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// 	id AA04155; Wed, 28 Jun 1995 14:29:59 -0400 (hitzm from vega.cs.rpi.edu)
// Message-Id: <199506281829.AA04155@cs.rpi.edu>
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// To: kaltofen
// Cc: hitzm
// Subject: Re: STL program for index generation 
// In-Reply-To: Your message of "Wed, 28 Jun 1995 12:32:25 EDT."
//              <9506281632.AA13343@blackbox.cs.rpi.edu> 
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// Date: Wed, 28 Jun 1995 14:29:57 -0400
// From: Markus Hitz <hitzm@cs.rpi.edu>
// Status: RO
// 
// 
// Erich:
// 
//   the program is attached below. You have to compile it with
// Apogee's "apCC". In order to get the STL files included, you
// can use the following one-line script:
// 
// 	apCC $1 $2 $3 $4 $5 $6 $7 $8 $9 -I/dept/cs/include/stl
// 
// (Write it to a file "astl" and chmod it +x). I think the program
// is too crude to be useful for other people right know. It could
// be easily improved by adding some "kill set" which would allow to
// filter out non-keywords like "the", as well as TeX and LaTeX commands.
// 
// Markus
// 
// --------------------------- C++ program --------------------------------- 
// 
//
// Generates "compressed" index of text files
//
// interface:	a.out	<filename>
//
// output:	file named "filename.index"
//

#include <ctype.h>
#include <iostream>
#include <fstream>
#include <string>
#include <cstring>
#include <iterator>
#include <set>

using namespace std;
typedef std::string mystring;

// use overloaded operator for bidirection iterator

template<typename _Key >
// should be typename std::multiset< _Key, std::less< _Key > >::iterator&
// but must use actual iterator type (red-black tree)
typename std::_Rb_tree_const_iterator< _Key >&
operator+(// typename std::multiset< _Key, std::less< _Key > >::iterator& p
          typename std::_Rb_tree_const_iterator< _Key >& p
         ,int count
         )
       {int i; for(i = 1; i <= count; i++) p++; return p;}

#ifdef explicit_inst // toggle to explicitly instantiate template

template // instantiate template
std::multiset< mystring, std::less< mystring > >::iterator&
//don't need: std::_Rb_tree_const_iterator< mystring >&
operator+(std::multiset<mystring>::iterator&
          //don't need: std::_Rb_tree_const_iterator< mystring >&
         ,int
         );
#endif

int main (int argc, char *argv[])
{
  char  buf[128];
  int   c, i=0;

  if (argc < 2)
  {
    cerr << argv[0]
         << ": missing argument" << endl;
    return 1;
  }

  ifstream  text (argv[1], ios::in);

  if (!text)
  {
    cerr << argv[0]
         << ": cannot open "
         << argv[1] << endl;
    return 2;
  }

  strcpy (buf, argv[1]);
  strcat (buf, ".index");

  ofstream  idxfile (buf, ios::out);

  if (!idxfile)
  {
    cerr << argv[0]
         << ": cannot open output file" << endl;
    return 3;
  }

  multiset <basic_string<char>,
            less<basic_string<char> >
           > idxset;

  while ((c = text.get ()) != EOF)
  {
    c = tolower (c);

    if (isalpha(c))
    {
      buf[i++] = c;
    }
    else if (i)
    {
      buf[i] = '\0';
      if (i > 2) idxset.insert (basic_string<char>(buf));
      i = 0;
    }
  }

  multiset< mystring >::iterator curr;

  for(curr = idxset.begin(); curr != idxset.end(); curr++)
     {basic_string<char> word = *curr;
      int count = idxset.count(word);
      idxfile << word << " (" << count << ")" << endl;
      int i;

      // for(i = 2; i <= count; i++) curr++; // skip over repeated words
      // handled by operartor+ template above
      
      curr = curr+(count-1); // possibly implicit instantiation

     }

  return 0;
}