mirror of
https://github.com/boostorg/iterator.git
synced 2026-07-05 16:10:48 +02:00
Jeremy W. Murphy
286c9885d6
* Constrain distance function using is_iterator type trait * Add enable_if include * Fix template syntax in distance function * Fix syntax issue in distance enable_if * Test which overload of distance is called Added a test for custom distance function using Foo struct. * Fix wrong spelling of std::ptrdiff_t * Move Foo struct to global scope * Andrey magic * Fix headers, add copyright * Constrain advance to iterators * Test contraint of advance function with int overload Added overload for advance function to handle integers. * Fix enable_if condition for advance function * Fix template syntax in advance constraint * Fix advance test * Remove constexpr specifier * Make advance overload require conversion in parameter * Explain choice of type long for n parameter
99 lines
2.5 KiB
C++
99 lines
2.5 KiB
C++
// Copyright (C) 2017 Michel Morin.
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#include <cstddef>
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#include <vector>
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#include <list>
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#include <boost/container/slist.hpp>
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#include <boost/core/lightweight_test.hpp>
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#include <boost/iterator/distance.hpp>
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#include <boost/iterator/transform_iterator.hpp>
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int twice(int x) { return x + x; }
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template <typename Iterator>
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void test_distance(Iterator it_from, Iterator it_to, int n)
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{
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BOOST_TEST(boost::distance(it_from, it_to) == n);
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}
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// Definitely not an iterator.
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struct Foo
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{
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constexpr friend
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std::ptrdiff_t distance(Foo const &, Foo const &) { return -1; }
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};
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int main()
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{
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int array[3] = {1, 2, 3};
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int* ptr1 = array;
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int* ptr2 = array + 3;
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{
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test_distance(ptr1, ptr2, 3);
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test_distance(ptr2, ptr1, -3);
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test_distance(
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boost::make_transform_iterator(ptr1, twice)
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, boost::make_transform_iterator(ptr2, twice)
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, 3
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);
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test_distance(
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boost::make_transform_iterator(ptr2, twice)
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, boost::make_transform_iterator(ptr1, twice)
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, -3
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);
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}
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{
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std::vector<int> ints(ptr1, ptr2);
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test_distance(ints.begin(), ints.end(), 3);
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test_distance(ints.end(), ints.begin(), -3);
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test_distance(
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boost::make_transform_iterator(ints.begin(), twice)
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, boost::make_transform_iterator(ints.end(), twice)
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, 3
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);
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test_distance(
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boost::make_transform_iterator(ints.end(), twice)
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, boost::make_transform_iterator(ints.begin(), twice)
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, -3
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);
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}
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{
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std::list<int> ints(ptr1, ptr2);
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test_distance(ints.begin(), ints.end(), 3);
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test_distance(
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boost::make_transform_iterator(ints.begin(), twice)
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, boost::make_transform_iterator(ints.end(), twice)
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, 3
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);
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}
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{
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boost::container::slist<int> ints(ptr1, ptr2);
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test_distance(ints.begin(), ints.end(), 3);
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test_distance(
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boost::make_transform_iterator(ints.begin(), twice)
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, boost::make_transform_iterator(ints.end(), twice)
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, 3
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);
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}
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{
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// Make boost::distance visible since we're not actually in the boost namespace here.
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using boost::distance;
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auto result = distance(Foo{}, Foo{});
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BOOST_TEST(result == -1);
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}
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return boost::report_errors();
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}
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