ccafile.h

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// $Id: ccafile.h 1282 2006-06-09 09:46:49Z alex $
/* @@tag:xara-cn@@ DO NOT MODIFY THIS LINE
================================XARAHEADERSTART===========================
 
               Xara LX, a vector drawing and manipulation program.
                    Copyright (C) 1993-2006 Xara Group Ltd.
       Copyright on certain contributions may be held in joint with their
              respective authors. See AUTHORS file for details.

LICENSE TO USE AND MODIFY SOFTWARE
----------------------------------

This file is part of Xara LX.

Xara LX is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License version 2 as published
by the Free Software Foundation.

Xara LX and its component source files are distributed in the hope
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implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along
with Xara LX (see the file GPL in the root directory of the
distribution); if not, write to the Free Software Foundation, Inc., 51
Franklin St, Fifth Floor, Boston, MA  02110-1301 USA


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-----------------

Conditional upon your continuing compliance with the GNU General Public
License described above, Xara Group Ltd grants to you certain additional
rights. 

The additional rights are to use, modify, and distribute the software
together with the wxWidgets library, the wxXtra library, and the "CDraw"
library and any other such library that any version of Xara LX relased
by Xara Group Ltd requires in order to compile and execute, including
the static linking of that library to XaraLX. In the case of the
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----------------

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      Xara Group Ltd, Gaddesden Place, Hemel Hempstead, HP2 6EX, UK.
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=================================XARAHEADEREND============================
 */



#ifndef INC_CCASYNCHFILE
#define INC_CCASYNCHFILE

//#include "ccfile.h" - in camtypes.h [AUTOMATICALLY REMOVED]

class LoadContext;



/********************************************************************************************
>   class asynchstreambuf : public streambuf

    Author:     Chris_Parks (Xara Group Ltd) <camelotdev@xara.com>
    Created:    5/8/96
    Purpose:    an asynch version of streambuf 
                It is assumed that two versions of the file will be open i.e. read and write.
                The read and write will run in seperate threads. Any access to the file that 
                might fail due to lack of data will cause the read thread to sleep until more 
                data is available.
                It is assumed that the write thread will never seek - this would corrupt the 
                BytesAvailable count.
                
    SeeAlso:    streambuf; ios; costream
********************************************************************************************/

class asynchstreambuf : public filebuf
{
private:
    
        
    // determine whether a read or seek can succed
    BOOL DataAvailable(INT32 Length);

    LoadContext * pLoadContext;

    wxCondition         *WakeEvents[2];

    // allow xsgetn to return less bytes than required without failing
    // this is used for LoadInitialSegment
    BOOL DontFail;

public:
    asynchstreambuf();
    ~asynchstreambuf();

    void DownloadHasEnded(HRESULT Status);
    void SetDontFail(BOOL state){ DontFail = state;};
    
    virtual streampos seekoff(streamoff sOff ,ios::seekdir eDir,INT32 mode =ios::in|ios::out);
    virtual streampos seekpos(streampos,INT32 mode =ios::in|ios::out);  

    virtual INT32 xsputn(const char *,INT32);
    virtual INT32 xsgetn(char *,INT32);
    void SetLoadContext(LoadContext *pLContext);
    LoadContext *GetLoadContext() const {return pLoadContext;}

    // the total set of virtual functions in streambuf 
    /*
    // Creation & destruction.
    asynchstreambuf(IStream* pIStream = 0);
    virtual INT32 sync();
    virtual streambuf* setbuf(char *, INT32);
    virtual INT32 overflow(INT32 i =EOF) ; // pure virtual function
    virtual INT32 underflow() ;        // pure virtual function
    virtual INT32 pbackfail(INT32);
    */

    
};




/********************************************************************************************

>   class CCAsynchDiskFile : public CCDiskFile

    Author:     Chris_Parks (Xara Group Ltd) <camelotdev@xara.com>
    Created:    31/8/1993          
    Purpose:    a file class that can be used for asynchronous loading. It contains an
                asynchstreambuf (see above)
                
********************************************************************************************/

class CCAPI CCAsynchDiskFile : public CCDiskFile
{                             
CC_DECLARE_DYNAMIC(CCAsynchDiskFile);
    
public:

    CCAsynchDiskFile(UINT32 bufferSize = CCFILE_DEFAULTSIZE,
               BOOL ErrorReporting = TRUE,
               BOOL ExceptionThrowing = FALSE);
     
                                              
    CCAsynchDiskFile(PathName fPath, INT32 fileMode, 
               INT32 fileAccess  = 0,
               UINT32 bufferSize = CCFILE_DEFAULTSIZE,
               BOOL ErrorReporting = TRUE,
               BOOL ExceptionThrowing = FALSE);

    
    ~CCAsynchDiskFile();



    // Uses the above flags to determine whether to report errors and/or throw exceptions
    virtual void GotError( UINT32 errorID, const TCHAR* errorString);   
    virtual void GotError( UINT32 errorID);
    
    virtual size_t   Size();
    virtual BOOL     eof() const;

    void SetDownloadContext(LoadContext * pLContext)
        { ((asynchstreambuf*)(IOFile->rdbuf()))->SetLoadContext(pLContext);};

    void DownloadHasEnded(HRESULT Status);
    void SetDontFail(BOOL state){ ((asynchstreambuf*)(IOFile->rdbuf()))->SetDontFail(state);
                                    DontFail=state;};


};



/********************************************************************************************
>   class async_fstream : public fstream

    Author:     Justin_Flude (Xara Group Ltd) <camelotdev@xara.com>
    Created:    9/9/96
    Purpose:        Converts fstream to use an async_filebuf.
********************************************************************************************/

class async_fstream : public fstream
{
public:
    async_fstream();
    async_fstream(const char * name, INT32 mode, INT32 prot);
    async_fstream(filedesc fd);
    async_fstream(filedesc fd, char* sbuf, INT32 len);

protected:
    streambuf * set_streambuf(streambuf* pbuf);
};



#endif

---