CODEWITHSUNDEEP
c++booststlboost-mpl
Tom Brinkman
Tom Brinkman

Reputation: 65

boost::mpl for_each with normal 'C' Array

Using boost::mpl, I can create a typedef of a three element vector like follows:

typedef boost::mpl::vector_c<int,1,2,3> height_t;

I can pull the values out of this typedef with the following snippit:

std::vector<int> height;
boost::mpl::for_each<height_t>(boost::bind(&std::vector<int>::push_back, &height, _1));   

assert(height[0] == 1);
assert(height[1] == 2);
assert(height[2] == 3);

I'm wondering if there is a way to do this same thing but with a normal 'C' array instead of a std::vector. Unfortunately, I can't use STL containers in this project.

uint32_t height[3];
boost::mpl::for_each<height_t>(????, &height, _1));

I suspect that I need to replace the ???? with another bind clause. Any ideas?

Upvotes: 1

Views: 1205

Answers (2)

Tom Brinkman
Tom Brinkman

Reputation: 65

Yes, your idea would work. I rewrote it slighly. However, what I am wondering is if there is a way to do this same thing with an inplace functor, using bind and lambda. In the mean time, I'll use your idea.

template <typename type_t>
struct static_assign
{ 
    type_t* a;
    static_assign(type_t* a) : a(a) {}

    template<typename T> 
    void operator()(T t) 
    { 
        *a++ = t; 
    }
};

uint32_t color[MAX_COLORS];
uint32_t* pcolor = (uint32_t*)&color;
boost::mpl::for_each<typename static_color<scheme_t>::type>(static_assign<uint32_t>(pcolor));
pcolor += indicator;

Upvotes: 0

KitsuneYMG
KitsuneYMG

Reputation: 12901

Try something like

 struct foo { 
     int c;
     int* arr;
     template<class U> 
     void operator(U& u) { arr[c++] = u; }
     foo(int a*) : c(0), arr(a) {}
 };

 for_each<height_t>(foo(height));

Upvotes: 2

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