A page is a slice of a column that is mapped into memory.

The page provides an opaque memory buffer for uncompressed, unpacked data. It does not interpret the contents but it does now about the size (and thus the number) of the elements inside as well as the element number range within the backing column/cluster. For reading, pages are allocated and filled by the page source and then registered with the page pool. For writing, the page sink allocates uninitialized pages of a given size. The page has a pointer to its memory allocator so that it can release itself.

Definition at line 47 of file RPage.hxx.

Classes
class	RClusterInfo
	Stores information about the cluster in which this page resides. More...

Public Member Functions
	RPage ()=default

	RPage (const RPage &)=delete

	RPage (RPage &&other)

	RPage (void buffer, RPageAllocator pageAllocator, ClusterSize_t::ValueType elementSize, ClusterSize_t::ValueType maxElements)

	~RPage ()

bool	Contains (NTupleSize_t globalIndex) const

bool	Contains (RClusterIndex clusterIndex) const

void *	GetBuffer () const

std::size_t	GetCapacity () const

const RClusterInfo &	GetClusterInfo () const

ClusterSize_t::ValueType	GetClusterRangeFirst () const

ClusterSize_t::ValueType	GetClusterRangeLast () const

std::uint32_t	GetElementSize () const

NTupleSize_t	GetGlobalRangeFirst () const

NTupleSize_t	GetGlobalRangeLast () const

std::uint32_t	GetMaxElements () const

std::size_t	GetNBytes () const
	The space taken by column elements in the buffer.

std::uint32_t	GetNElements () const

void *	GrowUnchecked (ClusterSize_t::ValueType nElements)
	Increases the number elements in the page.

bool	IsEmpty () const

bool	IsNull () const

bool	operator!= (const RPage &other) const

RPage &	operator= (const RPage &)=delete

RPage &	operator= (RPage &&other)

bool	operator== (const RPage &other) const

void	Reset (NTupleSize_t rangeFirst)
	Forget all currently stored elements (size == 0) and set a new starting index.

void	ResetCluster (const RClusterInfo &clusterInfo)

void	SetWindow (const NTupleSize_t rangeFirst, const RClusterInfo &clusterInfo)
	Seek the page to a certain position of the column.

Static Public Member Functions
static const void *	GetPageZeroBuffer ()
	Return a pointer to the page zero buffer used if there is no on-disk data for a particular deferred column.

Static Public Attributes
static constexpr size_t	kPageZeroSize = 64 * 1024

Private Attributes
void *	fBuffer = nullptr

RClusterInfo	fClusterInfo

std::uint32_t	fElementSize = 0

std::uint32_t	fMaxElements = 0
	The capacity of the page in number of elements.

std::uint32_t	fNElements = 0

RPageAllocator *	fPageAllocator = nullptr
	The allocator used to allocate fBuffer. Can be null if the buffer doesn't need to be freed.

NTupleSize_t	fRangeFirst = 0

Friends
class	RPageRef

#include <ROOT/RPage.hxx>

Constructor & Destructor Documentation

◆ RPage() [1/4]

ROOT::Experimental::Internal::RPage::RPage ( )

default

◆ RPage() [2/4]

ROOT::Experimental::Internal::RPage::RPage	(	void *	buffer,
		RPageAllocator *	pageAllocator,
		ClusterSize_t::ValueType	elementSize,
		ClusterSize_t::ValueType	maxElements
	)

inline

Definition at line 82 of file RPage.hxx.

◆ RPage() [3/4]

ROOT::Experimental::Internal::RPage::RPage ( const RPage & )

delete

◆ RPage() [4/4]

ROOT::Experimental::Internal::RPage::RPage ( RPage && other )

inline

Definition at line 88 of file RPage.hxx.

◆ ~RPage()

ROOT::Experimental::Internal::RPage::~RPage ( )

Definition at line 19 of file RPage.cxx.

Member Function Documentation

◆ Contains() [1/2]

bool ROOT::Experimental::Internal::RPage::Contains ( NTupleSize_t globalIndex ) const

inline

Definition at line 134 of file RPage.hxx.

