forked from boostorg/algorithm
Add new algorithm 'gather'
[SVN r82584]
This commit is contained in:
@ -58,6 +58,7 @@ Thanks to all the people who have reviewed this library and made suggestions for
|
||||
|
||||
[section:Misc Other Algorithms]
|
||||
[include clamp-hpp.qbk]
|
||||
[include gather.qbk]
|
||||
[include hex.qbk]
|
||||
[endsect]
|
||||
|
||||
|
79
doc/gather.qbk
Normal file
79
doc/gather.qbk
Normal file
@ -0,0 +1,79 @@
|
||||
[/ File gather.qbk]
|
||||
|
||||
[section:gather gather]
|
||||
|
||||
[/license
|
||||
Copyright (c) 2013 Marshall Clow
|
||||
|
||||
Distributed under the Boost Software License, Version 1.0.
|
||||
(See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
||||
]
|
||||
|
||||
The header file 'boost/algorithm/gather.hpp' contains two variants of a single algorithm, `gather`.
|
||||
|
||||
`gather()` takes a collection of elements defined by a pair of iterators and moves the ones satisfying a predicate to them to a position (called the pivot) within the sequence. The algorithm is stable. The result is a pair of iterators that contains the items that satisfy the predicate.
|
||||
|
||||
[heading Interface]
|
||||
|
||||
The function `gather` returns a `std::pair` of iterators that denote the elements that satisfy the predicate.
|
||||
|
||||
There are two versions; one takes two iterators, and the other takes a range.
|
||||
|
||||
``
|
||||
namespace boost { namespace algorithm {
|
||||
|
||||
template <typename ForwardIterator, typename Pred>
|
||||
std::pair<ForwardIterator,ForwardIterator>
|
||||
gather ( ForwardIterator first, ForwardIterator last, ForwardIterator pivot, Pred pred );
|
||||
|
||||
template <typename ForwardRange, typename Pred>
|
||||
std::pair<typename boost::range_iterator<ForwardRange>::type, typename boost::range_iterator<ForwardRange>::type>
|
||||
gather ( ForwardRange &range, typename boost::range_iterator<ForwardRange>::type pivot, Pred pred );
|
||||
|
||||
}}
|
||||
``
|
||||
|
||||
[heading Examples]
|
||||
|
||||
Given an sequence containing:
|
||||
``
|
||||
0 1 2 3 4 5 6 7 8 9
|
||||
``
|
||||
|
||||
a call to gather ( arr, arr + 10, arr + 4, IsEven ) will result in:
|
||||
|
||||
``
|
||||
1 3 0 2 4 6 8 5 7 9
|
||||
|---|-----|
|
||||
first | second
|
||||
pivot
|
||||
``
|
||||
where `first` and `second` are the fields of the pair that is returned by the call.
|
||||
|
||||
|
||||
[heading Iterator Requirements]
|
||||
|
||||
`gather` work on all iterators except input or output iterators.
|
||||
|
||||
[heading Storage Requirements]
|
||||
|
||||
`gather` uses stable_partition, which will attempt to allocate temporary memory, but will work in-situ if there is none available.
|
||||
|
||||
[heading Complexity]
|
||||
|
||||
If there is sufficient memory available, the run time is linear: `O(N)`
|
||||
|
||||
If there is not any memory available, then the run time is `O(N log N)`.
|
||||
|
||||
[heading Exception Safety]
|
||||
|
||||
[heading Notes]
|
||||
|
||||
[endsect]
|
||||
|
||||
[/ File gather.qbk
|
||||
Copyright 2013 Marshall Clow
|
||||
Distributed under the Boost Software License, Version 1.0.
|
||||
(See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt).
|
||||
]
|
||||
|
122
include/boost/algorithm/gather.hpp
Normal file
122
include/boost/algorithm/gather.hpp
Normal file
@ -0,0 +1,122 @@
|
||||
/*
|
||||
Copyright 2008 Adobe Systems Incorporated
|
||||
|
||||
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
||||
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
Revision history:
|
||||
January 2008 mtc Version for Adobe Source Library
|
||||
January 2013 mtc Version for Boost.Algorithm
|
||||
|
||||
*/
|
||||
|
||||
/**************************************************************************************************/
|
||||
|
||||
/*!
