8dec4a987f
sequence could give a false negative result
* Add a 'clear' attribute to the xmlErrorGet functions that indicates whether
the error should be cleared or not
* detect more xml syntax errors
141 lines
4.6 KiB
Text
141 lines
4.6 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 requestiong 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 = xmlNodeGetDouble(xid, "/configuration/x-pos");
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ypos = xmlNodeGetDouble(xid, "/configuration/y-pos");
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zpos = xmlNodeGetDouble(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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xmlNodeGet(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 = xmlNodeGet(id, "/configuration/setup/");
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version = xmlNodeGetDouble(xnid, "version");
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s = xmlNodeGetString(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 = xmlNodeGet(id, "/path/to/specified/node");
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#
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void *xmlNodeGet(const void *, const char *);
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void *xmlNodeCopy(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 = xmlNodeGetNum(xmid);
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# for (i=0; i<num; i++) {
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# if (xmlNodeGetPos(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 xmlNodeGetNum(void *, const char *);
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void *xmlNodeGetPos(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 *xmlNodeGetName(void *);
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size_t xmlNodeCopyName(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 = xmlNodeGet(id, "/path/to/last/node");
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# i = xmlGetInt(xnid);
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# or
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# xnid = xmlNodeGet(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 = xmlNodeGetDouble(id, "/path/to/node");
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# or
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# xnid = xmlNodeGet(id, "/path/to");
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# i = xmlNodeGetInt(xnid, "node");
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#
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long int xmlNodeGetInt(void *, const char *);
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double xmlNodeGetDouble(void *, const char *);
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char *xmlNodeGetString(void *, const char *);
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size_t xmlNodeCopyString(void *, const char *, char *, const size_t);
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int xmlNodeCompareString(const void *, const char *, const char *);
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#
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# These functions work on a specified atribute
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# e.g.
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# i = xmlAttributeGetInt(id, "n");
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#
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# or
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# s = xmlNodeGetString(id, "type");
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# if (s) printf("node is of type '%s'\n", s);
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# free(s);
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#
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long int xmlAttributeGetInt(const void *, const char *);
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double xmlAttributeGetDouble(const void *, const char *);
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char *xmlAttributeGetString(const void *, const char *);
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size_t xmlAttributeCopyString(const void *, const char *, const char *, size_t);
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int xmlAttributeCompareString(const void *, const char *, const char *);
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#
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# Error detection and reporting functions
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#
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# char *err_str = xmlErrorGetString(id, 0);
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# size_t err_lineno = xmlErrorGetLineNo(id, 0);
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# int err = xmlErrorGetNo(id, 1); /* clear last error */
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# if (err) printf("Error #%i at line %u: '%s'\n", err, err_lineno, err_str);
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#
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int xmlErrorGetNo(const void *, int);
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size_t xmlErrorGetLineNo(const void *, int);
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const char *xmlErrorGetString(const void *, int);
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