87 lines
2.5 KiB
C++
87 lines
2.5 KiB
C++
// Copyright (c) 2012- PPSSPP Project.
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, version 2.0 or later versions.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License 2.0 for more details.
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// A copy of the GPL 2.0 should have been included with the program.
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// If not, see http://www.gnu.org/licenses/
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// Official git repository and contact information can be found at
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// https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.
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#pragma once
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#include <map>
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#include "base/mutex.h"
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#include "Common/CommonTypes.h"
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#include "Core/Loaders.h"
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class CachingFileLoader : public FileLoader {
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public:
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CachingFileLoader(FileLoader *backend);
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virtual ~CachingFileLoader() override;
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virtual bool Exists() override;
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virtual bool IsDirectory() override;
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virtual s64 FileSize() override;
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virtual std::string Path() const override;
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virtual void Seek(s64 absolutePos) override;
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virtual size_t Read(size_t bytes, size_t count, void *data) override {
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return ReadAt(filepos_, bytes, count, data);
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}
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virtual size_t Read(size_t bytes, void *data) override {
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return ReadAt(filepos_, bytes, data);
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}
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virtual size_t ReadAt(s64 absolutePos, size_t bytes, size_t count, void *data) override {
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return ReadAt(absolutePos, bytes * count, data) / bytes;
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}
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virtual size_t ReadAt(s64 absolutePos, size_t bytes, void *data) override;
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private:
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void InitCache();
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void ShutdownCache();
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size_t ReadFromCache(s64 pos, size_t bytes, void *data);
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// Guaranteed to read at least one block into the cache.
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void SaveIntoCache(s64 pos, size_t bytes, bool readingAhead = false);
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bool MakeCacheSpaceFor(size_t blocks, bool readingAhead);
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void StartReadAhead(s64 pos);
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enum {
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BLOCK_SIZE = 65536,
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BLOCK_SHIFT = 16,
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MAX_BLOCKS_PER_READ = 16,
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MAX_BLOCKS_CACHED = 4096, // 256 MB
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BLOCK_READAHEAD = 4,
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};
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s64 filesize_;
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s64 filepos_;
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FileLoader *backend_;
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int exists_;
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int isDirectory_;
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u64 generation_;
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u64 oldestGeneration_;
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size_t cacheSize_;
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struct BlockInfo {
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u8 *ptr;
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u64 generation;
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BlockInfo() : ptr(nullptr), generation(0) {
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}
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BlockInfo(u8 *p) : ptr(p), generation(0) {
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}
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};
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std::map<s64, BlockInfo> blocks_;
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recursive_mutex blocksMutex_;
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mutable recursive_mutex backendMutex_;
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bool aheadThread_;
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};
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