// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
// Object model for scalar (non-Array) values. Not intended for use with large
// amounts of data
#pragma once
#include <iosfwd>
#include <memory>
#include <ratio>
#include <string>
#include <string_view>
#include <utility>
#include <vector>
#include "arrow/compare.h"
#include "arrow/extension_type.h"
#include "arrow/result.h"
#include "arrow/status.h"
#include "arrow/type.h"
#include "arrow/type_fwd.h"
#include "arrow/type_traits.h"
#include "arrow/util/compare.h"
#include "arrow/util/decimal.h"
#include "arrow/util/visibility.h"
#include "arrow/visit_type_inline.h"
namespace arrow {
class Array;
/// \brief Base class for scalar values
///
/// A Scalar represents a single value with a specific DataType.
/// Scalars are useful for passing single value inputs to compute functions,
/// or for representing individual array elements (with a non-trivial
/// wrapping cost, though).
struct ARROW_EXPORT Scalar : public std::enable_shared_from_this<Scalar>,
public util::EqualityComparable<Scalar> {
virtual ~Scalar() = default;
/// \brief The type of the scalar value
std::shared_ptr<DataType> type;
/// \brief Whether the value is valid (not null) or not
bool is_valid = false;
bool Equals(const Scalar& other,
const EqualOptions& options = EqualOptions::Defaults()) const;
bool ApproxEquals(const Scalar& other,
const EqualOptions& options = EqualOptions::Defaults()) const;
struct ARROW_EXPORT Hash {
size_t operator()(const Scalar& scalar) const { return scalar.hash(); }
size_t operator()(const std::shared_ptr<Scalar>& scalar) const {
return scalar->hash();
}
};
size_t hash() const;
std::string ToString() const;
/// \brief Perform cheap validation checks
///
/// This is O(k) where k is the number of descendents.
///
/// \return Status
Status Validate() const;
/// \brief Perform extensive data validation checks
///
/// This is potentially O(k*n) where k is the number of descendents and n
/// is the length of descendents (if list scalars are involved).
///
/// \return Status
Status ValidateFull() const;
static Result<std::shared_ptr<Scalar>> Parse(const std::shared_ptr<DataType>& type,
std::string_view repr);
// TODO(bkietz) add compute::CastOptions
Result<std::shared_ptr<Scalar>> CastTo(std::shared_ptr<DataType> to) const;
/// \brief Apply the ScalarVisitor::Visit() method specialized to the scalar type
Status Accept(ScalarVisitor* visitor) const;
/// \brief EXPERIMENTAL Enable obtaining shared_ptr<Scalar> from a const
/// Scalar& context.
std::shared_ptr<Scalar> GetSharedPtr() const {
return const_cast<Scalar*>(this)->shared_from_this();
}
protected:
Scalar(std::shared_ptr<DataType> type, bool is_valid)
: type(std::move(type)), is_valid(is_valid) {}
};
ARROW_EXPORT void PrintTo(const Scalar& scalar, std::ostream* os);
/// \defgroup concrete-scalar-classes Concrete Scalar subclasses
///
/// @{
/// \brief A scalar value for NullType. Never valid
struct ARROW_EXPORT NullScalar : public Scalar {
public:
using TypeClass = NullType;
NullScalar() : Scalar{null(), false} {}
};
/// @}
namespace internal {
constexpr auto kScalarScratchSpaceSize = sizeof(int64_t) * 2;
template <typename Impl>
struct ArraySpanFillFromScalarScratchSpace {
// 16 bytes of scratch space to enable ArraySpan to be a view onto any
// Scalar- including binary scalars where we need to create a buffer
// that looks like two 32-bit or 64-bit offsets.
alignas(int64_t) mutable uint8_t scratch_space_[kScalarScratchSpaceSize];
private:
template <typename... Args>
explicit ArraySpanFillFromScalarScratchSpace(Args&&... args) {
Impl::FillScratchSpace(scratch_space_, std::forward<Args>(args)...);
}
ArraySpanFillFromScalarScratchSpace() = delete;
friend Impl;
};
struct ARROW_EXPORT PrimitiveScalarBase : public Scalar {
explicit PrimitiveScalarBase(std::shared_ptr<DataType> type)
: Scalar(std::move(type), false) {}
using Scalar::Scalar;
/// \brief Get a const pointer to the value of this scalar. May be null.
virtual const void* data() const = 0;
/// \brief Get an immutable view of the value of this scalar as bytes.
virtual std::string_view view() const = 0;
};
template <typename T, typename CType = typename T::c_type>
struct PrimitiveScalar : public PrimitiveScalarBase {
using PrimitiveScalarBase::PrimitiveScalarBase;
using TypeClass = T;
using ValueType = CType;
// Non-null constructor.
