2022-05-23 00:16:32 +04:00

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C++

// 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.
// Array accessor classes for List, LargeList, FixedSizeList, Map, Struct, and
// Union
#pragma once
#include <cstdint>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include "arrow/array/array_base.h"
#include "arrow/array/data.h"
#include "arrow/result.h"
#include "arrow/status.h"
#include "arrow/type.h"
#include "arrow/type_fwd.h"
#include "arrow/util/checked_cast.h"
#include "arrow/util/macros.h"
#include "arrow/util/visibility.h"
namespace arrow {
/// \addtogroup nested-arrays
///
/// @{
// ----------------------------------------------------------------------
// ListArray
template <typename TYPE>
class BaseListArray;
namespace internal {
// Private helper for ListArray::SetData.
// Unfortunately, trying to define BaseListArray::SetData outside of this header
// doesn't play well with MSVC.
template <typename TYPE>
void SetListData(BaseListArray<TYPE>* self, const std::shared_ptr<ArrayData>& data,
Type::type expected_type_id = TYPE::type_id);
} // namespace internal
/// Base class for variable-sized list arrays, regardless of offset size.
template <typename TYPE>
class BaseListArray : public Array {
public:
using TypeClass = TYPE;
using offset_type = typename TypeClass::offset_type;
const TypeClass* list_type() const { return list_type_; }
/// \brief Return array object containing the list's values
std::shared_ptr<Array> values() const { return values_; }
/// Note that this buffer does not account for any slice offset
std::shared_ptr<Buffer> value_offsets() const { return data_->buffers[1]; }
std::shared_ptr<DataType> value_type() const { return list_type_->value_type(); }
/// Return pointer to raw value offsets accounting for any slice offset
const offset_type* raw_value_offsets() const {
return raw_value_offsets_ + data_->offset;
}
// The following functions will not perform boundschecking
offset_type value_offset(int64_t i) const {
return raw_value_offsets_[i + data_->offset];
}
offset_type value_length(int64_t i) const {
i += data_->offset;
return raw_value_offsets_[i + 1] - raw_value_offsets_[i];
}
std::shared_ptr<Array> value_slice(int64_t i) const {
return values_->Slice(value_offset(i), value_length(i));
}
protected:
friend void internal::SetListData<TYPE>(BaseListArray<TYPE>* self,
const std::shared_ptr<ArrayData>& data,
Type::type expected_type_id);
const TypeClass* list_type_ = NULLPTR;
std::shared_ptr<Array> values_;
const offset_type* raw_value_offsets_ = NULLPTR;
};
/// Concrete Array class for list data
class ARROW_EXPORT ListArray : public BaseListArray<ListType> {
public:
explicit ListArray(std::shared_ptr<ArrayData> data);
ListArray(std::shared_ptr<DataType> type, int64_t length,
std::shared_ptr<Buffer> value_offsets, std::shared_ptr<Array> values,
std::shared_ptr<Buffer> null_bitmap = NULLPTR,
int64_t null_count = kUnknownNullCount, int64_t offset = 0);
/// \brief Construct ListArray from array of offsets and child value array
///
/// This function does the bare minimum of validation of the offsets and
/// input types, and will allocate a new offsets array if necessary (i.e. if
/// the offsets contain any nulls). If the offsets do not have nulls, they
/// are assumed to be well-formed
///
/// \param[in] offsets Array containing n + 1 offsets encoding length and
/// size. Must be of int32 type
/// \param[in] values Array containing list values
/// \param[in] pool MemoryPool in case new offsets array needs to be
/// allocated because of null values
static Result<std::shared_ptr<ListArray>> FromArrays(
const Array& offsets, const Array& values,
MemoryPool* pool = default_memory_pool());
static Result<std::shared_ptr<ListArray>> FromArrays(
std::shared_ptr<DataType> type, const Array& offsets, const Array& values,
MemoryPool* pool = default_memory_pool());
/// \brief Return an Array that is a concatenation of the lists in this array.
///
/// Note that it's different from `values()` in that it takes into
/// consideration of this array's offsets as well as null elements backed
/// by non-empty lists (they are skipped, thus copying may be needed).