|
||||
\author Marshall Clow
|
||||
\date January 2008
|
||||
*/
|
||||
|
||||
#ifndef BOOST_ALGORITHM_GATHER_HPP
|
||||
#define ADOBE_ALGORITHM_GATHER_HPP
|
||||
|
||||
#include <algorithm> // for std::stable_partition
|
||||
#include <functional>
|
||||
|
||||
#include <boost/bind.hpp> // for boost::bind
|
||||
#include <boost/range/begin.hpp> // for boost::begin(range)
|
||||
#include <boost/range/end.hpp> // for boost::end(range)
|
||||
|
||||
|
||||
/**************************************************************************************************/
|
||||
/*!
|
||||
\defgroup gather gather
|
||||
\ingroup mutating_algorithm
|
||||
|
||||
\c gather() takes a collection of elements defined by a pair of iterators and moves
|
||||
the ones satisfying a predicate to them to a position (called the pivot) within
|
||||
the sequence. The algorithm is stable. The result is a pair of iterators that
|
||||
contains the items that satisfy the predicate.
|
||||
|
||||
Given an sequence containing:
|
||||
<pre>
|
||||
0 1 2 3 4 5 6 7 8 9
|
||||
</pre>
|
||||
|
||||
a call to gather ( arr, arr + 10, arr + 4, IsEven ()) will result in:
|
||||
|
||||
<pre>
|
||||
1 3 0 2 4 6 8 5 7 9
|
||||
|---|-----|
|
||||
first | second
|
||||
pivot
|
||||
</pre>
|
||||
|
||||
|
||||
The problem is broken down into two basic steps, namely, moving the items before the pivot
|
||||
and then moving the items from the pivot to the end. These "moves" are done with calls to
|
||||
stable_partition.
|
||||
|
||||
\par Storage Requirements:
|
||||
|
||||
The algorithm uses stable_partition, which will attempt to allocate temporary memory,
|
||||
but will work in-situ if there is none available.
|
||||
|
||||
\par Time Complexity:
|
||||
|
||||
If there is sufficient memory available, the run time is linear in <code>N</code>.
|
||||
If there is not any memory available, then the run time is <code>O(N log N)</code>.
|
||||
*/
|
||||
|
||||
/**************************************************************************************************/
|
||||
|
||||
namespace boost { namespace algorithm {
|
||||
|
||||
/**************************************************************************************************/
|
||||
|
||||
/*!
|
||||
\ingroup gather
|
||||
\brief iterator-based gather implementation
|
||||
*/
|
||||
|
||||
template <
|
||||
typename ForwardIterator, // Iter models ForwardIterator
|
||||
typename Pred> // Pred models UnaryPredicate
|
||||
std::pair<ForwardIterator,ForwardIterator> gather ( ForwardIterator first, ForwardIterator last, ForwardIterator pivot, Pred pred )
|
||||
{
|
||||
// The first call partitions everything up to (but not including) the pivot element,
|
||||
// while the second call partitions the rest of the sequence.
|
||||
return std::make_pair (
|
||||
std::stable_partition ( first, pivot, !boost::bind<bool> ( pred, _1 )),
|
||||
std::stable_partition ( pivot, last, boost::bind<bool> ( pred, _1 )));
|
||||
}
|
||||
|
||||
/**************************************************************************************************/
|
||||
|
||||
/*!
