Array Builders¶
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class
arrow::ArrayBuilder¶ Base class for all data array builders.
This class provides a facilities for incrementally building the null bitmap (see Append methods) and as a side effect the current number of slots and the null count.
Note
Users are expected to use builders as one of the concrete types below. For example, ArrayBuilder* pointing to BinaryBuilder should be downcast before use.
Subclassed by arrow::BaseBinaryBuilder< TYPE >, arrow::BaseListBuilder< TYPE >, arrow::BasicUnionBuilder, arrow::BooleanBuilder, arrow::FixedSizeBinaryBuilder, arrow::FixedSizeListBuilder, arrow::internal::AdaptiveIntBuilderBase, arrow::internal::DictionaryBuilderBase< BuilderType, T >, arrow::internal::DictionaryBuilderBase< BuilderType, NullType >, arrow::MapBuilder, arrow::NullBuilder, arrow::NumericBuilder< T >, arrow::StructBuilder, arrow::BaseBinaryBuilder< BinaryType >, arrow::BaseBinaryBuilder< LargeBinaryType >, arrow::BaseListBuilder< LargeListType >, arrow::BaseListBuilder< ListType >, arrow::internal::DictionaryBuilderBase< AdaptiveIntBuilder, T >, arrow::internal::DictionaryBuilderBase< Int32Builder, T >, arrow::NumericBuilder< DayTimeIntervalType >
Public Functions
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inline ArrayBuilder *
child(int i)¶ For nested types.
Since the objects are owned by this class instance, we skip shared pointers and just return a raw pointer
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virtual Status
Resize(int64_t capacity)¶ 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] capacity – the minimum number of total array values to accommodate. Must be greater than the current capacity.
- Returns
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inline Status
Reserve(int64_t additional_capacity)¶ Ensure that there is enough space allocated to append the indicated number of elements without any further reallocation.
Overallocation is used in order to minimize the impact of incremental Reserve() calls. Note that additional_capacity is relative to the current number of elements rather than to the current capacity, so calls to Reserve() which are not interspersed with addition of new elements may not increase the capacity.
- Parameters
[in] additional_capacity – the number of additional array values
- Returns
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virtual void
Reset()¶ Reset the builder.
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virtual Status
AppendEmptyValue() = 0¶ Append a non-null value to builder.
The appended value is an implementation detail, but the corresponding memory slot is guaranteed to be initialized. This method is useful when appending a null value to a parent nested type.
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virtual Status
AppendEmptyValues(int64_t length) = 0¶ Append a number of non-null values to builder.
The appended values are an implementation detail, but the corresponding memory slot is guaranteed to be initialized. This method is useful when appending null values to a parent nested type.
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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.
It is your responsibility to use this function responsibly.
Return result of builder as an internal generic ArrayData object.
Resets builder except for dictionary builder
- Parameters
[out] out – the finalized ArrayData object
- Returns
Return result of builder as an Array object.
The builder is reset except for DictionaryBuilder.
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inline ArrayBuilder *
Concrete builder subclasses¶
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class
arrow::NullBuilder: public arrow::ArrayBuilder¶ Public Functions
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inline virtual Status
AppendNulls(int64_t length) final¶ Append the specified number of null elements.
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inline virtual Status
AppendEmptyValues(int64_t length) final¶ Append a number of non-null values to builder.
The appended values are an implementation detail, but the corresponding memory slot is guaranteed to be initialized. This method is useful when appending null values to a parent nested type.
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inline virtual Status
AppendEmptyValue() final¶ Append a non-null value to builder.
The appended value is an implementation detail, but the corresponding memory slot is guaranteed to be initialized. This method is useful when appending a null value to a parent nested type.
Return result of builder as an internal generic ArrayData object.
Resets builder except for dictionary builder
- Parameters
[out] out – the finalized ArrayData object
- Returns
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inline virtual Status
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class
arrow::BooleanBuilder: public arrow::ArrayBuilder¶ Public Functions
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inline virtual Status
AppendNulls(int64_t length) final¶ Write nulls as uint8_t* (0 value indicates null) into pre-allocated memory.
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inline virtual Status
AppendEmptyValue() final¶ Append a non-null value to builder.
The appended value is an implementation detail, but the corresponding memory slot is guaranteed to be initialized. This method is useful when appending a null value to a parent nested type.
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inline virtual Status
AppendEmptyValues(int64_t length) final¶ Append a number of non-null values to builder.
The appended values are an implementation detail, but the corresponding memory slot is guaranteed to be initialized. This method is useful when appending null values to a parent nested type.
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Status
AppendValues(const uint8_t *values, int64_t length, const uint8_t *valid_bytes = NULLPTR)¶ Append a sequence of elements in one shot.
