Regina Calculation Engine
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regina::LightweightSequence< T >::SubsequenceCompareFirstPtr< Iterator > Class Template Reference

A binary function object for comparing subsequences, for use in associative containers whose keys are pointers to sequences. More...

#include <utilities/sequence.h>

Public Member Functions

 SubsequenceCompareFirstPtr (size_t nSub, const size_t *sub)
 Creates a new function object. More...
 
 SubsequenceCompareFirstPtr (const SubsequenceCompareFirstPtr< Iterator > &)=default
 Copies the given function object into this new object. More...
 
SubsequenceCompareFirstPtr< Iterator > & operator= (const SubsequenceCompareFirstPtr< Iterator > &)=default
 Copies the given function object into this object. More...
 
bool equal (Iterator a, Iterator b) const
 Tests whether the subsequences referred to by the given pair of iterators are identical. More...
 
bool less (Iterator a, Iterator b) const
 Lexicographically compares the subsequences referred to by the given pair of iterators. More...
 
bool operator() (Iterator a, Iterator b) const
 Lexicographically compares the subsequences referred to by the given pair of iterators. More...
 

Detailed Description

template<typename T>
template<typename Iterator>
class regina::LightweightSequence< T >::SubsequenceCompareFirstPtr< Iterator >

A binary function object for comparing subsequences, for use in associative containers whose keys are pointers to sequences.

This is a very specialised comparison object, for use in the following settings:

More precisely: suppose the indices of the elements to compare are i0, i1, i2, ..., and that we are comparing iterators a, b. Then this function object will consider the sequences s = *(a->first) and t = *(b->first), and will lexicographically compare their subsequences s[i0], s[i1], ... and t[i0], t[i1], ....

Note that the indices i0, i1, ... do not need to be in increasing order.

This class is meant to be lightweight: it merely stores a reference to the list of elements to compare, and it is safe and fast to pass around by value. The cost of this is that the caller must ensure that the list of elements to compare (which is a C-style array) has a lifespan at least as long as this object. This behaviour is new as of Regina 5.3; in past versions of Regina the list of elements was copied on construction.

Constructor & Destructor Documentation

◆ SubsequenceCompareFirstPtr() [1/2]

template<typename T >
template<typename Iterator >
regina::LightweightSequence< T >::SubsequenceCompareFirstPtr< Iterator >::SubsequenceCompareFirstPtr ( size_t  nSub,
const size_t *  sub 
)
inline

Creates a new function object.

As explained in the class notes, this object compares just some, not necessarily all, elements of two sequences. The indices of the elements to compare should be passed to this constructor.

Warning
This class merely copies the pointer sub, and does not take a deep copy. The caller of this routine must ensure that the array sub has a lifespan at least as long as this function object and any function objects that are copied from it.
Parameters
nSubthe number of elements to compare from each sequence.
subthe indices of the elements to compare from each sequence; that is, the indices i0, i1, ..., as described in the class notes.

◆ SubsequenceCompareFirstPtr() [2/2]

template<typename T >
template<typename Iterator >
regina::LightweightSequence< T >::SubsequenceCompareFirstPtr< Iterator >::SubsequenceCompareFirstPtr ( const SubsequenceCompareFirstPtr< Iterator > &  )
default

Copies the given function object into this new object.

Member Function Documentation

◆ equal()

template<typename T >
template<typename Iterator >
bool regina::LightweightSequence< T >::SubsequenceCompareFirstPtr< Iterator >::equal ( Iterator  a,
Iterator  b 
) const
inline

Tests whether the subsequences referred to by the given pair of iterators are identical.

See the class notes for details on how each iterator is converted into a subsequence.

Parameters
aan iterator indicating the first of the two subsequences to compare.
ban iterator indicating the second of the two subsequences to compare.
Returns
true if and only if the two subsequences are identical.

◆ less()

template<typename T >
template<typename Iterator >
bool regina::LightweightSequence< T >::SubsequenceCompareFirstPtr< Iterator >::less ( Iterator  a,
Iterator  b 
) const
inline

Lexicographically compares the subsequences referred to by the given pair of iterators.

See the class notes for details on how each iterator is converted into a subsequence.

This member function is identical to the bracket operator.

Parameters
aan iterator indicating the first of the two subsequences to compare.
ban iterator indicating the second of the two subsequences to compare.
Returns
true if and only if the subsequence indicated by a is lexicographically smaller than the subsequence indicated by b.

◆ operator()()

template<typename T >
template<typename Iterator >
bool regina::LightweightSequence< T >::SubsequenceCompareFirstPtr< Iterator >::operator() ( Iterator  a,
Iterator  b 
) const
inline

Lexicographically compares the subsequences referred to by the given pair of iterators.

See the class notes for details on how each iterator is converted into a subsequence.

This bracket operator is identical to the less() member function.

Parameters
aan iterator indicating the first of the two subsequences to compare.
ban iterator indicating the second of the two subsequences to compare.
Returns
true if and only if the subsequence indicated by a is lexicographically smaller than the subsequence indicated by b.

◆ operator=()

template<typename T >
template<typename Iterator >
SubsequenceCompareFirstPtr<Iterator>& regina::LightweightSequence< T >::SubsequenceCompareFirstPtr< Iterator >::operator= ( const SubsequenceCompareFirstPtr< Iterator > &  )
default

Copies the given function object into this object.

Returns
a reference to this function object.

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

Copyright © 1999-2018, The Regina development team
This software is released under the GNU General Public License, with some additional permissions; see the source code for details.
For further information, or to submit a bug or other problem, please contact Ben Burton (bab@maths.uq.edu.au).