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<!DOCTYPE task
  PUBLIC "-//OASIS//DTD DITA Task//EN" "task.dtd">
<task id="GUID-548CC331-8E38-5627-A925-EA386BE90258" xml:lang="en"><title>Compressing
and Decompressing File - GZip Format </title><abstract><shortdesc>The Zip Compression Library, EZLib provides file compression
and decompression functionality for the Symbian platforms. The files can be
compressed to two formats namely zip and gzip. gzip is normally used to compress
single files. </shortdesc> <p/> </abstract><prolog><metadata><keywords/></metadata></prolog><taskbody>
<context id="GUID-48E514AC-C78B-570F-A96C-389BABA02472"><p>Compression and
Decompression are performed iteratively, till the completion of required task. </p> </context>
<steps id="GUID-2D2DC7F3-64FA-5C96-95DE-615650E10160">
<step id="GUID-C384EAE0-B1EE-5098-A557-1231D35F8A2A"><cmd/>
<info>Input the source file and the name of the target gzip file to an instance
of the <xref href="GUID-417AB4E0-FF07-34CB-A4A8-CEF31C48A162.dita"><apiname>CEZFileToGZip</apiname></xref> class. </info>
</step>
<step id="GUID-2A30A687-A777-5790-8145-5AE956F35FFC"><cmd/>
<info> <xref href="GUID-417AB4E0-FF07-34CB-A4A8-CEF31C48A162.dita#GUID-417AB4E0-FF07-34CB-A4A8-CEF31C48A162/GUID-4E51D7C5-C624-3F27-A5CD-01E92F96F72B"><apiname>CEZFileToGZip::DeflateL()</apiname></xref> is used to compress the
file. </info>
</step>
</steps>
<example><p>The code below depicts how the source file "input.doc" file is
converted to target file "output.gz". </p><codeblock xml:space="preserve">/*
 * If input and output file names are not specified then it is assumed that 
 * the file names are contained in a provided .ini file.
 */

void CEZlibEZipTests::DoEZlibGZipDeflateL()
    {
    

 RFs iFs;
 iFS.connect();
    

    //Open the source file in read mode
_LIT(KInputFileLocation, "c:\\private\\E80000B7\\zip\\input\\input.doc");
TFileName inputFile(KInputFileLocation);

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

    if(err != KErrNone)
        {
        INFO_PRINTF1(KOpenFileError);
        User::Leave(err);
        }   
    
    
    //create a target file

_LIT(KOutputFileLocation, "c:\\private\\E80000B7\\zip\\input\\output.gz");
TFileName outputFile(KOutputFileLocation);


    
    CEZFileToGZip *compressor = CEZFileToGZip::NewLC(iFs, outputFile, input);

    
    while(compressor-&gt;DeflateL())
        {       
        }   
input.Close();
    iFS.Close();
        
    
    }
</codeblock></example>
<postreq><p>The decompression of a gzip file can be achieved through the following
the steps: </p> <ol id="GUID-A4771CC4-2704-56E3-BBD5-4AB2A58F9468">
<li id="GUID-4E130CBF-C626-5CD0-9A83-A2F138B12B68"><p>Pass the file to the
constructor of the <xref href="GUID-8DE05785-D058-3855-A11F-7132EB4DE078.dita"><apiname>CEZGZipToFile</apiname></xref> class. </p> </li>
<li id="GUID-CB642B02-8A19-5CB9-96E4-80AB7596F6E1"><p> <xref href="GUID-8DE05785-D058-3855-A11F-7132EB4DE078.dita#GUID-8DE05785-D058-3855-A11F-7132EB4DE078/GUID-4A30D99E-EC51-359F-90B5-9CFA3841A538"><apiname>CEZGZipToFile::InflateL()</apiname></xref> is
called repeatedly to complete the decompression. </p> </li>
</ol> <p>The code below depicts how "output.gz" is decompressed to "input.doc". </p> <codeblock id="GUID-01545D8D-CE1F-5903-9558-CE35D4C3067E" xml:space="preserve">/*
 *  If  input and output file names are not specified then it is assumed that 
 * the file names are contained in a provided .ini file.
 */
void CEZlibEZipTests::DoEZlibGZipInflateL()
    {
      RFs iFs;
  iFS.connect();
    

    //open output file

_LIT(KOutputFile, "c:\\private\\E80000B7\\zip\\input\\input.doc");
TFileName outputFile(KOutputFile);
    RFile output;
    err = output.Replace(iFs, outputFile, EFileStream | EFileWrite | EFileShareExclusive);
    if(err != KErrNone)
        {
        INFO_PRINTF1(KCreateFileError);
        User::Leave(err);
        }    
        

//input file


_LIT(KInputFileLocation, "c:\\private\\E80000B7\\zip\\input\\output.gz");
TFileName inputFile(KInputFileLocation);

    CEZGZipToFile *decompressor = CEZGZipToFile::NewLC(iFs, inputFile, output);

        while(decompressor-&gt;InflateL())
        {        
        }    

        output.Close();
    iFS.Close();
    ;
    }</codeblock> </postreq>
</taskbody></task>