/*

    File:       CBuffFileStream.h

    Contains:   Buffer handling.

    Written by: Tim Carroll

    Copyright:  Copyright (c) 1999 Apple Computer, Inc., All Rights Reserved.

                You may incorporate this Apple sample source code into your program(s) without

                restriction. This Apple sample source code has been provided "AS IS" and the

                responsibility for its operation is yours. You are not permitted to redistribute

                this Apple sample source code as "Apple sample source code" after having made

                changes. If you're going to re-distribute the source, we require that you make

                it clear in the source that the code was descended from Apple sample source

                code, but that you've made changes.

*/

#pragma once

#ifdef __cplusplus

extern "C" {

#endif

enum

{

    eBuffFileStreamBufferMaxSize = 4096

};

enum

{

    eBuffFileStreamIamReading,

    eBuffFileStreamIamWriting

};

typedef struct CBuffFileStreamData

{

// This is a buffer which we will slide around as a window into the file

    char                        mFileWindow[eBuffFileStreamBufferMaxSize];

// This is the file ref num of the opened file

    short                       mFileRefNum;

// The current length of the buffer. This cannot exceed the maximum size

    unsigned                    mBufferLength;

// The offset into the buffer where we are currently reading from

    unsigned                    mBufferCurPos;

// The offset into the file where the window begins

// This is used only to adjust our location when we flush the buffer

    long                        mWindowLocation;

// The permissions we have for accessing the file

// This is determined upon open, however it can change if things

// change behind our back.

    short                       mFilePerms;

// Whether or not the buffer we have is for writing

    int                         mBufferMode;

} CBuffFileStreamData;

OSErr   BFSOpenFile(CBuffFileStreamData **newdata, FSSpec *inFileInfo, long inPrivileges);

OSErr   BFSCloseFile(CBuffFileStreamData *fdata);

OSErr   BFSSetMarker(CBuffFileStreamData *fdata, long inOffset, long fromWhere);

long    BFSGetMarker(CBuffFileStreamData *fdata);

OSErr   BFSSetLength(CBuffFileStreamData *fdata, long inLength);

long    BFSGetLength(CBuffFileStreamData *fdata);

OSErr   BFSWrite(CBuffFileStreamData *fdata, long *writeAmt, const void *inBuffer);

OSErr   BFSRead(CBuffFileStreamData *fdata, long *readAmt, void *outBuffer);

long    BFSGetFilePermissions(CBuffFileStreamData *fdata);

OSErr   BFSFlushFile(CBuffFileStreamData *fdata);

#ifdef __cplusplus

}

#endif