123 lines
4.0 KiB
C++
123 lines
4.0 KiB
C++
/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef TNT_UTILS_ZIP2ITERATOR_H
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#define TNT_UTILS_ZIP2ITERATOR_H
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#include <iterator>
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#include <type_traits>
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#include <utils/compiler.h>
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namespace utils {
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/*
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* A random access iterator that wraps two other random access iterators.
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* This mostly exists so that one can sort an array using values from another.
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*/
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template<typename It1, typename It2>
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class Zip2Iterator {
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std::pair<It1, It2> mIt;
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using Ref1 = typename std::iterator_traits<It1>::reference;
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using Ref2 = typename std::iterator_traits<It2>::reference;
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using Val1 = typename std::iterator_traits<It1>::value_type;
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using Val2 = typename std::iterator_traits<It2>::value_type;
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public:
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struct Ref : public std::pair<Ref1, Ref2> {
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using std::pair<Ref1, Ref2>::pair;
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using std::pair<Ref1, Ref2>::operator=;
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private:
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friend void swap(Ref lhs, Ref rhs) {
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using std::swap;
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swap(lhs.first, rhs.first);
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swap(lhs.second, rhs.second);
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}
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};
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using value_type = std::pair<Val1, Val2>;
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using reference = Ref;
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using pointer = value_type*;
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using difference_type = ptrdiff_t;
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using iterator_category = std::random_access_iterator_tag;
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Zip2Iterator() = default;
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Zip2Iterator(It1 first, It2 second) : mIt({first, second}) {}
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Zip2Iterator(Zip2Iterator const& rhs) noexcept = default;
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Zip2Iterator& operator=(Zip2Iterator const& rhs) = default;
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reference operator*() const { return { *mIt.first, *mIt.second }; }
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reference operator[](size_t n) const { return *(*this + n); }
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Zip2Iterator& operator++() {
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++mIt.first;
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++mIt.second;
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return *this;
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}
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Zip2Iterator& operator--() {
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--mIt.first;
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--mIt.second;
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return *this;
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}
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// Postfix operator needed by Microsoft C++
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const Zip2Iterator operator++(int) {
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Zip2Iterator t(*this);
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mIt.first++;
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mIt.second++;
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return t;
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}
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const Zip2Iterator operator--(int) {
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Zip2Iterator t(*this);
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mIt.first--;
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mIt.second--;
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return t;
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}
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Zip2Iterator& operator+=(size_t v) {
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mIt.first += v;
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mIt.second += v;
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return *this;
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}
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Zip2Iterator& operator-=(size_t v) {
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mIt.first -= v;
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mIt.second -= v;
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return *this;
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}
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Zip2Iterator operator+(size_t rhs) const { return { mIt.first + rhs, mIt.second + rhs }; }
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Zip2Iterator operator+(size_t rhs) { return { mIt.first + rhs, mIt.second + rhs }; }
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Zip2Iterator operator-(size_t rhs) const { return { mIt.first - rhs, mIt.second - rhs }; }
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difference_type operator-(Zip2Iterator const& rhs) const { return mIt.first - rhs.mIt.first; }
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bool operator==(Zip2Iterator const& rhs) const { return (mIt.first == rhs.mIt.first); }
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bool operator!=(Zip2Iterator const& rhs) const { return (mIt.first != rhs.mIt.first); }
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bool operator>=(Zip2Iterator const& rhs) const { return (mIt.first >= rhs.mIt.first); }
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bool operator> (Zip2Iterator const& rhs) const { return (mIt.first > rhs.mIt.first); }
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bool operator<=(Zip2Iterator const& rhs) const { return (mIt.first <= rhs.mIt.first); }
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bool operator< (Zip2Iterator const& rhs) const { return (mIt.first < rhs.mIt.first); }
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};
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} // namespace utils
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#endif /* TNT_UTILS_ZIP2ITERATOR_H */
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