dlib C++ Library - xml_parser_ex.cpp

// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
/*
 This is an example illustrating the use of the xml_parser component in 
 the dlib C++ Library.
 This example simply reads in an xml file and prints the parsing events
 to the screen. 
*/
#include <dlib/xml_parser.h>
#include <iostream>
#include <fstream>
using namespace std;
using namespace dlib;
// ----------------------------------------------------------------------------------------
class doc_handler : public document_handler
{
 /*
 As the parser runs it generates events when it encounters tags and
 data in an XML file. To be able to receive these events all you have to 
 do is make a class that inherits from dlib::document_handler and
 implements its virtual methods. Then you simply associate an
 instance of your class with the xml_parser.
 So this class is a simple example document handler that just prints
 all the events to the screen.
 */
public:
 virtual void start_document (
 )
 {
 cout << "parsing begins" << endl;
 }
 virtual void end_document (
 )
 {
 cout << "Parsing done" << endl;
 }
 virtual void start_element ( 
 const unsigned long line_number,
 const std::string& name,
 const dlib::attribute_list& atts
 )
 {
 cout << "on line " << line_number << " we hit the <" << name << "> tag" << endl;
 // print all the tag's attributes
 atts.reset();
 while (atts.move_next())
 {
 cout << "\tattribute: " << atts.element().key() << " = " << atts.element().value() << endl;
 }
 }
 virtual void end_element ( 
 const unsigned long line_number,
 const std::string& name
 )
 {
 cout << "on line " << line_number << " we hit the closing tag </" << name << ">" << endl;
 }
 virtual void characters ( 
 const std::string& data
 )
 {
 cout << "Got some data between tags and it is:\n" << data << endl;
 }
 virtual void processing_instruction (
 const unsigned long line_number,
 const std::string& target,
 const std::string& data
 )
 {
 cout << "on line " << line_number << " we hit a processing instruction with a target of '" 
 << target << "' and data '" << data << "'" << endl;
 }
};
// ----------------------------------------------------------------------------------------
int main(int argc, char** argv)
{
 try
 {
 // Check if the user entered an argument to this application. 
 if (argc != 2)
 {
 cout << "Please enter an xml file to parse on the command line" << endl;
 return 1;
 }
 doc_handler dh;
 // Now run the parser and tell it to call our doc_handler for each of the parsing
 // events.
 parse_xml(argv[1], dh);
 }
 catch (std::exception& e)
 {
 cout << e.what() << endl;
 }
}