59 lines
1.6 KiB
C++
59 lines
1.6 KiB
C++
#ifndef INTEGER_RANGE_HPP
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#define INTEGER_RANGE_HPP
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#include <boost/assert.hpp>
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#include <type_traits>
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#include <cstdint>
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namespace osrm
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{
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namespace util
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{
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// Warning: do not try to replace this with Boost's irange, as it is broken on Boost 1.55:
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// auto r = boost::irange<unsigned int>(0, 15);
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// std::cout << r.size() << std::endl;
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// results in -4294967281. Latest Boost versions fix this, but we still support older ones.
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template <typename Integer> class range
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{
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private:
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const Integer last;
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Integer iter;
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public:
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range(Integer start, Integer end) noexcept : last(end), iter(start)
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{
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BOOST_ASSERT_MSG(start <= end, "backwards counting ranges not suppoted");
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static_assert(std::is_integral<Integer>::value, "range type must be integral");
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}
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// Iterable functions
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const range &begin() const noexcept { return *this; }
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const range &end() const noexcept { return *this; }
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Integer front() const noexcept { return iter; }
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Integer back() const noexcept { return last - 1; }
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std::size_t size() const noexcept { return static_cast<std::size_t>(last - iter); }
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// Iterator functions
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bool operator!=(const range &) const noexcept { return iter < last; }
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void operator++() noexcept { ++iter; }
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Integer operator*() const noexcept { return iter; }
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};
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// convenience function to construct an integer range with type deduction
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template <typename Integer>
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range<Integer>
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irange(const Integer first,
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const Integer last,
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typename std::enable_if<std::is_integral<Integer>::value>::type * = 0) noexcept
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{
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return range<Integer>(first, last);
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}
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}
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}
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#endif // INTEGER_RANGE_HPP
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