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- #ifndef BASE_NUMERICS_SAFE_CONVERSIONS_H_
- #define BASE_NUMERICS_SAFE_CONVERSIONS_H_
- #include <stddef.h>
- #include <cmath>
- #include <limits>
- #include <type_traits>
- #include "base/numerics/safe_conversions_impl.h"
- #if !defined(__native_client__) && (defined(__ARMEL__) || defined(__arch64__))
- #include "base/numerics/safe_conversions_arm_impl.h"
- #define BASE_HAS_OPTIMIZED_SAFE_CONVERSIONS (1)
- #else
- #define BASE_HAS_OPTIMIZED_SAFE_CONVERSIONS (0)
- #endif
- #if !BASE_NUMERICS_DISABLE_OSTREAM_OPERATORS
- #include <ostream>
- #endif
- namespace base {
- namespace internal {
- #if !BASE_HAS_OPTIMIZED_SAFE_CONVERSIONS
- template <typename Dst, typename Src>
- struct SaturateFastAsmOp {
- static constexpr bool is_supported = false;
- static constexpr Dst Do(Src) {
-
- return CheckOnFailure::template HandleFailure<Dst>();
- }
- };
- #endif
- #undef BASE_HAS_OPTIMIZED_SAFE_CONVERSIONS
- template <typename Dst, typename Src, typename Enable = void>
- struct IsValueInRangeFastOp {
- static constexpr bool is_supported = false;
- static constexpr bool Do(Src value) {
-
- return CheckOnFailure::template HandleFailure<bool>();
- }
- };
- template <typename Dst, typename Src>
- struct IsValueInRangeFastOp<
- Dst,
- Src,
- typename std::enable_if<
- std::is_integral<Dst>::value && std::is_integral<Src>::value &&
- std::is_signed<Dst>::value && std::is_signed<Src>::value &&
- !IsTypeInRangeForNumericType<Dst, Src>::value>::type> {
- static constexpr bool is_supported = true;
- static constexpr bool Do(Src value) {
-
-
- return value == static_cast<Dst>(value);
- }
- };
- template <typename Dst, typename Src>
- struct IsValueInRangeFastOp<
- Dst,
- Src,
- typename std::enable_if<
- std::is_integral<Dst>::value && std::is_integral<Src>::value &&
- !std::is_signed<Dst>::value && std::is_signed<Src>::value &&
- !IsTypeInRangeForNumericType<Dst, Src>::value>::type> {
- static constexpr bool is_supported = true;
- static constexpr bool Do(Src value) {
-
-
- return as_unsigned(value) <= as_unsigned(CommonMax<Src, Dst>());
- }
- };
- template <typename Dst, typename Src>
- constexpr bool IsValueInRangeForNumericType(Src value) {
- using SrcType = typename internal::UnderlyingType<Src>::type;
- return internal::IsValueInRangeFastOp<Dst, SrcType>::is_supported
- ? internal::IsValueInRangeFastOp<Dst, SrcType>::Do(
- static_cast<SrcType>(value))
- : internal::DstRangeRelationToSrcRange<Dst>(
- static_cast<SrcType>(value))
- .IsValid();
- }
- template <typename Dst,
- class CheckHandler = internal::CheckOnFailure,
- typename Src>
- constexpr Dst checked_cast(Src value) {
-
-
- using SrcType = typename internal::UnderlyingType<Src>::type;
- return BASE_NUMERICS_LIKELY((IsValueInRangeForNumericType<Dst>(value)))
- ? static_cast<Dst>(static_cast<SrcType>(value))
- : CheckHandler::template HandleFailure<Dst>();
- }
- template <typename T>
- struct SaturationDefaultLimits : public std::numeric_limits<T> {
- static constexpr T NaN() {
- return std::numeric_limits<T>::has_quiet_NaN
- ? std::numeric_limits<T>::quiet_NaN()
- : T();
- }
- using std::numeric_limits<T>::max;
- static constexpr T Overflow() {
- return std::numeric_limits<T>::has_infinity
- ? std::numeric_limits<T>::infinity()