PrimitiveScalar(ValueType value, std::shared_ptr<DataType> type)
: PrimitiveScalarBase(std::move(type), true), value(value) {}
explicit PrimitiveScalar(std::shared_ptr<DataType> type)
: PrimitiveScalarBase(std::move(type), false) {}
ValueType value{};
const void* data() const override { return &value; }
std::string_view view() const override {
return std::string_view(reinterpret_cast<const char*>(&value), sizeof(ValueType));
};
};
} // namespace internal
/// \addtogroup concrete-scalar-classes Concrete Scalar subclasses
///
/// @{
struct ARROW_EXPORT BooleanScalar : public internal::PrimitiveScalar<BooleanType, bool> {
using Base = internal::PrimitiveScalar<BooleanType, bool>;
using Base::Base;
explicit BooleanScalar(bool value) : Base(value, boolean()) {}
BooleanScalar() : Base(boolean()) {}
};
template <typename T>
struct NumericScalar : public internal::PrimitiveScalar<T> {
using Base = typename internal::PrimitiveScalar<T>;
using Base::Base;
using TypeClass = typename Base::TypeClass;
using ValueType = typename Base::ValueType;
explicit NumericScalar(ValueType value)
: Base(value, TypeTraits<T>::type_singleton()) {}
NumericScalar() : Base(TypeTraits<T>::type_singleton()) {}
};
struct ARROW_EXPORT Int8Scalar : public NumericScalar<Int8Type> {
using NumericScalar<Int8Type>::NumericScalar;
};
struct ARROW_EXPORT Int16Scalar : public NumericScalar<Int16Type> {
using NumericScalar<Int16Type>::NumericScalar;
};
struct ARROW_EXPORT Int32Scalar : public NumericScalar<Int32Type> {
using NumericScalar<Int32Type>::NumericScalar;
};
struct ARROW_EXPORT Int64Scalar : public NumericScalar<Int64Type> {
using NumericScalar<Int64Type>::NumericScalar;
};
struct ARROW_EXPORT UInt8Scalar : public NumericScalar<UInt8Type> {
using NumericScalar<UInt8Type>::NumericScalar;
};
struct ARROW_EXPORT UInt16Scalar : public NumericScalar<UInt16Type> {
using NumericScalar<UInt16Type>::NumericScalar;
};
struct ARROW_EXPORT UInt32Scalar : public NumericScalar<UInt32Type> {
using NumericScalar<UInt32Type>::NumericScalar;
};
struct ARROW_EXPORT UInt64Scalar : public NumericScalar<UInt64Type> {
using NumericScalar<UInt64Type>::NumericScalar;
};
struct ARROW_EXPORT HalfFloatScalar : public NumericScalar<HalfFloatType> {
using NumericScalar<HalfFloatType>::NumericScalar;
};
struct ARROW_EXPORT FloatScalar : public NumericScalar<FloatType> {
using NumericScalar<FloatType>::NumericScalar;
};
struct ARROW_EXPORT DoubleScalar : public NumericScalar<DoubleType> {
using NumericScalar<DoubleType>::NumericScalar;
};
struct ARROW_EXPORT BaseBinaryScalar : public internal::PrimitiveScalarBase {
using ValueType = std::shared_ptr<Buffer>;
// The value is not supposed to be modified after construction, because subclasses have
// a scratch space whose content need to be kept consistent with the value. It is also
// the user of this class's responsibility to ensure that the buffer is not written to
// accidentally.
