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92 lines
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92 lines
3.6 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
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<HTML>
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<HEAD>
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<TITLE>Mini-XML Programmers Manual, Version 2.2.1</TITLE>
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<META NAME="author" CONTENT="Michael Sweet">
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<META NAME="copyright" CONTENT="Copyright 2003-2005">
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<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-iso-8859-1">
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<LINK REL="Start" HREF="index.html">
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<LINK REL="Contents" HREF="toc.html">
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<LINK REL="Prev" HREF="TheBasics.html">
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<LINK REL="Next" HREF="LoadingXML.html">
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<STYLE TYPE="text/css"><!--
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BODY { font-family: serif }
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H1 { font-family: sans-serif }
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H2 { font-family: sans-serif }
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H3 { font-family: sans-serif }
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H4 { font-family: sans-serif }
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H5 { font-family: sans-serif }
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H6 { font-family: sans-serif }
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SUB { font-size: smaller }
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SUP { font-size: smaller }
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PRE { font-family: monospace }
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--></STYLE>
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</HEAD>
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<BODY>
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<A HREF="toc.html">Contents</A>
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<A HREF="TheBasics.html">Previous</A>
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<A HREF="LoadingXML.html">Next</A>
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<HR NOSHADE>
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<H2><A NAME="3_2">Nodes</A></H2>
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<P>Every piece of information in an XML file (elements, text, numbers)
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is stored in memory in "nodes". Nodes are defined by the <A href="mxmlnodet.html#mxml_node_t">
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<TT>mxml_node_t</TT></A> structure. The <A href="mxmltypet.html#mxml_type_t">
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<TT>type</TT></A> member defines the node type (element, integer,
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opaque, real, or text) which determines which value you want to look at
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in the <A href="mxmlvaluet.html#mxml_value_t"><TT>value</TT></A> union.</P>
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<P>New nodes can be created using the <A href="mxmlNewElement.html#mxmlNewElement">
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<TT>mxmlNewElement()</TT></A>, <A href="mxmlNewInteger.html#mxmlNewInteger">
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<TT>mxmlNewInteger()</TT></A>, <A href="mxmlNewOpaque.html#mxmlNewOpaque">
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<TT>mxmlNewOpaque()</TT></A>, <A href="mxmlNewReal.html#mxmlNewReal"><TT>
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mxmlNewReal()</TT></A>, and <A href="mxmlNewText.html#mxmlNewText"><TT>
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mxmlNewText()</TT></A> functions. Only elements can have child nodes,
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and the top node must be an element, usually "?xml".</P>
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<P>Each node has pointers for the node above (<TT>parent</TT>), below (<TT>
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child</TT>), to the left (<TT>prev</TT>), and to the right (<TT>next</TT>
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) of the current node. If you have an XML file like the following:</P>
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<PRE>
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<?xml version="1.0"?>
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<data>
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<node>val1</node>
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<node>val2</node>
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<node>val3</node>
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<group>
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<node>val4</node>
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<node>val5</node>
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<node>val6</node>
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</group>
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<node>val7</node>
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<node>val8</node>
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<node>val9</node>
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</data>
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</PRE>
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<P>the node tree returned by <TT>mxmlLoadFile()</TT> would look like the
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following in memory:</P>
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<PRE>
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?xml
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data
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node - node - node - group - node - node - node
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| | | | | | |
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val1 val2 val3 | val7 val8 val9
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node - node - node
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| | |
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val4 val5 val6
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</PRE>
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<P>where "-" is a pointer to the next node and "|" is a pointer to the
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first child node.</P>
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<P>Once you are done with the XML data, use the <A href="mxmlDelete.html#mxmlDelete">
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<TT>mxmlDelete()</TT></A> function to recursively free the memory that
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is used for a particular node or the entire tree:</P>
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<PRE>
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mxmlDelete(tree);
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</PRE>
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<HR NOSHADE>
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<A HREF="toc.html">Contents</A>
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<A HREF="TheBasics.html">Previous</A>
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<A HREF="LoadingXML.html">Next</A>
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</BODY>
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</HTML>
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