Result<std::shared_ptr<Array>> Flatten(
MemoryPool* memory_pool = default_memory_pool()) const;
/// \brief Return list offsets as an Int32Array
///
/// The returned array will not have a validity bitmap, so you cannot expect
/// to pass it to ListArray::FromArrays() and get back the same list array
/// if the original one has nulls.
std::shared_ptr<Array> offsets() const;
protected:
// This constructor defers SetData to a derived array class
ListArray() = default;
void SetData(const std::shared_ptr<ArrayData>& data);
};
/// Concrete Array class for large list data (with 64-bit offsets)
class ARROW_EXPORT LargeListArray : public BaseListArray<LargeListType> {
public:
explicit LargeListArray(const std::shared_ptr<ArrayData>& data);
LargeListArray(const std::shared_ptr<DataType>& type, int64_t length,
const std::shared_ptr<Buffer>& value_offsets,
const std::shared_ptr<Array>& values,
const std::shared_ptr<Buffer>& null_bitmap = NULLPTR,
int64_t null_count = kUnknownNullCount, int64_t offset = 0);
/// \brief Construct LargeListArray from array of offsets and child value array
///
/// This function does the bare minimum of validation of the offsets and
/// input types, and will allocate a new offsets array if necessary (i.e. if
/// the offsets contain any nulls). If the offsets do not have nulls, they
/// are assumed to be well-formed
///
/// \param[in] offsets Array containing n + 1 offsets encoding length and
/// size. Must be of int64 type
/// \param[in] values Array containing list values
/// \param[in] pool MemoryPool in case new offsets array needs to be
/// allocated because of null values
static Result<std::shared_ptr<LargeListArray>> FromArrays(
const Array& offsets, const Array& values,
MemoryPool* pool = default_memory_pool());
static Result<std::shared_ptr<LargeListArray>> FromArrays(
std::shared_ptr<DataType> type, const Array& offsets, const Array& values,
MemoryPool* pool = default_memory_pool());
/// \brief Return an Array that is a concatenation of the lists in this array.
///
/// Note that it's different from `values()` in that it takes into
/// consideration of this array's offsets as well as null elements backed
/// by non-empty lists (they are skipped, thus copying may be needed).
Result<std::shared_ptr<Array>> Flatten(
MemoryPool* memory_pool = default_memory_pool()) const;
/// \brief Return list offsets as an Int64Array
std::shared_ptr<Array> offsets() const;
protected:
void SetData(const std::shared_ptr<ArrayData>& data);
};
// ----------------------------------------------------------------------
// MapArray
/// Concrete Array class for map data
///
/// NB: "value" in this context refers to a pair of a key and the corresponding item
class ARROW_EXPORT MapArray : public ListArray {
public:
using TypeClass = MapType;
explicit MapArray(const std::shared_ptr<ArrayData>& data);
MapArray(const std::shared_ptr<DataType>& type, int64_t length,
const std::shared_ptr<Buffer>& value_offsets,
const std::shared_ptr<Array>& keys, const std::shared_ptr<Array>& items,
const std::shared_ptr<Buffer>& null_bitmap = NULLPTR,
int64_t null_count = kUnknownNullCount, int64_t offset = 0);
MapArray(const std::shared_ptr<DataType>& type, int64_t length,
const std::shared_ptr<Buffer>& value_offsets,
const std::shared_ptr<Array>& values,
const std::shared_ptr<Buffer>& null_bitmap = NULLPTR,
int64_t null_count = kUnknownNullCount, int64_t offset = 0);
/// \brief Construct MapArray from array of offsets and child key, item arrays
///
/// This function does the bare minimum of validation of the offsets and
/// input types, and will allocate a new offsets array if necessary (i.e. if
/// the offsets contain any nulls). If the offsets do not have nulls, they
/// are assumed to be well-formed
///
/// \param[in] offsets Array containing n + 1 offsets encoding length and
/// size. Must be of int32 type
/// \param[in] keys Array containing key values
/// \param[in] items Array containing item values
/// \param[in] pool MemoryPool in case new offsets array needs to be
/// allocated because of null values
static Result<std::shared_ptr<Array>> FromArrays(
const std::shared_ptr<Array>& offsets, const std::shared_ptr<Array>& keys,
const std::shared_ptr<Array>& items, MemoryPool* pool = default_memory_pool());
static Result<std::shared_ptr<Array>> FromArrays(
std::shared_ptr<DataType> type, const std::shared_ptr<Array>& offsets,
const std::shared_ptr<Array>& keys, const std::shared_ptr<Array>& items,
MemoryPool* pool = default_memory_pool());
const MapType* map_type() const { return map_type_; }
/// \brief Return array object containing all map keys
std::shared_ptr<Array> keys() const { return keys_; }
/// \brief Return array object containing all mapped items
std::shared_ptr<Array> items() const { return items_; }
/// Validate child data before constructing the actual MapArray.
