Implement midpoint for floating point types. Reviewed as https://reviews.llvm.org/D61014.

llvm-svn: 359184

1 files changed, 46 insertions, 0 deletions

diff --git a/libcxx/test/support/fp_compare.h b/libcxx/test/support/fp_compare.h
new file mode 100644
index 00000000000..f14ea96f579
--- /dev/null
+++ b/libcxx/test/support/fp_compare.h
@@ -0,0 +1,46 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef SUPPORT_FP_COMPARE_H
+#define SUPPORT_FP_COMPARE_H
+
+#include <cmath>      // for std::abs
+#include <algorithm>  // for std::max
+#include <cassert>
+
+// See https://www.boost.org/doc/libs/1_70_0/libs/test/doc/html/boost_test/testing_tools/extended_comparison/floating_point/floating_points_comparison_theory.html
+
+template<typename T>
+bool fptest_close(T val, T expected, T eps)
+{
+	constexpr T zero = T(0);
+	assert(eps >= zero);
+
+//	Handle the zero cases
+	if (eps      == zero) return val == expected;
+	if (val      == zero) return std::abs(expected) <= eps;
+	if (expected == zero) return std::abs(val)      <= eps;
+
+	return std::abs(val - expected) < eps
+	    && std::abs(val - expected)/std::abs(val) < eps;
+}
+
+template<typename T>
+bool fptest_close_pct(T val, T expected, T percent)
+{
+	constexpr T zero = T(0);
+	assert(percent >= zero);
+
+//	Handle the zero cases
+	if (percent == zero) return val == expected;
+	T eps = (percent / T(100)) * std::max(std::abs(val), std::abs(expected));
+
+	return fptest_close(val, expected, eps);
+}
+
+
+#endif // SUPPORT_FP_COMPARE_H