const std::shared_ptr<Buffer> value = NULLPTR;
const void* data() const override {
return value ? reinterpret_cast<const void*>(value->data()) : NULLPTR;
}
std::string_view view() const override {
return value ? std::string_view(*value) : std::string_view();
}
explicit BaseBinaryScalar(std::shared_ptr<DataType> type)
: internal::PrimitiveScalarBase(std::move(type)) {}
BaseBinaryScalar(std::shared_ptr<Buffer> value, std::shared_ptr<DataType> type)
: internal::PrimitiveScalarBase{std::move(type), true}, value(std::move(value)) {}
BaseBinaryScalar(std::string s, std::shared_ptr<DataType> type);
};
struct ARROW_EXPORT BinaryScalar
: public BaseBinaryScalar,
private internal::ArraySpanFillFromScalarScratchSpace<BinaryScalar> {
using TypeClass = BinaryType;
using ArraySpanFillFromScalarScratchSpace =
internal::ArraySpanFillFromScalarScratchSpace<BinaryScalar>;
explicit BinaryScalar(std::shared_ptr<DataType> type)
: BaseBinaryScalar(std::move(type)),
ArraySpanFillFromScalarScratchSpace(this->value) {}
BinaryScalar(std::shared_ptr<Buffer> value, std::shared_ptr<DataType> type)
: BaseBinaryScalar(std::move(value), std::move(type)),
ArraySpanFillFromScalarScratchSpace(this->value) {}
BinaryScalar(std::string s, std::shared_ptr<DataType> type)
: BaseBinaryScalar(std::move(s), std::move(type)),
ArraySpanFillFromScalarScratchSpace(this->value) {}
explicit BinaryScalar(std::shared_ptr<Buffer> value)
: BinaryScalar(std::move(value), binary()) {}
explicit BinaryScalar(std::string s) : BinaryScalar(std::move(s), binary()) {}
BinaryScalar() : BinaryScalar(binary()) {}
private:
static void FillScratchSpace(uint8_t* scratch_space,
const std::shared_ptr<Buffer>& value);
friend ArraySpan;
friend ArraySpanFillFromScalarScratchSpace;
};
struct ARROW_EXPORT StringScalar : public BinaryScalar {
using BinaryScalar::BinaryScalar;
using TypeClass = StringType;
explicit StringScalar(std::shared_ptr<Buffer> value)
: StringScalar(std::move(value), utf8()) {}
explicit StringScalar(std::string s) : BinaryScalar(std::move(s), utf8()) {}
StringScalar() : StringScalar(utf8()) {}
};
struct ARROW_EXPORT BinaryViewScalar
: public BaseBinaryScalar,
private internal::ArraySpanFillFromScalarScratchSpace<BinaryViewScalar> {
using TypeClass = BinaryViewType;
using ArraySpanFillFromScalarScratchSpace =
internal::ArraySpanFillFromScalarScratchSpace<BinaryViewScalar>;
explicit BinaryViewScalar(std::shared_ptr<DataType> type)
: BaseBinaryScalar(std::move(type)),
ArraySpanFillFromScalarScratchSpace(this->value) {}
BinaryViewScalar(std::shared_ptr<Buffer> value, std::shared_ptr<DataType> type)
: BaseBinaryScalar(std::move(value), std::move(type)),
ArraySpanFillFromScalarScratchSpace(this->value) {}
BinaryViewScalar(std::string s, std::shared_ptr<DataType> type)
: BaseBinaryScalar(std::move(s), std::move(type)),
ArraySpanFillFromScalarScratchSpace(this->value) {}
explicit BinaryViewScalar(std::shared_ptr<Buffer> value)
: BinaryViewScalar(std::move(value), binary_view()) {}
explicit BinaryViewScalar(std::string s)
: BinaryViewScalar(std::move(s), binary_view()) {}
BinaryViewScalar() : BinaryViewScalar(binary_view()) {}
std::string_view view() const override { return std::string_view(*this->value); }
private:
static void FillScratchSpace(uint8_t* scratch_space,
const std::shared_ptr<Buffer>& value);
friend ArraySpan;
friend ArraySpanFillFromScalarScratchSpace;
};
struct ARROW_EXPORT StringViewScalar : public BinaryViewScalar {
using BinaryViewScalar::BinaryViewScalar;
using TypeClass = StringViewType;
explicit StringViewScalar(std::shared_ptr<Buffer> value)
: StringViewScalar(std::move(value), utf8_view()) {}
explicit StringViewScalar(std::string s)
: BinaryViewScalar(std::move(s), utf8_view()) {}
StringViewScalar() : StringViewScalar(utf8_view()) {}
};
struct ARROW_EXPORT LargeBinaryScalar
: public BaseBinaryScalar,
private internal::ArraySpanFillFromScalarScratchSpace<LargeBinaryScalar> {
using TypeClass = LargeBinaryType;
using ArraySpanFillFromScalarScratchSpace =
internal::ArraySpanFillFromScalarScratchSpace<LargeBinaryScalar>;
explicit LargeBinaryScalar(std::shared_ptr<DataType> type)
: BaseBinaryScalar(std::move(type)),
ArraySpanFillFromScalarScratchSpace(this->value) {}
LargeBinaryScalar(std::shared_ptr<Buffer> value, std::shared_ptr<DataType> type)
: BaseBinaryScalar(std::move(value), std::move(type)),
