libxml-xpath.html

xml开源解析代码.版本为libxml2-2.6.29,可支持GB3212.网络消息发送XML时很有用.

</pre><p>Evaluate the Precompiled XPath expression in the given context.</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>comp</tt></i>:</span></td><td>the compiled XPath expression</td></tr><tr><td><span class="term"><i><tt>ctx</tt></i>:</span></td><td>the XPath context</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the <a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> resulting from the evaluation or NULL. the caller has to free the object.</td></tr></tbody></table></div><h3><a name="xmlXPathCompiledEvalToBoolean" id="xmlXPathCompiledEvalToBoolean"></a>Function: xmlXPathCompiledEvalToBoolean</h3><pre class="programlisting">int	xmlXPathCompiledEvalToBoolean	(<a href="libxml-xpath.html#xmlXPathCompExprPtr">xmlXPathCompExprPtr</a> comp, <br />					 <a href="libxml-xpath.html#xmlXPathContextPtr">xmlXPathContextPtr</a> ctxt)<br />
</pre><p>Applies the XPath boolean() function on the result of the given compiled expression.</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>comp</tt></i>:</span></td><td>the compiled XPath expression</td></tr><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>the XPath context</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>1 if the expression evaluated to true, 0 if to false and -1 in API and internal errors.</td></tr></tbody></table></div><h3><a name="xmlXPathContextSetCache" id="xmlXPathContextSetCache"></a>Function: xmlXPathContextSetCache</h3><pre class="programlisting">int	xmlXPathContextSetCache		(<a href="libxml-xpath.html#xmlXPathContextPtr">xmlXPathContextPtr</a> ctxt, <br />					 int active, <br />					 int value, <br />					 int options)<br />
</pre><p>Creates/frees an object cache on the XPath context. If activates XPath objects (xmlXPathObject) will be cached internally to be reused. @options: 0: This will set the XPath object caching: @value: This will set the maximum number of XPath objects to be cached per slot There are 5 slots for: node-set, string, number, boolean, and misc objects. Use &lt;0 for the default number (100). Other values for @options have currently no effect.</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>the XPath context</td></tr><tr><td><span class="term"><i><tt>active</tt></i>:</span></td><td>enables/disables (creates/frees) the cache</td></tr><tr><td><span class="term"><i><tt>value</tt></i>:</span></td><td>a value with semantics dependant on @options</td></tr><tr><td><span class="term"><i><tt>options</tt></i>:</span></td><td>options (currently only the value 0 is used)</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>0 if the setting succeeded, and -1 on API or internal errors.</td></tr></tbody></table></div><h3><a name="xmlXPathConvertBoolean" id="xmlXPathConvertBoolean"></a>Function: xmlXPathConvertBoolean</h3><pre class="programlisting"><a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a>	xmlXPathConvertBoolean	(<a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> val)<br />
</pre><p>Converts an existing object to its boolean() equivalent</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>val</tt></i>:</span></td><td>an XPath object</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the new object, the old one is freed (or the operation is done directly on @val)</td></tr></tbody></table></div><h3><a name="xmlXPathConvertFunc" id="xmlXPathConvertFunc"></a>Function type: xmlXPathConvertFunc</h3><pre class="programlisting">Function type: xmlXPathConvertFunc
int	xmlXPathConvertFunc		(<a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> obj, <br />					 int type)
</pre><p>A conversion function is associated to a type and used to cast the new type to primitive values.</p><div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>obj</tt></i>:</span></td><td>an XPath object</td></tr><tr><td><span class="term"><i><tt>type</tt></i>:</span></td><td>the number of the target type</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>-1 in case of error, 0 otherwise</td></tr></tbody></table></div><br />
<h3><a name="xmlXPathConvertNumber" id="xmlXPathConvertNumber"></a>Function: xmlXPathConvertNumber</h3><pre class="programlisting"><a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a>	xmlXPathConvertNumber	(<a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> val)<br />
