Some more data types; dynamic arguments

git-svn-id: svn://svn.code.sf.net/p/magicseteditor/code/trunk@5 0fc631ac-6414-0410-93d0-97cfa31319b6

src/util/dynamic_arg.hpp

@@ -0,0 +1,68 @@
+//+----------------------------------------------------------------------------+
+//| Description:  Magic Set Editor - Program to make Magic (tm) cards          |
+//| Copyright:    (C) 2001 - 2006 Twan van Laarhoven                           |
+//| License:      GNU General Public License 2 or later (see file COPYING)     |
+//+----------------------------------------------------------------------------+
+
+#ifndef HEADER_UTIL_DYNAMIC_ARG
+#define HEADER_UTIL_DYNAMIC_ARG
+
+/** @file util/dynamic_arg.hpp
+ *
+ *  @brief Support for 'dynamicly scopped' arguments.
+ *  This header
+ */
+
+// ----------------------------------------------------------------------------- : Includes
+
+#include <util/prec.hpp>
+
+// ----------------------------------------------------------------------------- : Dynamic argument
+
+#ifdef _MSC_VER
+#	define THREAD_LOCAL __declspec(thread)
+#else
+#	define THREAD_LOCAL __thread
+#endif
+
+/// Declare a dynamic argument.
+/** The value of the argument can be got with: name()
+ *  To change the value use WITH_DYNAMIC_ARG(name, newValue) { ... }
+ *  To be used in a header file. Use IMPLEMENT_DYN_ARG in a source file
+ */
+#define DECLARE_DYNAMIC_ARG(Type, name)					\
+	extern THREAD_LOCAL Type name##_private;			\
+	inline Type name() { return name##_private; }		\
+	class name##_changer {								\
+	  public:											\
+		inline name##_changer(Type const& newValue)		\
+			: oldValue(name##_private) {				\
+			name##_private = newValue;					\
+		}												\
+		inline ~name##_changer() {						\
+			name##_private = oldValue;					\
+		}												\
+		inline operator bool() { return true; }			\
+	  private:											\
+		Type oldValue;									\
+	}
+
+/// Implementation of a dynamic argument
+#define IMPLEMENT_DYNAMIC_ARG(Type, name, initial)		\
+	THREAD_LOCAL Type name##_private = initial;
+
+/// Locally change the value of a dynamic argument
+/** Usage:
+ *  @code
+ *   // here name() == old value
+ *   WITH_DYNAMIC_ARG(name, newValue) {
+ *      // here name() == newValue
+ *   }
+ *   // here name() == old value
+ *  @endcode
+ */
+#define WITH_DYNAMIC_ARG(name, value)					\
+	if (name##_changer(value))
+
+// ----------------------------------------------------------------------------- : EOF
+#endif