ArraySpanFillFromScalarScratchSpace(this->value) {}
LargeBinaryScalar(std::string s, std::shared_ptr<DataType> type)
: BaseBinaryScalar(std::move(s), std::move(type)),
ArraySpanFillFromScalarScratchSpace(this->value) {}
explicit LargeBinaryScalar(std::shared_ptr<Buffer> value)
: LargeBinaryScalar(std::move(value), large_binary()) {}
explicit LargeBinaryScalar(std::string s)
: LargeBinaryScalar(std::move(s), large_binary()) {}
LargeBinaryScalar() : LargeBinaryScalar(large_binary()) {}
private:
static void FillScratchSpace(uint8_t* scratch_space,
const std::shared_ptr<Buffer>& value);
friend ArraySpan;
friend ArraySpanFillFromScalarScratchSpace;
};
struct ARROW_EXPORT LargeStringScalar : public LargeBinaryScalar {
using LargeBinaryScalar::LargeBinaryScalar;
using TypeClass = LargeStringType;
explicit LargeStringScalar(std::shared_ptr<Buffer> value)
: LargeStringScalar(std::move(value), large_utf8()) {}
explicit LargeStringScalar(std::string s)
: LargeBinaryScalar(std::move(s), large_utf8()) {}
LargeStringScalar() : LargeStringScalar(large_utf8()) {}
};
struct ARROW_EXPORT FixedSizeBinaryScalar : public BinaryScalar {
using TypeClass = FixedSizeBinaryType;
FixedSizeBinaryScalar(std::shared_ptr<Buffer> value, std::shared_ptr<DataType> type,
bool is_valid = true);
explicit FixedSizeBinaryScalar(const std::shared_ptr<Buffer>& value,
bool is_valid = true);
explicit FixedSizeBinaryScalar(std::string s, bool is_valid = true);
};
template <typename T>
struct TemporalScalar : internal::PrimitiveScalar<T> {
using internal::PrimitiveScalar<T>::PrimitiveScalar;
using ValueType = typename internal::PrimitiveScalar<T>::ValueType;
TemporalScalar(ValueType value, std::shared_ptr<DataType> type)
: internal::PrimitiveScalar<T>(std::move(value), type) {}
};
template <typename T>
struct DateScalar : public TemporalScalar<T> {
using TemporalScalar<T>::TemporalScalar;
using ValueType = typename TemporalScalar<T>::ValueType;
explicit DateScalar(ValueType value)
: TemporalScalar<T>(std::move(value), TypeTraits<T>::type_singleton()) {}
DateScalar() : TemporalScalar<T>(TypeTraits<T>::type_singleton()) {}
};
struct ARROW_EXPORT Date32Scalar : public DateScalar<Date32Type> {
using DateScalar<Date32Type>::DateScalar;
};
struct ARROW_EXPORT Date64Scalar : public DateScalar<Date64Type> {
using DateScalar<Date64Type>::DateScalar;
};
template <typename T>
struct TimeScalar : public TemporalScalar<T> {
using TemporalScalar<T>::TemporalScalar;
TimeScalar(typename TemporalScalar<T>::ValueType value, TimeUnit::type unit)
: TimeScalar(std::move(value), std::make_shared<T>(unit)) {}
};
struct ARROW_EXPORT Time32Scalar : public TimeScalar<Time32Type> {
using TimeScalar<Time32Type>::TimeScalar;
};
struct ARROW_EXPORT Time64Scalar : public TimeScalar<Time64Type> {
using TimeScalar<Time64Type>::TimeScalar;
};
struct ARROW_EXPORT TimestampScalar : public TemporalScalar<TimestampType> {
using TemporalScalar<TimestampType>::TemporalScalar;
TimestampScalar(typename TemporalScalar<TimestampType>::ValueType value,
TimeUnit::type unit, std::string tz = "")
: TimestampScalar(std::move(value), timestamp(unit, std::move(tz))) {}
static Result<TimestampScalar> FromISO8601(std::string_view iso8601,
TimeUnit::type unit);
};
template <typename T>
struct IntervalScalar : public TemporalScalar<T> {
using TemporalScalar<T>::TemporalScalar;
using ValueType = typename TemporalScalar<T>::ValueType;
explicit IntervalScalar(ValueType value)
: TemporalScalar<T>(value, TypeTraits<T>::type_singleton()) {}
IntervalScalar() : TemporalScalar<T>(TypeTraits<T>::type_singleton()) {}
};
struct ARROW_EXPORT MonthIntervalScalar : public IntervalScalar<MonthIntervalType> {
using IntervalScalar<MonthIntervalType>::IntervalScalar;
};
struct ARROW_EXPORT DayTimeIntervalScalar : public IntervalScalar<DayTimeIntervalType> {
using IntervalScalar<DayTimeIntervalType>::IntervalScalar;
};
struct ARROW_EXPORT MonthDayNanoIntervalScalar
: public IntervalScalar<MonthDayNanoIntervalType> {
using IntervalScalar<MonthDayNanoIntervalType>::IntervalScalar;
};
struct ARROW_EXPORT DurationScalar : public TemporalScalar<DurationType> {
using TemporalScalar<DurationType>::TemporalScalar;
DurationScalar(typename TemporalScalar<DurationType>::ValueType value,
TimeUnit::type unit)
: DurationScalar(std::move(value), duration(unit)) {}
// Convenience constructors for a DurationScalar from std::chrono::nanoseconds
