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107 lines
2.9 KiB
C++
107 lines
2.9 KiB
C++
2 years ago
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/*
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* This file is part of OpenTTD.
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* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
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* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
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*/
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/** @file pod_pool.hpp A pool-type container for POD data. */
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#ifndef POD_POOL_HPP
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#define POD_POOL_HPP
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#include <vector>
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/**
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* Pool-type container for POD data..
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*/
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template <typename PTR, size_t SIZE, uint N_PER_CHUNK, typename IDX = uint32>
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class PodPool {
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static_assert(SIZE >= sizeof(IDX));
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std::vector<void *> used_blocks;
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void *current_block = nullptr;
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IDX last_freed = (IDX)(-1);
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IDX next_position = 0;
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void NewBlock()
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{
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current_block = malloc(SIZE * N_PER_CHUNK);
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assert(current_block != nullptr);
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next_position = 0;
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used_blocks.push_back(current_block);
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}
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public:
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PodPool() = default;
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PodPool(const PodPool &other) = delete;
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PodPool& operator=(const PodPool &other) = delete;
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PodPool(PodPool &&other)
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{
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*this = std::move(other);
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}
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PodPool& operator=(PodPool &&other)
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{
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this->used_blocks = std::move(other.used_blocks);
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this->current_block = other.current_block;
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this->last_freed = other.last_freed;
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this->next_position = other.next_position;
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other.used_blocks.clear();
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other.current_block = nullptr;
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other.last_freed = (IDX)(-1);
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other.next_position = 0;
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return *this;
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}
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~PodPool()
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{
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this->Clear();
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}
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void Clear()
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{
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this->current_block = nullptr;
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this->last_freed = (IDX)(-1);
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this->next_position = 0;
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for (void *block : this->used_blocks) {
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free(block);
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}
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this->used_blocks.clear();
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}
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inline PTR operator[](IDX idx) { return reinterpret_cast<PTR>(reinterpret_cast<char *>(this->used_blocks[idx / N_PER_CHUNK]) + (SIZE * (idx % N_PER_CHUNK))); }
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std::pair<IDX, PTR> Allocate() {
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if (this->last_freed != (IDX)(-1)) {
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IDX idx = this->last_freed;
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PTR item = (*this)[idx];
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this->last_freed = *reinterpret_cast<IDX*>(item);
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return std::make_pair(idx, item);
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} else {
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if (current_block == nullptr || next_position == N_PER_CHUNK) {
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NewBlock();
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}
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IDX idx = this->next_position + ((IDX)(this->used_blocks.size() - 1) * N_PER_CHUNK);
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PTR item = reinterpret_cast<PTR>(reinterpret_cast<char *>(current_block) + (SIZE * next_position));
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this->next_position++;
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return std::make_pair(idx, item);
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}
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}
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void Free(IDX idx) {
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this->Free(idx, (*this)[idx]);
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}
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void Free(IDX idx, PTR item) {
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dbg_assert(current_block != nullptr);
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*reinterpret_cast<IDX*>(item) = this->last_freed;
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this->last_freed = idx;
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}
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};
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#endif /* POD_POOL_HPP */
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