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// Copyright 2017 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 BASE_NUMERICS_CLAMPED_MATH_H_
#define BASE_NUMERICS_CLAMPED_MATH_H_
#include <stddef.h>
#include <limits>
#include <type_traits>
#include "base/numerics/clamped_math_impl.h"
namespace base {
namespace internal {
template <typename T>
class ClampedNumeric {
static_assert(std::is_arithmetic<T>::value,
"ClampedNumeric<T>: T must be a numeric type.");
public:
using type = T;
constexpr ClampedNumeric() : value_(0) {}
// Copy constructor.
template <typename Src>
constexpr ClampedNumeric(const ClampedNumeric<Src>& rhs)
: value_(saturated_cast<T>(rhs.value_)) {}
template <typename Src>
friend class ClampedNumeric;
// This is not an explicit constructor because we implicitly upgrade regular
// numerics to ClampedNumerics to make them easier to use.
template <typename Src>
constexpr ClampedNumeric(Src value) // NOLINT(runtime/explicit)
: value_(saturated_cast<T>(value)) {
static_assert(std::is_arithmetic<Src>::value, "Argument must be numeric.");
}
// This is not an explicit constructor because we want a seamless conversion
// from StrictNumeric types.
template <typename Src>
constexpr ClampedNumeric(
StrictNumeric<Src> value) // NOLINT(runtime/explicit)
: value_(saturated_cast<T>(static_cast<Src>(value))) {}
// Returns a ClampedNumeric of the specified type, cast from the current
// ClampedNumeric, and saturated to the destination type.
template <typename Dst>
constexpr ClampedNumeric<typename UnderlyingType<Dst>::type> Cast() const {
return *this;
}
// Prototypes for the supported arithmetic operator overloads.
template <typename Src>
constexpr ClampedNumeric& operator+=(const Src rhs);
template <typename Src>
constexpr ClampedNumeric& operator-=(const Src rhs);
template <typename Src>
constexpr ClampedNumeric& operator*=(const Src rhs);
template <typename Src>
constexpr ClampedNumeric& operator/=(const Src rhs);
template <typename Src>
constexpr ClampedNumeric& operator%=(const Src rhs);
template <typename Src>
constexpr ClampedNumeric& operator<<=(const Src rhs);
template <typename Src>
constexpr ClampedNumeric& operator>>=(const Src rhs);
template <typename Src>
constexpr ClampedNumeric& operator&=(const Src rhs);
template <typename Src>
constexpr ClampedNumeric& operator|=(const Src rhs);
template <typename Src>
constexpr ClampedNumeric& operator^=(const Src rhs);
constexpr ClampedNumeric operator-() const {
// The negation of two's complement int min is int min, so that's the
// only overflow case where we will saturate.
return ClampedNumeric<T>(SaturatedNegWrapper(value_));
}
constexpr ClampedNumeric operator~() const {
return ClampedNumeric<decltype(InvertWrapper(T()))>(InvertWrapper(value_));
}
constexpr ClampedNumeric Abs() const {
// The negation of two's complement int min is int min, so that's the
// only overflow case where we will saturate.
return ClampedNumeric<T>(SaturatedAbsWrapper(value_));
}
template <typename U>
constexpr ClampedNumeric<typename MathWrapper<ClampedMaxOp, T, U>::type> Max(
const U rhs) const {
using result_type = typename MathWrapper<ClampedMaxOp, T, U>::type;
return ClampedNumeric<result_type>(
ClampedMaxOp<T, U>::Do(value_, Wrapper<U>::value(rhs)));
}
template <typename U>
constexpr ClampedNumeric<typename MathWrapper<ClampedMinOp, T, U>::type> Min(
const U rhs) const {
using result_type = typename MathWrapper<ClampedMinOp, T, U>::type;
return ClampedNumeric<result_type>(
ClampedMinOp<T, U>::Do(value_, Wrapper<U>::value(rhs)));
}
// This function is available only for integral types. It returns an unsigned
// integer of the same width as the source type, containing the absolute value
// of the source, and properly handling signed min.
constexpr ClampedNumeric<typename UnsignedOrFloatForSize<T>::type>
UnsignedAbs() const {
return ClampedNumeric<typename UnsignedOrFloatForSize<T>::type>(
SafeUnsignedAbs(value_));
}
constexpr ClampedNumeric& operator++() {
*this += 1;
return *this;
}
constexpr ClampedNumeric operator++(int) {
ClampedNumeric value = *this;
*this += 1;
return value;
}
constexpr ClampedNumeric& operator--() {
*this -= 1;
return *this;
}
constexpr ClampedNumeric operator--(int) {
ClampedNumeric value = *this;
*this -= 1;
return value;
}
// These perform the actual math operations on the ClampedNumerics.
