htmlstripper2.cpp

C语言数值算法程序大全（第二版）,课本文件

//: C04:HTMLStripper2.cpp
// From "Thinking in C++, 2nd Edition, Volume 2"
// by Bruce Eckel & Chuck Allison, (c) 2003 MindView, Inc.
// Available at www.BruceEckel.com.
//{L} ../c03/replaceAll
// Filter to remove html tags and markers
#include <cstddef>
#include <cstdlib>
#include <fstream>
#include <iostream>
#include <sstream>
#include <stdexcept>
#include <string>
#include "../require.h"
using namespace std;

string& replaceAll(string& context, const string& from,
  const string& to);

string& stripHTMLTags(string& s) throw(runtime_error) {
  size_t leftPos;
  while ((leftPos = s.find('<')) != string::npos) {
    size_t rightPos = s.find('>', leftPos+1);
    if (rightPos == string::npos) {
      ostringstream msg;
      msg << "Incomplete HTML tag starting in position "
          << leftPos;
      throw runtime_error(msg.str());
    }
    s.erase(leftPos, rightPos - leftPos + 1);
  }
  // Remove all special HTML characters
  replaceAll(s, "&lt;", "<");
  replaceAll(s, "&gt;", ">");
  replaceAll(s, "&amp;", "&");
  replaceAll(s, "&nbsp;", " ");
  // Etc...
  return s;
}

int main(int argc, char* argv[]) {
  requireArgs(argc, 1, 
    "usage: HTMLStripper2 InputFile");
  ifstream in(argv[1]);
  assure(in, argv[1]);
  // Read entire file into string; then strip
  ostringstream ss;
  ss << in.rdbuf();
  try {
    string s = ss.str();
    cout << stripHTMLTags(s) << endl;
    return EXIT_SUCCESS;
  }
  catch (runtime_error& x) {
    cout << x.what() << endl;
    return EXIT_FAILURE;
  }
} ///:~