- : std::numeric_limits<T>::max();
- }
- using std::numeric_limits<T>::lowest;
- static constexpr T Underflow() {
- return std::numeric_limits<T>::has_infinity
- ? std::numeric_limits<T>::infinity() * -1
- : std::numeric_limits<T>::lowest();
- }
- };
- template <typename Dst, template <typename> class S, typename Src>
- constexpr Dst saturated_cast_impl(Src value, RangeCheck constraint) {
-
-
- return !constraint.IsOverflowFlagSet()
- ? (!constraint.IsUnderflowFlagSet() ? static_cast<Dst>(value)
- : S<Dst>::Underflow())
-
- : (std::is_integral<Src>::value || !constraint.IsUnderflowFlagSet()
- ? S<Dst>::Overflow()
- : S<Dst>::NaN());
- }
- template <typename Dst, typename Src, typename Enable = void>
- struct SaturateFastOp {
- static constexpr bool is_supported = false;
- static constexpr Dst Do(Src value) {
-
- return CheckOnFailure::template HandleFailure<Dst>();
- }
- };
- template <typename Dst, typename Src>
- struct SaturateFastOp<
- Dst,
- Src,
- typename std::enable_if<std::is_integral<Src>::value &&
- std::is_integral<Dst>::value &&
- SaturateFastAsmOp<Dst, Src>::is_supported>::type> {
- static constexpr bool is_supported = true;
- static constexpr Dst Do(Src value) { return SaturateFastAsmOp<Dst, Src>::Do(value); }
- };
- template <typename Dst, typename Src>
- struct SaturateFastOp<
- Dst,
- Src,
- typename std::enable_if<std::is_integral<Src>::value &&
- std::is_integral<Dst>::value &&
- !SaturateFastAsmOp<Dst, Src>::is_supported>::type> {
- static constexpr bool is_supported = true;
- static constexpr Dst Do(Src value) {
-
-
-
- const Dst saturated = CommonMaxOrMin<Dst, Src>(
- IsMaxInRangeForNumericType<Dst, Src>() ||
- (!IsMinInRangeForNumericType<Dst, Src>() && IsValueNegative(value)));
- return BASE_NUMERICS_LIKELY(IsValueInRangeForNumericType<Dst>(value))
- ? static_cast<Dst>(value)
- : saturated;
- }
- };
- template <typename Dst,
- template <typename> class SaturationHandler = SaturationDefaultLimits,
- typename Src>
- constexpr Dst saturated_cast(Src value) {
- using SrcType = typename UnderlyingType<Src>::type;
- return !IsCompileTimeConstant(value) &&
- SaturateFastOp<Dst, SrcType>::is_supported &&
- std::is_same<SaturationHandler<Dst>,
- SaturationDefaultLimits<Dst>>::value
- ? SaturateFastOp<Dst, SrcType>::Do(static_cast<SrcType>(value))
- : saturated_cast_impl<Dst, SaturationHandler, SrcType>(
- static_cast<SrcType>(value),
- DstRangeRelationToSrcRange<Dst, SaturationHandler, SrcType>(
- static_cast<SrcType>(value)));
- }
- template <typename Dst, typename Src>
- constexpr Dst strict_cast(Src value) {
- using SrcType = typename UnderlyingType<Src>::type;
- static_assert(UnderlyingType<Src>::is_numeric, "Argument must be numeric.");
- static_assert(std::is_arithmetic<Dst>::value, "Result must be numeric.");
-
-
-
-
-
-
- static_assert(StaticDstRangeRelationToSrcRange<Dst, SrcType>::value ==
- NUMERIC_RANGE_CONTAINED,
- "The source type is out of range for the destination type. "
- "Please see strict_cast<> comments for more information.");
- return static_cast<Dst>(static_cast<SrcType>(value));
- }
- template <typename Dst, typename Src, class Enable = void>
- struct IsNumericRangeContained {
- static constexpr bool value = false;
- };
- template <typename Dst, typename Src>
