A non-owning, immutable view of device data as a column of elements, some of which may be null as indicated by a bitmask. More...

#include <column_view.hpp>

Inheritance diagram for cudf::detail::column_view_base:

Public Member Functions
template<typename T = void, CUDF_ENABLE_IF(std::is_same_v< T, void > or is_rep_layout_compatible< T >()) >
T const *	head () const noexcept
	Returns pointer to the base device memory allocation casted to the specified type. More...

template<typename T , CUDF_ENABLE_IF(is_rep_layout_compatible< T >()) >
T const *	data () const noexcept
	Returns the underlying data casted to the specified type, plus the offset. More...

template<typename T , CUDF_ENABLE_IF(is_rep_layout_compatible< T >()) >
T const *	begin () const noexcept
	Return first element (accounting for offset) after underlying data is casted to the specified type. More...

template<typename T , CUDF_ENABLE_IF(is_rep_layout_compatible< T >()) >
T const *	end () const noexcept
	Return one past the last element after underlying data is casted to the specified type. More...

size_type	size () const noexcept
	Returns the number of elements in the column. More...

bool	is_empty () const noexcept
	Returns true if `size()` returns zero, or false otherwise. More...

data_type	type () const noexcept
	Returns the element `data_type` More...

bool	nullable () const noexcept
	Indicates if the column can contain null elements, i.e., if it has an allocated bitmask. More...

size_type	null_count () const
	Returns the count of null elements. More...

size_type	null_count (size_type begin, size_type end) const
	Returns the count of null elements in the range [begin, end) More...

bool	has_nulls () const
	Indicates if the column contains null elements, i.e., `null_count() > 0` More...

bool	has_nulls (size_type begin, size_type end) const
	Indicates if the column contains null elements in the range [begin, end), i.e., `null_count(begin, end) > 0` More...

bitmask_type const *	null_mask () const noexcept
	Returns raw pointer to the underlying bitmask allocation. More...

size_type	offset () const noexcept
	Returns the index of the first element relative to the base memory allocation, i.e., what is returned from `head<T>()`. More...

Protected Member Functions
	column_view_base (column_view_base const &)=default
	Copy constructor.

	column_view_base (column_view_base &&)=default
	Move constructor.

column_view_base &	operator= (column_view_base const &)=default
	Copy assignment operator. More...

column_view_base &	operator= (column_view_base &&)=default
	Move assignment operator. More...

	column_view_base (data_type type, size_type size, void const data, bitmask_type const null_mask, size_type null_count, size_type offset=0)
	Construct a `column_view_base` from pointers to device memory for the elements and bitmask of the column. More...

Protected Attributes
data_type	_type {type_id::EMPTY}
	Element type.

size_type	_size {}
	Number of elements.

void const *	_data {}
	Pointer to device memory containing elements.

bitmask_type const *	_null_mask {}

size_type	_null_count {}
	The number of null elements.

size_type	_offset {}

Detailed Description

A non-owning, immutable view of device data as a column of elements, some of which may be null as indicated by a bitmask.

A column_view_base can be constructed implicitly from a cudf::column, or may be constructed explicitly from a pointer to pre-existing device memory.

Unless otherwise noted, the memory layout of the column_view_base's data and bitmask is expected to adhere to the Arrow Physical Memory Layout Specification: https://arrow.apache.org/docs/memory_layout.html

Because column_view_base is non-owning, no device memory is allocated nor freed when column_view_base objects are created or destroyed.

To enable zero-copy slicing, a column_view_base has an offset that indicates the index of the first element in the column relative to the base device memory allocation. By default, offset() is zero.

Definition at line 53 of file column_view.hpp.

Constructor & Destructor Documentation

◆ column_view_base()

cudf::detail::column_view_base::column_view_base	(	data_type	type,
		size_type	size,
		void const *	data,
		bitmask_type const *	null_mask,
		size_type	null_count,
		size_type	offset = `0`
	)

protected

Construct a column_view_base from pointers to device memory for the elements and bitmask of the column.

If null_count() is zero, null_mask is optional.

If type is EMPTY, the specified null_count will be ignored and null_count() will always return the same value as size()

Exceptions

cudf::logic_error	if `size < 0`
cudf::logic_error	if `size > 0` but `data == nullptr`
cudf::logic_error	if `type.id() == EMPTY` but `data != nullptr` or `null_mask != nullptr`
cudf::logic_error	if `null_count > 0`, but `null_mask == nullptr`
cudf::logic_error	if `offset < 0`

Parameters

type	The element type
size	The number of elements
data	Pointer to device memory containing the column elements
null_mask	Pointer to device memory containing the null indicator bitmask
null_count	The number of null elements.
offset	Optional, index of the first element

Member Function Documentation

◆ begin()

template<typename T , CUDF_ENABLE_IF(is_rep_layout_compatible< T >()) >

T const* cudf::detail::column_view_base::begin ( ) const

inlinenoexcept

Return first element (accounting for offset) after underlying data is casted to the specified type.

This function does not participate in overload resolution if is_rep_layout_compatible<T> is false.

Template Parameters

T	The desired type

Returns: Pointer to the first element after casting

Definition at line 107 of file column_view.hpp.

◆ data()

template<typename T , CUDF_ENABLE_IF(is_rep_layout_compatible< T >()) >

T const* cudf::detail::column_view_base::data ( ) const

inlinenoexcept

Returns the underlying data casted to the specified type, plus the offset.

Note: If offset() == 0, then head<T>() == data<T>()

This function does not participate in overload resolution if is_rep_layout_compatible<T> is false.

Template Parameters

T	The type to cast to

Returns: Typed pointer to underlying data, including the offset

Definition at line 91 of file column_view.hpp.

