ppsspp/Core/FileLoaders/RamCachingFileLoader.h
2019-09-28 11:18:42 -07:00

73 lines
2.0 KiB
C++

// Copyright (c) 2015- PPSSPP Project.
// This program 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 2.0 or later versions.
// This program 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. See the
// GNU General Public License 2.0 for more details.
// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/
// Official git repository and contact information can be found at
// https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.
#pragma once
#include <vector>
#include <mutex>
#include <thread>
#include "Common/CommonTypes.h"
#include "Core/Loaders.h"
class RamCachingFileLoader : public ProxiedFileLoader {
public:
RamCachingFileLoader(FileLoader *backend);
~RamCachingFileLoader() override;
bool Exists() override;
bool ExistsFast() override;
bool IsDirectory() override;
s64 FileSize() override;
size_t ReadAt(s64 absolutePos, size_t bytes, size_t count, void *data, Flags flags = Flags::NONE) override {
return ReadAt(absolutePos, bytes * count, data, flags) / bytes;
}
size_t ReadAt(s64 absolutePos, size_t bytes, void *data, Flags flags = Flags::NONE) override;
void Cancel() override;
private:
void InitCache();
void ShutdownCache();
size_t ReadFromCache(s64 pos, size_t bytes, void *data);
// Guaranteed to read at least one block into the cache.
void SaveIntoCache(s64 pos, size_t bytes, Flags flags);
void StartReadAhead(s64 pos);
u32 NextAheadBlock();
enum {
BLOCK_SIZE = 65536,
BLOCK_SHIFT = 16,
MAX_BLOCKS_PER_READ = 16,
BLOCK_READAHEAD = 4,
};
s64 filesize_ = 0;
u8 *cache_ = nullptr;
int exists_ = -1;
int isDirectory_ = -1;
std::vector<u8> blocks_;
std::mutex blocksMutex_;
u32 aheadRemaining_;
s64 aheadPos_;
std::thread aheadThread_;
bool aheadThreadRunning_ = false;
bool aheadCancel_ = false;
};