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gecko-dev/mfbt/CheckedInt.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* Provides checked integers, detecting integer overflow and divide-by-0. */
#ifndef mozilla_CheckedInt_h
#define mozilla_CheckedInt_h
#include <stdint.h>
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include "mozilla/IntegerTypeTraits.h"
#include <limits>
#include <type_traits>
#define MOZILLA_CHECKEDINT_COMPARABLE_VERSION(major, minor, patch) \
(major << 16 | minor << 8 | patch)
// Probe for builtin math overflow support. Disabled for 32-bit builds for now
// since "gcc -m32" claims to support these but its implementation is buggy.
// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82274
// Also disabled for clang before version 7 (resp. Xcode clang 10.0.1): while
// clang 5 and 6 have a working __builtin_add_overflow, it is not constexpr.
#if defined(HAVE_64BIT_BUILD)
# if defined(__has_builtin) && \
(!defined(__clang_major__) || \
(!defined(__apple_build_version__) && __clang_major__ >= 7) || \
(defined(__apple_build_version__) && \
MOZILLA_CHECKEDINT_COMPARABLE_VERSION( \
__clang_major__, __clang_minor__, __clang_patchlevel__) >= \
MOZILLA_CHECKEDINT_COMPARABLE_VERSION(10, 0, 1)))
# define MOZ_HAS_BUILTIN_OP_OVERFLOW (__has_builtin(__builtin_add_overflow))
# elif defined(__GNUC__)
// (clang also defines __GNUC__ but it supports __has_builtin since at least
// v3.1 (released in 2012) so it won't get here.)
# define MOZ_HAS_BUILTIN_OP_OVERFLOW (__GNUC__ >= 5)
# else
# define MOZ_HAS_BUILTIN_OP_OVERFLOW (0)
# endif
#else
# define MOZ_HAS_BUILTIN_OP_OVERFLOW (0)
#endif
#undef MOZILLA_CHECKEDINT_COMPARABLE_VERSION
namespace mozilla {
template <typename T>
class CheckedInt;
namespace detail {
/*
* Step 1: manually record supported types
*
* What's nontrivial here is that there are different families of integer
* types: basic integer types and stdint types. It is merrily undefined which
* types from one family may be just typedefs for a type from another family.
*
* For example, on GCC 4.6, aside from the basic integer types, the only other
* type that isn't just a typedef for some of them, is int8_t.
*/
struct UnsupportedType {};
template <typename IntegerType>
struct IsSupportedPass2 {
static const bool value = false;
};
template <typename IntegerType>
struct IsSupported {
static const bool value = IsSupportedPass2<IntegerType>::value;
};
template <>
struct IsSupported<int8_t> {
static const bool value = true;
};
template <>
struct IsSupported<uint8_t> {
static const bool value = true;
};
template <>
struct IsSupported<int16_t> {
static const bool value = true;
};
template <>
struct IsSupported<uint16_t> {
static const bool value = true;
};
template <>
struct IsSupported<int32_t> {
static const bool value = true;
};
template <>
struct IsSupported<uint32_t> {
static const bool value = true;
};
template <>
struct IsSupported<int64_t> {
static const bool value = true;
};
template <>
struct IsSupported<uint64_t> {
static const bool value = true;
};
template <>
struct IsSupportedPass2<char> {
static const bool value = true;
};
template <>
struct IsSupportedPass2<signed char> {
static const bool value = true;
};
template <>
struct IsSupportedPass2<unsigned char> {
static const bool value = true;
};
template <>
struct IsSupportedPass2<short> {
static const bool value = true;
};
template <>
struct IsSupportedPass2<unsigned short> {
static const bool value = true;
};
template <>
struct IsSupportedPass2<int> {
static const bool value = true;
};
template <>
struct IsSupportedPass2<unsigned int> {
static const bool value = true;
};
template <>
struct IsSupportedPass2<long> {
static const bool value = true;
};
template <>
struct IsSupportedPass2<unsigned long> {
static const bool value = true;
};
template <>
struct IsSupportedPass2<long long> {
static const bool value = true;
};
template <>
struct IsSupportedPass2<unsigned long long> {
static const bool value = true;
};
/*
* Step 2: Implement the actual validity checks.
*
* Ideas taken from IntegerLib, code different.
