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_FORWARD_DECL:
  32  * @id: The name of a struct
  33  *
  34  * Forward declaration of struct @id. For example,
  35  * <code>ADG_FORWARD_DECL(test)</code> will expand to:
  36  *
  37  * <informalexample><programlisting>
  38  * typedef struct _test test
  39  * </programlisting></informalexample>
  40  *
  41  * This macro is useful to trick <command>gtk-doc</command>, as up
  42  * to now (v.1.12) it generates two conflicting links when using
  43  * forward declarations: the first in the source with the declaration
  44  * and the second where the type is defined. Using ADG_FORWARD_DECL()
  45  * instead of the usual typedef avoids the parsing of the declaration
  46  * in the first file (<command>gtk-doc</command> is not able to do C
  47  * preprocessing).
  48  *
  49  * The same principle can be applied in the definition file. Following
  50  * the previous example, you can use something like this where struct
  51  * _type is defined:
  52  *
  53  * <informalexample><programlisting>
  54  * #if 0
  55  * // This is declared in another file
  56  * typedef struct _type type;
  57  * #endif
  58  * struct _type {
  59  * ...
  60  * };
  61  * </programlisting></informalexample>
  62  **/
  63
  64
  65 #include <string.h>
  66 #include <limits.h>
  67
  68
  69 /**
  70  * adg_strcmp:
  71  * @s1: first string to compare
  72  * @s2: second string to compare
  73  *
  74  * A strcmp() function guarded against %NULL values. It works in the
  75  * same way exept for the following situations:
  76  *
  77  * <itemizedlist>
  78  * <listitem><code>s1 == NULL && s2 == NULL</code>: returns %0;</listitem>
  79  * <listitem><code>s1 == NULL</code>: returns %INT_MIN;</listitem>
  80  * <listitem><code>s2 == NULL</code>: returns %INT_MAX.</listitem>
  81  * </itemizedlist>
  82  *
  83  * Returns: %0 if @s1 matches @s2, a value less than %0 if @s1 is less
  84  *          than @s2 or greather than %0 if @s1 is greather than @s2
  85  **/
  86 int
  87 adg_strcmp(const char *s1, const char *s2)
  88 {
  89     /* This will also catch the NULL == NULL case */
  90     if (s1 == s2)
  91         return 0;
  92
  93     if (s1 == NULL)
  94         return INT_MIN;
  95
  96     if (s2 == NULL)
  97         return INT_MAX;
  98
  99     return strcmp(s1, s2);
 100 }