textquery.cpp

#include "textquery.h"

#include<fstream>
using std::ifstream;

#include <sstream>
using std::istringstream;

#include<memory>
using std::shared_ptr; using std::make_shared;

#include<vector>
using std::vector;

#include<string>
using std::string;

#include<map>
using std::map;

#include<set>
using std::set;

#include "queryresult.h"


TextQuery::TextQuery(ifstream& is) :file(new vector<string>)
{
	using std::getline;

	string text;
    while(getline(is,text))
    {
        file->push_back(text);
		int n = file->size() - 1;
		istringstream line(text);
        string word;
        while(line >> word)
        {
			auto p = handlePunct(word);
			for (auto w : *p)
			{
				auto &lines = wm[w];
				if (!lines)
					lines.reset(new set<line_no>);
				lines->insert(n);
			}
        }
    }
}

QueryResult TextQuery::query(const string &sought) const
{
    static shared_ptr<set<line_no>> nodata(new set<line_no>);

    //! fetch the iterator to the matching element in the map<word, lines>.
    //std::map<std::string, std::shared_ptr<std::set<line_no>>>::const_iterator
    auto loc = wm.find(sought);
    if(loc == wm.end())
        return QueryResult(sought, nodata, file);
    else
        return QueryResult(sought, loc->second, file);
}

shared_ptr<vector<string>> TextQuery::handlePunct(const string &s)
{
	shared_ptr<vector<string>> p =
		make_shared<vector<string>>();
	size_t first = 0, index = 0;
	while(index != s.size())
	{
		if (ispunct(s[index]))
		{
			string word = s.substr(first, index - first);
			if (!word.empty())
				p->push_back(word);
			p->push_back(s.substr(index, 1));
			++index;
			first = index;
		}
		else
			++index;
	}
	string trail = s.substr(first);
	if (!trail.empty())
		p->push_back(trail);

	return p;
}