- struct IsNumericRangeContained<
- Dst,
- Src,
- typename std::enable_if<ArithmeticOrUnderlyingEnum<Dst>::value &&
- ArithmeticOrUnderlyingEnum<Src>::value>::type> {
- static constexpr bool value =
- StaticDstRangeRelationToSrcRange<Dst, Src>::value ==
- NUMERIC_RANGE_CONTAINED;
- };
- template <typename T>
- class StrictNumeric {
- public:
- using type = T;
- constexpr StrictNumeric() : value_(0) {}
-
- template <typename Src>
- constexpr StrictNumeric(const StrictNumeric<Src>& rhs)
- : value_(strict_cast<T>(rhs.value_)) {}
-
-
- template <typename Src>
- constexpr StrictNumeric(Src value)
- : value_(strict_cast<T>(value)) {}
-
-
-
-
-
-
-
-
-
-
-
-
- template <typename Dst,
- typename std::enable_if<
- IsNumericRangeContained<Dst, T>::value>::type* = nullptr>
- constexpr operator Dst() const {
- return static_cast<typename ArithmeticOrUnderlyingEnum<Dst>::type>(value_);
- }
- private:
- const T value_;
- };
- template <typename T>
- constexpr StrictNumeric<typename UnderlyingType<T>::type> MakeStrictNum(
- const T value) {
- return value;
- }
- #if !BASE_NUMERICS_DISABLE_OSTREAM_OPERATORS
- template <typename T>
- std::ostream& operator<<(std::ostream& os, const StrictNumeric<T>& value) {
- os << static_cast<T>(value);
- return os;
- }
- #endif
- #define BASE_NUMERIC_COMPARISON_OPERATORS(CLASS, NAME, OP) \
- template <typename L, typename R, \
- typename std::enable_if< \
- internal::Is##CLASS##Op<L, R>::value>::type* = nullptr> \
- constexpr bool operator OP(const L lhs, const R rhs) { \
- return SafeCompare<NAME, typename UnderlyingType<L>::type, \
- typename UnderlyingType<R>::type>(lhs, rhs); \
- }
- BASE_NUMERIC_COMPARISON_OPERATORS(Strict, IsLess, <)
- BASE_NUMERIC_COMPARISON_OPERATORS(Strict, IsLessOrEqual, <=)
- BASE_NUMERIC_COMPARISON_OPERATORS(Strict, IsGreater, >)
- BASE_NUMERIC_COMPARISON_OPERATORS(Strict, IsGreaterOrEqual, >=)
- BASE_NUMERIC_COMPARISON_OPERATORS(Strict, IsEqual, ==)
- BASE_NUMERIC_COMPARISON_OPERATORS(Strict, IsNotEqual, !=)
- }
- using internal::as_signed;
- using internal::as_unsigned;
- using internal::checked_cast;
- using internal::strict_cast;
- using internal::saturated_cast;
- using internal::SafeUnsignedAbs;
- using internal::StrictNumeric;
- using internal::MakeStrictNum;
- using internal::IsValueInRangeForNumericType;
- using internal::IsTypeInRangeForNumericType;
- using internal::IsValueNegative;
- using SizeT = StrictNumeric<size_t>;
- template <typename Dst = int,
- typename Src,
- typename = std::enable_if_t<std::is_integral<Dst>::value &&
- std::is_floating_point<Src>::value>>
- Dst ClampFloor(Src value) {
- return saturated_cast<Dst>(std::floor(value));
- }
- template <typename Dst = int,
- typename Src,
- typename = std::enable_if_t<std::is_integral<Dst>::value &&
- std::is_floating_point<Src>::value>>
- Dst ClampCeil(Src value) {
- return saturated_cast<Dst>(std::ceil(value));
- }
- template <typename Dst = int,
- typename Src,
- typename = std::enable_if_t<std::is_integral<Dst>::value &&
- std::is_floating_point<Src>::value>>
- Dst ClampRound(Src value) {
- const Src rounded =
- (value >= 0.0f) ? std::floor(value + 0.5f) : std::ceil(value - 0.5f);
- return saturated_cast<Dst>(rounded);
- }
- }
- #endif
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