  25 #ifdef __cplusplus
  26 extern "C" {
  27 #endif /* __cplusplus */
  28
  29
  30 /* we may want to add aggregate types here some day, if requested
  31  * by users. the basic C types are covered already, everything
  32  * smaller than an int is promoted to an integer and floats are
  33  * always promoted to doubles for varargs call constructions.
  34  */
  35 enum    /*< skip >*/
  36 {
  37   G_VALUE_COLLECT_INT           = 'i',
  38   G_VALUE_COLLECT_LONG          = 'l',
  39   G_VALUE_COLLECT_DOUBLE        = 'd',
  40   G_VALUE_COLLECT_POINTER       = 'p'
  41 };
  42
  43
  44 /* vararg union holding actuall values collected
  45  */
  46 union _GTypeCValue
  47 {
  48   gint     v_int;
  49   glong    v_long;
  50   gdouble  v_double;
  51   gpointer v_pointer;
  52 };
  53
  54
  55 /* G_VALUE_COLLECT() collects a variable argument value
  56  * from a va_list. we have to implement the varargs collection as a
  57  * macro, because on some systems va_list variables cannot be passed
  58  * by reference.
  59  * value is supposed to be initialized according to the value
  60  * type to be collected.
  61  * var_args is the va_list variable and may be evaluated multiple times.
  62  * __error is a gchar** variable that will be modified to hold a g_new()
  63  * allocated error messages if something fails.
  64  */
  65 #define G_VALUE_COLLECT(value, var_args, flags, __error)                                \
  66 G_STMT_START {                                                                          \
  67   GValue *_value = (value);                                                             \
  68   guint _flags = (flags);                                                               \
  69   GType _value_type = G_VALUE_TYPE (_value);                                            \
  70   GTypeValueTable *_vtable = g_type_value_table_peek (_value_type);                     \
  71   gchar *_collect_format = _vtable->collect_format;                                     \
  72   GTypeCValue _cvalues[G_VALUE_COLLECT_FORMAT_MAX_LENGTH] = { { 0, }, };                \
  73   guint _n_values = 0;                                                                  \
  74                                                                                         \
  75   if (_vtable->value_free)                                                              \
  76     _vtable->value_free (_value);                                                       \
  77   _value->g_type = _value_type;         /* value_meminit() from gvalue.c */             \
  78   memset (_value->data, 0, sizeof (_value->data));                                      \
  79   while (*_collect_format)                                                              \
  80     {                                                                                   \
  81       GTypeCValue *_cvalue = _cvalues + _n_values++;                                    \
  82                                                                                         \
  83       switch (*_collect_format++)                                                       \
  84         {                                                                               \
  85         case G_VALUE_COLLECT_INT:                                                       \
  86           _cvalue->v_int = va_arg ((var_args), gint);                                   \
  87           break;                                                                        \
  88         case G_VALUE_COLLECT_LONG:                                                      \
  89           _cvalue->v_long = va_arg ((var_args), glong);                                 \
  90           break;                                                                        \
  91         case G_VALUE_COLLECT_DOUBLE:                                                    \
  92           _cvalue->v_double = va_arg ((var_args), gdouble);                             \
  93           break;                                                                        \
  94         case G_VALUE_COLLECT_POINTER:                                                   \
  95           _cvalue->v_pointer = va_arg ((var_args), gpointer);                           \
  96           break;                                                                        \
  97         default:                                                                        \
  98           g_assert_not_reached ();                                                      \
  99         }                                                                               \
 100     }                                                                                   \
 101   *(__error) = _vtable->collect_value (_value,                                          \
 102                                        _n_values,                                       \
 103                                        _cvalues,                                        \
 104                                        _flags);                                         \
 105 } G_STMT_END
 106
 107
 108 /* G_VALUE_LCOPY() collects a value's variable argument
 109  * locations from a va_list. usage is analogous to G_VALUE_COLLECT().
 110  */
 111 #define G_VALUE_LCOPY(value, var_args, flags, __error)                                  \
 112 G_STMT_START {                                                                          \
 113   GValue *_value = (value);                                                             \
 114   guint _flags = (flags);                                                               \
 115   GType _value_type = G_VALUE_TYPE (_value);                                            \
 116   GTypeValueTable *_vtable = g_type_value_table_peek (_value_type);                     \
 117   gchar *_lcopy_format = _vtable->lcopy_format;                                         \
 118   GTypeCValue _cvalues[G_VALUE_COLLECT_FORMAT_MAX_LENGTH] = { { 0, }, };                \
 119   guint _n_values = 0;                                                                  \
 120                                                                                         \
 121   while (*_lcopy_format)                                                                \
 122     {                                                                                   \
 123       GTypeCValue *_cvalue = _cvalues + _n_values++;                                    \
 124                                                                                         \
 125       switch (*_lcopy_format++)                                                         \
 126         {                                                                               \
 127         case G_VALUE_COLLECT_INT:                                                       \
 128           _cvalue->v_int = va_arg ((var_args), gint);                                   \
 129           break;                                                                        \
 130         case G_VALUE_COLLECT_LONG:                                                      \
 131           _cvalue->v_long = va_arg ((var_args), glong);                                 \
 132           break;                                                                        \
 133         case G_VALUE_COLLECT_DOUBLE:                                                    \
 134           _cvalue->v_double = va_arg ((var_args), gdouble);                             \
 135           break;                                                                        \
 136         case G_VALUE_COLLECT_POINTER:                                                   \
 137           _cvalue->v_pointer = va_arg ((var_args), gpointer);                           \
 138           break;                                                                        \
 139         default:                                                                        \
 140           g_assert_not_reached ();                                                      \
 141         }                                                                               \
 142     }                                                                                   \
 143   *(__error) = _vtable->lcopy_value (_value,                                            \
 144                                      _n_values,                                         \
 145                                      _cvalues,                                          \
 146                                      _flags);                                           \
 147 } G_STMT_END
 148
 149
 150 #define G_VALUE_COLLECT_FORMAT_MAX_LENGTH       (8)
 151
 152
 153
 154 #ifdef __cplusplus
 155 }
 156 #endif /* __cplusplus */
 157
 158 #endif /* __G_VALUE_COLLECTOR_H__ */