pretty_stream.hpp

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//=======================================================================
// Copyright (c) 2013 Piotr Wygocki
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
#ifndef PAAL_PRETTY_STREAM_HPP
#define PAAL_PRETTY_STREAM_HPP

#include <cmath>
#include <iostream>
#include <string>

namespace paal {

inline std::string pretty_to_string(double x, double epsilon = 1e-9) {
    auto r = static_cast<int>(std::round(x));
    if (utils::compare<double>{
        epsilon
    }.e(x, r)) {
        return std::to_string(r);
    } else {
        return std::to_string(x);
    }
}

template <typename T> std::string pretty_to_string(T &&t) {
    return std::to_string(t);
}

template <typename Stream> struct pretty_stream {
    pretty_stream(Stream &stream, double epsilon = 1e-9)
        :
          // TODO curly braces doesn't work here (gcc compiles error)
          m_stream(stream),
          m_epsilon{ epsilon } {}

    inline std::string pretty_to_string(double x, double epsilon = 1e-9) {
        int r = std::round(x);
        if (utils::compare<double>{
            epsilon
        }.e(x, r)) {
            return std::to_string(r);
        } else {
            return std::to_string(x);
        }
    }

    template <typename T> pretty_stream<Stream> &operator<<(T &&t) {
        m_stream << t;
        return *this;
    }

    using Manipulator = Stream & (Stream &);

    pretty_stream<Stream> &operator<<(Manipulator m) {
        m_stream << m;
        return *this;
    }

  private:

    Stream &m_stream;
    double m_epsilon;
};

template <typename Stream>
pretty_stream<Stream> make_pretty_stream(Stream &s, double epsilon = 1e-9) {
    return pretty_stream<Stream>(s, epsilon);
}

}      
#endif // PAAL_PRETTY_STREAM_HPP