+This library is specially designed for reading xml configuration files and
+to be as low on memory management as possible. Modifying or writing xml files
+is not planned for the future. In most situations being able to gather data
+by reading an xml file is more than enough and the read-only decision
+provides a number of advantages over a one-size fits all approach. For isntance
+the memory footprint can be kept low and the library can be kept simple.
+
+To achieve these goals the mmap function is used to map the configuration file
+to a memory region. The only places where memory is allocated is when creating
+a new XML-id, when requesting a string from a node, when requestiong the node
+name or when a request is made to copy a node into a new memory region.
+
+Using this library should be pretty simple for most tasks; just open a file,
+read every parameter one by one and close the id again.
+{
+ void *xid;
+
+ xid = xmlOpen("/tmp/file.xml");
+ xpos = xmlNodeGetDouble(xid, "/configuration/x-pos");
+ ypos = xmlNodeGetDouble(xid, "/configuration/y-pos");
+ zpos = xmlNodeGetDouble(xid, "/configuration/z-pos");
+ xmlClose(xid);
+}
+
+While it is certainly possible to access every node directly by calling the
+xmlNodeGet(Int/Double/String) functions, when more than one node need to be
+gathered from a parent node it is advised to get the id of the parent node
+and work from there since the XML-id holds the boundaries of the (parent)node
+which limits the searching area resulting in improved searching speed.
+{
+ void *xnid;
+ char *s;
+
+ xnid = xmlNodeGet(id, "/configuration/setup/");
+ version = xmlNodeGetDouble(xnid, "version");
+ s = xmlNodeGetString(xnid, "author");
+ if (s) author = s;
+ free(s);
+ free(xnid);
+}
+
+Overview of the available functions:
+ -----------------------------------------------------------------------------
#
# Functions to Open and Close the XML file
# e.g.
# id = xmlOpen("/tmp/file.xml");
# xmlClose(id);
#
-void *xmlOpen(const char *);
-void xmlClose(const void *);
+void *xmlOpen(const char *filename);
+void *xmlInitBuffer(const char *buffer, size_t size);
+void xmlClose(void *xid);
#
# Get the Id of a node at the specified path
# e.g.
-# xnid = xmlGetNode(id, "/path/to/specified/node");
+# xnid = xmlNodeGet(id, "/path/to/specified/node");
#
-void *xmlGetNode(const void *, const char *);
-void *xmlCopyNode(void *, const char *);
+void *xmlNodeGet(const void *xid, const char *path);
+void *xmlNodeCopy(const void *xid, const char *path);
#
-# Functions to walk the node tree an process them one by one.
+# Functions to walk the node tree and process them one by one.
# e.g.
# xmid = xmlMarkId(id);
-# num = xmlGetNumElements(xmid);
+# num = xmlNodeGetNum(xmid, "node");
# for (i=0; i<num; i++) {
-# if (xmlGetNextElement(id, xmid, "element") != 0) {
+# if (xmlNodeGetPos(id, xmid, "element", i) != 0) {
# if ((s = xmlGetString(xmid)) != 0) {
# printf("%s\n", s);
# free(s);
# }
# }
# }
+# free(xmid);
#
-void *xmlMarkId(void *);
-unsigned int xmlGetNumElements(void *, const char *);
-void *xmlGetNextElement(const void *, void *, const char *);
+void *xmlMarkId(const void *xid);
+unsigned int xmlNodeGetNum(const void *xid, const char *path);
+void *xmlNodeGetPos(const void *pid, void *xid, const char *element, int pos);
+
+#
+# Get the name of the current node
+#
+char *xmlNodeGetName(const void *xid);
+size_t xmlNodeCopyName(const void *xid, const char *buffer, size_t size);
#
# These functions work on the current node.
# e.g.
-# xnid = xmlGetNode(id, "/path/to/last/node");
+# xnid = xmlNodeGet(id, "/path/to/last/node");
# i = xmlGetInt(xnid);
# or
-# xnid = xmlGetNode(id, "/path/to/specified/node");
+# xnid = xmlNodeGet(id, "/path/to/specified/node");
# if (xmlCompareString(xnid, "value") == 0) printf("We have a match!\n");
#
-long int xmlGetInt(void *);
-double xmlGetDouble(void *);
-char *xmlGetString(void *);
-int xmlCompareString(const void *, const char *);
+long int xmlGetInt(const void *xid);
+double xmlGetDouble(const void *xid);
+char *xmlGetString(const void *xid);
+size_t xmlCopyString(const void *xid, char *buffer, const size_t size);
+int xmlCompareString(const void *xid, const char *str);
#
# These functions work on a specified node path
# e.g.
-# d = xmlGetNodeDouble(id, "/path/to/node");
+# d = xmlNodeGetDouble(id, "/path/to/node");
+# or
+# xnid = xmlNodeGet(id, "/path/to");
+# i = xmlNodeGetInt(xnid, "node");
+#
+long int xmlNodeGetInt(const void *xid, const char *path);
+double xmlNodeGetDouble(const void *xid, const char *path);
+char *xmlNodeGetString(const void *xid, const char *path);
+size_t xmlNodeCopyString(const void *xid, const char *path,
+ char *buffer, const size_t size);
+int xmlNodeCompareString(const void *xid, const char *path, const char *str);
+
+#
+# These functions work on a specified atribute
+# e.g.
+# i = xmlAttributeGetInt(id, "n");
+#
# or
-# xnid = xmlGetNode(id, "/path/to");
-# i = xmlGetNodeInt(xnid, "node");
-#
-long int xmlGetNodeInt(void *, const char *);
-double xmlGetNodeDouble(void *, const char *);
-char *xmlGetNodeString(void *, const char *);
-unsigned xmlCopyNodeString(void *, const char *, char *, const unsigned int);
-int xmlCompareNodeString(const void *, const char *, const char *);
+# s = xmlAttributeGetString(id, "type");
+# if (s) printf("node is of type '%s'\n", s);
+# free(s);
+#
+long int xmlAttributeGetInt(const void *xid, const char *attr);
+double xmlAttributeGetDouble(const void *xid, const char *attr);
+char *xmlAttributeGetString(const void *xid, const char *attr);
+size_t xmlAttributeCopyString(const void *xid, const char *attr,
+ const char *buffer, size_t size);
+int xmlAttributeCompareString(const void *xid, const char *attr,
+ const char *str);
+
+#
+# Error detection and reporting functions
+#
+# char *err_str = xmlErrorGetString(id, 0);
+# size_t err_lineno = xmlErrorGetLineNo(id, 0);
+# int err = xmlErrorGetNo(id, 1); /* clear last error */
+# if (err) printf("Error #%i at line %u: '%s'\n", err, err_lineno, err_str);
+#
+int xmlErrorGetNo(const void *xid, int clear);
+size_t xmlErrorGetLineNo(const void *xid, int clear);
+size_t xmlErrorGetColumnNo(const void *xid, int clear);
+const char *xmlErrorGetString(const void *xid, int clear);
projects / flightgear.git / blobdiff