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// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UTIL_SIMPLE_FRACTION_H_
#define UTIL_SIMPLE_FRACTION_H_
#include <cmath>
#include <limits>
#include <string>
#include "absl/strings/string_view.h"
#include "platform/base/error.h"
namespace openscreen {
// SimpleFraction is used to represent simple (or "common") fractions, composed
// of a rational number written a/b where a and b are both integers.
// Some helpful notes on SimpleFraction assumptions/limitations:
// 1. SimpleFraction does not perform reductions. 2/4 != 1/2, and -1/-1 != 1/1.
// 2. denominator = 0 is considered undefined.
// 3. numerator = saturates range to int min or int max
// 4. A SimpleFraction is "positive" if and only if it is defined and at least
// equal to zero. Since reductions are not performed, -1/-1 is negative.
class SimpleFraction {
public:
static ErrorOr<SimpleFraction> FromString(absl::string_view value);
std::string ToString() const;
constexpr SimpleFraction() = default;
constexpr SimpleFraction(int numerator) // NOLINT
: numerator_(numerator) {}
constexpr SimpleFraction(int numerator, int denominator)
: numerator_(numerator), denominator_(denominator) {}
constexpr SimpleFraction(const SimpleFraction&) = default;
constexpr SimpleFraction(SimpleFraction&&) noexcept = default;
constexpr SimpleFraction& operator=(const SimpleFraction&) = default;
constexpr SimpleFraction& operator=(SimpleFraction&&) = default;
~SimpleFraction() = default;
constexpr bool operator==(const SimpleFraction& other) const {
return numerator_ == other.numerator_ && denominator_ == other.denominator_;
}
constexpr bool operator!=(const SimpleFraction& other) const {
return !(*this == other);
}
constexpr bool is_defined() const { return denominator_ != 0; }
constexpr bool is_positive() const {
return (numerator_ >= 0) && (denominator_ > 0);
}
constexpr explicit operator double() const {
if (denominator_ == 0) {
return nan("");
}
return static_cast<double>(numerator_) / static_cast<double>(denominator_);
}
constexpr int numerator() const { return numerator_; }
constexpr int denominator() const { return denominator_; }
private:
int numerator_ = 0;
int denominator_ = 1;
};
} // namespace openscreen
#endif // UTIL_SIMPLE_FRACTION_H_
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