libcxx/test/support/fp_compare.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef SUPPORT_FP_COMPARE_H
  10 #define SUPPORT_FP_COMPARE_H
  11
  12 #include <cmath>     // for std::abs
  13 #include <algorithm> // for std::max
  14 #include <cassert>
  15 #include <__config>
  16
  17 // 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
  18
  19 template <typename T>
  20 bool fptest_close(T val, T expected, T eps) {
  21   _LIBCPP_CONSTEXPR T zero = T(0);
  22   assert(eps >= zero);
  23
  24   // Handle the zero cases
  25   if (eps == zero)
  26     return val == expected;
  27   if (val == zero)
  28     return std::abs(expected) <= eps;
  29   if (expected == zero)
  30     return std::abs(val) <= eps;
  31
  32   return std::abs(val - expected) < eps && std::abs(val - expected) / std::abs(val) < eps;
  33 }
  34
  35 template <typename T>
  36 bool fptest_close_pct(T val, T expected, T percent) {
  37   assert(percent >= T(0));
  38   T eps = (percent / T(100)) * std::max(std::abs(val), std::abs(expected));
  39   return fptest_close(val, expected, eps);
  40 }
  41
  42 #endif // SUPPORT_FP_COMPARE_H