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