70 lines
1.5 KiB
C++
70 lines
1.5 KiB
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2020
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#pragma once
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#include "td/utils/common.h"
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#include "td/utils/Span.h"
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#include <utility>
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namespace td {
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template <class T>
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class VectorQueue {
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public:
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template <class S>
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void push(S &&s) {
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vector_.emplace_back(std::forward<S>(s));
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}
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template <class... Args>
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void emplace(Args &&... args) {
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vector_.emplace_back(std::forward<Args>(args)...);
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}
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T pop() {
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try_shrink();
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return std::move(vector_[read_pos_++]);
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}
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void pop_n(size_t n) {
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read_pos_ += n;
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try_shrink();
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}
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const T &front() const {
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return vector_[read_pos_];
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}
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const T &back() const {
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return vector_.back();
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}
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bool empty() const {
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return size() == 0;
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}
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size_t size() const {
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return vector_.size() - read_pos_;
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}
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const T *data() const {
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return vector_.data() + read_pos_;
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}
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Span<T> as_span() const {
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return {data(), size()};
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}
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MutableSpan<T> as_mutable_span() {
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return {vector_.data() + read_pos_, size()};
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}
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private:
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vector<T> vector_;
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size_t read_pos_{0};
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void try_shrink() {
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if (read_pos_ * 2 > vector_.size() && read_pos_ > 4) {
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vector_.erase(vector_.begin(), vector_.begin() + read_pos_);
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read_pos_ = 0;
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}
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}
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};
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} // namespace td
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