static Status ValidateChildData(
const std::vector<std::shared_ptr<ArrayData>>& child_data);
protected:
void SetData(const std::shared_ptr<ArrayData>& data);
static Result<std::shared_ptr<Array>> FromArraysInternal(
std::shared_ptr<DataType> type, const std::shared_ptr<Array>& offsets,
const std::shared_ptr<Array>& keys, const std::shared_ptr<Array>& items,
MemoryPool* pool);
private:
const MapType* map_type_;
std::shared_ptr<Array> keys_, items_;
};
// ----------------------------------------------------------------------
// FixedSizeListArray
/// Concrete Array class for fixed size list data
class ARROW_EXPORT FixedSizeListArray : public Array {
public:
using TypeClass = FixedSizeListType;
using offset_type = TypeClass::offset_type;
explicit FixedSizeListArray(const std::shared_ptr<ArrayData>& data);
FixedSizeListArray(const std::shared_ptr<DataType>& type, int64_t length,
const std::shared_ptr<Array>& values,
const std::shared_ptr<Buffer>& null_bitmap = NULLPTR,
int64_t null_count = kUnknownNullCount, int64_t offset = 0);
const FixedSizeListType* list_type() const;
/// \brief Return array object containing the list's values
std::shared_ptr<Array> values() const;
std::shared_ptr<DataType> value_type() const;
// The following functions will not perform boundschecking
int64_t value_offset(int64_t i) const {
i += data_->offset;
return list_size_ * i;
}
int32_t value_length(int64_t i = 0) const {
ARROW_UNUSED(i);
return list_size_;
}
std::shared_ptr<Array> value_slice(int64_t i) const {
return values_->Slice(value_offset(i), value_length(i));
}
/// \brief Return an Array that is a concatenation of the lists in this array.
///
/// Note that it's different from `values()` in that it takes into
/// consideration null elements (they are skipped, thus copying may be needed).
Result<std::shared_ptr<Array>> Flatten(
MemoryPool* memory_pool = default_memory_pool()) const;
/// \brief Construct FixedSizeListArray from child value array and value_length
///
/// \param[in] values Array containing list values
/// \param[in] list_size The fixed length of each list
/// \return Will have length equal to values.length() / list_size
static Result<std::shared_ptr<Array>> FromArrays(const std::shared_ptr<Array>& values,
int32_t list_size);
/// \brief Construct FixedSizeListArray from child value array and type
///
/// \param[in] values Array containing list values
/// \param[in] type The fixed sized list type
/// \return Will have length equal to values.length() / type.list_size()
static Result<std::shared_ptr<Array>> FromArrays(const std::shared_ptr<Array>& values,
std::shared_ptr<DataType> type);
protected:
void SetData(const std::shared_ptr<ArrayData>& data);
int32_t list_size_;
private:
std::shared_ptr<Array> values_;
};
// ----------------------------------------------------------------------
// Struct
/// Concrete Array class for struct data
class ARROW_EXPORT StructArray : public Array {
public:
using TypeClass = StructType;
explicit StructArray(const std::shared_ptr<ArrayData>& data);
StructArray(const std::shared_ptr<DataType>& type, int64_t length,
const std::vector<std::shared_ptr<Array>>& children,
std::shared_ptr<Buffer> null_bitmap = NULLPTR,
int64_t null_count = kUnknownNullCount, int64_t offset = 0);
/// \brief Return a StructArray from child arrays and field names.
