examples/Base/BufsAndStrings/DynamicBuffers/DynamicBuffers.cpp

// Copyright (c) 2000-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
//

#include "CommonFramework.h"

//
// Common literal text
//
_LIT(KTxtNewLine,"\n");

LOCAL_C void writeBuf(CBufBase* aBuf);
LOCAL_C void standardBufferStuffL(CBufBase* aBuf);
LOCAL_C void showExpandL();
LOCAL_C void waitForKey();
//
// do the example
//
LOCAL_C void doExampleL()
    {
        //
        // do flat buffer demonstration
        //
        _LIT(KTxtFlatBufDemo,"Flat buffer demonstration\n");
        console->Printf(KTxtFlatBufDemo);
        CBufFlat* flatBuf=CBufFlat::NewL(4);
        CleanupStack::PushL(flatBuf);
        flatBuf->SetReserveL(32);
        _LIT(KTxtFlatBufCapacity,"flat buffer capacity=%d\n");
        console->Printf(KTxtFlatBufCapacity,flatBuf->Capacity());
        standardBufferStuffL(flatBuf);
        CleanupStack::PopAndDestroy();
        waitForKey();
        //
        // do segmented buffer demonstration
        //
        _LIT(KTxtSegBufDemo,"Segmented buffer demonstration\n");
        console->Printf(KTxtSegBufDemo);
        CBufSeg* segBuf=CBufSeg::NewL(4);
        CleanupStack::PushL(segBuf);
        standardBufferStuffL(segBuf);
        CleanupStack::PopAndDestroy();
        waitForKey();
        //
        // show ExpandL() and ResizeL()
        //
        showExpandL();
        }


LOCAL_C void standardBufferStuffL(CBufBase* aBuf)
        {
        //
        // insert text into buffer (6 chars)
        //
        _LIT(KTxtHello,"Hello!");
        aBuf->InsertL(0,(TAny*)(&KTxtHello)->Ptr(),(&KTxtHello)->Size());
        writeBuf(aBuf);
        //
        // append more text into buffer (another 6 chars)
        //
        //
        _LIT(KTxtWorld," world");
        aBuf->InsertL(10,(TAny*)(&KTxtWorld)->Ptr(),(&KTxtWorld)->Size());
        writeBuf(aBuf);
        //
        // read the 5 characters starting at character
        // position 3 from the buffer into a descriptor.
        //
        //
        TBuf<5> des;
        aBuf->Read(6,(TAny*)des.Ptr(),des.Size());
        _LIT(KTxtRead,"read: %S\n");
        console->Printf(KTxtRead,&des);
        //
        // [over]write 5 characters at character position 6
        //
        //
        _LIT(KTxtFolks,"folks");
        aBuf->Write(12,(TAny*)(&KTxtFolks)->Ptr(),(&KTxtFolks)->Size());
        writeBuf(aBuf);
        //
        // delete characters
        //
        TInt startpos = 5;
        TInt length   = 6;
        startpos <<= 1;
        length   <<= 1;
        aBuf->Delete(startpos,length);
        writeBuf(aBuf);
        //
        // compress
        //
        aBuf->Compress();
        writeBuf(aBuf);
        }

LOCAL_C void writeBuf(CBufBase* aBuf)
        {
        //
        // print, segment by segment
        //
        _LIT(KTxtBuffer,"buffer:");
        console->Printf(KTxtBuffer);
        TInt  bufpos=0;
        TPtrC8 bufptr=aBuf->Ptr(bufpos);
        while (bufptr.Length()>0)
                {
                //
                // write out this segment of the buffer.
                // Note that the descriptor 'display' is built differently
                // for Unicode; it also assumes an even number of bytes;
                // this is valid because the granularity of the buffer is 4.
                //
                TPtrC display;
                display.Set((TUint16*)bufptr.Ptr(),(bufptr.Length()>>1));
                _LIT(KFormat1," [%d,%d] %S");
                console->Printf(KFormat1, bufpos, bufptr.Length(), &display);
                //
                // update position within the buffer
                // and the pointer-descriptor.
                //
                bufpos+=bufptr.Length();       // update position
                bufptr.Set(aBuf->Ptr(bufpos)); // should be the next segment
                }
        console->Printf(KTxtNewLine);
        }

        

LOCAL_C void showExpandL()
        {
        _LIT(KTxtShowExpand,"Showing ExpandL()\n");
        console->Printf(KTxtShowExpand);
        //
        // allocate the segmented buffer with 
        // a granularity of 4
        //
        CBufBase* buf=CBufSeg::NewL(4);
        CleanupStack::PushL(buf);
        //
        // insert text into buffer (12 UNICODE chars)
        //
        _LIT(KTxtHelloWorld,"Hello world!");
        buf->InsertL(0,(TAny*)(&KTxtHelloWorld)->Ptr(),(&KTxtHelloWorld)->Size());
        //
        // reserve space for (or 16 16-bit chars (32 bytes))
        //
        buf->ExpandL(12,32); // expand by 32 - may fail
        _LIT(KTxtBufExpanded,"Buffer expanded with uninitialized space: ");
        console->Printf(KTxtBufExpanded);
        writeBuf(buf);
        //
        // now insert 16 16-bit characters
        // one at time.
        //
        // This is CLEARLY INEFFICIENT but shows
        // how successive calls to Write() can be done
        // without risk of failing for lack of memory.
        //
        _LIT(KTxtAtoP,"abcdefghijklmnop");
        TBufC<16> source(KTxtAtoP);
        for (TInt i=0; i<16; i++)
                {
                buf->Write((i+6)<<1,(TAny*)&source[i],2);
                }
        _LIT(KTxtExpandedFilled,"expanded space filled: ");
        console->Printf(KTxtExpandedFilled);
        writeBuf(buf);
        //
        // now adjust size down to 18
        //
        buf->ResizeL(18);
        _LIT(KTxtResized,"resized:");
        console->Printf(KTxtResized);
        writeBuf(buf);
        //
        // destroy buffer
        //
        CleanupStack::PopAndDestroy();
        }

LOCAL_C void waitForKey()
        {
        _LIT(KTxtPressAnyKey,"[press any key]");
        console->Printf(KTxtPressAnyKey);
        console->Getch();
        console->Printf(KTxtNewLine);
        }

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