|
||||
\ingroup gather
|
||||
\brief range-based gather implementation
|
||||
*/
|
||||
|
||||
template <
|
||||
typename ForwardRange, //
|
||||
typename Pred> // Pred models UnaryPredicate
|
||||
std::pair<
|
||||
typename boost::range_iterator<ForwardRange>::type,
|
||||
typename boost::range_iterator<ForwardRange>::type>
|
||||
gather (
|
||||
ForwardRange &range,
|
||||
typename boost::range_iterator<ForwardRange>::type pivot,
|
||||
Pred pred )
|
||||
{
|
||||
return boost::algorithm::gather ( boost::begin ( range ), boost::end ( range ), pivot, pred );
|
||||
}
|
||||
|
||||
/**************************************************************************************************/
|
||||
|
||||
}} // namespace
|
||||
|
||||
/**************************************************************************************************/
|
||||
|
||||
#endif
|
||||
|
@ -46,10 +46,14 @@ import testing ;
|
||||
[ run hex_test2.cpp : : : : hex_test2 ]
|
||||
[ run hex_test3.cpp : : : : hex_test3 ]
|
||||
[ run hex_test4.cpp : : : : hex_test4 ]
|
||||
[ compile-fail hex_fail1.cpp ]
|
||||
[ compile-fail hex_fail1.cpp ]
|
||||
|
||||
# Wrapper tests
|
||||
[ run wrapper_test1.cpp : : : : wrapper_test1 ]
|
||||
|
||||
# Gather tests
|
||||
[ run gather_test1.cpp : : : : gather_test1 ]
|
||||
[ compile-fail gather_fail1.cpp ]
|
||||
;
|
||||
}
|
||||
|
||||
|
39
test/gather_fail1.cpp
Normal file
39
test/gather_fail1.cpp
Normal file
@ -0,0 +1,39 @@
|
||||
/*
|
||||
Copyright (c) Marshall Clow 2011-2012.
|
||||
|
||||
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
||||
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
For more information, see http://www.boost.org
|
||||
*/
|
||||
|
||||
#include <iostream>
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <boost/algorithm/gather.hpp>
|
||||
#include <boost/test/included/test_exec_monitor.hpp>
|
||||
|
||||
#include <string>
|
||||
#include <vector>
|
||||
#include <list>
|
||||
|
||||
#include "iterator_test.hpp"
|
||||
|
||||
namespace ba = boost::algorithm;
|
||||
|
||||
bool is_ten ( int i ) { return i == 10; }
|
||||
|
||||
void test_sequence1 () {
|
||||
std::vector<int> v;
|
||||
typedef input_iterator<std::vector<int>::iterator> II;
|
||||
|
||||
// This should fail to compile, since gather doesn't work with input iterators
|
||||
(void) ba::gather ( II( v.begin ()), II( v.end ()), II( v.begin ()), is_even );
|
||||
}
|
||||
|
||||
|
||||
int test_main( int , char* [] )
|
||||
{
|
||||
test_sequence1 ();
|
||||
return 0;
|
||||
}
|
139
test/gather_test1.cpp
Normal file
139
test/gather_test1.cpp
Normal file
@ -0,0 +1,139 @@
|
||||
/*
|
||||
Copyright (c) Marshall Clow 2011-2012.
|
||||
|
||||
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
||||
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
||||
|
||||
For more information, see http://www.boost.org
|
||||
*/
|
||||
|
||||
#include <iostream>
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <boost/algorithm/gather.hpp>
|
||||
#include <boost/test/included/test_exec_monitor.hpp>
|
||||
|
||||
#include <string>
|
||||
#include <vector>
|
||||
#include <list>
|
||||
|
||||
#include "iterator_test.hpp"
|
||||
|
||||
namespace ba = boost::algorithm;
|
||||
|
||||
template <typename Container>
|
||||
void print ( const char *prompt, const Container &c ) {
|
||||
std::cout << prompt << " { ";
|
||||
std::copy ( c.begin (), c.end (), std::ostream_iterator<typename Container::value_type>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
}
|
||||
|
||||
template <typename Iterator, typename Predicate>
|
||||
void test_iterators ( Iterator first, Iterator last, Predicate comp, std::size_t offset ) {
|
||||
// Create the pivot point
|
||||
Iterator off = first;
|
||||
std::advance(off, offset);
|
||||
|
||||
// Gather the elements
|
||||
std::pair<Iterator, Iterator> res = ba::gather ( first, last, off, comp );
|
||||
|
||||
// We should now have three sequences, any of which may be empty:
|
||||
// * [begin .. result.first) - items that do not satisfy the predicate