</pre><p>Converts an existing object to its number() equivalent</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>val</tt></i>:</span></td><td>an XPath object</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the new object, the old one is freed (or the operation is done directly on @val)</td></tr></tbody></table></div><h3><a name="xmlXPathConvertString" id="xmlXPathConvertString"></a>Function: xmlXPathConvertString</h3><pre class="programlisting"><a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a>	xmlXPathConvertString	(<a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> val)<br />
</pre><p>Converts an existing object to its string() equivalent</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>val</tt></i>:</span></td><td>an XPath object</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the new object, the old one is freed (or the operation is done directly on @val)</td></tr></tbody></table></div><h3><a name="xmlXPathCtxtCompile" id="xmlXPathCtxtCompile"></a>Function: xmlXPathCtxtCompile</h3><pre class="programlisting"><a href="libxml-xpath.html#xmlXPathCompExprPtr">xmlXPathCompExprPtr</a>	xmlXPathCtxtCompile	(<a href="libxml-xpath.html#xmlXPathContextPtr">xmlXPathContextPtr</a> ctxt, <br />						 const <a href="libxml-xmlstring.html#xmlChar">xmlChar</a> * str)<br />
</pre><p>Compile an XPath expression</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>an XPath context</td></tr><tr><td><span class="term"><i><tt>str</tt></i>:</span></td><td>the XPath expression</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the <a href="libxml-xpath.html#xmlXPathCompExprPtr">xmlXPathCompExprPtr</a> resulting from the compilation or NULL. the caller has to free the object.</td></tr></tbody></table></div><h3><a name="xmlXPathEval" id="xmlXPathEval"></a>Function: xmlXPathEval</h3><pre class="programlisting"><a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a>	xmlXPathEval	(const <a href="libxml-xmlstring.html#xmlChar">xmlChar</a> * str, <br />					 <a href="libxml-xpath.html#xmlXPathContextPtr">xmlXPathContextPtr</a> ctx)<br />
</pre><p>Evaluate the XPath Location Path in the given context.</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>str</tt></i>:</span></td><td>the XPath expression</td></tr><tr><td><span class="term"><i><tt>ctx</tt></i>:</span></td><td>the XPath context</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the <a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> resulting from the evaluation or NULL. the caller has to free the object.</td></tr></tbody></table></div><h3><a name="xmlXPathEvalExpression" id="xmlXPathEvalExpression"></a>Function: xmlXPathEvalExpression</h3><pre class="programlisting"><a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a>	xmlXPathEvalExpression	(const <a href="libxml-xmlstring.html#xmlChar">xmlChar</a> * str, <br />						 <a href="libxml-xpath.html#xmlXPathContextPtr">xmlXPathContextPtr</a> ctxt)<br />
</pre><p>Evaluate the XPath expression in the given context.</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>str</tt></i>:</span></td><td>the XPath expression</td></tr><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>the XPath context</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the <a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> resulting from the evaluation or NULL. the caller has to free the object.</td></tr></tbody></table></div><h3><a name="xmlXPathEvalFunc" id="xmlXPathEvalFunc"></a>Function type: xmlXPathEvalFunc</h3><pre class="programlisting">Function type: xmlXPathEvalFunc
void	xmlXPathEvalFunc		(<a href="libxml-xpath.html#xmlXPathParserContextPtr">xmlXPathParserContextPtr</a> ctxt, <br />					 int nargs)
</pre><p>An XPath evaluation function, the parameters are on the XPath context stack.</p><div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>an XPath parser context</td></tr><tr><td><span class="term"><i><tt>nargs</tt></i>:</span></td><td>the number of arguments passed to the function</td></tr></tbody></table></div><br />
<h3><a name="xmlXPathEvalPredicate" id="xmlXPathEvalPredicate"></a>Function: xmlXPathEvalPredicate</h3><pre class="programlisting">int	xmlXPathEvalPredicate		(<a href="libxml-xpath.html#xmlXPathContextPtr">xmlXPathContextPtr</a> ctxt, <br />					 <a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> res)<br />
