d015bfe72f
* fix a problem where the wrong node-name length was returned
* xmlgrep now also works when only the -e options is specified
* fix xmlgrep to show the correct node-name (it reported the parent
node-name in the previous version)
113 lines
3.7 KiB
Text
113 lines
3.7 KiB
Text
This library is specially designed for reading xml configuration files and
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to be as low on memory management as possible. Modifying or writing xml files
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is not planned for the future. In most situations being able to gather data
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by reading an xml file is more than enough and the read-only decision
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provides a number of advantages over a one-size fits all approach. For isntance
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the memory footprint can be kept low and the library can be kept simple.
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To achieve these goals the mmap function is used to map the configuration file
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to a memory region. The only places where memory is allocated is when creating
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a new XML-id, when requesting a string from a node, when requesting the node
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name or when a request is made to copy a node into a new memory region.
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Using this library should be pretty simple for most tasks; just open a file,
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read every parameter one by one and close the id again.
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{
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void *xid;
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xid = xmlOpen("/tmp/file.xml");
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xpos = xmlGetNodeDouble(xid, "/configuration/x-pos");
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ypos = xmlGetNodeDouble(xid, "/configuration/y-pos");
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zpos = xmlGetNodeDouble(xid, "/configuration/z-pos");
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xmlClose(xid);
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}
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While it is certainly possible to access every node directly by calling the
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xmlGetNode(Int/Double/String) functions, when more than one node need to be
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gathered from a parent node it is advised to get the id of the parent node
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and work from there since the XML-id holds the boundaries of the (parent)node
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which limits the searching area resulting in improved searching speed.
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{
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void *xnid;
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char *s;
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xnid = xmlGetNode(id, "/configuration/setup/");
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version = xmlGetNodeDouble(xnid, "version");
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s = xmlGetNodeString(xnid, "author");
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if (s) author = s;
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free(s);
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free(xnid);
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}
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Overview of the available functions:
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-----------------------------------------------------------------------------
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#
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# Functions to Open and Close the XML file
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# e.g.
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# id = xmlOpen("/tmp/file.xml");
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# xmlClose(id);
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#
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void *xmlOpen(const char *);
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void xmlClose(const void *);
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#
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# Get the Id of a node at the specified path
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# e.g.
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# xnid = xmlGetNode(id, "/path/to/specified/node");
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#
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void *xmlGetNode(const void *, const char *);
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void *xmlCopyNode(void *, const char *);
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#
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# Functions to walk the node tree and process them one by one.
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# e.g.
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# xmid = xmlMarkId(id);
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# num = xmlGetNumNodes(xmid);
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# for (i=0; i<num; i++) {
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# if (xmlGetNodeNum(id, xmid, "element", i) != 0) {
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# if ((s = xmlGetString(xmid)) != 0) {
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# printf("%s\n", s);
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# free(s);
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# }
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# }
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# }
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# free(xmid);
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#
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void *xmlMarkId(void *);
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unsigned int xmlGetNumNodes(void *, const char *);
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void *xmlGetNodeNum(const void *, void *, const char *, int);
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#
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# Get the name of the current node
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#
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char *xmlGetNodeName(void *);
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size_t xmlCopyNodeName(void *, const char *, size_t);
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#
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# These functions work on the current node.
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# e.g.
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# xnid = xmlGetNode(id, "/path/to/last/node");
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# i = xmlGetInt(xnid);
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# or
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# xnid = xmlGetNode(id, "/path/to/specified/node");
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# if (xmlCompareString(xnid, "value") == 0) printf("We have a match!\n");
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#
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long int xmlGetInt(void *);
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double xmlGetDouble(void *);
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char *xmlGetString(void *);
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size_t xmlCopyString(void *, char *, const size_t);
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int xmlCompareString(const void *, const char *);
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#
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# These functions work on a specified node path
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# e.g.
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# d = xmlGetNodeDouble(id, "/path/to/node");
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# or
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# xnid = xmlGetNode(id, "/path/to");
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# i = xmlGetNodeInt(xnid, "node");
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#
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long int xmlGetNodeInt(void *, const char *);
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double xmlGetNodeDouble(void *, const char *);
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char *xmlGetNodeString(void *, const char *);
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size_t xmlCopyNodeString(void *, const char *, char *, const size_t);
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int xmlCompareNodeString(const void *, const char *, const char *);
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