- Parameters
[in] values – a contiguous array of bytes (non-zero is 1)
[in] length – the number of values to append
[in] valid_bytes – an optional sequence of bytes where non-zero indicates a valid (non-null) value
- Returns
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Status
AppendValues(const uint8_t *values, int64_t length, const std::vector<bool> &is_valid)¶ Append a sequence of elements in one shot.
- Parameters
[in] values – a contiguous C array of values
[in] length – the number of values to append
[in] is_valid – an std::vector<bool> indicating valid (1) or null (0). Equal in length to values
- Returns
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Status
AppendValues(const std::vector<uint8_t> &values, const std::vector<bool> &is_valid)¶ Append a sequence of elements in one shot.
- Parameters
[in] values – a std::vector of bytes
[in] is_valid – an std::vector<bool> indicating valid (1) or null (0). Equal in length to values
- Returns
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Status
AppendValues(const std::vector<uint8_t> &values)¶ Append a sequence of elements in one shot.
- Parameters
[in] values – a std::vector of bytes
- Returns
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Status
AppendValues(const std::vector<bool> &values, const std::vector<bool> &is_valid)¶ Append a sequence of elements in one shot.
- Parameters
[in] values – an std::vector<bool> indicating true (1) or false
[in] is_valid – an std::vector<bool> indicating valid (1) or null (0). Equal in length to values
- Returns
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Status
AppendValues(const std::vector<bool> &values)¶ Append a sequence of elements in one shot.
- Parameters
[in] values – an std::vector<bool> indicating true (1) or false
- Returns
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template<typename
ValuesIter>
inline StatusAppendValues(ValuesIter values_begin, ValuesIter values_end)¶ Append a sequence of elements in one shot.
- Parameters
[in] values_begin – InputIterator to the beginning of the values
[in] values_end – InputIterator pointing to the end of the values or null(0) values
- Returns
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template<typename
ValuesIter, typenameValidIter>
inline enable_if_t<!std::is_pointer<ValidIter>::value, Status>AppendValues(ValuesIter values_begin, ValuesIter values_end, ValidIter valid_begin)¶ Append a sequence of elements in one shot, with a specified nullmap.
- Parameters
[in] values_begin – InputIterator to the beginning of the values
[in] values_end – InputIterator pointing to the end of the values
[in] valid_begin – InputIterator with elements indication valid(1) or null(0) values
- Returns
Return result of builder as an internal generic ArrayData object.
Resets builder except for dictionary builder
- Parameters
[out] out – the finalized ArrayData object
- Returns
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virtual void
Reset() override¶ Reset the builder.
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virtual 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.
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] capacity – the minimum number of total array values to accommodate. Must be greater than the current capacity.
- Returns
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inline virtual Status
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template<typename
T>
classarrow::NumericBuilder: public arrow::ArrayBuilder¶ Base class for all Builders that emit an Array of a scalar numerical type.
Public Functions
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inline Status
Append(const value_type val)¶ Append a single scalar and increase the size if necessary.
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inline virtual Status
AppendNulls(int64_t length) final¶ Write nulls as uint8_t* (0 value indicates null) into pre-allocated memory The memory at the corresponding data slot is set to 0 to prevent uninitialized memory access.
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inline virtual void
Reset() override¶ Reset the builder.
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inline virtual 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.
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] capacity – the minimum number of total array values to accommodate. Must be greater than the current capacity.
- Returns
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inline Status
AppendValues(const value_type *values, int64_t length, const uint8_t *valid_bytes = NULLPTR)¶ Append a sequence of elements in one shot.
- Parameters
[in] values – a contiguous C array of values
[in] length – the number of values to append
[in] valid_bytes – an optional sequence of bytes where non-zero indicates a valid (non-null) value
- Returns
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inline Status
AppendValues(const value_type *values, int64_t length, const std::vector<bool> &is_valid)¶ Append a sequence of elements in one shot.
- Parameters
[in] values – a contiguous C array of values
[in] length – the number of values to append
[in] is_valid – an std::vector<bool> indicating valid (1) or null (0). Equal in length to values
- Returns
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inline Status
AppendValues(const std::vector<value_type> &values, const std::vector<bool> &is_valid)¶ Append a sequence of elements in one shot.
- Parameters
[in] values – a std::vector of values
[in] is_valid – an std::vector<bool> indicating valid (1) or null (0). Equal in length to values
- Returns
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inline Status
AppendValues(const std::vector<value_type> &values)¶ Append a sequence of elements in one shot.
- Parameters
[in] values – a std::vector of values
- Returns
Return result of builder as an internal generic ArrayData object.
Resets builder except for dictionary builder
- Parameters
[out] out – the finalized ArrayData object
- Returns
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template<typename
ValuesIter>
inline StatusAppendValues(ValuesIter values_begin, ValuesIter values_end)¶ Append a sequence of elements in one shot.
