SG::JaggedVecEltBase Class Reference

Describe one element of a jagged vector (base class). More...

#include <JaggedVecImpl.h>

Inheritance diagram for SG::JaggedVecEltBase:

Collaboration diagram for SG::JaggedVecEltBase:

Classes
struct	Shift
	Helper to shift indices. More...

Public Types
using	index_type = uint32_t
	Type for the indices. More...

Public Member Functions
	JaggedVecEltBase ()=default
	Default constructor. More...
	JaggedVecEltBase (index_type end)
	Constructor. More...
index_type	begin (size_t elt_ndx) const
	Return the index of the beginning of the range. More...
index_type	end () const
	Return the index of the end of the range. More...
size_t	size (size_t elt_ndx) const
	Return the number of items in this range. More...
bool	operator== (const JaggedVecEltBase &other) const
	Equality test. More...

Private Attributes
index_type	m_end = 0
	End index. More...

Friends
struct	Shift

Detailed Description

Describe one element of a jagged vector (base class).

Each jagged vector element holds its end index into the linked payload vector. The begin index is given by the end index of the previous element. Thus, these elements must be allocated as a contiguous vector. Further, in order to get the begin index, we need to know the index of this element object within its vector — because we have to special-case the first element.

For example, if we have a jagged vector with three elements of sizes 3, 1, 2, then what we would store is {3, 4, 6}.

This implies that one cannot interpret a JaggedVecElt in isolation (or a range of them); we need to know where they are stored in the xAOD variable vector. Fortunately, that's not something that is typically done, since jagged vectors are accessed via the specialized Accessor classes.

This non-templated base class holds the actual data. However, users should use the JaggedVecElt<PAYLOAD> derived types, to allow specifying the payload type.

Definition at line 51 of file JaggedVecImpl.h.

Member Typedef Documentation

index_type

using SG::JaggedVecEltBase::index_type = uint32_t

Type for the indices.

16 bits is probably too small, 64 bits is pretty definitely too large. Use 32.

Definition at line 56 of file JaggedVecImpl.h.

Constructor & Destructor Documentation

JaggedVecEltBase() [1/2]

SG::JaggedVecEltBase::JaggedVecEltBase ( )

default

Default constructor.

Makes a null range.

JaggedVecEltBase() [2/2]

SG::JaggedVecEltBase::JaggedVecEltBase

(

index_type

end

)

Constructor.

Parameters

beg	Index of the start of the range.
end	Index of the end of the range.

Member Function Documentation

begin()

index_type SG::JaggedVecEltBase::begin

(

size_t

elt_ndx

)

const

Return the index of the beginning of the range.

Parameters

elt_ndx

The index of this element in its container.

end()

index_type SG::JaggedVecEltBase::end

(

)

const

Return the index of the end of the range.

operator==()

bool SG::JaggedVecEltBase::operator==

(

const JaggedVecEltBase &

other

)

const

Equality test.

Parameters

other

Other element with which to compare.

size()

size_t SG::JaggedVecEltBase::size

(

size_t

elt_ndx

)

const

Return the number of items in this range.

Parameters

elt_ndx

The index of this element in its container.

Friends And Related Function Documentation

Shift

friend struct Shift

friend

Definition at line 119 of file JaggedVecImpl.h.

Member Data Documentation

m_end

index_type SG::JaggedVecEltBase::m_end = 0

private

End index.

Definition at line 122 of file JaggedVecImpl.h.

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

• JaggedVecImpl.h