*/
template <typename IntegerType, size_t Size = sizeof(IntegerType)>
struct TwiceBiggerType {
typedef typename detail::StdintTypeForSizeAndSignedness<
sizeof(IntegerType) * 2, std::is_signed_v<IntegerType>>::Type Type;
};
template <typename IntegerType>
struct TwiceBiggerType<IntegerType, 8> {
typedef UnsupportedType Type;
};
template <typename T>
constexpr bool HasSignBit(T aX) {
// In C++, right bit shifts on negative values is undefined by the standard.
// Notice that signed-to-unsigned conversions are always well-defined in the
// standard, as the value congruent modulo 2**n as expected. By contrast,
// unsigned-to-signed is only well-defined if the value is representable.
return bool(std::make_unsigned_t<T>(aX) >> PositionOfSignBit<T>::value);
}
// Bitwise ops may return a larger type, so it's good to use this inline
// helper guaranteeing that the result is really of type T.
template <typename T>
constexpr T BinaryComplement(T aX) {
return ~aX;
}
template <typename T, typename U, bool IsTSigned = std::is_signed_v<T>,
bool IsUSigned = std::is_signed_v<U>>
struct DoesRangeContainRange {};
template <typename T, typename U, bool Signedness>
struct DoesRangeContainRange<T, U, Signedness, Signedness> {
static const bool value = sizeof(T) >= sizeof(U);
};
template <typename T, typename U>
struct DoesRangeContainRange<T, U, true, false> {
static const bool value = sizeof(T) > sizeof(U);
};
template <typename T, typename U>
struct DoesRangeContainRange<T, U, false, true> {
static const bool value = false;
};
template <typename T, typename U, bool IsTSigned = std::is_signed_v<T>,
bool IsUSigned = std::is_signed_v<U>,
bool DoesTRangeContainURange = DoesRangeContainRange<T, U>::value>
struct IsInRangeImpl {};
template <typename T, typename U, bool IsTSigned, bool IsUSigned>
struct IsInRangeImpl<T, U, IsTSigned, IsUSigned, true> {
static constexpr bool run(U) { return true; }
};
template <typename T, typename U>
struct IsInRangeImpl<T, U, true, true, false> {
static constexpr bool run(U aX) {
return aX <= std::numeric_limits<T>::max() &&
aX >= std::numeric_limits<T>::min();
}
};
template <typename T, typename U>
struct IsInRangeImpl<T, U, false, false, false> {
static constexpr bool run(U aX) {
return aX <= std::numeric_limits<T>::max();
}
};
template <typename T, typename U>
struct IsInRangeImpl<T, U, true, false, false> {
static constexpr bool run(U aX) {
return sizeof(T) > sizeof(U) || aX <= U(std::numeric_limits<T>::max());
}
};
template <typename T, typename U>
struct IsInRangeImpl<T, U, false, true, false> {
static constexpr bool run(U aX) {
return sizeof(T) >= sizeof(U)
? aX >= 0
: aX >= 0 && aX <= U(std::numeric_limits<T>::max());
}
};
template <typename T, typename U>
constexpr bool IsInRange(U aX) {
return IsInRangeImpl<T, U>::run(aX);
}
template <typename T>
constexpr bool IsAddValid(T aX, T aY) {
#if MOZ_HAS_BUILTIN_OP_OVERFLOW
T dummy;
return !__builtin_add_overflow(aX, aY, &dummy);
#else
// Addition is valid if the sign of aX+aY is equal to either that of aX or
// that of aY. Since the value of aX+aY is undefined if we have a signed
// type, we compute it using the unsigned type of the same size. Beware!
// These bitwise operations can return a larger integer type, if T was a
// small type like int8_t, so we explicitly cast to T.
std::make_unsigned_t<T> ux = aX;
std::make_unsigned_t<T> uy = aY;
std::make_unsigned_t<T> result = ux + uy;
return std::is_signed_v<T>
? HasSignBit(BinaryComplement(T((result ^ aX) & (result ^ aY))))
: BinaryComplement(aX) >= aY;
#endif
}
template <typename T>
constexpr bool IsSubValid(T aX, T aY) {
#if MOZ_HAS_BUILTIN_OP_OVERFLOW
T dummy;
return !__builtin_sub_overflow(aX, aY, &dummy);
#else
// Subtraction is valid if either aX and aY have same sign, or aX-aY and aX
// have same sign. Since the value of aX-aY is undefined if we have a signed
// type, we compute it using the unsigned type of the same size.
