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<!DOCTYPE task

  PUBLIC "-//OASIS//DTD DITA Task//EN" "task.dtd">

<task id="GUID-FDDAF8E9-4CAB-5489-B578-A5362E2140C1" xml:lang="en"><title>Decompressing

File Archives</title><abstract><shortdesc>The Zip Compression Library, EZLib provides file archive

decompression functionality for the Symbian platforms. </shortdesc> <p>EZLib

allows clients to decompress data from file archives. The decompression task

is performed by calling the decompression functions iteratively, until the

required task completion. </p> </abstract><prolog><metadata><keywords/></metadata></prolog><taskbody>

<context><p>The input archive file is opened and the properties of all the

files in the archive are retrieved. </p> </context>

<steps id="GUID-0D781F2C-8D11-5792-98D5-76091DA8EBBB">

<step id="GUID-E92A26A2-F56D-5FA0-A583-43B227AE670C"><cmd/>

<info>Pass the input file archive and create an instance of the <xref href="GUID-79C613E8-35F8-319B-BE8B-1411CBE5AF00.dita"><apiname>CZipFile</apiname></xref> class.</info>

<info> The <xref href="GUID-79C613E8-35F8-319B-BE8B-1411CBE5AF00.dita"><apiname>CZipFile</apiname></xref> is a read only interface. It does not

support file compression to a single or multiple zip file archives. </info>

</step>

<step id="GUID-8E916762-869C-5E9C-B38C-43B55805EB73"><cmd/>

<info>Invoke <xref href="GUID-79C613E8-35F8-319B-BE8B-1411CBE5AF00.dita#GUID-79C613E8-35F8-319B-BE8B-1411CBE5AF00/GUID-7F528528-1814-39A6-BE14-CA1F7AABFD06"><apiname>CZipFile::GetMembersL()</apiname></xref> that returns a pointer

of <xref href="GUID-D458AE6A-EC64-3882-BCEA-A44A43DAA99A.dita"><apiname>CZipFileMemberIterator</apiname></xref>  </info>

<info>The <xref href="GUID-D458AE6A-EC64-3882-BCEA-A44A43DAA99A.dita"><apiname>CZipFileMemberIterator</apiname></xref> iterator

class provides functions that point to the first file in the archive and to

navigate through all the entries in the archive. </info>

<info>The <xref href="GUID-D458AE6A-EC64-3882-BCEA-A44A43DAA99A.dita"><apiname>CZipFileMemberIterator</apiname></xref> iterator class can access

each member of the zip archive using <xref href="GUID-D458AE6A-EC64-3882-BCEA-A44A43DAA99A.dita#GUID-D458AE6A-EC64-3882-BCEA-A44A43DAA99A/GUID-610F12F0-C1B7-39BB-A446-7616BBF84B2C"><apiname>CZipFileMemberIterator::NextL()</apiname></xref>  </info>

</step>

<step id="GUID-BB056063-4391-5EC7-A223-ED752E2F1B32"><cmd/>

<info>The properties of the member file are retrieved using the functions

of <xref href="GUID-02A8BC62-D653-39A3-BE0C-92A5F3F43E85.dita"><apiname>CZipFileMember</apiname></xref>. </info>

<info>The <xref href="GUID-02A8BC62-D653-39A3-BE0C-92A5F3F43E85.dita"><apiname>CZipFileMember</apiname></xref> class retrieves the properties

of the member file once the member file is accessible. </info>

</step>

<step id="GUID-4EAC4BD5-551B-58A3-A6B4-D4433027F5C8"><cmd/>

<info>The files extracted from the archive are stored in the output folder. </info>

<info>If the output folder is unavailable a new folder is created prior to

archive decompression. </info>

</step>

</steps>

<example><p>The following example code illustrates the decompression of file

archive. </p><codeblock xml:space="preserve">/*

    * Decompresses all the files in "inputarchive.zip" using the EZlib.

    *  If an input filename is not specified it is assumed that the

    * input file name is contained in a provided .ini file.

    */

    void CEZlibEZipTests::DoEZlibZipArchiveDecompressL()

    {

    RFs iFs;

    iFS.connect();

    CleanupClosePushL(iFS);

    TInt err = KErrNone;

    HBufC8 *outputBuffer = HBufC8::NewLC(outputBufferSize);

    _LIT(KInputFileLocation, "c:\\private\\E80000B7\\zip\\input\\inputarchive.zip");

    TFileName inputFile(KInputFileLocation);

    RFile input;

    err = input.Open(iFs, inputFile, EFileStream | EFileRead | EFileShareExclusive);

    if(err != KErrNone)

        {

        INFO_PRINTF1(KOpenFileError);

        User::Leave(err);

        }

    CleanupClosePushL(input);

    CZipFile *zipFile = CZipFile::NewL(iFs,input);

    CleanupStack::PushL(zipFile);

    CZipFileMemberIterator *fileMemberIter = zipFile->GetMembersL();

    //  iZipArchiveEzlibFolder = GenerateZipArchiveFolderNameL(aInputFileName);

    //  iZipArchiveEzlibFolder.Append(KZipArchiveEzlib);

    for(TOLDEZIP::CZipFileMember *fileMember = fileMemberIter->NextL(); fileMember != NULL; fileMember = fileMemberIter->NextL())

        {

        TFileName tmpfilename(*(fileMember->Name()));

        // Check if we have a folder or file

        TPtrC lastChar = tmpfilename.Right(1);

        if(lastChar.Compare(_L("\\")) != 0 && lastChar.Compare(_L("/")) != 0)

            {

            RFile output;

            err = output.Replace(iFs, tmpfilename, EFileStream | EFileWrite | EFileShareExclusive);

            if(err != KErrNone)

                {

                INFO_PRINTF1(KCreateFileError);

                User::Leave(err);

                }

            CleanupClosePushL(output);

            TOLDEZIP::RZipFileMemberReaderStream *readerStream;

            zipFile->GetInputStreamL(fileMember, readerStream);

            CleanupStack::PushL(readerStream);

            TPtr8 pOutputBuffer = outputBuffer->Des();

            do

                {

                err = readerStream->Read(pOutputBuffer, outputBufferSize);

                output.Write(pOutputBuffer);

                } while(err == KErrNone);

            if(err != KErrEof)

                {

                User::Leave(err);

                }

            CleanupStack::PopAndDestroy(2);

            }

        else

            {

            TFileName fullPath("c:\\private\\E80000B7\\zip\\input\\");

            fullPath.Append(tmpfilename);

            iRfs.MkDir(fullPath);

            }

        }

    CleanupStack::PopAndDestroy(3);

    }

</codeblock></example>