[gobject-introspection] Add a method to compare infos

[Simon van der Linden <svdlinden src gnome org>]

commit 869ef1ada512d2c47995f9dfbbe7c814d784aff8
Author: Simon van der Linden <svdlinden src gnome org>
Date:   Fri Nov 20 10:38:36 2009 +0100

    Add a method to compare infos
    
    Add g_base_info_equal.

 girepository/ginfo.c        |   20 ++++++++++++++++++++
 girepository/girepository.h |    2 ++
 2 files changed, 22 insertions(+), 0 deletions(-)
---
diff --git a/girepository/ginfo.c b/girepository/ginfo.c
index 1f14cb6..2aacb76 100644
--- a/girepository/ginfo.c
+++ b/girepository/ginfo.c
@@ -554,6 +554,26 @@ g_base_info_get_typelib (GIBaseInfo *info)
   return info->typelib;
 }
 
+/*
+ * g_base_info_equal:
+ * @info1: A #GIBaseInfo
+ * @info2: A #GIBaseInfo
+ *
+ * Compare two #GIBaseInfo.
+ *
+ * Using pointer comparison is not practical since many functions return
+ * different instances of #GIBaseInfo that refers to the same part of the
+ * TypeLib; use this function instead to do #GIBaseInfo comparisons.
+ *
+ * Return value: TRUE if and only if @info1 equals @info2.
+ */
+gboolean
+g_base_info_equal (GIBaseInfo *info1, GIBaseInfo *info2)
+{
+  /* Compare the TypeLib pointers, which are mmapped. */
+  return info1->typelib->data + info1->offset == info2->typelib->data + info2->offset;
+}
+
 /* GIFunctionInfo functions */
 const gchar *
 g_function_info_get_symbol (GIFunctionInfo *info)
diff --git a/girepository/girepository.h b/girepository/girepository.h
index c881c8b..c30418a 100644
--- a/girepository/girepository.h
+++ b/girepository/girepository.h
@@ -203,6 +203,8 @@ gboolean               g_base_info_iterate_attributes (GIBaseInfo      *info,
                                                        char          **value);
 GIBaseInfo *           g_base_info_get_container    (GIBaseInfo   *info);
 GTypelib *             g_base_info_get_typelib      (GIBaseInfo   *info);
+gboolean               g_base_info_equal            (GIBaseInfo   *info1,
+                                                     GIBaseInfo   *info2);
 
 GIBaseInfo *           g_info_new                   (GIInfoType    type,
 						     GIBaseInfo   *container,