gobject/gvaluecollector.h

   1 /* GObject - GLib Type, Object, Parameter and Signal Library
   2  * Copyright (C) 1998, 1999, 2000 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_NONE,
  38   G_VALUE_COLLECT_INT,
  39   G_VALUE_COLLECT_LONG,
  40   G_VALUE_COLLECT_DOUBLE,
  41   G_VALUE_COLLECT_POINTER
  42 };
  43
  44 union _GParamCValue
  45 {
  46   gint     v_int;
  47   glong    v_long;
  48   gdouble  v_double;
  49   gpointer v_pointer;
  50 };
  51
  52
  53 /* G_PARAM_COLLECT_VALUE() collects a parameter's variable arguments
  54  * from a va_list. we have to implement the varargs collection as a
  55  * macro, because on some systems va_list variables cannot be passed
  56  * by reference.
  57  * param_value is supposed to be initialized according to the param
  58  * type to be collected.
  59  * the param_spec argument is optional, but probably needed by most
  60  * param class' param_collect_value() implementations.
  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_PARAM_COLLECT_VALUE(param_value, param_spec, var_args, __error)               \
  66 G_STMT_START {                                                                          \
  67   GValue *_value = (param_value);                                                       \
  68   GParamSpecClass *_pclass = g_type_class_ref (_value->g_type);                         \
  69   GParamSpec *_pspec = (param_spec);                                                    \
  70   gchar *_error_msg = NULL;                                                             \
  71   guint _collect_type = _pclass->collect_type;                                          \
  72   guint _nth_value = 0;                                                                 \
  73                                                                                         \
  74   if (_pspec)                                                                           \
  75     g_param_spec_ref (_pspec);                                                          \
  76   g_value_reset (_value);                                                               \
  77   while (_collect_type && !_error_msg)                                                  \
  78     {                                                                                   \
  79       GParamCValue _cvalue;                                                             \
  80                                                                                         \
  81       memset (&_cvalue, 0, sizeof (_cvalue));                                           \
  82       switch (_collect_type)                                                            \
  83         {                                                                               \
  84         case G_VALUE_COLLECT_INT:                                                       \
  85           _cvalue.v_int = va_arg ((var_args), gint);                                    \
  86           break;                                                                        \
  87         case G_VALUE_COLLECT_LONG:                                                      \
  88           _cvalue.v_long = va_arg ((var_args), glong);                                  \
  89           break;                                                                        \
  90         case G_VALUE_COLLECT_DOUBLE:                                                    \
  91           _cvalue.v_double = va_arg ((var_args), gdouble);                              \
  92           break;                                                                        \
  93         case G_VALUE_COLLECT_POINTER:                                                   \
  94           _cvalue.v_pointer = va_arg ((var_args), gpointer);                            \
  95           break;                                                                        \
  96         default:                                                                        \
  97           _error_msg  = g_strdup_printf ("%s: invalid collect type (%d) used for %s",   \
  98                                          G_STRLOC,                                      \
  99                                          _collect_type,                                 \
 100                                          "G_PARAM_COLLECT_VALUE()");                    \
 101           continue;                                                                     \
 102         }                                                                               \
 103       _error_msg = _pclass->param_collect_value (_value,                                \
 104                                                  _pspec,                                \
 105                                                  _nth_value++,                          \
 106                                                  &_collect_type,                        \
 107                                                  &_cvalue);                             \
 108     }                                                                                   \
 109   *(__error) = _error_msg;                                                              \
 110   if (_pspec)                                                                           \
 111     g_param_spec_unref (_pspec);                                                        \
 112   g_type_class_unref (_pclass);                                                         \
 113 } G_STMT_END
 114
 115
 116 /* G_PARAM_LCOPY_VALUE() collects a parameter's variable argument
 117  * locations from a va_list. usage is analogous to G_PARAM_COLLECT_VALUE().
 118  */
 119 #define G_PARAM_LCOPY_VALUE(param_value, param_spec, var_args, __error)                 \
 120 G_STMT_START {                                                                          \
 121   GValue *_value = (param_value);                                                       \
 122   GParamSpecClass *_pclass = g_type_class_ref (_value->g_type);                         \
 123   GParamSpec *_pspec = (param_spec);                                                    \
 124   gchar *_error_msg = NULL;                                                             \
 125   guint _lcopy_type = _pclass->lcopy_type;                                              \
 126   guint _nth_value = 0;                                                                 \
 127                                                                                         \
 128   if (_pspec)                                                                           \
 129     g_param_spec_ref (_pspec);                                                          \
 130   while (_lcopy_type && !_error_msg)                                                    \
 131     {                                                                                   \
 132       GParamCValue _cvalue;                                                             \
 133                                                                                         \
 134       memset (&_cvalue, 0, sizeof (_cvalue));                                           \
 135       switch (_lcopy_type)                                                              \
 136         {                                                                               \
 137         case G_VALUE_COLLECT_INT:                                                       \
 138           _cvalue.v_int = va_arg ((var_args), gint);                                    \
 139           break;                                                                        \
 140         case G_VALUE_COLLECT_LONG:                                                      \
 141           _cvalue.v_long = va_arg ((var_args), glong);                                  \
 142           break;                                                                        \
 143         case G_VALUE_COLLECT_DOUBLE:                                                    \
 144           _cvalue.v_double = va_arg ((var_args), gdouble);                              \
 145           break;                                                                        \
 146         case G_VALUE_COLLECT_POINTER:                                                   \
 147           _cvalue.v_pointer = va_arg ((var_args), gpointer);                            \
 148           break;                                                                        \
 149         default:                                                                        \
 150           _error_msg  = g_strdup_printf ("%s: invalid collect type (%d) used for %s",   \
 151                                          G_STRLOC,                                      \
 152                                          _lcopy_type,                                   \
 153                                          "G_PARAM_LCOPY_VALUE()");                      \
 154           continue;                                                                     \
 155         }                                                                               \
 156       _error_msg = _pclass->param_lcopy_value (_value,                                  \
 157                                                _pspec,                                  \
 158                                                _nth_value++,                            \
 159                                                &_lcopy_type,                            \
 160                                                &_cvalue);                               \
 161     }                                                                                   \
 162   *(__error) = _error_msg;                                                              \
 163   if (_pspec)                                                                           \
 164     g_param_spec_unref (_pspec);                                                        \
 165   g_type_class_unref (_pclass);                                                         \
 166 } G_STMT_END
 167
 168
 169
 170 #ifdef __cplusplus
 171 }
 172 #endif /* __cplusplus */
 173
 174 #endif /* __G_VALUE_COLLECTOR_H__ */