|
||||
// * [result.first .. result.second) - items that do satisfy the predicate
|
||||
// * [result.second .. end) - items that do not satisfy the predicate
|
||||
Iterator iter = first;
|
||||
for ( ; iter != res.first; ++iter )
|
||||
BOOST_CHECK ( !comp ( *iter ));
|
||||
for ( ; iter != res.second; ++iter)
|
||||
BOOST_CHECK ( comp ( *iter ));
|
||||
for ( ; iter != last; ++iter )
|
||||
BOOST_CHECK ( !comp ( *iter ));
|
||||
}
|
||||
|
||||
template <typename Container, typename Predicate>
|
||||
void test_iterator_types ( const Container &c, Predicate comp, std::size_t offset ) {
|
||||
typedef std::vector<typename Container::value_type> vec;
|
||||
typedef forward_iterator<typename vec::iterator> FI;
|
||||
typedef bidirectional_iterator<typename vec::iterator> BDI;
|
||||
typedef random_access_iterator<typename vec::iterator> RAI;
|
||||
|
||||
vec v;
|
||||
v.assign ( c.begin (), c.end ());
|
||||
test_iterators ( FI ( v.begin ()), FI ( v.end ()), comp, offset );
|
||||
v.assign ( c.begin (), c.end ());
|
||||
test_iterators ( BDI ( v.begin ()), BDI ( v.end ()), comp, offset );
|
||||
v.assign ( c.begin (), c.end ());
|
||||
test_iterators ( RAI ( v.begin ()), RAI ( v.end ()), comp, offset );
|
||||
}
|
||||
|
||||
|
||||
template <typename T>
|
||||
struct less_than {
|
||||
public:
|
||||
// typedef T argument_type;
|
||||
// typedef bool result_type;
|
||||
|
||||
less_than ( T foo ) : val ( foo ) {}
|
||||
less_than ( const less_than &rhs ) : val ( rhs.val ) {}
|
||||
|
||||
bool operator () ( const T &v ) const { return v < val; }
|
||||
private:
|
||||
less_than ();
|
||||
less_than operator = ( const less_than &rhs );
|
||||
T val;
|
||||
};
|
||||
|
||||
bool is_even ( int i ) { return i % 2 == 0; }
|
||||
bool is_ten ( int i ) { return i == 10; }
|
||||
|
||||
void test_sequence1 () {
|
||||
std::vector<int> v;
|
||||
|
||||
for ( int i = 5; i < 15; ++i )
|
||||
v.push_back ( i );
|
||||
test_iterator_types ( v, less_than<int>(10), 0 ); // at beginning
|
||||
test_iterator_types ( v, less_than<int>(10), 5 );
|
||||
test_iterator_types ( v, less_than<int>(10), v.size () - 1 ); // at end
|
||||
|
||||
test_iterator_types ( v, is_even, 0 );
|
||||
test_iterator_types ( v, is_even, 5 );
|
||||
test_iterator_types ( v, is_even, v.size () - 1 );
|
||||
|
||||
// Exactly one element in the sequence matches
|
||||
test_iterator_types ( v, is_ten, 0 );
|
||||
test_iterator_types ( v, is_ten, 5 );
|
||||
test_iterator_types ( v, is_ten, v.size () - 1 );
|
||||
|
||||
// Everything in the sequence matches
|
||||
test_iterator_types ( v, less_than<int>(99), 0 );
|
||||
test_iterator_types ( v, less_than<int>(99), 5 );
|
||||
test_iterator_types ( v, less_than<int>(99), v.size () - 1 );
|
||||
|
||||
// Nothing in the sequence matches
|
||||
test_iterator_types ( v, less_than<int>(0), 0 );
|
||||
test_iterator_types ( v, less_than<int>(0), 5 );
|
||||
test_iterator_types ( v, less_than<int>(0), v.size () - 1 );
|
||||
|
||||
// All the elements in the sequence are the same
|
||||
v.clear ();
|
||||
for ( int i = 0; i < 11; ++i )
|
||||
v.push_back ( 10 );
|
||||
|
||||
// Everything in the sequence matches
|
||||
test_iterator_types ( v, is_ten, 0 );
|
||||
test_iterator_types ( v, is_ten, 5 );
|
||||
test_iterator_types ( v, is_ten, v.size () - 1 );
|
||||
|
||||
// Nothing in the sequence matches
|
||||
test_iterator_types ( v, less_than<int>(5), 0 );
|
||||
test_iterator_types ( v, less_than<int>(5), 5 );
|
||||
test_iterator_types ( v, less_than<int>(5), v.size () - 1 );
|
||||
|
||||
}
|
||||
|
||||
|
||||
int test_main( int , char* [] )
|
||||
{
|
||||
test_sequence1 ();
|
||||
return 0;
|
||||
}
|
296
test/iterator_test.hpp
Normal file
296
test/iterator_test.hpp
Normal file
@ -0,0 +1,296 @@
|
||||
#ifndef ITERATOR_TEST_H
|
||||
#define ITERATOR_TEST_H
|
||||
|
||||
/*
|
||||
A set of iterator adapters for constructing test cases
|
||||
From an iterator (or a pointer), you can make any class of iterator.
