catch2/include/internal/catch_tostring.hpp

/*
 *  Created by Phil on 8/5/2012.
 *  Copyright 2012 Two Blue Cubes Ltd. All rights reserved.
 *
 *  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 TWOBLUECUBES_CATCH_TOSTRING_HPP_INCLUDED
#define TWOBLUECUBES_CATCH_TOSTRING_HPP_INCLUDED

#include "catch_common.h"
#include "catch_sfinae.hpp"

#include <sstream>
#include <iomanip>
#include <limits>

#ifdef __OBJC__
#include "catch_objc_arc.hpp"
#endif

namespace Catch {
namespace Detail {

// SFINAE is currently disabled by default for all compilers.
// If the non SFINAE version of IsStreamInsertable is ambiguous for you
// and your compiler supports SFINAE, try #defining CATCH_CONFIG_SFINAE
#ifdef CATCH_CONFIG_SFINAE

    template<typename T>
    class IsStreamInsertableHelper {
        template<int N> struct TrueIfSizeable : TrueType {};

        template<typename T2>
        static TrueIfSizeable<sizeof((*(std::ostream*)0) << *((T2 const*)0))> dummy(T2*);
        static FalseType dummy(...);

    public:
        typedef SizedIf<sizeof(dummy((T*)0))> type;
    };
    
    template<typename T>
    struct IsStreamInsertable : IsStreamInsertableHelper<T>::type {};

#else

    struct BorgType {
        template<typename T> BorgType( T const& );
    };
  
    TrueType& testStreamable( std::ostream& );
    FalseType testStreamable( FalseType );
    
    FalseType operator<<( std::ostream const&, BorgType const& );

    template<typename T>
    struct IsStreamInsertable {
        static std::ostream &s;
        static T  const&t;
        enum { value = sizeof( testStreamable(s << t) ) == sizeof( TrueType ) };
    };
    
#endif

    template<bool C>
    struct StringMakerBase {
        template<typename T>
        static std::string convert( T const& ) { return "{?}"; }
    };

    template<>
    struct StringMakerBase<true> {
        template<typename T>
        static std::string convert( T const& _value ) {
            std::ostringstream oss;
            oss << _value;
            return oss.str();
        }
    };
    
} // end namespace Detail

template<typename T>
struct StringMaker :
    Detail::StringMakerBase<Detail::IsStreamInsertable<T>::value> {};

template<typename T>
struct StringMaker<T*> {
    static std::string convert( T const* p ) {
        if( !p )
            return INTERNAL_CATCH_STRINGIFY( NULL );
        std::ostringstream oss;
        oss << p;
        return oss.str();
    }
};

template<typename T>
struct StringMaker<std::vector<T> > {
    static std::string convert( std::vector<T> const& v ) {
        std::ostringstream oss;
        oss << "{ ";
        for( std::size_t i = 0; i < v.size(); ++ i ) {
            oss << toString( v[i] );
            if( i < v.size() - 1 )
                oss << ", ";
        }
        oss << " }";
        return oss.str();
    }
};

namespace Detail {
    template<typename T>
    inline std::string makeString( T const& value ) {
        return StringMaker<T>::convert( value );
    }   
} // end namespace Detail

/// \brief converts any type to a string
///
/// The default template forwards on to ostringstream - except when an 
/// ostringstream overload does not exist - in which case it attempts to detect 
/// that and writes {?}.
/// Overload (not specialise) this template for custom typs that you don't want
/// to provide an ostream overload for.
template<typename T>
std::string toString( T const& value ) {
    return StringMaker<T>::convert( value );
}
    
// Built in overloads

inline std::string toString( std::string const& value ) {
    return "\"" + value + "\"";
}

inline std::string toString( std::wstring const& value ) {
    std::ostringstream oss;
    oss << "\"";
    for(size_t i = 0; i < value.size(); ++i )
        oss << static_cast<char>( value[i] <= 0xff ? value[i] : '?');
    oss << "\"";
    return oss.str();
}

inline std::string toString( const char* const value ) {
    return value ? Catch::toString( std::string( value ) ) : std::string( "{null string}" );
}   

inline std::string toString( char* const value ) {
    return Catch::toString( static_cast<const char*>( value ) );
}        

inline std::string toString( int value ) {
    std::ostringstream oss;
    oss << value;
    return oss.str();
}

inline std::string toString( unsigned long value ) {
    std::ostringstream oss;
    if( value > 8192 )
        oss << "0x" << std::hex << value;
    else
        oss << value;
    return oss.str();
}
    
inline std::string toString( unsigned int value ) {
    return toString( static_cast<unsigned long>( value ) );
}
    
inline std::string toString( const double value ) {
    std::ostringstream oss;
    oss << std::setprecision (std::numeric_limits<double>::digits10 + 1)
        << value;
    return oss.str();
}    

inline std::string toString( bool value ) {
    return value ? "true" : "false";
}

inline std::string toString( char value ) {
    return value < ' '
        ? toString( static_cast<unsigned int>( value ) )
        : Detail::makeString( value );
}

inline std::string toString( signed char value ) {
    return toString( static_cast<char>( value ) );
}

inline std::string toString( unsigned char value ) {
    return toString( static_cast<char>( value ) );
}

#ifdef CATCH_CONFIG_CPP11_NULLPTR
inline std::string toString( std::nullptr_t ) {
    return "nullptr";
}
#endif

#ifdef __OBJC__
    inline std::string toString( NSString const * const& nsstring ) {
        if( !nsstring )
            return "nil";
        return std::string( "@\"" ) + [nsstring UTF8String] + "\"";
    }
    inline std::string toString( NSString * CATCH_ARC_STRONG const& nsstring ) {
        if( !nsstring )
            return "nil";
        return std::string( "@\"" ) + [nsstring UTF8String] + "\"";
    }
    inline std::string toString( NSObject* const& nsObject ) {
        return toString( [nsObject description] );
    }
#endif

} // end namespace Catch

#endif // TWOBLUECUBES_CATCH_TOSTRING_HPP_INCLUDED