///
/// The length and data type are automatically inferred from the arguments.
/// There should be at least one child array.
static Result<std::shared_ptr<StructArray>> Make(
const ArrayVector& children, const std::vector<std::string>& field_names,
std::shared_ptr<Buffer> null_bitmap = NULLPTR,
int64_t null_count = kUnknownNullCount, int64_t offset = 0);
/// \brief Return a StructArray from child arrays and fields.
///
/// The length is automatically inferred from the arguments.
/// There should be at least one child array. This method does not
/// check that field types and child array types are consistent.
static Result<std::shared_ptr<StructArray>> Make(
const ArrayVector& children, const FieldVector& fields,
std::shared_ptr<Buffer> null_bitmap = NULLPTR,
int64_t null_count = kUnknownNullCount, int64_t offset = 0);
const StructType* struct_type() const;
// Return a shared pointer in case the requestor desires to share ownership
// with this array. The returned array has its offset, length and null
// count adjusted.
std::shared_ptr<Array> field(int pos) const;
const ArrayVector& fields() const;
/// Returns null if name not found
std::shared_ptr<Array> GetFieldByName(const std::string& name) const;
/// \brief Flatten this array as a vector of arrays, one for each field
///
/// \param[in] pool The pool to allocate null bitmaps from, if necessary
Result<ArrayVector> Flatten(MemoryPool* pool = default_memory_pool()) const;
/// \brief Get one of the child arrays, combining its null bitmap
/// with the parent struct array's bitmap.
///
/// \param[in] index Which child array to get
/// \param[in] pool The pool to allocate null bitmaps from, if necessary
Result<std::shared_ptr<Array>> GetFlattenedField(
int index, MemoryPool* pool = default_memory_pool()) const;
private:
// For caching boxed child data
// XXX This is not handled in a thread-safe manner.
mutable ArrayVector boxed_fields_;
};
// ----------------------------------------------------------------------
// Union
/// Base class for SparseUnionArray and DenseUnionArray
class ARROW_EXPORT UnionArray : public Array {
public:
using type_code_t = int8_t;
/// Note that this buffer does not account for any slice offset
std::shared_ptr<Buffer> type_codes() const { return data_->buffers[1]; }
const type_code_t* raw_type_codes() const { return raw_type_codes_ + data_->offset; }
/// The logical type code of the value at index.
type_code_t type_code(int64_t i) const { return raw_type_codes_[i + data_->offset]; }
/// The physical child id containing value at index.
int child_id(int64_t i) const {
return union_type_->child_ids()[raw_type_codes_[i + data_->offset]];
}
const UnionType* union_type() const { return union_type_; }
UnionMode::type mode() const { return union_type_->mode(); }
/// \brief Return the given field as an individual array.
///
/// For sparse unions, the returned array has its offset, length and null
/// count adjusted.
std::shared_ptr<Array> field(int pos) const;
protected:
void SetData(std::shared_ptr<ArrayData> data);
const type_code_t* raw_type_codes_;
const UnionType* union_type_;
// For caching boxed child data
mutable std::vector<std::shared_ptr<Array>> boxed_fields_;
};
/// Concrete Array class for sparse union data
class ARROW_EXPORT SparseUnionArray : public UnionArray {
public:
using TypeClass = SparseUnionType;
explicit SparseUnionArray(std::shared_ptr<ArrayData> data);
SparseUnionArray(std::shared_ptr<DataType> type, int64_t length, ArrayVector children,
std::shared_ptr<Buffer> type_ids, int64_t offset = 0);
/// \brief Construct SparseUnionArray from type_ids and children
///
/// This function does the bare minimum of validation of the input types.
///
/// \param[in] type_ids An array of logical type ids for the union type
/// \param[in] children Vector of children Arrays containing the data for each type.