</pre><p>Evaluate a predicate result for the current node. A PredicateExpr is evaluated by evaluating the Expr and converting the result to a boolean. If the result is a number, the result will be converted to true if the number is equal to the position of the context node in the context node list (as returned by the position function) and will be converted to false otherwise; if the result is not a number, then the result will be converted as if by a call to the boolean function.</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>the XPath context</td></tr><tr><td><span class="term"><i><tt>res</tt></i>:</span></td><td>the Predicate Expression evaluation result</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>1 if predicate is true, 0 otherwise</td></tr></tbody></table></div><h3><a name="xmlXPathFreeCompExpr" id="xmlXPathFreeCompExpr"></a>Function: xmlXPathFreeCompExpr</h3><pre class="programlisting">void	xmlXPathFreeCompExpr		(<a href="libxml-xpath.html#xmlXPathCompExprPtr">xmlXPathCompExprPtr</a> comp)<br />
</pre><p>Free up the memory allocated by @comp</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>comp</tt></i>:</span></td><td>an XPATH comp</td></tr></tbody></table></div><h3><a name="xmlXPathFreeContext" id="xmlXPathFreeContext"></a>Function: xmlXPathFreeContext</h3><pre class="programlisting">void	xmlXPathFreeContext		(<a href="libxml-xpath.html#xmlXPathContextPtr">xmlXPathContextPtr</a> ctxt)<br />
</pre><p>Free up an <a href="libxml-xpath.html#xmlXPathContext">xmlXPathContext</a></p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>the context to free</td></tr></tbody></table></div><h3><a name="xmlXPathFreeNodeSet" id="xmlXPathFreeNodeSet"></a>Function: xmlXPathFreeNodeSet</h3><pre class="programlisting">void	xmlXPathFreeNodeSet		(<a href="libxml-xpath.html#xmlNodeSetPtr">xmlNodeSetPtr</a> obj)<br />
</pre><p>Free the NodeSet compound (not the actual nodes !).</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>obj</tt></i>:</span></td><td>the <a href="libxml-xpath.html#xmlNodeSetPtr">xmlNodeSetPtr</a> to free</td></tr></tbody></table></div><h3><a name="xmlXPathFreeNodeSetList" id="xmlXPathFreeNodeSetList"></a>Function: xmlXPathFreeNodeSetList</h3><pre class="programlisting">void	xmlXPathFreeNodeSetList		(<a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> obj)<br />
</pre><p>Free up the <a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> @obj but don't deallocate the objects in the list contrary to xmlXPathFreeObject().</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>obj</tt></i>:</span></td><td>an existing NodeSetList object</td></tr></tbody></table></div><h3><a name="xmlXPathFreeObject" id="xmlXPathFreeObject"></a>Function: xmlXPathFreeObject</h3><pre class="programlisting">void	xmlXPathFreeObject		(<a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> obj)<br />
</pre><p>Free up an <a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> object.</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>obj</tt></i>:</span></td><td>the object to free</td></tr></tbody></table></div><h3><a name="xmlXPathFuncLookupFunc" id="xmlXPathFuncLookupFunc"></a>Function type: xmlXPathFuncLookupFunc</h3><pre class="programlisting">Function type: xmlXPathFuncLookupFunc
<a href="libxml-xpath.html#xmlXPathFunction">xmlXPathFunction</a>	xmlXPathFuncLookupFunc	(void * ctxt, <br />						 const <a href="libxml-xmlstring.html#xmlChar">xmlChar</a> * name, <br />						 const <a href="libxml-xmlstring.html#xmlChar">xmlChar</a> * ns_uri)
</pre><p>Prototype for callbacks used to plug function lookup in the XPath engine.</p><div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>an XPath context</td></tr><tr><td><span class="term"><i><tt>name</tt></i>:</span></td><td>name of the function</td></tr><tr><td><span class="term"><i><tt>ns_uri</tt></i>:</span></td><td>the namespace name hosting this function</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the XPath function or NULL if not found.</td></tr></tbody></table></div><br />
<h3><a name="xmlXPathFunction" id="xmlXPathFunction"></a>Function type: xmlXPathFunction</h3><pre class="programlisting">Function type: xmlXPathFunction
void	xmlXPathFunction		(<a href="libxml-xpath.html#xmlXPathParserContextPtr">xmlXPathParserContextPtr</a> ctxt, <br />					 int nargs)
</pre><p>An XPath function. The arguments (if any) are popped out from the context stack and the result is pushed on the stack.</p><div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>the XPath interprestation context</td></tr><tr><td><span class="term"><i><tt>nargs</tt></i>:</span></td><td>the number of arguments</td></tr></tbody></table></div><br />
<h3><a name="xmlXPathInit" id="xmlXPathInit"></a>Function: xmlXPathInit</h3><pre class="programlisting">void	xmlXPathInit			(void)<br />
</pre><p>Initialize the XPath environment</p>
<h3><a name="xmlXPathIsInf" id="xmlXPathIsInf"></a>Function: xmlXPathIsInf</h3><pre class="programlisting">int	xmlXPathIsInf			(double val)<br />
