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. The memory buffer is not managed by the page. It is normally registered with the page pool and allocated/freed by the page storage.

Definition at line 41 of file RPage.hxx.

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

Public Member Functions
	RPage ()

	RPage (ColumnId_t columnId, void *buffer, ClusterSize_t::ValueType elementSize, ClusterSize_t::ValueType maxElements)

	~RPage ()=default

void	ChangeIds (DescriptorId_t columnId, DescriptorId_t clusterId)
	Used by virtual page sources to map the physical column and cluster IDs to ther virtual counterparts.

bool	Contains (NTupleSize_t globalIndex) const

bool	Contains (RClusterIndex clusterIndex) const

void *	GetBuffer () const

const RClusterInfo &	GetClusterInfo () const

ClusterSize_t::ValueType	GetClusterRangeFirst () const

ClusterSize_t::ValueType	GetClusterRangeLast () const

ColumnId_t	GetColumnId () const

NTupleSize_t	GetGlobalRangeFirst () const

NTupleSize_t	GetGlobalRangeLast () const

std::uint32_t	GetMaxElements () const

std::uint32_t	GetNBytes () const
	The space taken by column elements in the buffer.

std::uint32_t	GetNElements () const

void *	GrowUnchecked (ClusterSize_t::ValueType nElements)
	Called during writing: returns a pointer after the last element and increases the element counter in anticipation of the caller filling nElements in the page.

bool	IsEmpty () const

bool	IsNull () const

bool	IsPageZero () const

bool	operator!= (const RPage &other) const

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 RPage	MakePageZero (ColumnId_t columnId, ClusterSize_t::ValueType elementSize)
	Make a 'zero' page for column `columnId` (that is comprised of 0x00 bytes only).

Static Public Attributes
static constexpr size_t	kPageZeroSize = 64 * 1024

Private Attributes
void *	fBuffer

RClusterInfo	fClusterInfo

ColumnId_t	fColumnId

std::uint32_t	fElementSize

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

std::uint32_t	fNElements

NTupleSize_t	fRangeFirst

#include <ROOT/RPage.hxx>

Constructor & Destructor Documentation

◆ RPage() [1/2]

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

inline

Definition at line 72 of file RPage.hxx.

◆ RPage() [2/2]

ROOT::Experimental::Internal::RPage::RPage	(	ColumnId_t	columnId,
		void *	buffer,
		ClusterSize_t::ValueType	elementSize,
		ClusterSize_t::ValueType	maxElements )

inline

Definition at line 75 of file RPage.hxx.

◆ ~RPage()

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

default

Member Function Documentation

◆ ChangeIds()

void ROOT::Experimental::Internal::RPage::ChangeIds	(	DescriptorId_t	columnId,
		DescriptorId_t	clusterId )

inline

Used by virtual page sources to map the physical column and cluster IDs to ther virtual counterparts.

Definition at line 126 of file RPage.hxx.

◆ Contains() [1/2]

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

inline

Definition at line 94 of file RPage.hxx.

◆ Contains() [2/2]

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

inline

Definition at line 98 of file RPage.hxx.

◆ GetBuffer()

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

inline

Definition at line 107 of file RPage.hxx.

◆ GetClusterInfo()

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

inline

Definition at line 92 of file RPage.hxx.

◆ GetClusterRangeFirst()

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

inline

Definition at line 88 of file RPage.hxx.

◆ GetClusterRangeLast()

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

inline

Definition at line 89 of file RPage.hxx.

◆ GetColumnId()

ColumnId_t ROOT::Experimental::Internal::RPage::GetColumnId ( ) const

inline

Definition at line 81 of file RPage.hxx.

◆ GetGlobalRangeFirst()

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

inline

Definition at line 86 of file RPage.hxx.

◆ GetGlobalRangeLast()

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

inline

Definition at line 87 of file RPage.hxx.

◆ GetMaxElements()

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

inline

Definition at line 85 of file RPage.hxx.

◆ GetNBytes()

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

inline

The space taken by column elements in the buffer.

Definition at line 83 of file RPage.hxx.

◆ GetNElements()

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

inline

Definition at line 84 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 18 of file RPage.cxx.

◆ GrowUnchecked()

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

inline

Called during writing: returns a pointer after the last element and increases the element counter in anticipation of the caller filling nElements in the page.

It is the responsibility of the caller to prevent page overflows, i.e. that fNElements + nElements <= fMaxElements

Definition at line 111 of file RPage.hxx.

◆ IsEmpty()

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

inline

Definition at line 144 of file RPage.hxx.

◆ IsNull()

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

inline

Definition at line 142 of file RPage.hxx.

◆ IsPageZero()

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

inline

Definition at line 143 of file RPage.hxx.

◆ MakePageZero()

static RPage ROOT::Experimental::Internal::RPage::MakePageZero	(	ColumnId_t	columnId,
		ClusterSize_t::ValueType	elementSize )

inlinestatic

Make a 'zero' page for column columnId (that is comprised of 0x00 bytes only).

The caller is responsible for invoking GrowUnchecked() and SetWindow() as appropriate.

Definition at line 134 of file RPage.hxx.

◆ operator!=()

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

inline

Definition at line 146 of file RPage.hxx.

◆ operator==()

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

inline

Definition at line 145 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 122 of file RPage.hxx.

◆ ResetCluster()

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

inline

Definition at line 123 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 117 of file RPage.hxx.

Member Data Documentation

◆ fBuffer

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

private

Definition at line 63 of file RPage.hxx.

◆ fClusterInfo

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

private

Definition at line 69 of file RPage.hxx.

◆ fColumnId

ColumnId_t ROOT::Experimental::Internal::RPage::fColumnId

private

Definition at line 62 of file RPage.hxx.

◆ fElementSize

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

private

Definition at line 64 of file RPage.hxx.

◆ fMaxElements

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

private

The capacity of the page in number of elements.

Definition at line 67 of file RPage.hxx.

◆ fNElements

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

private

Definition at line 65 of file RPage.hxx.

◆ fRangeFirst

NTupleSize_t ROOT::Experimental::Internal::RPage::fRangeFirst

private

Definition at line 68 of file RPage.hxx.

◆ kPageZeroSize

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

staticconstexpr

Definition at line 43 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

Constructor & Destructor Documentation

◆ RPage() [1/2]

◆ RPage() [2/2]

◆ ~RPage()

Member Function Documentation

◆ ChangeIds()

◆ Contains() [1/2]

◆ Contains() [2/2]

◆ GetBuffer()

◆ GetClusterInfo()

◆ GetClusterRangeFirst()

◆ GetClusterRangeLast()

◆ GetColumnId()

◆ GetGlobalRangeFirst()

◆ GetGlobalRangeLast()

◆ GetMaxElements()

◆ GetNBytes()

◆ GetNElements()

◆ GetPageZeroBuffer()

◆ GrowUnchecked()

◆ IsEmpty()

◆ IsNull()

◆ IsPageZero()

◆ MakePageZero()

◆ operator!=()

◆ operator==()

◆ Reset()

◆ ResetCluster()

◆ SetWindow()

Member Data Documentation

◆ fBuffer

◆ fClusterInfo

◆ fColumnId

◆ fElementSize

◆ fMaxElements

◆ fNElements

◆ fRangeFirst

◆ kPageZeroSize