std::make_unsigned_t<T> ux = aX;
std::make_unsigned_t<T> uy = aY;
std::make_unsigned_t<T> result = ux - uy;
return std::is_signed_v<T>
? HasSignBit(BinaryComplement(T((result ^ aX) & (aX ^ aY))))
: aX >= aY;
#endif
}
template <typename T, bool IsTSigned = std::is_signed_v<T>,
bool TwiceBiggerTypeIsSupported =
IsSupported<typename TwiceBiggerType<T>::Type>::value>
struct IsMulValidImpl {};
template <typename T, bool IsTSigned>
struct IsMulValidImpl<T, IsTSigned, true> {
static constexpr bool run(T aX, T aY) {
typedef typename TwiceBiggerType<T>::Type TwiceBiggerType;
TwiceBiggerType product = TwiceBiggerType(aX) * TwiceBiggerType(aY);
return IsInRange<T>(product);
}
};
template <typename T>
struct IsMulValidImpl<T, true, false> {
static constexpr bool run(T aX, T aY) {
const T max = std::numeric_limits<T>::max();
const T min = std::numeric_limits<T>::min();
if (aX == 0 || aY == 0) {
return true;
}
if (aX > 0) {
return aY > 0 ? aX <= max / aY : aY >= min / aX;
}
// If we reach this point, we know that aX < 0.
return aY > 0 ? aX >= min / aY : aY >= max / aX;
}
};
template <typename T>
struct IsMulValidImpl<T, false, false> {
static constexpr bool run(T aX, T aY) {
return aY == 0 || aX <= std::numeric_limits<T>::max() / aY;
}
};
template <typename T>
constexpr bool IsMulValid(T aX, T aY) {
#if MOZ_HAS_BUILTIN_OP_OVERFLOW
T dummy;
return !__builtin_mul_overflow(aX, aY, &dummy);
#else
return IsMulValidImpl<T>::run(aX, aY);
#endif
}
template <typename T>
constexpr bool IsDivValid(T aX, T aY) {
// Keep in mind that in the signed case, min/-1 is invalid because
// abs(min)>max.
return aY != 0 && !(std::is_signed_v<T> &&
aX == std::numeric_limits<T>::min() && aY == T(-1));
}
template <typename T, bool IsTSigned = std::is_signed_v<T>>
struct IsModValidImpl;
template <typename T>
constexpr bool IsModValid(T aX, T aY) {
return IsModValidImpl<T>::run(aX, aY);
}
/*
* Mod is pretty simple.
* For now, let's just use the ANSI C definition:
* If aX or aY are negative, the results are implementation defined.
* Consider these invalid.
* Undefined for aY=0.
* The result will never exceed either aX or aY.
*
* Checking that aX>=0 is a warning when T is unsigned.
*/
template <typename T>
struct IsModValidImpl<T, false> {
static constexpr bool run(T aX, T aY) { return aY >= 1; }
};
template <typename T>
struct IsModValidImpl<T, true> {
static constexpr bool run(T aX, T aY) {
if (aX < 0) {
return false;
}
return aY >= 1;
}
};
template <typename T, bool IsSigned = std::is_signed_v<T>>
struct NegateImpl;
template <typename T>
struct NegateImpl<T, false> {
static constexpr CheckedInt<T> negate(const CheckedInt<T>& aVal) {
// Handle negation separately for signed/unsigned, for simpler code and to
// avoid an MSVC warning negating an unsigned value.
static_assert(detail::IsInRange<T>(0), "Integer type can't represent 0");
return CheckedInt<T>(T(0), aVal.isValid() && aVal.mValue == 0);
}
};
template <typename T>
struct NegateImpl<T, true> {
static constexpr CheckedInt<T> negate(const CheckedInt<T>& aVal) {
// Watch out for the min-value, which (with twos-complement) can't be
// negated as -min-value is then (max-value + 1).
if (!aVal.isValid() || aVal.mValue == std::numeric_limits<T>::min()) {
return CheckedInt<T>(aVal.mValue, false);
}
/* For some T, arithmetic ops automatically promote to a wider type, so
* explitly do the narrowing cast here. The narrowing cast is valid because
* we did the check for min value above. */
return CheckedInt<T>(T(-aVal.mValue), true);
}
};
} // namespace detail
/*
* Step 3: Now define the CheckedInt class.
