We now have a current svn snapshot of libqxt in our contrib dir, and

[quassel.git] / src / contrib / libqxt-2007-10-24 / src / core / qxtnullable.h

diff --git a/src/contrib/libqxt-2007-10-24/src/core/qxtnullable.h b/src/contrib/libqxt-2007-10-24/src/core/qxtnullable.h
new file mode 100644 (file)
index 0000000..ae43147
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+++ b/src/contrib/libqxt-2007-10-24/src/core/qxtnullable.h
@@ -0,0 +1,145 @@
+/****************************************************************************
+**
+** Copyright (C) Qxt Foundation. Some rights reserved.
+**
+** This file is part of the QxtCore module of the Qt eXTension library
+**
+** This library is free software; you can redistribute it and/or modify it
+** under the terms of th Common Public License, version 1.0, as published by
+** IBM.
+**
+** This file is provided "AS IS", without WARRANTIES OR CONDITIONS OF ANY
+** KIND, EITHER EXPRESS OR IMPLIED INCLUDING, WITHOUT LIMITATION, ANY
+** WARRANTIES OR CONDITIONS OF TITLE, NON-INFRINGEMENT, MERCHANTABILITY OR
+** FITNESS FOR A PARTICULAR PURPOSE.
+**
+** You should have received a copy of the CPL along with this file.
+** See the LICENSE file and the cpl1.0.txt file included with the source
+** distribution for more information. If you did not receive a copy of the
+** license, contact the Qxt Foundation.
+**
+** <http://libqxt.sourceforge.net>  <foundation@libqxt.org>
+**
+****************************************************************************/
+
+/**
+\class QxtNullable QxtNullable
+\ingroup QxtCore
+\brief distinct null value compatible with any data type.
+
+in general it's a templated abstraction to allow any data type to be
+expressed with a null value distinct from any real value. An example
+of such a use is for optional arguments.
+\n
+prepare a function for argument skipping:
+
+\code
+void  somefunction( qxtNull(int,a) , qxtNull(int,b) )
+{
+
+if (!a.isNull())
+       {
+       int i = a.value();
+       //do something with i
+       }
+ if (!b.isNull())
+       {
+       int x = b.value();
+       //do something with x
+       }
+}
+\endcode
+
+usage:
+\code
+
+somefunction(SKIP,1,2);
+somefunction(3,4);
+somefunction(3,SKIP,6);
+somefunction(1);
+\endcode
+
+*/
+
+#ifndef QXTNULLABLE_H
+#define QXTNULLABLE_H
+#include <qxtglobal.h>
+
+/*! \relates QxtNullable
+ * defines a skipable argument with type \a t and variable name \a n
+ */
+#define qxtNull(t,n)     QxtNullable<t> n = QxtNullable<t>()
+
+#include <qxtnull.h>
+
+template<typename T>
+class /*QXT_CORE_EXPORT*/ QxtNullable
+{
+public:
+    QxtNullable(QxtNull);
+    QxtNullable(const T& p);
+    QxtNullable();
+
+    ///determinates if the Value is set to something meaningfull
+    bool isNull() const;
+
+    ///delete Value
+    void nullify();
+
+    T& value() const;
+    operator T() const;
+    void operator=(const T& p);
+
+private:
+    T* val;
+};
+
+template<typename T>
+QxtNullable<T>::QxtNullable(QxtNull)
+{
+    val = 0;
+}
+
+template<typename T>
+QxtNullable<T>::QxtNullable(const T& p)
+{
+    val = const_cast<T*>(&p);
+}
+
+template<typename T>
+QxtNullable<T>::QxtNullable()
+{
+    val = 0;
+}
+
+template<typename T>
+QxtNullable<T>::operator T() const
+{
+    return *val;
+}
+
+template<typename T>
+T& QxtNullable<T>::value() const
+{
+    return *val;
+}
+
+template<typename T>
+bool QxtNullable<T>::isNull() const
+{
+    return (val==0);
+}
+
+template<typename T>
+void QxtNullable<T>::nullify()
+{
+    val=0;
+}
+
+template<typename T>
+void QxtNullable<T>::operator=(const T& p)
+{
+    val = const_cast<T*>(&p);
+}
+
+#endif