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<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->+
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<!-- This component and the accompanying materials are made available under the terms of the License +
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and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->+
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<!-- Initial Contributors:+
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    Nokia Corporation - initial contribution.+
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Contributors: +
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-->+
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<!DOCTYPE concept+
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  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">+
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<concept id="GUID-017A0B4C-3FC2-5CFD-9D81-6A5ABF982D98" xml:lang="en"><title>EZLib+
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Interface</title><prolog><metadata><keywords/></metadata></prolog><conbody>+
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<p>The Symbian platform implements compression and decompression with the+
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open source ZLib library, which uses dynamic Huffman encoding and LZ77 compression. </p>+
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<p>The user needs to know about the below: </p>+
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<ul>+
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<li id="GUID-54501213-E449-5554-BF69-2C5A9FAB5B69"><p><xref href="GUID-017A0B4C-3FC2-5CFD-9D81-6A5ABF982D98.dita#GUID-017A0B4C-3FC2-5CFD-9D81-6A5ABF982D98/GUID-E1C36B5E-1750-5225-92CC-CE9DF8D6C981">About EZLib interfaces</xref>  </p> </li>+
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<li id="GUID-26FF852D-5F70-52D6-9C62-E406CA9138E5"><p><xref href="GUID-017A0B4C-3FC2-5CFD-9D81-6A5ABF982D98.dita#GUID-017A0B4C-3FC2-5CFD-9D81-6A5ABF982D98/GUID-2D4AD89D-501C-52DB-83E9-691F9FA86095">How to select an EZLib interface</xref>  </p> </li>+
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</ul>+
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<section id="GUID-E1C36B5E-1750-5225-92CC-CE9DF8D6C981"><title>About EZLib+
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interfaces</title> <p>The EZLib interfaces accomodates the following libraries: </p> <ul>+
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<li id="GUID-E730EA7A-1C78-592D-AFB1-15BC4178E5FE"><p>ZLib : It is the original+
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open source code, written in C and slightly modified to run on the Symbian+
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platform. </p> </li>+
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<li id="GUID-C3AD9FDD-A3CA-50FE-B93D-75845C8E1F97"><p>EZLib : It consists+
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of a direct interface to the original C API and a C++ wrapper round that same+
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API. </p> <p>Earlier versions of EZLib are still supported by the Symbian+
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platform but are deprecated for new development. The current implementation+
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is backwards compatible with previous ones. </p> </li>+
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</ul> <p>EZLib consists of the following dlls: </p> <ul>+
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<li id="GUID-421EBE71-9F2E-57C8-9989-437781822668"><p>libz.dll, a set of C+
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APIs with the functionality of ZLib version 1.2.3. </p> </li>+
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<li id="GUID-7108B065-C9CD-5DC6-89CA-2F81F847BEF0"><p>ezlib.dll, a set of+
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C++ APIs with the same functionality as the C APIs, packaged to offer different+
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variations of the functionality. </p> </li>+
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<li id="GUID-7445BFDB-D54E-5ED2-9081-5975709F7C98"><p>ezip.dll, a set of C+++
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APIs with the same functionality as the C APIs, packaged to offer different+
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variations of the functionality. </p> </li>+
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</ul> </section>+
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<section id="GUID-2D4AD89D-501C-52DB-83E9-691F9FA86095"><title>How to select+
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an EZLib interface</title> <p>DLLs are used to implement the EZLib interface+
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features. </p> <p>Symbian Developers must therefore decide about the interfaces+
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(C or C++) and DLLs to be used. </p> <ul>+
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<li id="GUID-0AB51ACE-999E-5EB2-BF67-443BD60F790B"><p>If you want to read+
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from a zip archive you must use C++ and include ezip.dll because this functionality+
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is specific to the Symbian platform and is not part of the open source ZLib+
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library. </p> </li>+
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<li id="GUID-59EE6445-2DA3-5716-90BC-C2EE6DF4BE51"><p>If you are writing client+
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applications to run purely on the Symbian platform you must use C++. </p> </li>+
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<li id="GUID-2E16494D-7DDE-5063-A3B0-640F359DF4D1"><p>If you are integrating+
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an existing application which already interfaces to the open source version+
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of zlib you must choose C. </p> </li>+
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<li id="GUID-768ADF17-B2B1-5933-91ED-6E5759E14255"><p>If you are writing a+
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cross-platform application to run on various platforms including the Symbian+
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platform you should probably choose C. </p> </li>+
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<li id="GUID-915F6514-1421-53C8-B11C-0DC73C1B9C3D"><p>If you simply want the+
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compression and decompression functionality without file input and output+
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you should include ezlib.dll. This DLL excludes the API functions with names+
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beginning in gz such as gzread() and gzwrite() supplying the I/O functionality+
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known as gzio. The Symbian platform which previously used EZlib+
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does not use gzio and you should chooose ezlib.dll when working with it. </p> </li>+
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<li id="GUID-9AB5CEB8-19FB-574E-B56E-E7312CF53815"><p>If you want gzio input+
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and output functionality you should choose libz.dll. However, use of this+
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DLL entails memory and performance overheads so you should only use it if+
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you definitely need the additional functionality. </p> </li>+
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</ul> <p>The appropriate header file must be included in the application to+
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implement your choice of DLL. </p> </section>+
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</conbody><related-links>+
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<link href="GUID-4BEFF7BA-2A39-5601-919E-22AF08D06023.dita"><linktext>Zip Compression+
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Library Overview</linktext></link>+
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<link href="GUID-84922B27-FDCF-56FD-91ED-5E0BFE3ED0E4.dita"><linktext>Compressing+
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and Decompressing                 File - Zip Format </linktext></link>+
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<link href="GUID-548CC331-8E38-5627-A925-EA386BE90258.dita"><linktext>Compressing+
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and Decompressing                 File - GZip Format </linktext></link>+
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<link href="GUID-C3086910-D7B4-5549-BF65-374C8B602E8F.dita"><linktext>Compressing+
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and                 Decompressing Memory Streams </linktext></link>+
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<link href="GUID-FDDAF8E9-4CAB-5489-B578-A5362E2140C1.dita"><linktext>Decompressing+
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File Archives</linktext></link>+
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</related-links></concept>+
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