*/
/**
* @class CheckedInt
* @brief Integer wrapper class checking for integer overflow and other errors
* @param T the integer type to wrap. Can be any type among the following:
* - any basic integer type such as |int|
* - any stdint type such as |int8_t|
*
* This class implements guarded integer arithmetic. Do a computation, check
* that isValid() returns true, you then have a guarantee that no problem, such
* as integer overflow, happened during this computation, and you can call
* value() to get the plain integer value.
*
* The arithmetic operators in this class are guaranteed not to raise a signal
* (e.g. in case of a division by zero).
*
* For example, suppose that you want to implement a function that computes
* (aX+aY)/aZ, that doesn't crash if aZ==0, and that reports on error (divide by
* zero or integer overflow). You could code it as follows:
@code
bool computeXPlusYOverZ(int aX, int aY, int aZ, int* aResult)
{
CheckedInt<int> checkedResult = (CheckedInt<int>(aX) + aY) / aZ;
if (checkedResult.isValid()) {
*aResult = checkedResult.value();
return true;
} else {
return false;
}
}
@endcode
*
* Implicit conversion from plain integers to checked integers is allowed. The
* plain integer is checked to be in range before being casted to the
* destination type. This means that the following lines all compile, and the
* resulting CheckedInts are correctly detected as valid or invalid:
* @code
// 1 is of type int, is found to be in range for uint8_t, x is valid
CheckedInt<uint8_t> x(1);
// -1 is of type int, is found not to be in range for uint8_t, x is invalid
CheckedInt<uint8_t> x(-1);
// -1 is of type int, is found to be in range for int8_t, x is valid
CheckedInt<int8_t> x(-1);
// 1000 is of type int16_t, is found not to be in range for int8_t,
// x is invalid
CheckedInt<int8_t> x(int16_t(1000));
// 3123456789 is of type uint32_t, is found not to be in range for int32_t,
// x is invalid
CheckedInt<int32_t> x(uint32_t(3123456789));
* @endcode
* Implicit conversion from
* checked integers to plain integers is not allowed. As shown in the
* above example, to get the value of a checked integer as a normal integer,
* call value().
*
* Arithmetic operations between checked and plain integers is allowed; the
* result type is the type of the checked integer.
*
* Checked integers of different types cannot be used in the same arithmetic
* expression.
*
* There are convenience typedefs for all stdint types, of the following form
* (these are just 2 examples):
@code
typedef CheckedInt<int32_t> CheckedInt32;
typedef CheckedInt<uint16_t> CheckedUint16;
@endcode
*/
template <typename T>
class CheckedInt {
protected:
T mValue;
bool mIsValid;
template <typename U>
constexpr CheckedInt(U aValue, bool aIsValid)
: mValue(aValue), mIsValid(aIsValid) {
static_assert(std::is_same_v<T, U>,
"this constructor must accept only T values");
static_assert(detail::IsSupported<T>::value,
"This type is not supported by CheckedInt");
}
friend struct detail::NegateImpl<T>;
public:
/**
* Constructs a checked integer with given @a value. The checked integer is
* initialized as valid or invalid depending on whether the @a value
* is in range.
*
* This constructor is not explicit. Instead, the type of its argument is a
* separate template parameter, ensuring that no conversion is performed
* before this constructor is actually called. As explained in the above
* documentation for class CheckedInt, this constructor checks that its
* argument is valid.