|
||||
Assuming you want to degrade the capabilities.
|
||||
|
||||
Modeled closely on work that Howard Hinnant did for libc++.
|
||||
*/
|
||||
|
||||
#include <iterator>
|
||||
|
||||
// == Input Iterator ==
|
||||
template <typename It>
|
||||
class input_iterator {
|
||||
public:
|
||||
typedef std::input_iterator_tag iterator_category;
|
||||
typedef typename std::iterator_traits<It>::value_type value_type;
|
||||
typedef typename std::iterator_traits<It>::difference_type difference_type;
|
||||
typedef It pointer;
|
||||
typedef typename std::iterator_traits<It>::reference reference;
|
||||
|
||||
It base() const {return it_;}
|
||||
|
||||
input_iterator() : it_() {}
|
||||
explicit input_iterator(It it) : it_(it) {}
|
||||
|
||||
template <typename U>
|
||||
input_iterator(const input_iterator<U>& u) :it_(u.it_) {}
|
||||
|
||||
reference operator*() const {return *it_;}
|
||||
pointer operator->() const {return it_;}
|
||||
|
||||
input_iterator& operator++() {++it_; return *this;}
|
||||
input_iterator operator++(int) {input_iterator tmp(*this); ++(*this); return tmp;}
|
||||
|
||||
friend bool operator==(const input_iterator& x, const input_iterator& y)
|
||||
{return x.it_ == y.it_;}
|
||||
friend bool operator!=(const input_iterator& x, const input_iterator& y)
|
||||
{return !(x == y);}
|
||||
|
||||
private:
|
||||
It it_;
|
||||
template <typename U> friend class input_iterator;
|
||||
};
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator==(const input_iterator<T>& x, const input_iterator<U>& y)
|
||||
{
|
||||
return x.base() == y.base();
|
||||
}
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator!=(const input_iterator<T>& x, const input_iterator<U>& y)
|
||||
{
|
||||
return !(x == y);
|
||||
}
|
||||
|
||||
|
||||
// == Forward Iterator ==
|
||||
template <typename It>
|
||||
class forward_iterator {
|
||||
public:
|
||||
typedef std::forward_iterator_tag iterator_category;
|
||||
typedef typename std::iterator_traits<It>::value_type value_type;
|
||||
typedef typename std::iterator_traits<It>::difference_type difference_type;
|
||||
typedef It pointer;
|
||||
typedef typename std::iterator_traits<It>::reference reference;
|
||||
|
||||
It base() const {return it_;}
|
||||
|
||||
forward_iterator() : it_() {}
|
||||
explicit forward_iterator(It it) : it_(it) {}
|
||||
template <typename U>
|
||||
forward_iterator(const forward_iterator<U>& u) :it_(u.it_) {}
|
||||
|
||||
reference operator*() const {return *it_;}
|
||||
pointer operator->() const {return it_;}
|
||||
|
||||
forward_iterator& operator++() {++it_; return *this;}
|
||||
forward_iterator operator++(int) {forward_iterator tmp(*this); ++(*this); return tmp;}
|
||||
|
||||
friend bool operator==(const forward_iterator& x, const forward_iterator& y)
|
||||
{return x.it_ == y.it_;}
|
||||
friend bool operator!=(const forward_iterator& x, const forward_iterator& y)
|
||||
{return !(x == y);}
|
||||
private:
|
||||
It it_;
|
||||
|
||||
template <typename U> friend class forward_iterator;
|
||||
};
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator==(const forward_iterator<T>& x, const forward_iterator<U>& y)
|
||||
{
|
||||
return x.base() == y.base();
|
||||
}
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator!=(const forward_iterator<T>& x, const forward_iterator<U>& y)
|
||||
{
|
||||
return !(x == y);
|
