//===-- Unittests for frexpl ----------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "src/math/frexpl.h"
#include "utils/FPUtil/BasicOperations.h"
#include "utils/FPUtil/FPBits.h"
#include "utils/MPFRWrapper/MPFRUtils.h"
#include "utils/UnitTest/Test.h"
#include <math.h>

typedef long double LD;
using FPBits = __llvm_libc::fputil::FPBits<long double>;

namespace mpfr = __llvm_libc::testing::mpfr;

TEST(LlvmLibcFrexplTest, SpecialNumbers) {
  int exponent;

  EXPECT_TRUE(LD(FPBits::inf()) ==
              __llvm_libc::frexpl(LD(FPBits::inf()), &exponent));
  EXPECT_TRUE(LD(FPBits::negInf()) ==
              __llvm_libc::frexpl(LD(FPBits::negInf()), &exponent));

  EXPECT_TRUE(LD(FPBits::zero()) ==
              __llvm_libc::frexpl(LD(FPBits::zero()), &exponent));
  EXPECT_EQ(exponent, 0);

  EXPECT_TRUE(LD(FPBits::negZero()) ==
              __llvm_libc::frexpl(LD(FPBits::negZero()), &exponent));
  EXPECT_EQ(exponent, 0);

  EXPECT_TRUE(
      FPBits(__llvm_libc::frexpl(LD(FPBits::buildNaN(1)), &exponent)).isNaN());
}

TEST(LlvmLibcFrexplTest, PowersOfTwo) {
  int exponent;

  EXPECT_TRUE(0.5l == __llvm_libc::frexpl(1.0l, &exponent));
  EXPECT_EQ(exponent, 1);
  EXPECT_TRUE(-0.5l == __llvm_libc::frexpl(-1.0l, &exponent));
  EXPECT_EQ(exponent, 1);

  EXPECT_TRUE(0.5l == __llvm_libc::frexpl(2.0l, &exponent));
  EXPECT_EQ(exponent, 2);
  EXPECT_TRUE(-0.5l == __llvm_libc::frexpl(-2.0l, &exponent));
  EXPECT_EQ(exponent, 2);

  EXPECT_TRUE(0.5l == __llvm_libc::frexpl(4.0l, &exponent));
  EXPECT_EQ(exponent, 3);
  EXPECT_TRUE(-0.5l == __llvm_libc::frexpl(-4.0l, &exponent));
  EXPECT_EQ(exponent, 3);

  EXPECT_TRUE(0.5l == __llvm_libc::frexpl(8.0l, &exponent));
  EXPECT_EQ(exponent, 4);
  EXPECT_TRUE(-0.5l == __llvm_libc::frexpl(-8.0l, &exponent));
  EXPECT_EQ(exponent, 4);

  EXPECT_TRUE(0.5l == __llvm_libc::frexpl(16.0l, &exponent));
  EXPECT_EQ(exponent, 5);
  EXPECT_TRUE(-0.5l == __llvm_libc::frexpl(-16.0l, &exponent));
  EXPECT_EQ(exponent, 5);

  EXPECT_TRUE(0.5l == __llvm_libc::frexpl(32.0l, &exponent));
  EXPECT_EQ(exponent, 6);
  EXPECT_TRUE(-0.5l == __llvm_libc::frexpl(-32.0l, &exponent));
  EXPECT_EQ(exponent, 6);
}

TEST(LlvmLibcFrexplTest, SomeIntegers) {
  int exponent;

  EXPECT_TRUE(0.75l == __llvm_libc::frexpl(24.0l, &exponent));
  EXPECT_EQ(exponent, 5);
  EXPECT_TRUE(-0.75l == __llvm_libc::frexpl(-24.0l, &exponent));
  EXPECT_EQ(exponent, 5);

  EXPECT_TRUE(0.625l == __llvm_libc::frexpl(40.0l, &exponent));
  EXPECT_EQ(exponent, 6);
  EXPECT_TRUE(-0.625l == __llvm_libc::frexpl(-40.0l, &exponent));
  EXPECT_EQ(exponent, 6);

  EXPECT_TRUE(0.78125l == __llvm_libc::frexpl(800.0l, &exponent));
  EXPECT_EQ(exponent, 10);
  EXPECT_TRUE(-0.78125l == __llvm_libc::frexpl(-800.0l, &exponent));
  EXPECT_EQ(exponent, 10);
}

TEST(LlvmLibcFrexplTest, LongDoubleRange) {
  using UIntType = FPBits::UIntType;
  constexpr UIntType count = 10000000;
  constexpr UIntType step = UIntType(-1) / count;
  for (UIntType i = 0, v = 0; i <= count; ++i, v += step) {
    long double x = static_cast<long double>(FPBits(v));
    if (isnan(x) || isinf(x) || x == 0.0l)
      continue;

    mpfr::BinaryOutput<long double> result;
    result.f = __llvm_libc::frexpl(x, &result.i);

    ASSERT_TRUE(__llvm_libc::fputil::abs(result.f) < 1.0);
    ASSERT_TRUE(__llvm_libc::fputil::abs(result.f) >= 0.5);
    ASSERT_MPFR_MATCH(mpfr::Operation::Frexp, x, result, 0.0);
  }
}