*/
template <typename U>
MOZ_IMPLICIT MOZ_NO_ARITHMETIC_EXPR_IN_ARGUMENT constexpr CheckedInt(U aValue)
: mValue(T(aValue)), mIsValid(detail::IsInRange<T>(aValue)) {
static_assert(
detail::IsSupported<T>::value && detail::IsSupported<U>::value,
"This type is not supported by CheckedInt");
}
template <typename U>
friend class CheckedInt;
template <typename U>
constexpr CheckedInt<U> toChecked() const {
CheckedInt<U> ret(mValue);
ret.mIsValid = ret.mIsValid && mIsValid;
return ret;
}
/** Constructs a valid checked integer with initial value 0 */
constexpr CheckedInt() : mValue(T(0)), mIsValid(true) {
static_assert(detail::IsSupported<T>::value,
"This type is not supported by CheckedInt");
static_assert(detail::IsInRange<T>(0), "Integer type can't represent 0");
}
/** @returns the actual value */
constexpr T value() const {
MOZ_DIAGNOSTIC_ASSERT(
mIsValid,
"Invalid checked integer (division by zero or integer overflow)");
return mValue;
}
/**
* @returns true if the checked integer is valid, i.e. is not the result
* of an invalid operation or of an operation involving an invalid checked
* integer
*/
constexpr bool isValid() const { return mIsValid; }
template <typename U>
friend constexpr CheckedInt<U> operator+(const CheckedInt<U>& aLhs,
const CheckedInt<U>& aRhs);
template <typename U>
constexpr CheckedInt& operator+=(U aRhs);
constexpr CheckedInt& operator+=(const CheckedInt<T>& aRhs);
template <typename U>
friend constexpr CheckedInt<U> operator-(const CheckedInt<U>& aLhs,
const CheckedInt<U>& aRhs);
template <typename U>
constexpr CheckedInt& operator-=(U aRhs);
constexpr CheckedInt& operator-=(const CheckedInt<T>& aRhs);
template <typename U>
friend constexpr CheckedInt<U> operator*(const CheckedInt<U>& aLhs,
const CheckedInt<U>& aRhs);
template <typename U>
constexpr CheckedInt& operator*=(U aRhs);
constexpr CheckedInt& operator*=(const CheckedInt<T>& aRhs);
template <typename U>
friend constexpr CheckedInt<U> operator/(const CheckedInt<U>& aLhs,
const CheckedInt<U>& aRhs);
template <typename U>
constexpr CheckedInt& operator/=(U aRhs);
constexpr CheckedInt& operator/=(const CheckedInt<T>& aRhs);
template <typename U>
friend constexpr CheckedInt<U> operator%(const CheckedInt<U>& aLhs,
const CheckedInt<U>& aRhs);
template <typename U>
constexpr CheckedInt& operator%=(U aRhs);
constexpr CheckedInt& operator%=(const CheckedInt<T>& aRhs);
constexpr CheckedInt operator-() const {
return detail::NegateImpl<T>::negate(*this);
}
/**
* @returns true if the left and right hand sides are valid
* and have the same value.
*
* Note that these semantics are the reason why we don't offer
* a operator!=. Indeed, we'd want to have a!=b be equivalent to !(a==b)
* but that would mean that whenever a or b is invalid, a!=b
* is always true, which would be very confusing.
*
* For similar reasons, operators <, >, <=, >= would be very tricky to
* specify, so we just avoid offering them.
*
* Notice that these == semantics are made more reasonable by these facts:
* 1. a==b implies equality at the raw data level
* (the converse is false, as a==b is never true among invalids)
* 2. This is similar to the behavior of IEEE floats, where a==b
* means that a and b have the same value *and* neither is NaN.
*/
constexpr bool operator==(const CheckedInt& aOther) const {
return mIsValid && aOther.mIsValid && mValue == aOther.mValue;
}
/** prefix ++ */
constexpr CheckedInt& operator++() {
*this += 1;
return *this;
}
/** postfix ++ */
constexpr CheckedInt operator++(int) {
CheckedInt tmp = *this;
*this += 1;
return tmp;
}
/** prefix -- */
constexpr CheckedInt& operator--() {
*this -= 1;
return *this;
}
/** postfix -- */
constexpr CheckedInt operator--(int) {
CheckedInt tmp = *this;
*this -= 1;
return tmp;
}
private:
/**
* The !=, <, <=, >, >= operators are disabled:
* see the comment on operator==.
