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 #ifndef SUPPORT_FP_COMPARE_H
   9 #define SUPPORT_FP_COMPARE_H
  10
  11 #include <cmath>      // for std::abs
  12 #include <algorithm>  // for std::max
  13 #include <cassert>
  14
  15 // 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
  16
  17 template<typename T>
  18 bool fptest_close(T val, T expected, T eps)
  19 {
  20         constexpr T zero = T(0);
  21         assert(eps >= zero);
  22
  23 //      Handle the zero cases
  24         if (eps      == zero) return val == expected;
  25         if (val      == zero) return std::abs(expected) <= eps;
  26         if (expected == zero) return std::abs(val)      <= eps;
  27
  28         return std::abs(val - expected) < eps
  29             && std::abs(val - expected)/std::abs(val) < eps;
  30 }
  31
  32 template<typename T>
  33 bool fptest_close_pct(T val, T expected, T percent)
  34 {
  35         constexpr T zero = T(0);
  36         assert(percent >= zero);
  37
  38 //      Handle the zero cases
  39         if (percent == zero) return val == expected;
  40         T eps = (percent / T(100)) * std::max(std::abs(val), std::abs(expected));
  41
  42         return fptest_close(val, expected, eps);
  43 }
  44
  45
  46 #endif // SUPPORT_FP_COMPARE_H