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 #include <glib-object.h>
  25
  26 G_BEGIN_DECLS
  27
  28 /* we may want to add aggregate types here some day, if requested
  29  * by users. the basic C types are covered already, everything
  30  * smaller than an int is promoted to an integer and floats are
  31  * always promoted to doubles for varargs call constructions.
  32  */
  33 enum    /*< skip >*/
  34 {
  35   G_VALUE_COLLECT_INT           = 'i',
  36   G_VALUE_COLLECT_LONG          = 'l',
  37   G_VALUE_COLLECT_INT64         = 'q',
  38   G_VALUE_COLLECT_DOUBLE        = 'd',
  39   G_VALUE_COLLECT_POINTER       = 'p'
  40 };
  41
  42
  43 /* vararg union holding actuall values collected
  44  */
  45 union _GTypeCValue
  46 {
  47   gint     v_int;
  48   glong    v_long;
  49   gint64   v_int64;
  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_INT64:                                                     \
  92           _cvalue->v_int64 = va_arg ((var_args), gint64);                               \
  93           break;                                                                        \
  94         case G_VALUE_COLLECT_DOUBLE:                                                    \
  95           _cvalue->v_double = va_arg ((var_args), gdouble);                             \
  96           break;                                                                        \
  97         case G_VALUE_COLLECT_POINTER:                                                   \
  98           _cvalue->v_pointer = va_arg ((var_args), gpointer);                           \
  99           break;                                                                        \
 100         default:                                                                        \
 101           g_assert_not_reached ();                                                      \
 102         }                                                                               \
 103     }                                                                                   \
 104   *(__error) = _vtable->collect_value (_value,                                          \
 105                                        _n_values,                                       \
 106                                        _cvalues,                                        \
 107                                        _flags);                                         \
 108 } G_STMT_END
 109
 110
 111 /* G_VALUE_LCOPY() collects a value's variable argument
 112  * locations from a va_list. usage is analogous to G_VALUE_COLLECT().
 113  */
 114 #define G_VALUE_LCOPY(value, var_args, flags, __error)                                  \
 115 G_STMT_START {                                                                          \
 116   const GValue *_value = (value);                                                       \
 117   guint _flags = (flags);                                                               \
 118   GType _value_type = G_VALUE_TYPE (_value);                                            \
 119   GTypeValueTable *_vtable = g_type_value_table_peek (_value_type);                     \
 120   gchar *_lcopy_format = _vtable->lcopy_format;                                         \
 121   GTypeCValue _cvalues[G_VALUE_COLLECT_FORMAT_MAX_LENGTH] = { { 0, }, };                \
 122   guint _n_values = 0;                                                                  \
 123                                                                                         \
 124   while (*_lcopy_format)                                                                \
 125     {                                                                                   \
 126       GTypeCValue *_cvalue = _cvalues + _n_values++;                                    \
 127                                                                                         \
 128       switch (*_lcopy_format++)                                                         \
 129         {                                                                               \
 130         case G_VALUE_COLLECT_INT:                                                       \
 131           _cvalue->v_int = va_arg ((var_args), gint);                                   \
 132           break;                                                                        \
 133         case G_VALUE_COLLECT_LONG:                                                      \
 134           _cvalue->v_long = va_arg ((var_args), glong);                                 \
 135           break;                                                                        \
 136         case G_VALUE_COLLECT_INT64:                                                     \
 137           _cvalue->v_int64 = va_arg ((var_args), gint64);                               \
 138           break;                                                                        \
 139         case G_VALUE_COLLECT_DOUBLE:                                                    \
 140           _cvalue->v_double = va_arg ((var_args), gdouble);                             \
 141           break;                                                                        \
 142         case G_VALUE_COLLECT_POINTER:                                                   \
 143           _cvalue->v_pointer = va_arg ((var_args), gpointer);                           \
 144           break;                                                                        \
 145         default:                                                                        \
 146           g_assert_not_reached ();                                                      \
 147         }                                                                               \
 148     }                                                                                   \
 149   *(__error) = _vtable->lcopy_value (_value,                                            \
 150                                      _n_values,                                         \
 151                                      _cvalues,                                          \
 152                                      _flags);                                           \
 153 } G_STMT_END
 154
 155
 156 #define G_VALUE_COLLECT_FORMAT_MAX_LENGTH       (8)
 157
 158 G_END_DECLS
 159
 160 #endif /* __G_VALUE_COLLECTOR_H__ */