*/
template <typename U>
bool operator!=(U aOther) const = delete;
template <typename U>
bool operator<(U aOther) const = delete;
template <typename U>
bool operator<=(U aOther) const = delete;
template <typename U>
bool operator>(U aOther) const = delete;
template <typename U>
bool operator>=(U aOther) const = delete;
};
#define MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(NAME, OP) \
template <typename T> \
constexpr CheckedInt<T> operator OP(const CheckedInt<T>& aLhs, \
const CheckedInt<T>& aRhs) { \
if (!detail::Is##NAME##Valid(aLhs.mValue, aRhs.mValue)) { \
static_assert(detail::IsInRange<T>(0), \
"Integer type can't represent 0"); \
return CheckedInt<T>(T(0), false); \
} \
/* For some T, arithmetic ops automatically promote to a wider type, so \
* explitly do the narrowing cast here. The narrowing cast is valid \
* because we did the "Is##NAME##Valid" check above. */ \
return CheckedInt<T>(T(aLhs.mValue OP aRhs.mValue), \
aLhs.mIsValid && aRhs.mIsValid); \
}
#if MOZ_HAS_BUILTIN_OP_OVERFLOW
# define MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR2(NAME, OP, FUN) \
template <typename T> \
constexpr CheckedInt<T> operator OP(const CheckedInt<T>& aLhs, \
const CheckedInt<T>& aRhs) { \
auto result = T{}; \
if (FUN(aLhs.mValue, aRhs.mValue, &result)) { \
static_assert(detail::IsInRange<T>(0), \
"Integer type can't represent 0"); \
return CheckedInt<T>(T(0), false); \
} \
return CheckedInt<T>(result, aLhs.mIsValid && aRhs.mIsValid); \
}
MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR2(Add, +, __builtin_add_overflow)
MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR2(Sub, -, __builtin_sub_overflow)
MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR2(Mul, *, __builtin_mul_overflow)
# undef MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR2
#else
MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(Add, +)
MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(Sub, -)
MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(Mul, *)
#endif
MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(Div, /)
MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(Mod, %)
#undef MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR
// Implement castToCheckedInt<T>(x), making sure that
// - it allows x to be either a CheckedInt<T> or any integer type
// that can be casted to T
// - if x is already a CheckedInt<T>, we just return a reference to it,
// instead of copying it (optimization)
namespace detail {
template <typename T, typename U>
struct CastToCheckedIntImpl {
typedef CheckedInt<T> ReturnType;
static constexpr CheckedInt<T> run(U aU) { return aU; }
};
template <typename T>
struct CastToCheckedIntImpl<T, CheckedInt<T>> {
typedef const CheckedInt<T>& ReturnType;
static constexpr const CheckedInt<T>& run(const CheckedInt<T>& aU) {
return aU;
}
};
} // namespace detail
template <typename T, typename U>
constexpr typename detail::CastToCheckedIntImpl<T, U>::ReturnType
castToCheckedInt(U aU) {
static_assert(detail::IsSupported<T>::value && detail::IsSupported<U>::value,
"This type is not supported by CheckedInt");
return detail::CastToCheckedIntImpl<T, U>::run(aU);
}
#define MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(OP, COMPOUND_OP) \
template <typename T> \
template <typename U> \
constexpr CheckedInt<T>& CheckedInt<T>::operator COMPOUND_OP(U aRhs) { \
*this = *this OP castToCheckedInt<T>(aRhs); \
return *this; \
} \
template <typename T> \
constexpr CheckedInt<T>& CheckedInt<T>::operator COMPOUND_OP( \
const CheckedInt<T>& aRhs) { \
*this = *this OP aRhs; \
return *this; \
} \
template <typename T, typename U> \
constexpr CheckedInt<T> operator OP(const CheckedInt<T>& aLhs, U aRhs) { \
return aLhs OP castToCheckedInt<T>(aRhs); \
} \
template <typename T, typename U> \
constexpr CheckedInt<T> operator OP(U aLhs, const CheckedInt<T>& aRhs) { \
return castToCheckedInt<T>(aLhs) OP aRhs; \
}
MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(+, +=)
MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(*, *=)
MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(-, -=)
MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(/, /=)
MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(%, %=)
#undef MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS
template <typename T, typename U>
constexpr bool operator==(const CheckedInt<T>& aLhs, U aRhs) {
return aLhs == castToCheckedInt<T>(aRhs);
}
template <typename T, typename U>
constexpr bool operator==(U aLhs, const CheckedInt<T>& aRhs) {
return castToCheckedInt<T>(aLhs) == aRhs;
}
// Convenience typedefs.
typedef CheckedInt<int8_t> CheckedInt8;
typedef CheckedInt<uint8_t> CheckedUint8;
typedef CheckedInt<int16_t> CheckedInt16;
typedef CheckedInt<uint16_t> CheckedUint16;
typedef CheckedInt<int32_t> CheckedInt32;
typedef CheckedInt<uint32_t> CheckedUint32;
typedef CheckedInt<int64_t> CheckedInt64;
typedef CheckedInt<uint64_t> CheckedUint64;
} // namespace mozilla
#endif /* mozilla_CheckedInt_h */
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