ToString.h

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/*
 * Copyright (C) 2012 by
 *   MetraLabs GmbH (MLAB), GERMANY
 * and
 *   Neuroinformatics and Cognitive Robotics Labs (NICR) at TU Ilmenau, GERMANY
 * All rights reserved.
 *
 * Contact: info@mira-project.org
 *
 * Commercial Usage:
 *   Licensees holding valid commercial licenses may use this file in
 *   accordance with the commercial license agreement provided with the
 *   software or, alternatively, in accordance with the terms contained in
 *   a written agreement between you and MLAB or NICR.
 *
 * GNU General Public License Usage:
 *   Alternatively, this file may be used under the terms of the GNU
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 *   Foundation and appearing in the file LICENSE.GPL3 included in the
 *   packaging of this file. Please review the following information to
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 */

#ifndef _MIRA_TOSTRING_H_
#define _MIRA_TOSTRING_H_

#include <boost/algorithm/string/predicate.hpp>

#include <error/Exceptions.h>

#include <math/Math.h>



namespace mira {

static constexpr auto MIRA_TOSTRING_NAN = "nan";
static constexpr auto MIRA_TOSTRING_POSITIVE_INF = "inf";
static constexpr auto MIRA_TOSTRING_NEGATIVE_INF = "-inf";


namespace Private {

template <typename T>
inline std::string genericToString(const T& value, int precision)
{
    std::stringstream ss;
    if(precision>=0)
        ss << std::setprecision(precision);
    ss << value;
    if(ss.fail())
        MIRA_THROW(XIO, "Failed to convert value into a string");
    return ss.str();
}

template <typename T>
inline T genericFromString(const std::string& str)
{
    T value;
    std::stringstream ss(str);
    ss >> value;
    if(ss.fail()) // make sure that we have no error flag set
        MIRA_THROW(XIO, "Failed to convert value from string '" << str << "'");

    return value;
}

template <typename T>
inline std::string fpToString(const T& value, int precision)
{
    if(boost::math::isnan(value))
        return MIRA_TOSTRING_NAN;
    else if(boost::math::isinf(value)) {
        if(value>0)
            return MIRA_TOSTRING_POSITIVE_INF;
        else
            return MIRA_TOSTRING_NEGATIVE_INF;
    }
    else
        return genericToString<T>(value, precision);
}

template <typename T>
inline T fpFromString(const std::string& str)
{
    try {
        return genericFromString<T>(str);
    } catch(XIO&) {
        if(str==MIRA_TOSTRING_NAN)
            return std::numeric_limits<T>::quiet_NaN();
        else if(str==MIRA_TOSTRING_POSITIVE_INF)
            return std::numeric_limits<T>::infinity();
        else if(str==MIRA_TOSTRING_NEGATIVE_INF)
            return -std::numeric_limits<T>::infinity();
        else
            throw; // we could not handle the exception, so rethrow it
    }
}

template <typename T>
inline std::string charToString(const T& value)
{
    return genericToString<int>((int)value, 0);
}

template <typename T>
inline T charFromString(const std::string& str)
{
    int val = genericFromString<int>(str);

    if(val>std::numeric_limits<T>::max())
        MIRA_THROW(XIO, "Overflow while converting value from string '" << 
                   str << "', max: " << (int)std::numeric_limits<T>::max());
    if(val<std::numeric_limits<T>::min())
        MIRA_THROW(XIO, "Underflow while converting value from string '" << 
                   str << "', min: " << (int)std::numeric_limits<T>::min());

    return static_cast<T>(val);
}

} // Private


template <typename T>
class FromHex
{
public:
    operator T() const { return value; }
    friend std::istream& operator>>(std::istream& iStream, FromHex<T>& oValue)
    {
        iStream >> std::hex >> oValue.value;
        return iStream;
    }

    T value;
};

template <typename T>
class ToHex
{
public:
    ToHex(T v) : value(v) {}
    operator T() const { return value; }
    friend std::ostream& operator<<(std::ostream& oStream, const ToHex<T>& iValue)
    {
        oStream << std::hex << iValue.value;
        return oStream;
    }

    T value;
};

template <typename T>
class FromOct
{
public:
    operator T() const { return value; }
    friend std::istream& operator>>(std::istream& iStream, FromOct<T>& oValue)
    {
        iStream >> std::oct >> oValue.value;
        return iStream;
    }

    T value;
};

template <typename T>
class ToOct
{
public:
    ToOct(T v) : value(v) {}
    operator T() const { return value; }
    friend std::ostream& operator<<(std::ostream& oStream, const ToOct<T>& iValue)
    {
        oStream << std::oct << iValue.value;
        return oStream;
    }

    T value;
};


template <typename T>
std::string toString(const T& value, int precision=-1)
{
    return Private::genericToString<T>(value, precision);
}

template <typename T>
T fromString(const std::string& str)
{
    return Private::genericFromString<T>(str);
}


template<>
inline std::string toString<char>(const char& value, int precision)
{
    return Private::charToString<char>(value);
}

template <>
inline char fromString<char>(const std::string& str)
{
    return Private::charFromString<char>(str);
}

template<>
inline std::string toString<signed char>(const signed char& value, 
                                         int precision)
{
    return Private::charToString<signed char>(value);
}

template <>
inline signed char fromString<signed char>(const std::string& str)
{
    return Private::charFromString<signed char>(str);
}

template<>
inline std::string toString<unsigned char>(const unsigned char& value, 
                                           int precision)
{
    return Private::charToString<unsigned char>(value);
}

template <>
inline unsigned char fromString<unsigned char>(const std::string& str)
{
    return Private::charFromString<unsigned char>(str);
}


template<>
inline std::string toString<std::string>(const std::string& value, 
                                         int precision)
{
    return value;
}

template <>
inline std::string fromString<std::string>(const std::string& str)
{
    return str;
}

template<>
inline std::string toString<float>(const float& value, int precision)
{
    return Private::fpToString<float>(value, precision);
}

template <>
inline float fromString<float>(const std::string& str)
{
    return Private::fpFromString<float>(str);
}

template<>
inline std::string toString<double>(const double& value, int precision)
{
    return Private::fpToString<double>(value, precision);
}

template <>
inline double fromString<double>(const std::string& str)
{
    return Private::fpFromString<double>(str);
}

template<>
inline std::string toString<long double>(const long double& value, 
                                         int precision)
{
    return Private::fpToString<long double>(value, precision);
}

template <>
inline long double fromString<long double>(const std::string& str)
{
    return Private::fpFromString<long double>(str);
}

template<>
inline std::string toString<bool>(const bool& value, int precision)
{
    if ( value )
        return "true";
    else
        return "false";
}

template <>
inline bool fromString<bool>(const std::string & str)
{
    // case-insensitive compare
    if (boost::iequals(str, "true"))
        return true;

    if (!boost::iequals(str, "false"))
        MIRA_THROW(XIO, "Failed to convert bool value from string '" << str << "'");

    return false;
}


} // namespace

#endif