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
113 lines
2.8 KiB
C++
113 lines
2.8 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 <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/advance.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_advance(Iterator it_from, Iterator it_to, int n)
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{
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boost::advance(it_from, n);
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BOOST_TEST(it_from == it_to);
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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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int x = 0;
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// Don't use type "int" for "n", otherwise it matches literal int exactly
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// and doesn't demonstrate the effect of enable_if.
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friend
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void advance(Foo &value, long n)
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{
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value.x += 10 * n;
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}
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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_advance(ptr1, ptr2, 3);
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test_advance(ptr2, ptr1, -3);
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test_advance(
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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_advance(
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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_advance(ints.begin(), ints.end(), 3);
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test_advance(ints.end(), ints.begin(), -3);
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test_advance(
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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_advance(
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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_advance(ints.begin(), ints.end(), 3);
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test_advance(ints.end(), ints.begin(), -3);
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test_advance(
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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_advance(
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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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boost::container::slist<int> ints(ptr1, ptr2);
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test_advance(ints.begin(), ints.end(), 3);
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test_advance(
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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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using boost::advance;
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Foo bar;
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advance(bar, 3);
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BOOST_TEST(bar.x == 30);
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}
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return boost::report_errors();
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}
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