adg/adg-util.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007,2008,2009 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  * ADG_MESSAGE:
  96  * @message: the message string
  97  *
  98  * A convenient function to output debug information. It is similar
  99  * to g_message() but prepends @message with some text specifying
 100  * the position where this function has been called.
 101  **/
 102
 103
 104 #include "adg-util.h"
 105 #include <string.h>
 106 #include <limits.h>
 107
 108
 109 /**
 110  * adg_strcmp:
 111  * @s1: first string to compare
 112  * @s2: second string to compare
 113  *
 114  * A strcmp() function guarded against %NULL values. It works in the
 115  * same way exept for the following situations:
 116  *
 117  * <itemizedlist>
 118  * <listitem><code>s1 == NULL && s2 == NULL</code>: returns %0;</listitem>
 119  * <listitem><code>s1 == NULL</code>: returns %INT_MIN;</listitem>
 120  * <listitem><code>s2 == NULL</code>: returns %INT_MAX.</listitem>
 121  * </itemizedlist>
 122  *
 123  * Returns: %0 if @s1 matches @s2, a value less than %0 if @s1 is less
 124  *          than @s2 or greather than %0 if @s1 is greather than @s2
 125  **/
 126 gint
 127 adg_strcmp(const gchar *s1, const gchar *s2)
 128 {
 129     /* This will also catch the NULL == NULL case */
 130     if (s1 == s2)
 131         return 0;
 132
 133     if (s1 == NULL)
 134         return INT_MIN;
 135
 136     if (s2 == NULL)
 137         return INT_MAX;
 138
 139     return strcmp(s1, s2);
 140 }
 141
 142 /**
 143  * adg_is_empty:
 144  * @str: the subject string
 145  *
 146  * Checks if @str is an empty string, that is if is %NULL or if
 147  * its first character is %'\0'.
 148  *
 149  * Returns: %TRUE if @str is an empty string, %FALSE otherwise
 150  **/
 151 gboolean
 152 adg_is_empty(const gchar *str)
 153 {
 154     return str == NULL || str[0] == '\0';
 155 }