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| − | =VTD-XML Investigation=
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| − | VTD-XML ([http://vtd-xml.sourceforge.net/ http://vtd-xml.sourceforge.net/]) is a high-performance XML processing model that deals with XML in a binary form, instead of the traditional text form. VTD stands for '''V'''irtual '''T'''oken '''D'''escriptor.
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| − | VTD-XML parses an XML document and builds an internal data structure representing the entire XML document in <tt>byte[]</tt> form. Each "token" of the XML document is represented as the following 64-bit integer:
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| − | [[Image:Vtd_layout.jpg]]
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| − | * Big endian
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| − | * Starting offset: 30 bits (b29 ~ b0) maximum value is 2^30 -1 = 1G -1
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| − | * Length: 20 bits (b51 ~ b32) maximum value is 2^20-1 = 1M -1
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| − | ** For some token type
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| − | *** Prefix length: 9 bits (b51~ b43) max value 511
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| − | *** Q-name length: 11 bits (b42 ~ b 32) max value 1023
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| − | * Depth: 8 bits (b59~b52) max value is 2^8-1 = 255
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| − | * Token type: 4 bits (b63~b60)
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| − | * Reserved bit: 2 bits (b31: b30)
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| − | ==VTD-XML Core Concepts==
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| − | ===Unmarshalling a VTD-XML document===
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| − | <div style="width:900px">
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| − | <source lang="java">
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| − | VTDGen vg = new VTDGen();
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| − | // from existing byte[]
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| − | // true indicates namespace aware
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| − | vg.setDoc(byte[]); vg.parse(true);
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| − | // - or -
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| − | // from file
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| − | vg.parseFile("old.xml",false)
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| − | </source>
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| − | </div>
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