xnu-6153.11.26.tar.gz

[apple/xnu.git] / libkern / os / cpp_util.h

diff --git a/libkern/os/cpp_util.h b/libkern/os/cpp_util.h
new file mode 100644 (file)
index 0000000..dc7236b
--- /dev/null
+++ b/libkern/os/cpp_util.h
@@ -0,0 +1,49 @@
+#ifndef _OS_CPP_UTIL_H
+#define _OS_CPP_UTIL_H
+
+#include <sys/cdefs.h>
+
+#if __has_feature(cxx_nullptr) && __has_feature(cxx_decltype)
+# define OS_HAS_NULLPTR 1
+#endif
+
+#if __has_feature(cxx_rvalue_references) || __has_extension(cxx_rvalue_references)
+# define OS_HAS_RVALUE_REFERENCES 1
+#endif
+
+namespace os {
+#if OS_HAS_NULLPTR
+typedef decltype(nullptr) nullptr_t;
+#endif
+
+/*
+ * Reference removal
+ */
+
+template <class _T> struct remove_reference       {typedef _T type;};
+template <class _T> struct remove_reference<_T&>  {typedef _T type;};
+template <class _T> struct remove_reference<_T &&> {typedef _T type;};
+template <class _T> using remove_reference_t = typename remove_reference<_T>::type;
+
+/*
+ * Const removal
+ */
+
+template <class _T> struct remove_const           {typedef _T type;};
+template <class _T> struct remove_const<const _T> {typedef _T type;};
+template <class _T> using remove_const_t = typename remove_const<_T>::type;
+
+/*
+ * Move
+ */
+
+template <class _T>
+inline typename remove_reference<_T>::type &&
+move(_T && _t)
+{
+       typedef typename os::remove_reference<_T>::type _U;
+       return static_cast<_U &&>(_t);
+}
+}
+
+#endif /* _OS_CPP_UTIL_H */