template <template <typename, typename> class StdDuration, typename Rep>
explicit DurationScalar(StdDuration<Rep, std::nano> d)
: DurationScalar{DurationScalar(d.count(), duration(TimeUnit::NANO))} {}
// Convenience constructors for a DurationScalar from std::chrono::microseconds
template <template <typename, typename> class StdDuration, typename Rep>
explicit DurationScalar(StdDuration<Rep, std::micro> d)
: DurationScalar{DurationScalar(d.count(), duration(TimeUnit::MICRO))} {}
// Convenience constructors for a DurationScalar from std::chrono::milliseconds
template <template <typename, typename> class StdDuration, typename Rep>
explicit DurationScalar(StdDuration<Rep, std::milli> d)
: DurationScalar{DurationScalar(d.count(), duration(TimeUnit::MILLI))} {}
// Convenience constructors for a DurationScalar from std::chrono::seconds
// or from units which are whole numbers of seconds
template <template <typename, typename> class StdDuration, typename Rep, intmax_t Num>
explicit DurationScalar(StdDuration<Rep, std::ratio<Num, 1>> d)
: DurationScalar{DurationScalar(d.count() * Num, duration(TimeUnit::SECOND))} {}
};
template <typename TYPE_CLASS, typename VALUE_TYPE>
struct DecimalScalar : public internal::PrimitiveScalarBase {
using internal::PrimitiveScalarBase::PrimitiveScalarBase;
using TypeClass = TYPE_CLASS;
using ValueType = VALUE_TYPE;
DecimalScalar(ValueType value, std::shared_ptr<DataType> type)
: internal::PrimitiveScalarBase(std::move(type), true), value(value) {}
const void* data() const override {
return reinterpret_cast<const void*>(value.native_endian_bytes());
}
std::string_view view() const override {
return std::string_view(reinterpret_cast<const char*>(value.native_endian_bytes()),
ValueType::kByteWidth);
}
ValueType value;
};
struct ARROW_EXPORT Decimal32Scalar : public DecimalScalar<Decimal32Type, Decimal32> {
using DecimalScalar::DecimalScalar;
};
struct ARROW_EXPORT Decimal64Scalar : public DecimalScalar<Decimal64Type, Decimal64> {
using DecimalScalar::DecimalScalar;
};
struct ARROW_EXPORT Decimal128Scalar : public DecimalScalar<Decimal128Type, Decimal128> {
using DecimalScalar::DecimalScalar;
};
struct ARROW_EXPORT Decimal256Scalar : public DecimalScalar<Decimal256Type, Decimal256> {
using DecimalScalar::DecimalScalar;
};
struct ARROW_EXPORT BaseListScalar : public Scalar {
using ValueType = std::shared_ptr<Array>;
BaseListScalar(std::shared_ptr<Array> value, std::shared_ptr<DataType> type,
bool is_valid = true);
// The value is not supposed to be modified after construction, because subclasses have
// a scratch space whose content need to be kept consistent with the value. It is also
// the user of this class's responsibility to ensure that the array is not modified
// accidentally.
const std::shared_ptr<Array> value;
};
struct ARROW_EXPORT ListScalar
: public BaseListScalar,
private internal::ArraySpanFillFromScalarScratchSpace<ListScalar> {
using TypeClass = ListType;
using ArraySpanFillFromScalarScratchSpace =
internal::ArraySpanFillFromScalarScratchSpace<ListScalar>;
ListScalar(std::shared_ptr<Array> value, std::shared_ptr<DataType> type,
bool is_valid = true)
: BaseListScalar(std::move(value), std::move(type), is_valid),
ArraySpanFillFromScalarScratchSpace(this->value) {}
explicit ListScalar(std::shared_ptr<Array> value, bool is_valid = true);
private:
static void FillScratchSpace(uint8_t* scratch_space,
const std::shared_ptr<Array>& value);
friend ArraySpan;
friend ArraySpanFillFromScalarScratchSpace;
};
struct ARROW_EXPORT LargeListScalar
: public BaseListScalar,
private internal::ArraySpanFillFromScalarScratchSpace<LargeListScalar> {
using TypeClass = LargeListType;
using ArraySpanFillFromScalarScratchSpace =
internal::ArraySpanFillFromScalarScratchSpace<LargeListScalar>;
LargeListScalar(std::shared_ptr<Array> value, std::shared_ptr<DataType> type,
bool is_valid = true)
: BaseListScalar(std::move(value), std::move(type), is_valid),
ArraySpanFillFromScalarScratchSpace(this->value) {}
explicit LargeListScalar(std::shared_ptr<Array> value, bool is_valid = true);
private:
static void FillScratchSpace(uint8_t* scratch_space,
const std::shared_ptr<Array>& value);
friend ArraySpan;
friend ArraySpanFillFromScalarScratchSpace;
};
struct ARROW_EXPORT ListViewScalar
: public BaseListScalar,