||||
}
|
||||
|
||||
// == Bidirectional Iterator ==
|
||||
template <typename It>
|
||||
class bidirectional_iterator
|
||||
{
|
||||
public:
|
||||
typedef std::bidirectional_iterator_tag iterator_category;
|
||||
typedef typename std::iterator_traits<It>::value_type value_type;
|
||||
typedef typename std::iterator_traits<It>::difference_type difference_type;
|
||||
typedef It pointer;
|
||||
typedef typename std::iterator_traits<It>::reference reference;
|
||||
|
||||
It base() const {return it_;}
|
||||
|
||||
bidirectional_iterator() : it_() {}
|
||||
explicit bidirectional_iterator(It it) : it_(it) {}
|
||||
template <typename U>
|
||||
bidirectional_iterator(const bidirectional_iterator<U>& u) :it_(u.it_) {}
|
||||
|
||||
reference operator*() const {return *it_;}
|
||||
pointer operator->() const {return it_;}
|
||||
|
||||
bidirectional_iterator& operator++() {++it_; return *this;}
|
||||
bidirectional_iterator operator++(int) {bidirectional_iterator tmp(*this); ++(*this); return tmp;}
|
||||
|
||||
bidirectional_iterator& operator--() {--it_; return *this;}
|
||||
bidirectional_iterator operator--(int) {bidirectional_iterator tmp(*this); --(*this); return tmp;}
|
||||
private:
|
||||
It it_;
|
||||
template <typename U> friend class bidirectional_iterator;
|
||||
};
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator==(const bidirectional_iterator<T>& x, const bidirectional_iterator<U>& y)
|
||||
{
|
||||
return x.base() == y.base();
|
||||
}
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator!=(const bidirectional_iterator<T>& x, const bidirectional_iterator<U>& y)
|
||||
{
|
||||
return !(x == y);
|
||||
}
|
||||
|
||||
|
||||
// == Random Access Iterator ==
|
||||
template <typename It>
|
||||
class random_access_iterator {
|
||||
public:
|
||||
typedef std::random_access_iterator_tag iterator_category;
|
||||
typedef typename std::iterator_traits<It>::value_type value_type;
|
||||
typedef typename std::iterator_traits<It>::difference_type difference_type;
|
||||
typedef It pointer;
|
||||
typedef typename std::iterator_traits<It>::reference reference;
|
||||
|
||||
It base() const {return it_;}
|
||||
|
||||
random_access_iterator() : it_() {}
|
||||
explicit random_access_iterator(It it) : it_(it) {}
|
||||
template <typename U>
|
||||
random_access_iterator(const random_access_iterator<U>& u) :it_(u.it_) {}
|
||||
|
||||
reference operator*() const {return *it_;}
|
||||
pointer operator->() const {return it_;}
|
||||
|
||||
random_access_iterator& operator++() {++it_; return *this;}
|
||||
random_access_iterator operator++(int) {random_access_iterator tmp(*this); ++(*this); return tmp;}
|
||||
|
||||
random_access_iterator& operator--() {--it_; return *this;}
|
||||
random_access_iterator operator--(int) {random_access_iterator tmp(*this); --(*this); return tmp;}
|
||||
|
||||
random_access_iterator& operator+=(difference_type n) {it_ += n; return *this;}
|
||||
random_access_iterator operator+ (difference_type n) const {random_access_iterator tmp(*this); tmp += n; return tmp;}
|
||||
friend random_access_iterator operator+(difference_type n, random_access_iterator x) {x += n; return x;}
|
||||
|
||||
random_access_iterator& operator-=(difference_type n) {return *this += -n;}
|
||||
random_access_iterator operator- (difference_type n) const {random_access_iterator tmp(*this); tmp -= n; return tmp;}
