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#pragma once
#include <cmath>
#include <type_traits>
#include <Common/Exception.h>
#include <Common/NaNUtils.h>
#include <DataTypes/NumberTraits.h>
#include "clickhouse_config.h"
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_DIVISION;
}
template <typename A, typename B>
inline void throwIfDivisionLeadsToFPE(A a, B b)
{
/// Is it better to use siglongjmp instead of checks?
if (unlikely(b == 0))
throw Exception(ErrorCodes::ILLEGAL_DIVISION, "Division by zero");
/// http://avva.livejournal.com/2548306.html
if (unlikely(is_signed_v<A> && is_signed_v<B> && a == std::numeric_limits<A>::min() && b == -1))
throw Exception(ErrorCodes::ILLEGAL_DIVISION, "Division of minimal signed number by minus one");
}
template <typename A, typename B>
inline bool divisionLeadsToFPE(A a, B b)
{
if (unlikely(b == 0))
return true;
if (unlikely(is_signed_v<A> && is_signed_v<B> && a == std::numeric_limits<A>::min() && b == -1))
return true;
return false;
}
template <typename A, typename B>
inline auto checkedDivision(A a, B b)
{
throwIfDivisionLeadsToFPE(a, b);
if constexpr (is_big_int_v<A> && std::is_floating_point_v<B>)
return static_cast<B>(a) / b;
else if constexpr (is_big_int_v<B> && std::is_floating_point_v<A>)
return a / static_cast<A>(b);
else if constexpr (is_big_int_v<A> && is_big_int_v<B>)
return static_cast<A>(a / b);
else if constexpr (!is_big_int_v<A> && is_big_int_v<B>)
return static_cast<A>(B(a) / b);
else
return a / b;
}
template <typename A, typename B>
struct DivideIntegralImpl
{
using ResultType = typename NumberTraits::ResultOfIntegerDivision<A, B>::Type;
static const constexpr bool allow_fixed_string = false;
static const constexpr bool allow_string_integer = false;
template <typename Result = ResultType>
static inline Result apply(A a, B b)
{
using CastA = std::conditional_t<is_big_int_v<B> && std::is_same_v<A, UInt8>, uint8_t, A>;
using CastB = std::conditional_t<is_big_int_v<A> && std::is_same_v<B, UInt8>, uint8_t, B>;
/// Otherwise overflow may occur due to integer promotion. Example: int8_t(-1) / uint64_t(2).
/// NOTE: overflow is still possible when dividing large signed number to large unsigned number or vice-versa. But it's less harmful.
if constexpr (is_integer<A> && is_integer<B> && (is_signed_v<A> || is_signed_v<B>))
{
using SignedCastA = make_signed_t<CastA>;
using SignedCastB = std::conditional_t<sizeof(A) <= sizeof(B), make_signed_t<CastB>, SignedCastA>;
return static_cast<Result>(checkedDivision(static_cast<SignedCastA>(a), static_cast<SignedCastB>(b)));
}
else
{
/// Comparisons are not strict to avoid rounding issues when operand is implicitly casted to float.
