ex12_32.cpp

//
//  ex12_32.cpp
//  Exercise 12.32
//
//  Created by pezy on 1/1/15.
//  Copyright (c) 2015 pezy. All rights reserved.
//
//  Rewrite the TextQuery and QueryResult classes to use a StrBlob
//  instead of a vector<string> to hold the input file.

#include "ex12_32.h"
#include <sstream>
#include <algorithm>

TextQuery::TextQuery(std::ifstream& ifs) : input(new StrBlob)
{
    StrBlob::size_type lineNo{0};
    for (string line; std::getline(ifs, line); ++lineNo) {
        input->push_back(line);
        std::istringstream line_stream(line);
        for (string text, word; line_stream >> text; word.clear()) {
            // avoid read a word followed by punctuation(such as: word, )
            std::remove_copy_if(text.begin(), text.end(),
                                std::back_inserter(word), ispunct);
            // use reference avoid count of shared_ptr add.
            auto& nos = result[word];
            if (!nos) nos.reset(new std::set<StrBlob::size_type>);
            nos->insert(lineNo);
        }
    }
}

QueryResult TextQuery::query(const string& str) const
{
    // use static just allocate once.
    static shared_ptr<std::set<StrBlob::size_type>> nodate(
        new std::set<StrBlob::size_type>);
    auto found = result.find(str);
    if (found == result.end())
        return QueryResult(str, nodate, input);
    else
        return QueryResult(str, found->second, input);
}

std::ostream& print(std::ostream& out, const QueryResult& qr)
{
    out << qr.word << " occurs " << qr.nos->size()
        << (qr.nos->size() > 1 ? " times" : " time") << std::endl;
    for (auto i : *qr.nos) {
        ConstStrBlobPtr p(*qr.input, i);
        out << "\t(line " << i + 1 << ") " << p.deref() << std::endl;
    }
    return out;
}