virtualx-engine/core/io/file_access_buffered.h

/*************************************************************************/
/*  file_access_buffered.h                                               */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                    http://www.godotengine.org                         */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
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/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
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/*************************************************************************/
#ifndef FILE_ACCESS_BUFFERED_H
#define FILE_ACCESS_BUFFERED_H

#include "os/file_access.h"

#include "dvector.h"
#include "ustring.h"

class FileAccessBuffered : public FileAccess {

public:
	enum {
		DEFAULT_CACHE_SIZE = 128 * 1024,
	};

private:
	int cache_size;

	int cache_data_left() const;
	mutable Error last_error;

protected:
	Error set_error(Error p_error) const;

	mutable struct File {

		bool open;
		int size;
		int offset;
		String name;
		int access_flags;
	} file;

	mutable struct Cache {

		Vector<uint8_t> buffer;
		int offset;
	} cache;

	virtual int read_data_block(int p_offset, int p_size, uint8_t *p_dest = 0) const = 0;

	void set_cache_size(int p_size);
	int get_cache_size();

public:
	virtual size_t get_pos() const; ///< get position in the file
	virtual size_t get_len() const; ///< get size of the file

	virtual void seek(size_t p_position); ///< seek to a given position
	virtual void seek_end(int64_t p_position = 0); ///< seek from the end of file

	virtual bool eof_reached() const;

	virtual uint8_t get_8() const;
	virtual int get_buffer(uint8_t *p_dst, int p_length) const; ///< get an array of bytes

	virtual bool is_open() const;

	virtual Error get_error() const;

	FileAccessBuffered();
	virtual ~FileAccessBuffered();
};

#endif