/// \param[in] type_codes Vector of type codes.
static Result<std::shared_ptr<Array>> Make(const Array& type_ids, ArrayVector children,
std::vector<type_code_t> type_codes) {
return Make(std::move(type_ids), std::move(children), std::vector<std::string>{},
std::move(type_codes));
}
/// \brief Construct SparseUnionArray with custom field names from type_ids and children
///
/// This function does the bare minimum of validation of the input types.
///
/// \param[in] type_ids An array of logical type ids for the union type
/// \param[in] children Vector of children Arrays containing the data for each type.
/// \param[in] field_names Vector of strings containing the name of each field.
/// \param[in] type_codes Vector of type codes.
static Result<std::shared_ptr<Array>> Make(const Array& type_ids, ArrayVector children,
std::vector<std::string> field_names = {},
std::vector<type_code_t> type_codes = {});
const SparseUnionType* union_type() const {
return internal::checked_cast<const SparseUnionType*>(union_type_);
}
/// \brief Get one of the child arrays, adjusting its null bitmap
/// where the union array type code does not match.
///
/// \param[in] index Which child array to get (i.e. the physical index, not the type
/// code) \param[in] pool The pool to allocate null bitmaps from, if necessary
Result<std::shared_ptr<Array>> GetFlattenedField(
int index, MemoryPool* pool = default_memory_pool()) const;
protected:
void SetData(std::shared_ptr<ArrayData> data);
};
/// \brief Concrete Array class for dense union data
///
/// Note that union types do not have a validity bitmap
class ARROW_EXPORT DenseUnionArray : public UnionArray {
public:
using TypeClass = DenseUnionType;
explicit DenseUnionArray(const std::shared_ptr<ArrayData>& data);
DenseUnionArray(std::shared_ptr<DataType> type, int64_t length, ArrayVector children,
std::shared_ptr<Buffer> type_ids,
std::shared_ptr<Buffer> value_offsets = NULLPTR, int64_t offset = 0);
/// \brief Construct DenseUnionArray from type_ids, value_offsets, and children
///
/// This function does the bare minimum of validation of the offsets and
/// input types.
///
/// \param[in] type_ids An array of logical type ids for the union type
/// \param[in] value_offsets An array of signed int32 values indicating the
/// relative offset into the respective child array for the type in a given slot.
/// The respective offsets for each child value array must be in order / increasing.
/// \param[in] children Vector of children Arrays containing the data for each type.
/// \param[in] type_codes Vector of type codes.
static Result<std::shared_ptr<Array>> Make(const Array& type_ids,
const Array& value_offsets,
ArrayVector children,
std::vector<type_code_t> type_codes) {
return Make(type_ids, value_offsets, std::move(children), std::vector<std::string>{},
std::move(type_codes));
}
/// \brief Construct DenseUnionArray with custom field names from type_ids,
/// value_offsets, and children
///
/// This function does the bare minimum of validation of the offsets and
/// input types.
///
/// \param[in] type_ids An array of logical type ids for the union type
/// \param[in] value_offsets An array of signed int32 values indicating the
/// relative offset into the respective child array for the type in a given slot.
/// The respective offsets for each child value array must be in order / increasing.
/// \param[in] children Vector of children Arrays containing the data for each type.
/// \param[in] field_names Vector of strings containing the name of each field.
/// \param[in] type_codes Vector of type codes.
static Result<std::shared_ptr<Array>> Make(const Array& type_ids,
const Array& value_offsets,
ArrayVector children,
std::vector<std::string> field_names = {},
std::vector<type_code_t> type_codes = {});
const DenseUnionType* union_type() const {
return internal::checked_cast<const DenseUnionType*>(union_type_);
}
/// Note that this buffer does not account for any slice offset
std::shared_ptr<Buffer> value_offsets() const { return data_->buffers[2]; }
int32_t value_offset(int64_t i) const { return raw_value_offsets_[i + data_->offset]; }
const int32_t* raw_value_offsets() const { return raw_value_offsets_ + data_->offset; }
protected:
const int32_t* raw_value_offsets_;
void SetData(const std::shared_ptr<ArrayData>& data);
};
/// @}
} // namespace arrow