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#pragma once
#include "typetraits.h"
#include "yexception.h"
#include <util/system/compat.h>
#include <util/system/type_name.h>
#include <util/system/unaligned_mem.h>
#include <util/system/yassert.h>
#include <cstdlib>
template <class T, class F>
static inline T VerifyDynamicCast(F f) {
if (!f) {
return nullptr;
}
T ret = dynamic_cast<T>(f);
Y_ABORT_UNLESS(ret, "verify cast failed");
return ret;
}
#if !defined(NDEBUG)
#define USE_DEBUG_CHECKED_CAST
#endif
namespace NPrivate {
template <typename T, typename F>
static T DynamicCast(F f) {
return dynamic_cast<T>(f);
}
}
/*
* replacement for dynamic_cast(dynamic_cast in debug mode, else static_cast)
*/
template <class T, class F>
static inline T CheckedCast(F f) {
#if defined(USE_DEBUG_CHECKED_CAST)
return VerifyDynamicCast<T>(f);
#else
/* Make sure F is polymorphic.
* Without this cast, CheckedCast with non-polymorphic F
* incorrectly compiled without error in release mode.
*/
{
auto&& x = &::NPrivate::DynamicCast<T, F>;
(void)x;
}
return static_cast<T>(f);
#endif // USE_DEBUG_CHECKED_CAST
}
/*
* be polite
*/
#undef USE_DEBUG_CHECKED_CAST
template <bool isUnsigned>
class TInteger;
template <>
class TInteger<true> {
public:
template <class TUnsigned>
static constexpr bool IsNegative(TUnsigned) noexcept {
return false;
}
};
template <>
class TInteger<false> {
public:
template <class TSigned>
static constexpr bool IsNegative(const TSigned value) noexcept {
return value < 0;
}
};
template <class TType>
constexpr bool IsNegative(const TType value) noexcept {
return TInteger<std::is_unsigned<TType>::value>::IsNegative(value);
}
namespace NPrivate {
template <class T>
using TUnderlyingTypeOrSelf = typename std::conditional<
std::is_enum<T>::value,
std::underlying_type<T>, // Lazy evaluatuion: do not call ::type here, because underlying_type<T> is undefined if T is not an enum.
std::enable_if<true, T> // Wrapping T in a class, that has member ::type typedef.
>::type::type; // Left ::type is for std::conditional, right ::type is for underlying_type/enable_if
template <class TSmall, class TLarge>
struct TSafelyConvertible {
using TSmallInt = TUnderlyingTypeOrSelf<TSmall>;
using TLargeInt = TUnderlyingTypeOrSelf<TLarge>;
static constexpr bool Result = std::is_integral<TSmallInt>::value && std::is_integral<TLargeInt>::value &&
((std::is_signed<TSmallInt>::value == std::is_signed<TLargeInt>::value && sizeof(TSmallInt) >= sizeof(TLargeInt)) ||
(std::is_signed<TSmallInt>::value && sizeof(TSmallInt) > sizeof(TLargeInt)));
};
}
template <class TSmallInt, class TLargeInt>
constexpr std::enable_if_t<::NPrivate::TSafelyConvertible<TSmallInt, TLargeInt>::Result, TSmallInt> SafeIntegerCast(TLargeInt largeInt) noexcept {
return static_cast<TSmallInt>(largeInt);
}
template <class TSmall, class TLarge>
inline std::enable_if_t<!::NPrivate::TSafelyConvertible<TSmall, TLarge>::Result, TSmall> SafeIntegerCast(TLarge largeInt) {
using TSmallInt = ::NPrivate::TUnderlyingTypeOrSelf<TSmall>;
using TLargeInt = ::NPrivate::TUnderlyingTypeOrSelf<TLarge>;
if (std::is_unsigned<TSmallInt>::value && std::is_signed<TLargeInt>::value) {
if (IsNegative(largeInt)) {
ythrow TBadCastException() << "Conversion '" << TypeName<TLarge>() << '{' << TLargeInt(largeInt) << "}' to '"
<< TypeName<TSmallInt>()
<< "', negative value converted to unsigned";
}
}
TSmallInt smallInt = TSmallInt(largeInt);
if (std::is_signed<TSmallInt>::value && std::is_unsigned<TLargeInt>::value) {
if (IsNegative(smallInt)) {
ythrow TBadCastException() << "Conversion '" << TypeName<TLarge>() << '{' << TLargeInt(largeInt) << "}' to '"
<< TypeName<TSmallInt>()
<< "', positive value converted to negative";
}
}
if (TLargeInt(smallInt) != largeInt) {
ythrow TBadCastException() << "Conversion '" << TypeName<TLarge>() << '{' << TLargeInt(largeInt) << "}' to '"
<< TypeName<TSmallInt>() << "', loss of data";
}
return static_cast<TSmall>(smallInt);
}
template <class TSmallInt, class TLargeInt>
inline TSmallInt IntegerCast(TLargeInt largeInt) noexcept {
try {
return SafeIntegerCast<TSmallInt>(largeInt);
} catch (const yexception& exc) {
Y_FAIL("IntegerCast: %s", exc.what());
}
}
/* Convert given enum value to its underlying type. This is just a shortcut for
* `static_cast<std::underlying_type_t<EEnum>>(enum_)`.
*/
template <typename T>
constexpr std::underlying_type_t<T> ToUnderlying(const T enum_) noexcept {
return static_cast<std::underlying_type_t<T>>(enum_);
}
// std::bit_cast from c++20
template <class TTarget, class TSource>
TTarget BitCast(const TSource& source) {
static_assert(sizeof(TSource) == sizeof(TTarget), "Size mismatch");
static_assert(std::is_trivially_copyable<TSource>::value, "TSource is not trivially copyable");
static_assert(std::is_trivial<TTarget>::value, "TTarget is not trivial");
// Support volatile qualifiers.
// ReadUnaligned does not work with volatile pointers, so cast away
// volatileness beforehand.
using TNonvolatileSource = std::remove_volatile_t<TSource>;
using TNonvolatileTarget = std::remove_volatile_t<TTarget>;
return ReadUnaligned<TNonvolatileTarget>(&const_cast<const TNonvolatileSource&>(source));
}
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