//----------------------------------------------------------------------
//  This software is part of the Haiku distribution and is covered
//  by the MIT License.
//---------------------------------------------------------------------
/*!
        \file OffsetFile.h
        OffsetFile interface declaration.
*/

#ifndef _OFFSET_FILE_H
#define _OFFSET_FILE_H

#include <DataIO.h>
#include <File.h>

namespace BPrivate {
namespace Storage {

/*!
        \class OffsetFile
        \brief Provides access to a file skipping a certain amount of bytes at
        the beginning.
        
        This class implements the BPositionIO interface to provide access to the
        data of a file past a certain offset. This is very handy e.g. for dealing
        with resources, as they always reside at the end of a file, but may start
        at arbitrary offsets.

        \author <a href='mailto:bonefish@users.sf.net'>Ingo Weinhold</a>
        
        \version 0.0.0
*/
class OffsetFile : public BPositionIO {
public:
        OffsetFile();
        OffsetFile(BFile *file, off_t offset);
        virtual ~OffsetFile();

        status_t SetTo(BFile *file, off_t offset);
        void Unset();
        status_t InitCheck() const;

        BFile *File() const;

        ssize_t ReadAt(off_t pos, void *buffer, size_t size);
        ssize_t WriteAt(off_t pos, const void *buffer,
                                                                size_t size);
        off_t Seek(off_t position, uint32 seekMode);
        off_t Position() const;

        status_t SetSize(off_t size);
        status_t GetSize(off_t *size) const;

        off_t Offset() const;

private:
        BFile*                          fFile;
        off_t                           fOffset;
        off_t                           fCurrentPosition;
};

};      // namespace Storage
};      // namespace BPrivate

#endif  // _OFFSET_FILE_H