</pre><p>Provides a portable isinf() function to detect whether a double is a +Infinite or -Infinite. Based on trio code http://sourceforge.net/projects/ctrio/</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>val</tt></i>:</span></td><td>a double value</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>1 vi the value is +Infinite, -1 if -Infinite, 0 otherwise</td></tr></tbody></table></div><h3><a name="xmlXPathIsNaN" id="xmlXPathIsNaN"></a>Function: xmlXPathIsNaN</h3><pre class="programlisting">int	xmlXPathIsNaN			(double val)<br />
</pre><p>Provides a portable isnan() function to detect whether a double is a NotaNumber. Based on trio code http://sourceforge.net/projects/ctrio/</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>val</tt></i>:</span></td><td>a double value</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>1 if the value is a NaN, 0 otherwise</td></tr></tbody></table></div><h3><a name="xmlXPathNewContext" id="xmlXPathNewContext"></a>Function: xmlXPathNewContext</h3><pre class="programlisting"><a href="libxml-xpath.html#xmlXPathContextPtr">xmlXPathContextPtr</a>	xmlXPathNewContext	(<a href="libxml-tree.html#xmlDocPtr">xmlDocPtr</a> doc)<br />
</pre><p>Create a new <a href="libxml-xpath.html#xmlXPathContext">xmlXPathContext</a></p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>doc</tt></i>:</span></td><td>the XML document</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the <a href="libxml-xpath.html#xmlXPathContext">xmlXPathContext</a> just allocated. The caller will need to free it.</td></tr></tbody></table></div><h3><a name="xmlXPathNodeSetCreate" id="xmlXPathNodeSetCreate"></a>Function: xmlXPathNodeSetCreate</h3><pre class="programlisting"><a href="libxml-xpath.html#xmlNodeSetPtr">xmlNodeSetPtr</a>	xmlXPathNodeSetCreate	(<a href="libxml-tree.html#xmlNodePtr">xmlNodePtr</a> val)<br />
</pre><p>Create a new <a href="libxml-xpath.html#xmlNodeSetPtr">xmlNodeSetPtr</a> of type double and of value @val</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>val</tt></i>:</span></td><td>an initial xmlNodePtr, or NULL</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the newly created object.</td></tr></tbody></table></div><h3><a name="xmlXPathObjectCopy" id="xmlXPathObjectCopy"></a>Function: xmlXPathObjectCopy</h3><pre class="programlisting"><a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a>	xmlXPathObjectCopy	(<a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a> val)<br />
</pre><p>allocate a new copy of a given object</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>val</tt></i>:</span></td><td>the original object</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the newly created object.</td></tr></tbody></table></div><h3><a name="xmlXPathOrderDocElems" id="xmlXPathOrderDocElems"></a>Function: xmlXPathOrderDocElems</h3><pre class="programlisting">long	xmlXPathOrderDocElems		(<a href="libxml-tree.html#xmlDocPtr">xmlDocPtr</a> doc)<br />
</pre><p>Call this routine to speed up XPath computation on static documents. This stamps all the element nodes with the document order Like for line information, the order is kept in the element-&gt;content field, the value stored is actually - the node number (starting at -1) to be able to differentiate from line numbers.</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>doc</tt></i>:</span></td><td>an input document</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the number of elements found in the document or -1 in case of error.</td></tr></tbody></table></div><h3><a name="xmlXPathVariableLookupFunc" id="xmlXPathVariableLookupFunc"></a>Function type: xmlXPathVariableLookupFunc</h3><pre class="programlisting">Function type: xmlXPathVariableLookupFunc
<a href="libxml-xpath.html#xmlXPathObjectPtr">xmlXPathObjectPtr</a>	xmlXPathVariableLookupFunc	(void * ctxt, <br />							 const <a href="libxml-xmlstring.html#xmlChar">xmlChar</a> * name, <br />							 const <a href="libxml-xmlstring.html#xmlChar">xmlChar</a> * ns_uri)
</pre><p>Prototype for callbacks used to plug variable lookup in the XPath engine.</p><div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>an XPath context</td></tr><tr><td><span class="term"><i><tt>name</tt></i>:</span></td><td>name of the variable</td></tr><tr><td><span class="term"><i><tt>ns_uri</tt></i>:</span></td><td>the namespace name hosting this variable</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the XPath object value or NULL if not found.</td></tr></tbody></table></div><br />
<p><a href="../bugs.html">Daniel Veillard</a></p></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td></tr></table></body></html>