Спринт 10. Синтаксис пространства имен.

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main.cpp
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#include <cassert>
#include <sstream>

#include "ini.h"

using namespace std;

int main() {
    std::istringstream input{
        "[vegetables]\n"
        "potatoes=10\n"
        "onions=1 \n"
        "\n"
        "cucumbers=12\n"
        "\n"
        "[guests] \n"
        "guest1_name = Ivan Durak\n"
        "guest2_name =  Vasilisa Premudraya\n"
        "[guest black list]"};
    ini::Document doc = ini::Load(input);

    assert(doc.GetSectionCount() == 3);
    assert((doc.GetSection("vegetables"s)
            == ini::Section{
                {"potatoes"s, "10"s},
                {"onions"s, "1"s},
                {"cucumbers"s, "12"s},
            }));
    assert((doc.GetSection("guests"s)
            == ini::Section{{"guest1_name"s, "Ivan Durak"s}, {"guest2_name"s, "Vasilisa Premudraya"s}}));
    assert((doc.GetSection("dragons"s) == ini::Section{}));
    assert((doc.GetSection("guest black list"s) == ini::Section{}));

    doc.AddSection("pets"s) = ini::Section{{"nasty"s, "rat"s}};
    assert(doc.GetSectionCount() == 4);
}
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ini.h
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#include <iostream>
#include <string>
#include <unordered_map>

namespace ini {

using Section = std::unordered_map<std::string, std::string>;

class Document {
public:
    Section& AddSection(std::string name);
    const Section& GetSection(const std::string& name) const;
    std::size_t GetSectionCount() const;

private:
    std::unordered_map<std::string, Section> sections_;
};

Document Load(std::istream& input);

}
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ini.cpp
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#include "ini.h"

using namespace std;

namespace ini {

Section& Document::AddSection(std::string name) {
        return sections_[name];
}

const Section& Document::GetSection(const std::string& name) const {

    static Section section_;

    if (!(sections_.end() == sections_.find(name))) {
        return sections_.at(name);
    } else {
        return section_;
    }
}

std::size_t Document::GetSectionCount() const {
    return sections_.size();
}

Document Load(std::istream& input) {

    Document result;
    Section* section;

    for (string str;
         getline(input, str);) {

        auto it = str.find_first_not_of(' ');

        if (str.npos == it) {
            continue;
        }

        str = str.substr(it);

        if (str[0] == '[') {
            auto section_ = str.substr(1, str.find(']') - 1);
            section = &result.AddSection(section_);

        } else {
            it = str.find('=');

            string name_ = str.substr(0, str.find_last_not_of(' ', it - 1) + 1);
            str = str.substr(str.find_first_not_of(' ', it + 1));

            string value_ = str.substr(0, str.find_last_not_of(' ') + 1);
            section->insert({name_,
                             value_ });
        }
    }
    return result;
}

}