private internal::ArraySpanFillFromScalarScratchSpace<ListViewScalar> {
using TypeClass = ListViewType;
using ArraySpanFillFromScalarScratchSpace =
internal::ArraySpanFillFromScalarScratchSpace<ListViewScalar>;
ListViewScalar(std::shared_ptr<Array> value, std::shared_ptr<DataType> type,
bool is_valid = true)
: BaseListScalar(std::move(value), std::move(type), is_valid),
ArraySpanFillFromScalarScratchSpace(this->value) {}
explicit ListViewScalar(std::shared_ptr<Array> value, bool is_valid = true);
private:
static void FillScratchSpace(uint8_t* scratch_space,
const std::shared_ptr<Array>& value);
friend ArraySpan;
friend ArraySpanFillFromScalarScratchSpace;
};
struct ARROW_EXPORT LargeListViewScalar
: public BaseListScalar,
private internal::ArraySpanFillFromScalarScratchSpace<LargeListViewScalar> {
using TypeClass = LargeListViewType;
using ArraySpanFillFromScalarScratchSpace =
internal::ArraySpanFillFromScalarScratchSpace<LargeListViewScalar>;
LargeListViewScalar(std::shared_ptr<Array> value, std::shared_ptr<DataType> type,
bool is_valid = true)
: BaseListScalar(std::move(value), std::move(type), is_valid),
ArraySpanFillFromScalarScratchSpace(this->value) {}
explicit LargeListViewScalar(std::shared_ptr<Array> value, bool is_valid = true);
private:
static void FillScratchSpace(uint8_t* scratch_space,
const std::shared_ptr<Array>& value);
friend ArraySpan;
friend ArraySpanFillFromScalarScratchSpace;
};
struct ARROW_EXPORT MapScalar
: public BaseListScalar,
private internal::ArraySpanFillFromScalarScratchSpace<MapScalar> {
using TypeClass = MapType;
using ArraySpanFillFromScalarScratchSpace =
internal::ArraySpanFillFromScalarScratchSpace<MapScalar>;
MapScalar(std::shared_ptr<Array> value, std::shared_ptr<DataType> type,
bool is_valid = true)
: BaseListScalar(std::move(value), std::move(type), is_valid),
ArraySpanFillFromScalarScratchSpace(this->value) {}
explicit MapScalar(std::shared_ptr<Array> value, bool is_valid = true);
private:
static void FillScratchSpace(uint8_t* scratch_space,
const std::shared_ptr<Array>& value);
friend ArraySpan;
friend ArraySpanFillFromScalarScratchSpace;
};
struct ARROW_EXPORT FixedSizeListScalar : public BaseListScalar {
using TypeClass = FixedSizeListType;
FixedSizeListScalar(std::shared_ptr<Array> value, std::shared_ptr<DataType> type,
bool is_valid = true);
explicit FixedSizeListScalar(std::shared_ptr<Array> value, bool is_valid = true);
};
struct ARROW_EXPORT StructScalar : public Scalar {
using TypeClass = StructType;
using ValueType = std::vector<std::shared_ptr<Scalar>>;
ScalarVector value;
Result<std::shared_ptr<Scalar>> field(FieldRef ref) const;
StructScalar(ValueType value, std::shared_ptr<DataType> type, bool is_valid = true)
: Scalar(std::move(type), is_valid), value(std::move(value)) {}
static Result<std::shared_ptr<StructScalar>> Make(ValueType value,
std::vector<std::string> field_names);
};
struct ARROW_EXPORT UnionScalar : public Scalar {
// The type code is not supposed to be modified after construction, because the scratch
// space's content need to be kept consistent with it.
const int8_t type_code;
virtual const std::shared_ptr<Scalar>& child_value() const = 0;
protected:
UnionScalar(std::shared_ptr<DataType> type, int8_t type_code, bool is_valid)
: Scalar(std::move(type), is_valid), type_code(type_code) {}
struct UnionScratchSpace {
alignas(int64_t) int8_t type_code;
alignas(int64_t) uint8_t offsets[sizeof(int32_t) * 2];
};
static_assert(sizeof(UnionScratchSpace) <= internal::kScalarScratchSpaceSize);
friend ArraySpan;
};
struct ARROW_EXPORT SparseUnionScalar
: public UnionScalar,
private internal::ArraySpanFillFromScalarScratchSpace<SparseUnionScalar> {
using TypeClass = SparseUnionType;
using ArraySpanFillFromScalarScratchSpace =
internal::ArraySpanFillFromScalarScratchSpace<SparseUnionScalar>;
// Even though only one of the union values is relevant for this scalar, we
// nonetheless construct a vector of scalars, one per union value, to have
// enough data to reconstruct a valid ArraySpan of length 1 from this scalar
using ValueType = std::vector<std::shared_ptr<Scalar>>;
// The value is not supposed to be modified after construction, because the scratch
// space's content need to be kept consistent with the value. It is also the user of
// this class's responsibility to ensure that the scalars of the vector is not modified
// to accidentally.
