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akode/akode/lib/file.h

122 lines
3.3 KiB

/* aKode: File abstract-type
Copyright (C) 2004 Allan Sandfeld Jensen <kde@carewolf.com>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#ifndef _AKODE_FILE_H
#define _AKODE_FILE_H
extern "C" {
#include <sys/types.h>
#include <unistd.h>
}
namespace aKode {
//! The generic interface to aKode's virtualised files
/*!
* An interface with the all the needed file/stream-operations
* the library needs.
*/
class File {
public:
/*!
* Creates a File with the given \a filename.
*/
File(const char* filename) : filename(filename) {};
virtual ~File() {};
/*!
* Opens the file as read-only.
* Returns whether the operation was succesfull.
*/
virtual bool openRO() { return false; };
/*!
* Opens the file as read and write.
* Returns whether the operation was succesfull.
*/
virtual bool openRW() { return false; };
/*!
* Open the file as write-only.
* Returns whether the operation was succesfull.
*/
virtual bool openWO() { return false; };
/*!
* Closes the file.
*/
virtual void close() = 0;
/*!
* Reads \a num bytes from the file and places the data in \a ptr.
* Returns number of read characters. Returns 0 if end-of-file.
* Returns negative at errors.
*/
virtual long read(char* ptr, long num) = 0;
/*!
* Writes \a num bytes from \a ptr to the file.
* Returns number of writen characters.
* Returns negative at errors.
*/
virtual long write(const char* ptr, long num) = 0;
/*!
* Seeks to the position.
* Behaves semantically as lseek.
*/
virtual ssize_t lseek(long to, int whence = SEEK_SET) = 0;
/*!
* Returns current position in file, or negative if unknown.
*/
virtual long position() const = 0;
/*!
* Returns length of file, or negative if unknown.
*/
virtual long length() const = 0;
/*!
* Returns true if the file is seekable
*/
virtual bool seekable() const = 0;
/*!
* Returns true if the file is readable
*/
virtual bool readable() const = 0;
/*!
* Returns true if the file is writeable
*/
virtual bool writeable() const = 0;
/*!
* Returns whether the file has reached end-of-file.
*/
virtual bool eof() const = 0;
/*!
* Returns true if the file has entered a non-recoverable error-state
*/
virtual bool error() const = 0;
/*!
* Advises the OS (if possible), that the file will be read
* sequentially from the current position and forward.
*/
virtual void fadvise() = 0;
/*!
* The name of the file.
*/
const char *filename;
};
} //namespace
#endif