// Binary arithmetic operations.
template <template <typename, typename, typename> class M,
typename L,
typename R>
static constexpr ClampedNumeric MathOp(const L lhs, const R rhs) {
using Math = typename MathWrapper<M, L, R>::math;
return ClampedNumeric<T>(
Math::template Do<T>(Wrapper<L>::value(lhs), Wrapper<R>::value(rhs)));
}
// Assignment arithmetic operations.
template <template <typename, typename, typename> class M, typename R>
constexpr ClampedNumeric& MathOp(const R rhs) {
using Math = typename MathWrapper<M, T, R>::math;
*this =
ClampedNumeric<T>(Math::template Do<T>(value_, Wrapper<R>::value(rhs)));
return *this;
}
template <typename Dst>
constexpr operator Dst() const {
return saturated_cast<typename ArithmeticOrUnderlyingEnum<Dst>::type>(
value_);
}
// This method extracts the raw integer value without saturating it to the
// destination type as the conversion operator does. This is useful when
// e.g. assigning to an auto type or passing as a deduced template parameter.
constexpr T RawValue() const { return value_; }
private:
T value_;
// These wrappers allow us to handle state the same way for both
// ClampedNumeric and POD arithmetic types.
template <typename Src>
struct Wrapper {
static constexpr Src value(Src value) {
return static_cast<typename UnderlyingType<Src>::type>(value);
}
};
};
// Convience wrapper to return a new ClampedNumeric from the provided arithmetic
// or ClampedNumericType.
template <typename T>
constexpr ClampedNumeric<typename UnderlyingType<T>::type> MakeClampedNum(
const T value) {
return value;
}
#if !BASE_NUMERICS_DISABLE_OSTREAM_OPERATORS
// Overload the ostream output operator to make logging work nicely.
template <typename T>
std::ostream& operator<<(std::ostream& os, const ClampedNumeric<T>& value) {
os << static_cast<T>(value);
return os;
}
#endif
// These implement the variadic wrapper for the math operations.
template <template <typename, typename, typename> class M,
typename L,
typename R>
constexpr ClampedNumeric<typename MathWrapper<M, L, R>::type> ClampMathOp(
const L lhs,
const R rhs) {
using Math = typename MathWrapper<M, L, R>::math;
return ClampedNumeric<typename Math::result_type>::template MathOp<M>(lhs,
rhs);
}
// General purpose wrapper template for arithmetic operations.
template <template <typename, typename, typename> class M,
typename L,
typename R,
typename... Args>
constexpr ClampedNumeric<typename ResultType<M, L, R, Args...>::type>
ClampMathOp(const L lhs, const R rhs, const Args... args) {
return ClampMathOp<M>(ClampMathOp<M>(lhs, rhs), args...);
}
BASE_NUMERIC_ARITHMETIC_OPERATORS(Clamped, Clamp, Add, +, +=)
BASE_NUMERIC_ARITHMETIC_OPERATORS(Clamped, Clamp, Sub, -, -=)
BASE_NUMERIC_ARITHMETIC_OPERATORS(Clamped, Clamp, Mul, *, *=)
BASE_NUMERIC_ARITHMETIC_OPERATORS(Clamped, Clamp, Div, /, /=)
BASE_NUMERIC_ARITHMETIC_OPERATORS(Clamped, Clamp, Mod, %, %=)
BASE_NUMERIC_ARITHMETIC_OPERATORS(Clamped, Clamp, Lsh, <<, <<=)
BASE_NUMERIC_ARITHMETIC_OPERATORS(Clamped, Clamp, Rsh, >>, >>=)
BASE_NUMERIC_ARITHMETIC_OPERATORS(Clamped, Clamp, And, &, &=)
BASE_NUMERIC_ARITHMETIC_OPERATORS(Clamped, Clamp, Or, |, |=)
BASE_NUMERIC_ARITHMETIC_OPERATORS(Clamped, Clamp, Xor, ^, ^=)
BASE_NUMERIC_ARITHMETIC_VARIADIC(Clamped, Clamp, Max)
BASE_NUMERIC_ARITHMETIC_VARIADIC(Clamped, Clamp, Min)
BASE_NUMERIC_COMPARISON_OPERATORS(Clamped, IsLess, <)
BASE_NUMERIC_COMPARISON_OPERATORS(Clamped, IsLessOrEqual, <=)
BASE_NUMERIC_COMPARISON_OPERATORS(Clamped, IsGreater, >)
BASE_NUMERIC_COMPARISON_OPERATORS(Clamped, IsGreaterOrEqual, >=)
BASE_NUMERIC_COMPARISON_OPERATORS(Clamped, IsEqual, ==)
BASE_NUMERIC_COMPARISON_OPERATORS(Clamped, IsNotEqual, !=)
} // namespace internal
using internal::ClampedNumeric;
using internal::MakeClampedNum;
using internal::ClampMax;
using internal::ClampMin;
using internal::ClampAdd;
using internal::ClampSub;
using internal::ClampMul;
using internal::ClampDiv;
using internal::ClampMod;
using internal::ClampLsh;
using internal::ClampRsh;
using internal::ClampAnd;
using internal::ClampOr;
using internal::ClampXor;
} // namespace base
#endif // BASE_NUMERICS_CLAMPED_MATH_H_