if constexpr (std::is_floating_point_v<A>)
if (isNaN(a) || a >= std::numeric_limits<CastA>::max() || a <= std::numeric_limits<CastA>::lowest())
throw Exception(ErrorCodes::ILLEGAL_DIVISION, "Cannot perform integer division on infinite or too large floating point numbers");
if constexpr (std::is_floating_point_v<B>)
if (isNaN(b) || b >= std::numeric_limits<CastB>::max() || b <= std::numeric_limits<CastB>::lowest())
throw Exception(ErrorCodes::ILLEGAL_DIVISION, "Cannot perform integer division on infinite or too large floating point numbers");
auto res = checkedDivision(CastA(a), CastB(b));
if constexpr (std::is_floating_point_v<decltype(res)>)
if (isNaN(res) || res >= static_cast<double>(std::numeric_limits<Result>::max()) || res <= std::numeric_limits<Result>::lowest())
throw Exception(ErrorCodes::ILLEGAL_DIVISION, "Cannot perform integer division, because it will produce infinite or too large number");
return static_cast<Result>(res);
}
}
#if USE_EMBEDDED_COMPILER
static constexpr bool compilable = false; /// don't know how to throw from LLVM IR
#endif
};
template <typename A, typename B>
struct ModuloImpl
{
using ResultType = typename NumberTraits::ResultOfModulo<A, B>::Type;
using IntegerAType = typename NumberTraits::ToInteger<A>::Type;
using IntegerBType = typename NumberTraits::ToInteger<B>::Type;
static const constexpr bool allow_fixed_string = false;
static const constexpr bool allow_string_integer = false;
template <typename Result = ResultType>
static inline Result apply(A a, B b)
{
if constexpr (std::is_floating_point_v<ResultType>)
{
/// This computation is similar to `fmod` but the latter is not inlined and has 40 times worse performance.
return static_cast<ResultType>(a) - trunc(static_cast<ResultType>(a) / static_cast<ResultType>(b)) * static_cast<ResultType>(b);
}
else
{
if constexpr (std::is_floating_point_v<A>)
if (isNaN(a) || a > std::numeric_limits<IntegerAType>::max() || a < std::numeric_limits<IntegerAType>::lowest())
throw Exception(ErrorCodes::ILLEGAL_DIVISION, "Cannot perform integer division on infinite or too large floating point numbers");
if constexpr (std::is_floating_point_v<B>)
if (isNaN(b) || b > std::numeric_limits<IntegerBType>::max() || b < std::numeric_limits<IntegerBType>::lowest())
throw Exception(ErrorCodes::ILLEGAL_DIVISION, "Cannot perform integer division on infinite or too large floating point numbers");
throwIfDivisionLeadsToFPE(IntegerAType(a), IntegerBType(b));
if constexpr (is_big_int_v<IntegerAType> || is_big_int_v<IntegerBType>)
{
using CastA = std::conditional_t<std::is_same_v<IntegerAType, UInt8>, uint8_t, IntegerAType>;
using CastB = std::conditional_t<std::is_same_v<IntegerBType, UInt8>, uint8_t, IntegerBType>;
CastA int_a(a);
CastB int_b(b);
if constexpr (is_big_int_v<IntegerBType> && sizeof(IntegerAType) <= sizeof(IntegerBType))
return static_cast<Result>(static_cast<CastB>(int_a) % int_b);
else
return static_cast<Result>(int_a % static_cast<CastA>(int_b));
}
else
return static_cast<Result>(IntegerAType(a) % IntegerBType(b));
}
}
#if USE_EMBEDDED_COMPILER
static constexpr bool compilable = false; /// don't know how to throw from LLVM IR
#endif
};
template <typename A, typename B>
struct ModuloLegacyImpl : ModuloImpl<A, B>
{
using ResultType = typename NumberTraits::ResultOfModuloLegacy<A, B>::Type;
};
template <typename A, typename B>
struct PositiveModuloImpl : ModuloImpl<A, B>
{
using OriginResultType = typename ModuloImpl<A, B>::ResultType;
using ResultType = typename NumberTraits::ResultOfPositiveModulo<A, B>::Type;
template <typename Result = ResultType>
static inline Result apply(A a, B b)
{
auto res = ModuloImpl<A, B>::template apply<OriginResultType>(a, b);
if constexpr (is_signed_v<A>)
{
if (res < 0)
{
if constexpr (is_unsigned_v<B>)
res += static_cast<OriginResultType>(b);
else
{
if (b == std::numeric_limits<B>::lowest())
throw Exception(ErrorCodes::ILLEGAL_DIVISION, "Division by the most negative number");
res += b >= 0 ? static_cast<OriginResultType>(b) : static_cast<OriginResultType>(-b);
}
}
}
return static_cast<ResultType>(res);
}
};
}
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