string_cast.h

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/** @file
 *  @author Bram de Greve (bram@cocamware.com)
 *  @author Tom De Muer (tom@cocamware.com)
 *
 *  *** BEGIN LICENSE INFORMATION ***
 *  
 *  The contents of this file are subject to the Common Public Attribution License 
 *  Version 1.0 (the "License"); you may not use this file except in compliance with 
 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
 *  
 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
 *  language governing rights and limitations under the License.
 *  
 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
 *  
 *  All portions of the code written by the Initial Developer are:
 *  Copyright (C) 2004-2023 the Initial Developer.
 *  All Rights Reserved.
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 *
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 *  GNU General Public License Version 2 or later (the GPL), in which case the 
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 *  *** END LICENSE INFORMATION ***
 */
 
#ifndef LASS_GUARDIAN_OF_INCLUSION_UTIL_STRING_CAST_H
#define LASS_GUARDIAN_OF_INCLUSION_UTIL_STRING_CAST_H
 
#include "util_common.h"
#include "../stde/extended_io.h"
#include <limits>
 
namespace lass
{
namespace util
{
 
class BadStringCast: public ExceptionMixin<BadStringCast>
{
public:
    BadStringCast(std::string msg, std::string loc): ExceptionMixin<BadStringCast>(std::move(msg), std::move(loc)) {}
    ~BadStringCast() noexcept {}
};
 
namespace impl
{
 
class StringCast
{
public:
    StringCast(const std::string& in):
        buffer_(in)
    {       
    }
    ~StringCast() {}
    template <typename In> StringCast(const In& in)
    {
        typedef std::numeric_limits<typename CallTraits<In>::TValue> TLimits;
        if (TLimits::is_specialized)
        {
            buffer_.precision(TLimits::digits10 + 1);
        }
        buffer_ << in;
    }
    bool read(std::string& out)
    {
        if (!buffer_.good())
        {
            return false;
        }
        out = buffer_.str();
        return true;
    }
    template <typename Out> bool read(Out& out)
    {
        if (!buffer_.good())
        {
            return false;
        }
        typedef std::numeric_limits<typename CallTraits<Out>::TValue> TLimits;
        if (TLimits::is_specialized)
        {
            buffer_.precision(TLimits::digits10 + 1);
        }
        return buffer_ >> out && (buffer_ >> std::ws).eof();
    }
private:
    std::stringstream buffer_;
};
 
}
 
template <typename Out, typename In>
Out stringCast(const In& in)
{
    impl::StringCast caster(in);
    Out out;
    if (!caster.read(out))
    {
        LASS_THROW("Failed to cast");
    }
    return out;
}
 
}
}
 
 
#endif
 
// EOF