libcruft-util/coord/ops.hpp

/*
 * This file is part of libgim.
 *
 * libgim is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 *
 * libgim is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright 2012-2015 Danny Robson <danny@nerdcruft.net>
 */

#ifndef __UTIL_COORDS_OPS
#define __UTIL_COORDS_OPS

#include "../preprocessor.hpp"
#include "../maths.hpp"

#include <cstdlib>

namespace util {
    // forward declerations for traits
    template <size_t,typename> struct point;
    template <size_t,typename> struct extent;
    template <size_t,typename> struct vector;

    ///////////////////////////////////////////////////////////////////////
    // operation traits
    namespace coord {
        template <
            size_t S,
            typename T,
            template <size_t,typename> class A,
            template <size_t,typename> class B
        >
        struct traits { };


        //-------------------------------------------------------------------------
        template <size_t S, typename T> struct traits<S,T,extent,extent> { typedef extent<S,T> result; };
        template <size_t S, typename T> struct traits<S,T,extent,vector> { typedef extent<S,T> result; };
        template <size_t S, typename T> struct traits<S,T,point,extent>  { typedef point<S,T> result; };
        template <size_t S, typename T> struct traits<S,T,point,vector>  { typedef point<S,T> result; };
        template <size_t S, typename T> struct traits<S,T,vector,point>  { typedef point<S,T> result; };
        template <size_t S, typename T> struct traits<S,T,vector,vector> { typedef vector<S,T> result; };
    }

    ///////////////////////////////////////////////////////////////////////////
    // vector operators
#define ELEMENT_OP(OP)                          \
    template <                                  \
        size_t S,                               \
        typename T,                             \
        template <size_t,typename> class A,     \
        template <size_t,typename> class B      \
    >                                           \
    typename coord::traits<S,T,A,B>::result            \
    operator OP (A<S,T> a, B<S,T> b)            \
    {                                           \
        typename coord::traits<S,T,A,B>::result out;   \
        for (size_t i = 0; i < S; ++i)          \
            out[i] = a[i] OP b[i];              \
        return out;                             \
    }                                           \
                                                \
    template <                                  \
        size_t S,                               \
        typename T,                             \
        template <size_t,typename> class A,     \
        template <size_t,typename> class B      \
    >                                           \
    typename coord::traits<S,T,A,B>::result&           \
    operator PASTE(OP,=) (A<S,T>& a, B<S,T> b)  \
    {                                           \
        for (size_t i = 0; i < S; ++i)          \
            a[i] PASTE(OP,=) b[i];              \
        return a;                               \
    }

    ELEMENT_OP(+)
    ELEMENT_OP(-)
    ELEMENT_OP(*)
    ELEMENT_OP(/)
#undef ELEMENT_OP

    ///////////////////////////////////////////////////////////////////////////
    // scalar operators
#define SCALAR_OP(OP)                           \
    template <                                  \
        size_t S,                               \
        typename T,                             \
        template <size_t,typename> class K      \
    >                                           \
    K<S,T>                                      \
    operator OP (T t, K<S,T> k)                 \
    {                                           \
        K<S,T> out;                             \
        for (size_t i = 0; i < S; ++i)          \
            out[i] = t OP k[i];                 \
        return out;                             \
    }                                           \
                                                \
    template <                                  \
        size_t S,                               \
        typename T,                             \
        template <size_t,typename> class K      \
    >                                           \
    K<S,T>                                      \
    operator OP (K<S,T> k, T t)                 \
    {                                           \
        K<S,T> out;                             \
        for (size_t i = 0; i < S; ++i)          \
            out[i] = k[i] OP t;                 \
        return out;                             \
    }

    SCALAR_OP(+)
    SCALAR_OP(-)
    SCALAR_OP(*)
    SCALAR_OP(/)

#undef SCALAR_OP


    //-------------------------------------------------------------------------
#define SCALAR_OP(OP)                           \
    template <                                  \
        size_t S,                               \
        typename T,                             \
        template <size_t,typename> class K      \
    >                                           \
    K<S,T>&                                     \
    operator OP (K<S,T> &k, T t)                \
    {                                           \
        for (size_t i = 0; i < S; ++i)          \
            k[i] OP t;                          \
        return k;                               \
    }

    SCALAR_OP(+=)
    SCALAR_OP(-=)
    SCALAR_OP(*=)
    SCALAR_OP(/=)
#undef SCALAR_OP

    //-------------------------------------------------------------------------
    // negation
    template <size_t S, typename T, template<size_t,typename> class K>
    K<S,T> operator- (K<S,T> k)
    {
        return k * T{-1};
    }


    ///////////////////////////////////////////////////////////////////////////
    // logic operators

    /// elementwise equality operator
    template <
        size_t S,
        typename T,
        template <size_t,typename> class K
    >
    bool
    operator== (K<S,T> a, K<S,T> b)
    {
        return std::equal (std::begin (a),
                           std::end   (a),
                           std::begin (b));
    }

    ///------------------------------------------------------------------------
    /// elementwise inquality operator
    template <
        size_t S,
        typename T,
        template <size_t,typename> class K
    >
    bool
    operator!= (K<S,T> a, K<S,T> b)
    {
        return !(a == b);
    }


    ///////////////////////////////////////////////////////////////////////////
    // special operators

    /// point-point subtraction giving a vector difference
    template <
        size_t S,
        typename T
    >
    vector<S,T>
    operator- (point<S,T> a, point<S,T> b)
    {
        vector<S,T> out;
        for (size_t i = 0; i < S; ++i)
            out[i] = a[i] - b[i];
        return out;
    }


    //-------------------------------------------------------------------------
    template <
        size_t S,
        typename T
    >
    vector<S,T> operator- (T t, point<S,T> p)
    {
        return point<S,T> {t} - p;
    }


    //-------------------------------------------------------------------------
    template <
        size_t S,
        typename T,
        template<size_t,typename> class A,
        template <size_t,typename> class B
    >
    T dot (A<S,T> a, B<S,T> b)
    {
        T sum { 0 };
        for (size_t i = 0; i < S; ++i)
            sum += a[i] * b[i];
        return sum;
    }

    ///////////////////////////////////////////////////////////////////////////
    // logical element operators

    /// return a coord type containing the max element at each offset
    template <
        size_t S,
        typename T,
        template <size_t,typename> class K
    >
    K<S,T>
    min (K<S,T> a, K<S,T> b)
    {
        K<S,T> out;
        for (size_t i = 0; i < S; ++i)
            out[i] = min (a[i], b[i]);
        return out;
    }


    ///------------------------------------------------------------------------
    // /return a coord type containing the max element at each offset
    template <
        size_t S,
        typename T,
        template <size_t,typename> class K
    >
    K<S,T>
    max (K<S,T> a, K<S,T> b)
    {
        K<S,T> out;
        for (size_t i = 0; i < S; ++i)
            out[i] = max (a[i], b[i]);
        return out;
    }


    ///------------------------------------------------------------------------
    /// return the minimum element of the coordinate type
    template <size_t S, typename T, template<size_t,typename> class K>
    T
    min (K<S,T> k)
    { return *std::min_element (k.begin (), k.end ()); }


    ///------------------------------------------------------------------------
    /// return the maximum element of the coordinate type
    template <size_t S, typename T, template<size_t,typename> class K>
    T
    max (K<S,T> k)
    { return *std::max_element (k.begin (), k.end ()); }
}

#endif