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Merge pull request #24 from morinmorin/add_advance_and_distance

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Add boost::advance and boost::distance
This commit is contained in:
Edward Diener
2017-06-29 15:02:38 -04:00
committed by GitHub
parent cccbd8c6aa bb54ee7900
commit 18268069d9
5 changed files with 281 additions and 0 deletions
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85
include/boost/iterator/advance.hpp Normal file
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// Copyright (C) 2017 Michel Morin.
//
// 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)
#ifndef BOOST_ITERATOR_ADVANCE_HPP
#define BOOST_ITERATOR_ADVANCE_HPP
#include <boost/config.hpp>
#include <boost/iterator/iterator_categories.hpp>
#include <boost/iterator/iterator_traits.hpp>
namespace boost {
namespace iterators {
namespace detail {
template <typename InputIterator>
inline BOOST_CXX14_CONSTEXPR void
advance_impl(
InputIterator& it
, typename iterator_difference<InputIterator>::type n
, incrementable_traversal_tag
)
{
while (n > 0) {
++it;
--n;
}
}
template <typename BidirectionalIterator>
inline BOOST_CXX14_CONSTEXPR void
advance_impl(
BidirectionalIterator& it
, typename iterator_difference<BidirectionalIterator>::type n
, bidirectional_traversal_tag
)
{
if (n >= 0) {
while (n > 0) {
++it;
--n;
}
}
else {
while (n < 0) {
--it;
++n;
}
}
}
template <typename RandomAccessIterator>
inline BOOST_CXX14_CONSTEXPR void
advance_impl(
RandomAccessIterator& it
, typename iterator_difference<RandomAccessIterator>::type n
, random_access_traversal_tag
)
{
it += n;
}
}
namespace advance_adl_barrier {
template <typename InputIterator>
inline BOOST_CXX14_CONSTEXPR void
advance(InputIterator& it, typename iterator_difference<InputIterator>::type n)
{
detail::advance_impl(
it, n, typename iterator_traversal<InputIterator>::type()
);
}
}
using namespace advance_adl_barrier;
} // namespace iterators
using iterators::advance;
} // namespace boost
#endif

65
include/boost/iterator/distance.hpp Normal file
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// Copyright (C) 2017 Michel Morin.
//
// 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)
#ifndef BOOST_ITERATOR_DISTANCE_HPP
#define BOOST_ITERATOR_DISTANCE_HPP
#include <boost/config.hpp>
#include <boost/iterator/iterator_categories.hpp>
#include <boost/iterator/iterator_traits.hpp>
namespace boost {
namespace iterators {
namespace detail {
template <typename SinglePassIterator>
inline BOOST_CXX14_CONSTEXPR typename iterator_difference<SinglePassIterator>::type
distance_impl(
SinglePassIterator first
, SinglePassIterator last
, single_pass_traversal_tag
)
{
typename iterator_difference<SinglePassIterator>::type n = 0;
while (first != last) {
++first;
++n;
}
return n;
}
template <typename RandomAccessIterator>
inline BOOST_CXX14_CONSTEXPR typename iterator_difference<RandomAccessIterator>::type
distance_impl(
RandomAccessIterator first
, RandomAccessIterator last
, random_access_traversal_tag
)
{
return last - first;
}
}
namespace distance_adl_barrier {
template <typename SinglePassIterator>
inline BOOST_CXX14_CONSTEXPR typename iterator_difference<SinglePassIterator>::type
distance(SinglePassIterator first, SinglePassIterator last)
{
return detail::distance_impl(
first, last, typename iterator_traversal<SinglePassIterator>::type()
);
}
}
using namespace distance_adl_barrier;
} // namespace iterators
using iterators::distance;
} // namespace boost
#endif

3
test/Jamfile.v2
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@ -55,4 +55,7 @@ test-suite iterator
[ run minimum_category.cpp ] [ run minimum_category.cpp ]
[ compile-fail minimum_category_compile_fail.cpp ] [ compile-fail minimum_category_compile_fail.cpp ]
[ run advance_test.cpp ]
[ run distance_test.cpp ]
; ;

65
test/advance_test.cpp Normal file
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// Copyright (C) 2017 Michel Morin.
//
// 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)
#include <vector>
#include <list>
#include <boost/container/slist.hpp>
#include <boost/core/lightweight_test.hpp>
#include <boost/iterator/advance.hpp>
#include <boost/iterator/transform_iterator.hpp>
int twice(int x) { return x + x; }
template <typename Iterator>
void test_advance(Iterator it_from, Iterator it_to, int n)
{
boost::advance(it_from, n);
BOOST_TEST(it_from == it_to);
}
int main()
{
int array[3] = {1, 2, 3};
int* ptr1 = array;
int* ptr2 = array + 3;
{
test_advance(ptr1, ptr2, 3);
test_advance(ptr2, ptr1, -3);
}
{
std::vector<int> ints(ptr1, ptr2);
test_advance(ints.begin(), ints.end(), 3);
test_advance(ints.end(), ints.begin(), -3);
}
{
test_advance(
boost::make_transform_iterator(ptr1, twice)
, boost::make_transform_iterator(ptr2, twice)
, 3
);
test_advance(
boost::make_transform_iterator(ptr2, twice)
, boost::make_transform_iterator(ptr1, twice)
, -3
);
}
{
std::list<int> ints(ptr1, ptr2);
test_advance(ints.begin(), ints.end(), 3);
test_advance(ints.end(), ints.begin(), -3);
}
{
boost::container::slist<int> ints(ptr1, ptr2);
test_advance(ints.begin(), ints.end(), 3);
}
return boost::report_errors();
}

63
test/distance_test.cpp Normal file
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// Copyright (C) 2017 Michel Morin.
//
// 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)
#include <vector>
#include <list>
#include <boost/container/slist.hpp>
#include <boost/core/lightweight_test.hpp>
#include <boost/iterator/distance.hpp>
#include <boost/iterator/transform_iterator.hpp>
int twice(int x) { return x + x; }
template <typename Iterator>
void test_distance(Iterator it_from, Iterator it_to, int n)
{
BOOST_TEST(boost::distance(it_from, it_to) == n);
}
int main()
{
int array[3] = {1, 2, 3};
int* ptr1 = array;
int* ptr2 = array + 3;
{
test_distance(ptr1, ptr2, 3);
test_distance(ptr2, ptr1, -3);
}
{
std::vector<int> ints(ptr1, ptr2);
test_distance(ints.begin(), ints.end(), 3);
test_distance(ints.end(), ints.begin(), -3);
}
{
test_distance(
boost::make_transform_iterator(ptr1, twice)
, boost::make_transform_iterator(ptr2, twice)
, 3
);
test_distance(
boost::make_transform_iterator(ptr2, twice)
, boost::make_transform_iterator(ptr1, twice)
, -3
);
}
{
std::list<int> ints(ptr1, ptr2);
test_distance(ints.begin(), ints.end(), 3);
}
{
boost::container::slist<int> ints(ptr1, ptr2);
test_distance(ints.begin(), ints.end(), 3);
}
return boost::report_errors();
}