|
||||
|
||||
reference operator[](difference_type n) const {return it_[n];}
|
||||
private:
|
||||
It it_;
|
||||
|
||||
template <typename U> friend class random_access_iterator;
|
||||
};
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator==(const random_access_iterator<T>& x, const random_access_iterator<U>& y)
|
||||
{
|
||||
return x.base() == y.base();
|
||||
}
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator!=(const random_access_iterator<T>& x, const random_access_iterator<U>& y)
|
||||
{
|
||||
return !(x == y);
|
||||
}
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator<(const random_access_iterator<T>& x, const random_access_iterator<U>& y)
|
||||
{
|
||||
return x.base() < y.base();
|
||||
}
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator<=(const random_access_iterator<T>& x, const random_access_iterator<U>& y)
|
||||
{
|
||||
return !(y < x);
|
||||
}
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator>(const random_access_iterator<T>& x, const random_access_iterator<U>& y)
|
||||
{
|
||||
return y < x;
|
||||
}
|
||||
|
||||
template <typename T, typename U>
|
||||
inline bool
|
||||
operator>=(const random_access_iterator<T>& x, const random_access_iterator<U>& y)
|
||||
{
|
||||
return !(x < y);
|
||||
}
|
||||
|
||||
template <typename T, typename U>
|
||||
inline typename std::iterator_traits<T>::difference_type
|
||||
operator-(const random_access_iterator<T>& x, const random_access_iterator<U>& y)
|
||||
{
|
||||
return x.base() - y.base();
|
||||
}
|
||||
|
||||
|
||||
// == Output Iterator ==
|
||||
template <typename It>
|
||||
class output_iterator {
|
||||
public:
|
||||
typedef std::output_iterator_tag iterator_category;
|
||||
typedef void value_type;
|
||||
typedef typename std::iterator_traits<It>::difference_type difference_type;
|
||||
typedef It pointer;
|
||||
typedef typename std::iterator_traits<It>::reference reference;
|
||||
|
||||
It base() const {return it_;}
|
||||
|
||||
output_iterator () {}
|
||||
explicit output_iterator(It it) : it_(it) {}
|
||||
|
||||
template <typename U>
|
||||
output_iterator(const output_iterator<U>& u) :it_(u.it_) {}
|
||||
|
||||
reference operator*() const {return *it_;}
|
||||
|
||||
output_iterator& operator++() {++it_; return *this;}
|
||||
output_iterator operator++(int) {output_iterator tmp(*this); ++(*this); return tmp;}
|
||||
|
||||
private:
|
||||
It it_;
|
||||
template <typename U> friend class output_iterator;
|
||||
};
|
||||
|
||||
// No comparison operators for output iterators
|
||||
|
||||
|
||||
// == Get the base of an iterator; used for comparisons ==
|
||||
template <typename Iter>
|
||||
inline Iter base(output_iterator<Iter> i) { return i.base(); }
|
||||
|
||||
template <typename Iter>
|
||||
inline Iter base(input_iterator<Iter> i) { return i.base(); }
|
||||
|
||||
template <typename Iter>
|
||||
inline Iter base(forward_iterator<Iter> i) { return i.base(); }
|
||||
|
||||
template <typename Iter>
|
||||
inline Iter base(bidirectional_iterator<Iter> i) { return i.base(); }
|
||||
|
||||
template <typename Iter>
|
||||
inline Iter base(random_access_iterator<Iter> i) { return i.base(); }
|
||||
|
||||
template <typename Iter> // everything else
|
||||
inline Iter base(Iter i) { return i; }
|
||||
|
||||
#endif // ITERATORS_H
|
Reference in New Issue
Block a user