- Parameters
[in] values_begin – InputIterator to the beginning of the values
[in] values_end – InputIterator pointing to the end of the values
- Returns
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template<typename
ValuesIter, typenameValidIter>
inline enable_if_t<!std::is_pointer<ValidIter>::value, Status>AppendValues(ValuesIter values_begin, ValuesIter values_end, ValidIter valid_begin)¶ Append a sequence of elements in one shot, with a specified nullmap.
- Parameters
[in] values_begin – InputIterator to the beginning of the values
[in] values_end – InputIterator pointing to the end of the values
[in] valid_begin – InputIterator with elements indication valid(1) or null(0) values.
- Returns
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inline Status
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class
arrow::BinaryBuilder: public arrow::BaseBinaryBuilder<BinaryType>¶ Builder class for variable-length binary data.
Subclassed by arrow::StringBuilder
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class
arrow::StringBuilder: public arrow::BinaryBuilder¶ Builder class for UTF8 strings.
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class
arrow::FixedSizeBinaryBuilder: public arrow::ArrayBuilder¶ Subclassed by arrow::Decimal128Builder, arrow::Decimal256Builder
Public Functions
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virtual Status
AppendEmptyValue() final¶ Append a non-null value to builder.
The appended value is an implementation detail, but the corresponding memory slot is guaranteed to be initialized. This method is useful when appending a null value to a parent nested type.
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virtual Status
AppendEmptyValues(int64_t length) final¶ Append a number of non-null values to builder.
The appended values are an implementation detail, but the corresponding memory slot is guaranteed to be initialized. This method is useful when appending null values to a parent nested type.
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inline Status
ReserveData(int64_t elements)¶ Ensures there is enough allocated capacity to append the indicated number of bytes to the value data buffer without additional allocations.
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virtual void
Reset() override¶ Reset the builder.
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virtual 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.
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] capacity – the minimum number of total array values to accommodate. Must be greater than the current capacity.
- Returns
Return result of builder as an internal generic ArrayData object.
Resets builder except for dictionary builder
- Parameters
[out] out – the finalized ArrayData object
- Returns
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inline int64_t
value_data_length() const¶ - Returns
size of values buffer so far
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const uint8_t *
GetValue(int64_t i) const¶ Temporary access to a value.
This pointer becomes invalid on the next modifying operation.
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util::string_view
GetView(int64_t i) const¶ Temporary access to a value.
This view becomes invalid on the next modifying operation.
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virtual Status
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class
arrow::Decimal128Builder: public arrow::FixedSizeBinaryBuilder¶
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class
arrow::ListBuilder: public arrow::BaseListBuilder<ListType>¶ 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 offsets 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.
Public Functions
Use this constructor to incrementally build the value array along with offsets and null bitmap.
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class
arrow::StructBuilder: public arrow::ArrayBuilder¶ Append, Resize and Reserve methods are acting on StructBuilder.
Please make sure all these methods of all child-builders’ are consistently called to maintain data-structure consistency.
Public Functions
If any of field_builders has indeterminate type, this builder will also.
Return result of builder as an internal generic ArrayData object.
Resets builder except for dictionary builder
- Parameters
[out] out – the finalized ArrayData object
- Returns
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inline Status
AppendValues(int64_t length, const uint8_t *valid_bytes)¶ Null bitmap is of equal length to every child field, and any zero byte will be considered as a null for that field, but users must using app- end methods or advance methods of the child builders’ independently to insert data.
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inline Status
Append(bool is_valid = true)¶ Append an element to the Struct.
All child-builders’ Append method must be called independently to maintain data-structure consistency.
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inline virtual Status
AppendNull() final¶ Append a null value.
Automatically appends an empty value to each child builder.
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inline virtual Status
AppendNulls(int64_t length) final¶ Append multiple null values.
Automatically appends empty values to each child builder.
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inline virtual Status
AppendEmptyValue() final¶ Append a non-null value to builder.
The appended value is an implementation detail, but the corresponding memory slot is guaranteed to be initialized. This method is useful when appending a null value to a parent nested type.
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inline virtual Status
AppendEmptyValues(int64_t length) final¶ Append a number of non-null values to builder.
The appended values are an implementation detail, but the corresponding memory slot is guaranteed to be initialized. This method is useful when appending null values to a parent nested type.
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virtual void
Reset() override¶ Reset the builder.
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template<typename
T>
classarrow::DictionaryBuilder: public arrow::internal::DictionaryBuilderBase<AdaptiveIntBuilder, T>¶ A DictionaryArray builder that uses AdaptiveIntBuilder to return the smallest index size that can accommodate the dictionary indices.