// // Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2023 // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #pragma once #include "td/utils/common.h" #include "td/utils/Span.h" #include <utility> namespace td { template <class T> class VectorQueue { public: template <class S> void push(S &&s) { vector_.emplace_back(std::forward<S>(s)); } template <class... Args> void emplace(Args &&...args) { vector_.emplace_back(std::forward<Args>(args)...); } T pop() { try_shrink(); return std::move(vector_[read_pos_++]); } template <class RndT> T pop_rand(RndT &rnd) { auto i = rnd() % size(); std::swap(vector_[i], vector_[read_pos_]); return pop(); } void pop_n(size_t n) { read_pos_ += n; try_shrink(); } const T &front() const { return vector_[read_pos_]; } T &front() { return vector_[read_pos_]; } const T &back() const { return vector_.back(); } T &back() { return vector_.back(); } bool empty() const { return size() == 0; } size_t size() const { return vector_.size() - read_pos_; } const T *data() const { return vector_.data() + read_pos_; } T *data() { return vector_.data() + read_pos_; } Span<T> as_span() const { return {data(), size()}; } MutableSpan<T> as_mutable_span() { return {vector_.data() + read_pos_, size()}; } private: vector<T> vector_; size_t read_pos_{0}; void try_shrink() { if (read_pos_ * 2 > vector_.size() && read_pos_ > 4) { vector_.erase(vector_.begin(), vector_.begin() + read_pos_); read_pos_ = 0; } } }; } // namespace td