PGMWrap.h

/***
    PGMWrap library.
    Copyright: Christopher Andrews.
    Licence: MIT
    Website: http://arduino.land/ (specific project page soon)
***/

#include <avr/pgmspace.h>

#if __cplusplus >= 201103L || defined(__GXX_EXPERIMENTAL_CXX0X__)
    #ifndef ISCPP11
        #define ISCPP11
    #endif
#endif

#ifndef HEADER_PGMWRAP
    #define HEADER_PGMWRAP

template< typename T > struct PGMWrap; //Forward declaration to allow PGMMode use.
    
namespace pgmtools{    
    
    /** Type traits for compile time optimization. **/

    /***
        Select different types based on a condition, an 'if statement' for types.
        The type Select<V,T,F>::Result is type T when V is true, otherwise it is set to type F.
    ***/
    template< bool V, typename T, typename F > struct select{ typedef T type; };
    template< typename T, typename F > struct select< false, T, F >{ typedef F type; };
    
    template<  typename T >
    struct PGMMultiByte{
        T PGMRead( const PGMWrap<T> *data ){
            T ret;
            memcpy_P(&ret, data, sizeof(T));
            return ret;
        }
    };

    template<  typename T >
    struct PGMSingleByte{
        T PGMRead( const PGMWrap<T> *data ){ return pgm_read_byte(data); }
    };
} //namespace pgm    
    
    /***
        PGMWrap class.
    ***/

    template< typename T >
        struct PGMWrap{
        
        #ifdef ISCPP11
            constexpr PGMWrap( const T &in ) : t(in) {}
        #endif
        
        typedef typename pgmtools::select<
            sizeof(T) == 1,
            pgmtools::PGMSingleByte<T>,
            pgmtools::PGMMultiByte<T>
        >::type PGMReader;

        operator const T() const { return PGMReader().PGMRead(this); }
        bool operator ==( const T &in ){ return PGMReader().PGMRead(this) == in; }

        T t;
    };

    typedef const PGMWrap< char > int8_p;                   //char
    typedef int8_p char_p;                                  //char
    typedef const PGMWrap< unsigned char > uint8_p;         //unsigned char
    typedef const PGMWrap< int > int16_p;                   //int
    typedef const PGMWrap< unsigned int > uint16_p;         //unsigned int
    typedef const PGMWrap< char16_t > char16_p;             //char16_t
    typedef const PGMWrap< long > int32_p;                  //long
    typedef const PGMWrap< unsigned long > uint32_p;        //unsigned long
    #ifdef ISCPP11
      typedef const PGMWrap< char32_t > char32_p;           //char32_t
    #endif
    typedef const PGMWrap< long long > int64_p;             //long long
    typedef const PGMWrap< unsigned long long > uint64_p;   //unsigned long long
    typedef const PGMWrap< bool > bool_p;                   //bool
    typedef const PGMWrap< float > float_p;                 //float
    typedef const PGMWrap< double > double_p;               //double
    typedef const PGMWrap< long double > long_double_p;     //long double
    typedef const PGMWrap< size_t > size_p;                 //size_t
#endif