const ValueType value;
// The value index corresponding to the active type code
int child_id;
SparseUnionScalar(ValueType value, int8_t type_code, std::shared_ptr<DataType> type);
const std::shared_ptr<Scalar>& child_value() const override {
return this->value[this->child_id];
}
/// \brief Construct a SparseUnionScalar from a single value, versus having
/// to construct a vector of scalars
static std::shared_ptr<Scalar> FromValue(std::shared_ptr<Scalar> value, int field_index,
std::shared_ptr<DataType> type);
private:
static void FillScratchSpace(uint8_t* scratch_space, int8_t type_code);
friend ArraySpan;
friend ArraySpanFillFromScalarScratchSpace;
};
struct ARROW_EXPORT DenseUnionScalar
: public UnionScalar,
private internal::ArraySpanFillFromScalarScratchSpace<DenseUnionScalar> {
using TypeClass = DenseUnionType;
using ArraySpanFillFromScalarScratchSpace =
internal::ArraySpanFillFromScalarScratchSpace<DenseUnionScalar>;
// For DenseUnionScalar, we can make a valid ArraySpan of length 1 from this
// scalar
using ValueType = std::shared_ptr<Scalar>;
// The value is not supposed to be modified after construction, because the scratch
// space's content need to be kept consistent with the value. It is also the user of
// this class's responsibility to ensure that the elements of the vector is not modified
// accidentally.
const ValueType value;
const std::shared_ptr<Scalar>& child_value() const override { return this->value; }
DenseUnionScalar(ValueType value, int8_t type_code, std::shared_ptr<DataType> type)
: UnionScalar(std::move(type), type_code, value->is_valid),
ArraySpanFillFromScalarScratchSpace(type_code),
value(std::move(value)) {}
private:
static void FillScratchSpace(uint8_t* scratch_space, int8_t type_code);
friend ArraySpan;
friend ArraySpanFillFromScalarScratchSpace;
};
struct ARROW_EXPORT RunEndEncodedScalar
: public Scalar,
private internal::ArraySpanFillFromScalarScratchSpace<RunEndEncodedScalar> {
using TypeClass = RunEndEncodedType;
using ValueType = std::shared_ptr<Scalar>;
using ArraySpanFillFromScalarScratchSpace =
internal::ArraySpanFillFromScalarScratchSpace<RunEndEncodedScalar>;
// The value is not supposed to be modified after construction, because the scratch
// space's content need to be kept consistent with the value. It is also the user of
// this class's responsibility to ensure that the wrapped scalar is not modified
// accidentally.
const ValueType value;
RunEndEncodedScalar(std::shared_ptr<Scalar> value, std::shared_ptr<DataType> type);
/// \brief Constructs a NULL RunEndEncodedScalar
explicit RunEndEncodedScalar(const std::shared_ptr<DataType>& type);
~RunEndEncodedScalar() override;
const std::shared_ptr<DataType>& run_end_type() const {
return ree_type().run_end_type();
}
const std::shared_ptr<DataType>& value_type() const { return ree_type().value_type(); }
private:
const TypeClass& ree_type() const { return internal::checked_cast<TypeClass&>(*type); }
static void FillScratchSpace(uint8_t* scratch_space, const DataType& type);
friend ArraySpan;
friend ArraySpanFillFromScalarScratchSpace;
};
/// \brief A Scalar value for DictionaryType
///
/// `is_valid` denotes the validity of the `index`, regardless of
/// the corresponding value in the `dictionary`.
struct ARROW_EXPORT DictionaryScalar : public internal::PrimitiveScalarBase {
using TypeClass = DictionaryType;
struct ValueType {
std::shared_ptr<Scalar> index;
std::shared_ptr<Array> dictionary;
} value;
explicit DictionaryScalar(std::shared_ptr<DataType> type);
DictionaryScalar(ValueType value, std::shared_ptr<DataType> type, bool is_valid = true)
: internal::PrimitiveScalarBase(std::move(type), is_valid),
value(std::move(value)) {}
static std::shared_ptr<DictionaryScalar> Make(std::shared_ptr<Scalar> index,
std::shared_ptr<Array> dict);
Result<std::shared_ptr<Scalar>> GetEncodedValue() const;
const void* data() const override {
return internal::checked_cast<internal::PrimitiveScalarBase&>(*value.index).data();
}
std::string_view view() const override {
return internal::checked_cast<const internal::PrimitiveScalarBase&>(*value.index)
.view();
}
};
/// \brief A Scalar value for ExtensionType
///
/// The value is the underlying storage scalar.
