hxbufdataf.h

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/* ***** BEGIN LICENSE BLOCK ***** 
 * Version: RCSL 1.0/RPSL 1.0 
 *  
 * Portions Copyright (c) 1995-2002 RealNetworks, Inc. All Rights Reserved. 
 *      
 * The contents of this file, and the files included with this file, are 
 * subject to the current version of the RealNetworks Public Source License 
 * Version 1.0 (the "RPSL") available at 
 * http://www.helixcommunity.org/content/rpsl unless you have licensed 
 * the file under the RealNetworks Community Source License Version 1.0 
 * (the "RCSL") available at http://www.helixcommunity.org/content/rcsl, 
 * in which case the RCSL will apply. You may also obtain the license terms 
 * directly from RealNetworks.  You may not use this file except in 
 * compliance with the RPSL or, if you have a valid RCSL with RealNetworks 
 * applicable to this file, the RCSL.  Please see the applicable RPSL or 
 * RCSL for the rights, obligations and limitations governing use of the 
 * contents of the file.  
 *  
 * This file is part of the Helix DNA Technology. RealNetworks is the 
 * developer of the Original Code and owns the copyrights in the portions 
 * it created. 
 *  
 * This file, and the files included with this file, is distributed and made 
 * available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS 
 * FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * 
 * Technology Compatibility Kit Test Suite(s) Location: 
 *    http://www.helixcommunity.org/content/tck 
 * 
 * Contributor(s): 
 *  
 * ***** END LICENSE BLOCK ***** */ 

#ifndef _HX_BUFFERED_DATA_FILE_H_
#define _HX_BUFFERED_DATA_FILE_H_

#include "hxtypes.h"
#include "hxcom.h"
#include "hxdataf.h"

class HXBufferedDataFile : public IHXDataFile {
public:
					HXBufferedDataFile();
    virtual				~HXBufferedDataFile();

    /*
     *  IUnknown methods
     */
    STDMETHOD(QueryInterface)		(THIS_
					REFIID riid,
					void** ppvObj);
    
    STDMETHOD_(ULONG32, AddRef)		(THIS);
    
    STDMETHOD_(ULONG32, Release)	(THIS);
    
    /*
     *  IHXDataFile methods
     */

    /* Bind DataFile Object with FileName */
    STDMETHOD_(void, Bind)		(THIS_
					const char* FileName);

    /* Creates a datafile using the specified mode
     * uOpenMode --- File Open mode - HX_FILE_READ/HX_FILE_WRITE/HX_FILE_BINARY
     */
    STDMETHOD(Create)			(THIS_
					UINT16 uOpenMode);

    /* Open will open a file with the specified mode
     */
    STDMETHOD(Open)			(THIS_
					UINT16 uOpenMode);

    /* Close closes a file 
     * If the reference count on the IHXDataFile object is greater than 1, 
     * then the underlying file cannot be safely closed, so Close() becomes 
     * a noop in that case. Close it only when the object is destroyed. 
     * This would be safe, but could lead to a file descriptor leak.
     */
    STDMETHOD(Close)			(THIS);

    /* Name returns the currently bound file name in FileName.
     * and returns TRUE, if the a name has been bound.  Otherwise
     * FALSE is returned.
     */
    STDMETHOD_(BOOL, Name)		(THIS_
					REF(IHXBuffer*) pFileName);

    /*
     * IsOpen returns TRUE if file is open.  Otherwise FALSE.
     */
    STDMETHOD_(BOOL, IsOpen)		(THIS);

    /* Seek moves the current file position to the offset from the
     * fromWhere specifier returns current position of file or -1 on
     * error.
     */
    STDMETHOD(Seek)			(THIS_
					ULONG32 offset, UINT16 fromWhere);

    /* Tell returns the current file position in the file */
    STDMETHOD_(ULONG32, Tell)		(THIS);

    /* Read reads up to count bytes of data into buf.
     * returns the number of bytes read, EOF, or -1 if the read failed 
     */
    STDMETHOD_(ULONG32, Read)		(THIS_
					REF(IHXBuffer*) pBuf, 
					ULONG32 count);

    /* Write writes up to count bytes of data from buf.
     * returns the number of bytes written, or -1 if the write failed 
     */
    STDMETHOD_(ULONG32, Write)		(THIS_
					REF(IHXBuffer*) pBuf); 

    /* Flush out the data in case of buffered I/O
     */
    STDMETHOD(Flush)			(THIS);

    /*
     * Return info about the data file such as permissions, time of creation
     * size in bytes, etc.
     */
    STDMETHOD(Stat)			(THIS_
					struct stat* buffer);

    /* Return the file descriptor */
    STDMETHOD_(INT16, GetFd)		(THIS);

    /* GetLastError returns the platform specific file error */
    STDMETHOD(GetLastError)		(THIS);

    /* GetLastError returns the platform specific file error in
     * string form.
     */
    STDMETHOD_(void, GetLastError)	(THIS_
					REF(IHXBuffer*) err);

protected:
    INT32 NewBuf();		// grab a new buffer
    INT32 FillBuf();		// fill buffer around current position
    INT32 FlushBuf();		// flush buffer
    void AllocBuf();		// allocate buffer
    void FreeBuf();		// free buffer
				// read data at given position
    INT32 Pread(void* buf, INT32 nbytes, ULONG32 off);
				// write data at given position
    INT32 Pwrite(const void* buf, INT32 nbytes, ULONG32 off);
    ULONG32 FlushSize();	// return flushed file size
    ULONG32 LogicalSize();	// return file size including unflushed data
    INT32 GetFileStat(struct stat* buf) const; // get file stat

    INT32 GetPageSize() const;	// get page size from system

private:
				// don't implement these
    HXBufferedDataFile(const HXBufferedDataFile&);
    HXBufferedDataFile& operator=(const HXBufferedDataFile&);

    LONG32 m_lRefCount;		// reference count
    UINT32 m_LastError;		// error from last operation
    IHXBuffer* m_pFileName;	// file name
    int m_Fd;			// file descriptor
    UINT16 m_Flags;		// open flags
    ULONG32 m_Begin;		// beginning of buffer
    UINT32 m_BufSize;		// buffer size
    UINT32 m_BufFill;		// bytes in buffer from last fill
    ULONG32 m_Offset;		// current seek offset
    ULONG32 m_FileOffset;	// current seek offset in file
    ULONG32 m_FlushSize;	// current flushed size of file
    char* m_pBuf;		// buffer
    UINT32 m_Dirty;		// buffer has been written over
};

#endif /* _HX_BUFFERED_DATA_FILE_H_ */