Enumerator Lists and Enumerated Arrays

// Copyright: Andreas Raczek
// This file is published under the The Code Project Open License (CPOL) 
// See the file "CPOL.html" for the full license governing this code. 
#pragma once

namespace lobster {

namespace tmp {

#pragma region power implementation for unsigned exponents

template<
    long base, 
    unsigned long exp
> struct power_enum {
    enum {
        value = base * power_enum<base, exp - 1>::value
    };
};


template<long base>
struct power_enum<
    base, 
    0
> {
    enum {
        value = 1
    };
};
#pragma endregion

#pragma region power implementation for signed exponents 

template<
    long base, 
    unsigned long exp, 
    bool negative> 
struct power_double_helper {
    const static double value;
};

template<long base, unsigned long exp, bool negative> 
const double power_double_helper<base, exp, negative>::value = (double) power_enum<base, exp>::value;

template<
    long base, 
    unsigned long exp> 
struct power_double_helper<
    base,
    exp,
    true
> {
    const static double value;
};


template<long base, unsigned long exp> 
const double power_double_helper<base, exp, true>::value = 1.0 / (double) power_enum<base, exp>::value;


template<long base, long exp>
struct power_double {
    const static double value;
};


template<long base, long exp>
const double power_double<base, exp>::value = 
    power_double_helper<
        base,
        exp >= 0 ? exp : -exp,
        exp < 0       
    >::value;
    
#pragma endregion

}

}