/// `is_valid` must only be true if `value` is non-null and `value->is_valid` is true
struct ARROW_EXPORT ExtensionScalar : public Scalar {
using TypeClass = ExtensionType;
using ValueType = std::shared_ptr<Scalar>;
ExtensionScalar(std::shared_ptr<Scalar> storage, std::shared_ptr<DataType> type,
bool is_valid = true)
: Scalar(std::move(type), is_valid), value(std::move(storage)) {}
template <typename Storage,
typename = enable_if_t<std::is_base_of<Scalar, Storage>::value>>
ExtensionScalar(Storage&& storage, std::shared_ptr<DataType> type, bool is_valid = true)
: ExtensionScalar(std::make_shared<Storage>(std::move(storage)), std::move(type),
is_valid) {}
std::shared_ptr<Scalar> value;
};
/// @}
namespace internal {
inline Status CheckBufferLength(...) { return Status::OK(); }
ARROW_EXPORT Status CheckBufferLength(const FixedSizeBinaryType* t,
const std::shared_ptr<Buffer>* b);
} // namespace internal
template <typename ValueRef>
struct MakeScalarImpl;
/// \defgroup scalar-factories Scalar factory functions
///
/// @{
/// \brief Scalar factory for null scalars
ARROW_EXPORT
std::shared_ptr<Scalar> MakeNullScalar(std::shared_ptr<DataType> type);
/// \brief Scalar factory for non-null scalars
template <typename Value>
Result<std::shared_ptr<Scalar>> MakeScalar(std::shared_ptr<DataType> type,
Value&& value) {
return MakeScalarImpl<Value&&>{type, std::forward<Value>(value), NULLPTR}.Finish();
}
/// \brief Type-inferring scalar factory for non-null scalars
///
/// Construct a Scalar instance with a DataType determined by the input C++ type.
/// (for example Int8Scalar for a int8_t input).
/// Only non-parametric primitive types and String are supported.
template <typename Value, typename Traits = CTypeTraits<typename std::decay<Value>::type>,
typename ScalarType = typename Traits::ScalarType,
typename Enable = decltype(ScalarType(std::declval<Value>(),
Traits::type_singleton()))>
std::shared_ptr<Scalar> MakeScalar(Value value) {
return std::make_shared<ScalarType>(std::move(value), Traits::type_singleton());
}
inline std::shared_ptr<Scalar> MakeScalar(std::string value) {
return std::make_shared<StringScalar>(std::move(value));
}
inline std::shared_ptr<Scalar> MakeScalar(const std::shared_ptr<Scalar>& scalar) {
return scalar;
}
/// @}
template <typename ValueRef>
struct MakeScalarImpl {
template <typename T, typename ScalarType = typename TypeTraits<T>::ScalarType,
typename ValueType = typename ScalarType::ValueType,
typename Enable = typename std::enable_if<
std::is_constructible<ScalarType, ValueType,
std::shared_ptr<DataType>>::value &&
std::is_convertible<ValueRef, ValueType>::value>::type>
Status Visit(const T& t) {
ARROW_RETURN_NOT_OK(internal::CheckBufferLength(&t, &value_));
// `static_cast<ValueRef>` makes a rvalue if ValueRef is `ValueType&&`
out_ = std::make_shared<ScalarType>(
static_cast<ValueType>(static_cast<ValueRef>(value_)), std::move(type_));
return Status::OK();
}
Status Visit(const ExtensionType& t) {
ARROW_ASSIGN_OR_RAISE(auto storage,
MakeScalar(t.storage_type(), static_cast<ValueRef>(value_)));
out_ = std::make_shared<ExtensionScalar>(std::move(storage), type_);
return Status::OK();
}
// Enable constructing string/binary scalars (but not decimal, etc) from std::string
template <typename T>
enable_if_t<
std::is_same<typename std::remove_reference<ValueRef>::type, std::string>::value &&
(is_base_binary_type<T>::value || std::is_same<T, FixedSizeBinaryType>::value),
Status>
Visit(const T& t) {
using ScalarType = typename TypeTraits<T>::ScalarType;
out_ = std::make_shared<ScalarType>(Buffer::FromString(std::move(value_)),
std::move(type_));
return Status::OK();
}
Status Visit(const DataType& t) {
return Status::NotImplemented("constructing scalars of type ", t,
" from unboxed values");
}
Result<std::shared_ptr<Scalar>> Finish() && {
ARROW_RETURN_NOT_OK(VisitTypeInline(*type_, this));
return std::move(out_);
}
std::shared_ptr<DataType> type_;
ValueRef value_;
std::shared_ptr<Scalar> out_;
};
} // namespace arrow