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. It is equivalent to a typical
  35  * struct forward declaration, for example:
  36  *
  37  * |[
  38  * ADG_FORWARD_DECL(test)
  39  * ]|
  40  *
  41  * will expand to:
  42  *
  43  * |[
  44  * typedef struct _test test
  45  * ]|
  46  *
  47  * This macro is needed to fake <command>gtk-doc</command>, because
  48  * up to now (v.1.12) it generates two conflicting links when using
  49  * forward declarations: the first in the source with the declaration
  50  * and the second where the type is defined. Using ADG_FORWARD_DECL()
  51  * instead of the usual typedef avoids the parsing of the declaration
  52  * in the first file (<command>gtk-doc</command> is not able to do C
  53  * preprocessing).
  54  *
  55  * The same principle can be applied in the definition file. Following
  56  * the previous example, you can use something like this where struct
  57  * _type is defined:
  58  *
  59  * |[
  60  * #if 0
  61  * // This is declared in another file
  62  * typedef struct _type type;
  63  * #endif
  64  * struct _type {
  65  * ...
  66  * };
  67  * ]|
  68  **/
  69
  70
  71 #include <string.h>
  72 #include <limits.h>
  73
  74
  75 /**
  76  * adg_strcmp:
  77  * @s1: first string to compare
  78  * @s2: second string to compare
  79  *
  80  * A strcmp() function guarded against %NULL values. It works in the
  81  * same way exept for the following situations:
  82  *
  83  * <itemizedlist>
  84  * <listitem><code>s1 == NULL && s2 == NULL</code>: returns %0;</listitem>
  85  * <listitem><code>s1 == NULL</code>: returns %INT_MIN;</listitem>
  86  * <listitem><code>s2 == NULL</code>: returns %INT_MAX.</listitem>
  87  * </itemizedlist>
  88  *
  89  * Returns: %0 if @s1 matches @s2, a value less than %0 if @s1 is less
  90  *          than @s2 or greather than %0 if @s1 is greather than @s2
  91  **/
  92 int
  93 adg_strcmp(const char *s1, const char *s2)
  94 {
  95     /* This will also catch the NULL == NULL case */
  96     if (s1 == s2)
  97         return 0;
  98
  99     if (s1 == NULL)
 100         return INT_MIN;
 101
 102     if (s2 == NULL)
 103         return INT_MAX;
 104
 105     return strcmp(s1, s2);
 106 }