◆ end()

template<typename T , CUDF_ENABLE_IF(is_rep_layout_compatible< T >()) >

T const* cudf::detail::column_view_base::end ( ) const

inlinenoexcept

Return one past the last element after underlying data is casted to the specified type.

This function does not participate in overload resolution if is_rep_layout_compatible<T> is false.

Template Parameters

T	The desired type

Returns: Pointer to one past the last element after casting

Definition at line 123 of file column_view.hpp.

◆ has_nulls() [1/2]

bool cudf::detail::column_view_base::has_nulls ( ) const

inline

Indicates if the column contains null elements, i.e., null_count() > 0

Returns: true One or more elements are null; false All elements are valid

Definition at line 190 of file column_view.hpp.

◆ has_nulls() [2/2]

bool cudf::detail::column_view_base::has_nulls	(	size_type	begin,
		size_type	end
	)		const

inline

Indicates if the column contains null elements in the range [begin, end), i.e., null_count(begin, end) > 0

Exceptions

cudf::logic_error for invalid range (if begin < 0, begin > end, begin >= size(), or end > size()).

Parameters

begin	The starting index of the range (inclusive).
end	The index of the last element in the range (exclusive).

Returns: true One or more elements are null in the range [begin, end); false All elements are valid in the range [begin, end)

Definition at line 204 of file column_view.hpp.

◆ head()

template<typename T = void, CUDF_ENABLE_IF(std::is_same_v< T, void > or is_rep_layout_compatible< T >()) >

T const* cudf::detail::column_view_base::head ( ) const

inlinenoexcept

Returns pointer to the base device memory allocation casted to the specified type.

Note: If offset() == 0, then head<T>() == data<T>(); It should be rare to need to access the head<T>() allocation of a column, and instead, accessing the elements should be done via data<T>().

This function will only participate in overload resolution if is_rep_layout_compatible<T>() or std::is_same_v<T,void> are true.

Template Parameters

The	type to cast to

Returns: Typed pointer to underlying data

Definition at line 73 of file column_view.hpp.

◆ is_empty()

bool cudf::detail::column_view_base::is_empty ( ) const

inlinenoexcept

Returns true if size() returns zero, or false otherwise.

Returns: True if size() returns zero, or false otherwise

Definition at line 140 of file column_view.hpp.

◆ null_count() [1/2]

size_type cudf::detail::column_view_base::null_count ( ) const

inline

Returns the count of null elements.

Returns: The count of null elements

Definition at line 165 of file column_view.hpp.

◆ null_count() [2/2]

size_type cudf::detail::column_view_base::null_count	(	size_type	begin,
		size_type	end
	)		const

Returns the count of null elements in the range [begin, end)

Note: If null_count() != 0, every invocation of null_count(begin, end) will recompute the count of null elements indicated by the null_mask in the range [begin, end).

Exceptions

cudf::logic_error for invalid range (if begin < 0, begin > end, begin >= size(), or end > size()).

Parameters

[in]	begin	The starting index of the range (inclusive).
[in]	end	The index of the last element in the range (exclusive).

Returns: The count of null elements in the given range

◆ null_mask()

bitmask_type const* cudf::detail::column_view_base::null_mask ( ) const

inlinenoexcept

Returns raw pointer to the underlying bitmask allocation.

Note: This function does not account for the offset().; If null_count() == 0, this may return nullptr.

Returns: Raw pointer to the bitmask

Definition at line 217 of file column_view.hpp.

◆ nullable()

bool cudf::detail::column_view_base::nullable ( ) const

inlinenoexcept

Indicates if the column can contain null elements, i.e., if it has an allocated bitmask.

Note: If null_count() > 0, this function must always return true.

Returns: true The bitmask is allocated; false The bitmask is not allocated

Definition at line 158 of file column_view.hpp.

◆ offset()

size_type cudf::detail::column_view_base::offset ( ) const

inlinenoexcept

Returns the index of the first element relative to the base memory allocation, i.e., what is returned from head<T>().

Returns: The index of the first element relative to head<T>()

Definition at line 225 of file column_view.hpp.

◆ operator=() [1/2]

column_view_base& cudf::detail::column_view_base::operator= ( column_view_base && )

protecteddefault

Move assignment operator.

Returns: Reference to this object (after transferring ownership)

◆ operator=() [2/2]

column_view_base& cudf::detail::column_view_base::operator= ( column_view_base const & )

protecteddefault

Copy assignment operator.

Returns: Reference to this object

◆ size()

size_type cudf::detail::column_view_base::size ( ) const

inlinenoexcept

Returns the number of elements in the column.

Returns: The number of elements in the column

Definition at line 133 of file column_view.hpp.

◆ type()

data_type cudf::detail::column_view_base::type ( ) const

inlinenoexcept

Returns the element data_type

Returns: The data_type of the elements in the column

Definition at line 147 of file column_view.hpp.

Member Data Documentation

◆ _null_mask

bitmask_type const* cudf::detail::column_view_base::_null_mask {}

protected

Pointer to device memory containing bitmask representing null elements. Optional if null_count() == 0

Definition at line 231 of file column_view.hpp.

◆ _offset

size_type cudf::detail::column_view_base::_offset {}

protected

Index position of the first element. Enables zero-copy slicing

Definition at line 235 of file column_view.hpp.

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

column_view.hpp

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ column_view_base()

Member Function Documentation

◆ begin()

◆ data()

◆ end()

◆ has_nulls() [1/2]

◆ has_nulls() [2/2]

◆ head()

◆ is_empty()

◆ null_count() [1/2]

◆ null_count() [2/2]

◆ null_mask()

◆ nullable()

◆ offset()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ size()

◆ type()

Member Data Documentation

◆ _null_mask

◆ _offset