Testing infastructure: A template for char_traits where all the functions are constexpr, and a comparison predicate which counts how many times it's been called.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@210381 91177308-0d34-0410-b5e6-96231b3b80d8

test/support/counting_predicates.hpp

@@ -0,0 +1,47 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __COUNTING_PREDICATES_H
+#define __COUNTING_PREDICATES_H
+
+
+template <typename Predicate>
+struct unary_counting_predicate {
+public:
+	unary_counting_predicate(Predicate p) : p_(p), count_(0) {}
+	~unary_counting_predicate() {}
+	
+	typedef typename Predicate::argument_type argument_type;
+	typedef bool result_type;
+	
+	bool operator () (const argument_type &a) const { ++count_; return p_(a); }
+	size_t count() const { return count_; }
+	
+private:
+	Predicate p_;
+	mutable size_t count_;
+	};
+
+
+template <typename Predicate, typename Arg1, typename Arg2=Arg1>
+struct binary_counting_predicate : public std::binary_function<Arg1, Arg2, bool> {
+public:
+
+	binary_counting_predicate ( Predicate p ) : p_(p), count_(0) {}
+	~binary_counting_predicate() {}
+	
+	bool operator () (const Arg1 &a1, const Arg2 &a2) const { ++count_; return p_(a1, a2); }
+	size_t count() const { return count_; }
+	
+private:
+	Predicate p_;
+	mutable size_t count_;
+	};
+
+#endif // __COUNTING_PREDICATES_H