◆ Contains() [2/2]

bool ROOT::Experimental::Internal::RPage::Contains ( RClusterIndex clusterIndex ) const

inline

Definition at line 138 of file RPage.hxx.

◆ GetBuffer()

void * ROOT::Experimental::Internal::RPage::GetBuffer ( ) const

inline

Definition at line 147 of file RPage.hxx.

◆ GetCapacity()

std::size_t ROOT::Experimental::Internal::RPage::GetCapacity ( ) const

inline

Definition at line 119 of file RPage.hxx.

◆ GetClusterInfo()

const RClusterInfo & ROOT::Experimental::Internal::RPage::GetClusterInfo ( ) const

inline

Definition at line 132 of file RPage.hxx.

◆ GetClusterRangeFirst()

ClusterSize_t::ValueType ROOT::Experimental::Internal::RPage::GetClusterRangeFirst ( ) const

inline

Definition at line 128 of file RPage.hxx.

◆ GetClusterRangeLast()

ClusterSize_t::ValueType ROOT::Experimental::Internal::RPage::GetClusterRangeLast ( ) const

inline

Definition at line 129 of file RPage.hxx.

◆ GetElementSize()

std::uint32_t ROOT::Experimental::Internal::RPage::GetElementSize ( ) const

inline

Definition at line 123 of file RPage.hxx.

◆ GetGlobalRangeFirst()

NTupleSize_t ROOT::Experimental::Internal::RPage::GetGlobalRangeFirst ( ) const

inline

Definition at line 126 of file RPage.hxx.

◆ GetGlobalRangeLast()

NTupleSize_t ROOT::Experimental::Internal::RPage::GetGlobalRangeLast ( ) const

inline

Definition at line 127 of file RPage.hxx.

◆ GetMaxElements()

std::uint32_t ROOT::Experimental::Internal::RPage::GetMaxElements ( ) const

inline

Definition at line 125 of file RPage.hxx.

◆ GetNBytes()

std::size_t ROOT::Experimental::Internal::RPage::GetNBytes ( ) const

inline

The space taken by column elements in the buffer.

Definition at line 115 of file RPage.hxx.

◆ GetNElements()

std::uint32_t ROOT::Experimental::Internal::RPage::GetNElements ( ) const

inline

Definition at line 124 of file RPage.hxx.

◆ GetPageZeroBuffer()

const void * ROOT::Experimental::Internal::RPage::GetPageZeroBuffer ( )

static

Return a pointer to the page zero buffer used if there is no on-disk data for a particular deferred column.

Definition at line 25 of file RPage.cxx.

◆ GrowUnchecked()

void * ROOT::Experimental::Internal::RPage::GrowUnchecked ( ClusterSize_t::ValueType nElements )

inline

Increases the number elements in the page.

The caller is responsible to respect the page capacity, i.e. to ensure that fNElements + nElements <= fMaxElements. Returns a pointer after the last element, which is used during writing in anticipation of the caller filling nElements in the page. When reading a page from disk, GrowUnchecked is used to set the actual number of elements. In this case, the return value is ignored.

Definition at line 154 of file RPage.hxx.

◆ IsEmpty()

bool ROOT::Experimental::Internal::RPage::IsEmpty ( ) const

inline

Definition at line 174 of file RPage.hxx.

◆ IsNull()

bool ROOT::Experimental::Internal::RPage::IsNull ( ) const

inline

Definition at line 173 of file RPage.hxx.

◆ operator!=()

bool ROOT::Experimental::Internal::RPage::operator!= ( const RPage & other ) const

inline

Definition at line 176 of file RPage.hxx.

◆ operator=() [1/2]

RPage & ROOT::Experimental::Internal::RPage::operator= ( const RPage & )

delete

◆ operator=() [2/2]

RPage & ROOT::Experimental::Internal::RPage::operator= ( RPage && other )

inline

Definition at line 99 of file RPage.hxx.

