Apache Arrow (C++)
A columnar in-memory analytics layer designed to accelerate big data.
Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
arrow::ListBuilder Class Reference

Builder class for variable-length list array value types. More...

#include <arrow/builder.h>

Inheritance diagram for arrow::ListBuilder:
arrow::ArrayBuilder

Public Member Functions

 ListBuilder (MemoryPool *pool, std::shared_ptr< ArrayBuilder > const &value_builder, const std::shared_ptr< DataType > &type=NULLPTR)
 Use this constructor to incrementally build the value array along with offsets and null bitmap. More...
 
Status Resize (int64_t capacity) override
 Ensure that enough memory has been allocated to fit the indicated number of total elements in the builder, including any that have already been appended. More...
 
void Reset () override
 Reset the builder. More...
 
Status FinishInternal (std::shared_ptr< ArrayData > *out) override
 Return result of builder as an internal generic ArrayData object. More...
 
Status AppendValues (const int32_t *offsets, int64_t length, const uint8_t *valid_bytes=NULLPTR)
 Vector append. More...
 
Status Append (bool is_valid=true)
 Start a new variable-length list slot. More...
 
Status AppendNull ()
 
ArrayBuildervalue_builder () const
 
- Public Member Functions inherited from arrow::ArrayBuilder
 ArrayBuilder (const std::shared_ptr< DataType > &type, MemoryPool *pool)
 
virtual ~ArrayBuilder ()=default
 
ArrayBuilderchild (int i)
 For nested types. More...
 
int num_children () const
 
int64_t length () const
 
int64_t null_count () const
 
int64_t capacity () const
 
Status AppendToBitmap (bool is_valid)
 Append to null bitmap. More...
 
Status AppendToBitmap (const uint8_t *valid_bytes, int64_t length)
 Vector append. More...
 
Status SetNotNull (int64_t length)
 Set the next length bits to not null (i.e. valid). More...
 
Status Reserve (int64_t additional_capacity)
 Ensure that there is enough space allocated to add the indicated number of elements without any further calls to Resize. More...
 
Status Advance (int64_t elements)
 For cases where raw data was memcpy'd into the internal buffers, allows us to advance the length of the builder. More...
 
Status Finish (std::shared_ptr< Array > *out)
 Return result of builder as an Array object. More...
 
std::shared_ptr< DataTypetype () const
 
void UnsafeAppendToBitmap (bool is_valid)
 
template<typename IterType >
void UnsafeAppendToBitmap (const IterType &begin, const IterType &end)
 

Protected Member Functions

Status AppendNextOffset ()
 
- Protected Member Functions inherited from arrow::ArrayBuilder
 ArrayBuilder ()
 
void UnsafeAppendToBitmap (const uint8_t *valid_bytes, int64_t length)
 
void UnsafeAppendToBitmap (const std::vector< bool > &is_valid)
 
void UnsafeSetNotNull (int64_t length)
 

Protected Attributes

TypedBufferBuilder< int32_t > offsets_builder_
 
std::shared_ptr< ArrayBuildervalue_builder_
 
std::shared_ptr< Arrayvalues_
 
- Protected Attributes inherited from arrow::ArrayBuilder
std::shared_ptr< DataTypetype_
 
MemoryPoolpool_
 
std::shared_ptr< ResizableBuffernull_bitmap_
 
int64_t null_count_
 
uint8_t * null_bitmap_data_
 
int64_t length_
 
int64_t capacity_
 
std::vector< std::unique_ptr< ArrayBuilder > > children_
 

Detailed Description

Builder class for variable-length list array value types.

To use this class, you must append values to the child array builder and use the Append function to delimit each distinct list value (once the values have been appended to the child array) or use the bulk API to append a sequence of offests and null values.

A note on types. Per arrow/type.h all types in the c++ implementation are logical so even though this class always builds list array, this can represent multiple different logical types. If no logical type is provided at construction time, the class defaults to List<T> where t is taken from the value_builder/values that the object is constructed with.

Constructor & Destructor Documentation

◆ ListBuilder()

arrow::ListBuilder::ListBuilder ( MemoryPool pool,
std::shared_ptr< ArrayBuilder > const &  value_builder,
const std::shared_ptr< DataType > &  type = NULLPTR 
)

Use this constructor to incrementally build the value array along with offsets and null bitmap.

Member Function Documentation

◆ Append()

Status arrow::ListBuilder::Append ( bool  is_valid = true)

Start a new variable-length list slot.

This function should be called before beginning to append elements to the value builder

◆ AppendNextOffset()

Status arrow::ListBuilder::AppendNextOffset ( )
protected

◆ AppendNull()

Status arrow::ListBuilder::AppendNull ( )
inline

◆ AppendValues()

Status arrow::ListBuilder::AppendValues ( const int32_t *  offsets,
int64_t  length,
const uint8_t *  valid_bytes = NULLPTR 
)

Vector append.

If passed, valid_bytes is of equal length to values, and any zero byte will be considered as a null for that slot

◆ FinishInternal()

Status arrow::ListBuilder::FinishInternal ( std::shared_ptr< ArrayData > *  out)
overridevirtual

Return result of builder as an internal generic ArrayData object.

Resets builder except for dictionary builder

Parameters
[out]outthe finalized ArrayData object
Returns
Status

Implements arrow::ArrayBuilder.

◆ Reset()

void arrow::ListBuilder::Reset ( )
overridevirtual

Reset the builder.

Reimplemented from arrow::ArrayBuilder.

◆ Resize()

Status arrow::ListBuilder::Resize ( int64_t  capacity)
overridevirtual

Ensure that enough memory has been allocated to fit the indicated number of total elements in the builder, including any that have already been appended.

Does not account for reallocations that may be due to variable size data, like binary values. To make space for incremental appends, use Reserve instead.

Parameters
[in]capacitythe minimum number of additional array values
Returns
Status

Reimplemented from arrow::ArrayBuilder.

◆ value_builder()

ArrayBuilder* arrow::ListBuilder::value_builder ( ) const

Member Data Documentation

◆ offsets_builder_

TypedBufferBuilder<int32_t> arrow::ListBuilder::offsets_builder_
protected

◆ value_builder_

std::shared_ptr<ArrayBuilder> arrow::ListBuilder::value_builder_
protected

◆ values_

std::shared_ptr<Array> arrow::ListBuilder::values_
protected

The documentation for this class was generated from the following file: