mirror of https://github.com/OpenTTD/OpenTTD.git
104 lines
2.9 KiB
C++
104 lines
2.9 KiB
C++
/*
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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 saveload_filter.h Declaration of filters used for saving and loading savegames. */
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#ifndef SAVELOAD_FILTER_H
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#define SAVELOAD_FILTER_H
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/** Interface for filtering a savegame till it is loaded. */
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struct LoadFilter {
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/** Chained to the (savegame) filters. */
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std::shared_ptr<LoadFilter> chain;
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/**
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* Initialise this filter.
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* @param chain The next filter in this chain.
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*/
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LoadFilter(std::shared_ptr<LoadFilter> chain) : chain(chain)
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{
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}
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/** Make sure the writers are properly closed. */
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virtual ~LoadFilter()
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{
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}
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/**
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* Read a given number of bytes from the savegame.
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* @param buf The bytes to read.
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* @param len The number of bytes to read.
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* @return The number of actually read bytes.
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*/
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virtual size_t Read(uint8_t *buf, size_t len) = 0;
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/**
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* Reset this filter to read from the beginning of the file.
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*/
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virtual void Reset()
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{
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this->chain->Reset();
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}
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};
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/**
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* Instantiator for a load filter.
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* @param chain The next filter in this chain.
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* @tparam T The type of load filter to create.
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*/
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template <typename T> std::shared_ptr<LoadFilter> CreateLoadFilter(std::shared_ptr<LoadFilter> chain)
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{
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return std::make_shared<T>(chain);
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}
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/** Interface for filtering a savegame till it is written. */
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struct SaveFilter {
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/** Chained to the (savegame) filters. */
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std::shared_ptr<SaveFilter> chain;
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/**
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* Initialise this filter.
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* @param chain The next filter in this chain.
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*/
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SaveFilter(std::shared_ptr<SaveFilter> chain) : chain(chain)
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{
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}
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/** Make sure the writers are properly closed. */
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virtual ~SaveFilter()
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{
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}
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/**
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* Write a given number of bytes into the savegame.
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* @param buf The bytes to write.
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* @param len The number of bytes to write.
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*/
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virtual void Write(uint8_t *buf, size_t len) = 0;
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/**
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* Prepare everything to finish writing the savegame.
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*/
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virtual void Finish()
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{
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if (this->chain != nullptr) this->chain->Finish();
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}
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};
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/**
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* Instantiator for a save filter.
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* @param chain The next filter in this chain.
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* @param compression_level The requested level of compression.
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* @tparam T The type of save filter to create.
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*/
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template <typename T> std::shared_ptr<SaveFilter> CreateSaveFilter(std::shared_ptr<SaveFilter> chain, uint8_t compression_level)
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{
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return std::make_shared<T>(chain, compression_level);
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}
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#endif /* SAVELOAD_FILTER_H */
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