src/adg/adg-util.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007,2008,2009,2010  Nicola Fontana <ntd at entidi.it>
   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 Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA  02110-1301, USA.
  18  */
  19
  20
  21 /**
  22  * SECTION:adg-util
  23  * @Section_Id:utilities
  24  * @title: Utilities
  25  * @short_description: Assorted macros and functions
  26  *
  27  * Collection of macros and functions that do not fit inside any other topic.
  28  **/
  29
  30 /**
  31  * ADG_DIR_RIGHT:
  32  *
  33  * Symbolic constant for the right direction (in radians).
  34  **/
  35
  36 /**
  37  * ADG_DIR_DOWN:
  38  *
  39  * Symbolic constant for the down direction (in radians).
  40  **/
  41
  42 /**
  43  * ADG_DIR_LEFT:
  44  *
  45  * Symbolic constant for the left direction (in radians).
  46  **/
  47
  48 /**
  49  * ADG_DIR_UP:
  50  *
  51  * Symbolic constant for the up direction (in radians).
  52  **/
  53
  54 /**
  55  * ADG_FORWARD_DECL:
  56  * @id: The name of a struct
  57  *
  58  * Forward declaration of struct @id. It is equivalent to a typical
  59  * struct forward declaration, for example:
  60  *
  61  * |[
  62  * ADG_FORWARD_DECL(test)
  63  * ]|
  64  *
  65  * will expand to:
  66  *
  67  * |[
  68  * typedef struct _test test
  69  * ]|
  70  *
  71  * This macro is needed to fake <command>gtk-doc</command>, because
  72  * up to now (v.1.12) it generates two conflicting links when using
  73  * forward declarations: the first in the source with the declaration
  74  * and the second where the type is defined. Using ADG_FORWARD_DECL()
  75  * instead of the usual typedef avoids the parsing of the declaration
  76  * in the first file (<command>gtk-doc</command> is not able to do C
  77  * preprocessing).
  78  *
  79  * The same principle can be applied in the definition file. Following
  80  * the previous example, you can use something like this where struct
  81  * _type is defined:
  82  *
  83  * |[
  84  * #if 0
  85  * // This is declared in another file
  86  * typedef struct _type type;
  87  * #endif
  88  * struct _type {
  89  * ...
  90  * };
  91  * ]|
  92  **/
  93
  94
  95 #include "adg-internal.h"
  96 #include "adg-util.h"
  97 #include <string.h>
  98 #include <limits.h>
  99
 100
 101 #if GLIB_CHECK_VERSION(2, 16, 0)
 102 #else
 103 /**
 104  * g_strcmp0:
 105  * @str1: a C string or %NULL
 106  * @str2: another C string or %NULL
 107  *
 108  * Compares @str1 and @str2 like strcmp(). Handles %NULL
 109  * gracefully by sorting it before non-%NULL strings.
 110  * This is a backward compatibility fallback for GLib
 111  * prior to 2.16.0
 112  *
 113  * Returns: -1, 0 or 1, if @str1 is <, == or > than @str2.
 114  */
 115 int
 116 g_strcmp0(const char *str1, const char *str2)
 117 {
 118     if (!str1)
 119         return -(str1 != str2);
 120
 121     if (!str2)
 122         return str1 != str2;
 123
 124     return strcmp(str1, str2);
 125 }
 126 #endif
 127
 128 /**
 129  * adg_is_string_empty:
 130  * @str: the subject string
 131  *
 132  * Checks if @str is an empty string, that is if is %NULL or if
 133  * its first character is %'\0'.
 134  *
 135  * Returns: %TRUE if @str is an empty string, %FALSE otherwise
 136  **/
 137 gboolean
 138 adg_is_string_empty(const gchar *str)
 139 {
 140     return str == NULL || str[0] == '\0';
 141 }
 142
 143 /**
 144  * adg_is_enum_value:
 145  * @value: the enum value to check
 146  * @enum_type: a #GEnum based type
 147  *
 148  * Checks if @value is a valid @enum_type value.
 149  *
 150  * Returns: %TRUE if @value is a valid @enum_type, %FALSE otherwise
 151  **/
 152 gboolean
 153 adg_is_enum_value(int value, GType enum_type)
 154 {
 155     GEnumClass *enum_class;
 156     gboolean found;
 157
 158     enum_class = g_type_class_ref(enum_type);
 159     g_return_val_if_fail(enum_class != NULL, FALSE);
 160
 161     found = FALSE;
 162
 163     if (value >= enum_class->minimum && value <= enum_class->maximum) {
 164         GEnumValue *enum_value;
 165         guint n;
 166
 167         for (n = 0; !found && n < enum_class->n_values; ++n) {
 168             enum_value = enum_class->values + n;
 169             found = value == enum_value->value;
 170         }
 171     }
 172
 173     g_type_class_unref(enum_class);
 174
 175     return found;
 176 }
 177
 178 /**
 179  * adg_is_boolean_value:
 180  * @value: the gboolean value to check
 181  *
 182  * Checks if @value is a valid #gboolean value, that is if it is %TRUE
 183  * or %FALSE. No other values are accepted.
 184  *
 185  * Returns: %TRUE if @value is a valid #gboolean, %FALSE otherwise
 186  **/
 187 gboolean
 188 adg_is_boolean_value(gboolean value)
 189 {
 190     return value == TRUE || value == FALSE;
 191 }