◆ operator==()

bool ROOT::Experimental::Internal::RPage::operator== ( const RPage & other ) const

inline

Definition at line 175 of file RPage.hxx.

◆ Reset()

void ROOT::Experimental::Internal::RPage::Reset ( NTupleSize_t rangeFirst )

inline

Forget all currently stored elements (size == 0) and set a new starting index.

Definition at line 167 of file RPage.hxx.

◆ ResetCluster()

void ROOT::Experimental::Internal::RPage::ResetCluster ( const RClusterInfo & clusterInfo )

inline

Definition at line 168 of file RPage.hxx.

◆ SetWindow()

void ROOT::Experimental::Internal::RPage::SetWindow	(	const NTupleSize_t	rangeFirst,
		const RClusterInfo &	clusterInfo
	)

inline

Seek the page to a certain position of the column.

Definition at line 162 of file RPage.hxx.

Friends And Related Symbol Documentation

◆ RPageRef

friend class RPageRef

friend

Definition at line 48 of file RPage.hxx.

Member Data Documentation

◆ fBuffer

void* ROOT::Experimental::Internal::RPage::fBuffer = nullptr

private

Definition at line 70 of file RPage.hxx.

◆ fClusterInfo

RClusterInfo ROOT::Experimental::Internal::RPage::fClusterInfo

private

Definition at line 78 of file RPage.hxx.

◆ fElementSize

std::uint32_t ROOT::Experimental::Internal::RPage::fElementSize = 0

private

Definition at line 73 of file RPage.hxx.

◆ fMaxElements

std::uint32_t ROOT::Experimental::Internal::RPage::fMaxElements = 0

private

The capacity of the page in number of elements.

Definition at line 76 of file RPage.hxx.

◆ fNElements

std::uint32_t ROOT::Experimental::Internal::RPage::fNElements = 0

private

Definition at line 74 of file RPage.hxx.

◆ fPageAllocator

RPageAllocator* ROOT::Experimental::Internal::RPage::fPageAllocator = nullptr

private

The allocator used to allocate fBuffer. Can be null if the buffer doesn't need to be freed.

Definition at line 72 of file RPage.hxx.

◆ fRangeFirst

NTupleSize_t ROOT::Experimental::Internal::RPage::fRangeFirst = 0

private

Definition at line 77 of file RPage.hxx.

◆ kPageZeroSize

constexpr size_t ROOT::Experimental::Internal::RPage::kPageZeroSize = 64 * 1024

staticconstexpr

Definition at line 51 of file RPage.hxx.

Libraries for ROOT::Experimental::Internal::RPage:

[legend]

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

tree/ntuple/v7/inc/ROOT/RPage.hxx
tree/ntuple/v7/src/RPage.cxx

Classes

Public Member Functions

Static Public Member Functions

Static Public Attributes

Private Attributes

Friends

Constructor & Destructor Documentation

◆ RPage() [1/4]

◆ RPage() [2/4]

◆ RPage() [3/4]

◆ RPage() [4/4]

◆ ~RPage()

Member Function Documentation

◆ Contains() [1/2]

◆ Contains() [2/2]

◆ GetBuffer()

◆ GetCapacity()

◆ GetClusterInfo()

◆ GetClusterRangeFirst()

◆ GetClusterRangeLast()

◆ GetElementSize()

◆ GetGlobalRangeFirst()

◆ GetGlobalRangeLast()

◆ GetMaxElements()

◆ GetNBytes()

◆ GetNElements()

◆ GetPageZeroBuffer()

◆ GrowUnchecked()

◆ IsEmpty()

◆ IsNull()

◆ operator!=()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ operator==()

◆ Reset()

◆ ResetCluster()

◆ SetWindow()

Friends And Related Symbol Documentation

◆ RPageRef

Member Data Documentation

◆ fBuffer

◆ fClusterInfo

◆ fElementSize

◆ fMaxElements

◆ fNElements

◆ fPageAllocator

◆ fRangeFirst

◆ kPageZeroSize