TextQuery.cpp

// Arbel Nathan 308366749
#include "TextQuery.h"
#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <iostream>
#include <regex>
#include <iterator>
using namespace std;

// read the input file and build the map of lines to line numbers
TextQuery::TextQuery(ifstream &is) : file(new vector<string>)
{
  string text;
 // regex words_regex("[\\w']+");
  while (getline(is, text))
  {                           // for each line in the file
    file->push_back(text);    // remember this line of text
    int n = file->size() - 1; // the current line number
//////////////////////////////////////////////////////////////////////////
    text= regex_replace(text, regex("([^'\\w])"), " ");
    istringstream line(text); // separate the line into words
    string word;
    while (line >> word)
    { // for each word in that line
   // cout<< word<<endl;

//////////////////////////////////////////////////////////////////////////
      // if word isn't already in wm, subscripting adds a new entry
      auto &lines = wm[word];          // lines is a shared_ptr
      if (!lines)                      // that pointer is null the first time we see word
        lines.reset(new set<line_no>); // allocate a new set
      lines->insert(n);                // insert this line number
    }
  }
}

QueryResult TextQuery::query(const string &sought) const
{
	// we'll return a pointer to this set if we don't find sought
	static shared_ptr<set<line_no>> nodata(new set<line_no>); 
    // we use find instead of subscript, to avoid adding words to wm
    auto loc = wm.find(sought);
	if (loc == wm.end()) 
		return QueryResult(sought, nodata, file);  // not found
	else 
		return QueryResult(sought, loc->second, file);
}

// debugging routine
void TextQuery::display_map()
{
    auto iter = wm.cbegin(), iter_end = wm.cend();
    for ( ; iter != iter_end; ++iter) {
        cout << iter->first << ": {";
        // fetch location vector as a const reference to avoid copying it
        auto text_locs = iter->second;
        auto loc_iter = text_locs->cbegin(),
                        loc_iter_end = text_locs->cend();
        // print all line numbers for this word
        while (loc_iter != loc_iter_end)
        {
            cout << *loc_iter + 1;
            if (++loc_iter != loc_iter_end)
                 cout << ", ";

         }
         cout << "}\n";  // end list of output this word
    }
    cout << endl;  // finished printing entire map
}

std::ostream &print(std::ostream &os, const QueryResult &qr)
{
  os << "\"" << qr.sought << "\"" << " occours " << 
    qr.lines->size() << " times:" <<std::endl;

  for (auto num : *qr.lines)
  {
    os << "\t(line " << num + 1 << ") " 
      << *(qr.file->begin() + num) << std::endl;
  }

  return os;
}