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Filename : swizzle_traits.hpp
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//Copyright (c) 2008-2016 Emil Dotchevski and Reverge Studios, Inc.

//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 BOOST_QVM_E831FAD6B38F11DE8CECBF0D56D89593
#define BOOST_QVM_E831FAD6B38F11DE8CECBF0D56D89593

#include <boost/qvm/inline.hpp>
#include <boost/qvm/deduce_vec.hpp>
#include <boost/qvm/enable_if.hpp>
#include <boost/qvm/assert.hpp>

namespace
boost
    {
    namespace
    qvm
        {
        namespace
        qvm_detail
            {
            BOOST_QVM_INLINE_CRITICAL
            void const *
            get_null()
                {
                static int const obj=0;
                return &obj;
                }

            template <int A,class Next=void> struct swizzle_idx { static int const value=A; typedef Next next; };

            template <class V,int Idx>
            struct
            const_value
                {
                static
                BOOST_QVM_INLINE_TRIVIAL
                typename vec_traits<V>::scalar_type
                value()
                    {
                    BOOST_QVM_ASSERT(0);
                    return typename vec_traits<V>::scalar_type();
                    }
                };

            template <class V>
            struct
            const_value<V,-1>
                {
                static
                BOOST_QVM_INLINE_TRIVIAL
                typename vec_traits<V>::scalar_type
                value()
                    {
                    return scalar_traits<typename vec_traits<V>::scalar_type>::value(0);
                    }
                };

            template <class V>
            struct
            const_value<V,-2>
                {
                static
                BOOST_QVM_INLINE_TRIVIAL
                typename vec_traits<V>::scalar_type
                value()
                    {
                    return scalar_traits<typename vec_traits<V>::scalar_type>::value(1);
                    }
                };

            template <int Index,bool Neg=(Index<0)>
            struct neg_zero;

            template <int Index>
            struct
            neg_zero<Index,true>
                {
                static int const value=0;
                };

            template <int Index>
            struct
            neg_zero<Index,false>
                {
                static int const value=Index;
                };

            template <class SwizzleList,int Index,int C=0>
            struct
            swizzle
                {
                static int const value=swizzle<typename SwizzleList::next,Index,C+1>::value;
                };

            template <class SwizzleList,int Match>
            struct
            swizzle<SwizzleList,Match,Match>
                {
                static int const value=SwizzleList::value;
                };

            template <int Index,int C>
            struct swizzle<void,Index,C>;

            template <class SwizzleList,int C=0>
            struct
            swizzle_list_length
                {
                static int const value=swizzle_list_length<typename SwizzleList::next,C+1>::value;
                };

            template <int C>
            struct
            swizzle_list_length<void,C>
                {
                static int const value=C;
                };

            template <class SwizzleList,int D>
            struct
            validate_swizzle_list
                {
                static bool const value =
                    ((SwizzleList::value)<D) && //don't touch extra (), MSVC parsing bug.
                    validate_swizzle_list<typename SwizzleList::next,D>::value;
                };

            template <int D>
            struct
            validate_swizzle_list<void,D>
                {
                static bool const value=true;
                };

            template <class OriginalType,class SwizzleList>
            class
            sw_
                {
                sw_( sw_ const & );
                sw_ & operator=( sw_ const & );
                ~sw_();

                BOOST_QVM_STATIC_ASSERT((validate_swizzle_list<SwizzleList,vec_traits<OriginalType>::dim>::value));

                public:

                template <class T>
                BOOST_QVM_INLINE_TRIVIAL
                sw_ &
                operator=( T const & x )
                    {
                    assign(*this,x);
                    return *this;
                    }

                template <class R>
                BOOST_QVM_INLINE_TRIVIAL
                operator R() const
                    {
                    R r;
                    assign(r,*this);
                    return r;
                    }
                };

            template <class SwizzleList>
            class
            sw01_
                {
                sw01_( sw01_ const & );
                sw01_ & operator=( sw01_ const & );
                ~sw01_();

                public:

                template <class R>
                BOOST_QVM_INLINE_TRIVIAL
                operator R() const
                    {
                    R r;
                    assign(r,*this);
                    return r;
                    }
                };

            template <class OriginalType,class SwizzleList>
            class
            sws_
                {
                sws_( sws_ const & );
                sws_ & operator=( sws_ const & );
                ~sws_();

                BOOST_QVM_STATIC_ASSERT((validate_swizzle_list<SwizzleList,1>::value));

                public:

                template <class R>
                BOOST_QVM_INLINE_TRIVIAL
                operator R() const
                    {
                    R r;
                    assign(r,*this);
                    return r;
                    }
                };
            }

        template <class OriginalVector,class SwizzleList>
        struct
        vec_traits<qvm_detail::sw_<OriginalVector,SwizzleList> >
            {
            typedef qvm_detail::sw_<OriginalVector,SwizzleList> this_vector;
            typedef typename vec_traits<OriginalVector>::scalar_type scalar_type;
            static int const dim=qvm_detail::swizzle_list_length<SwizzleList>::value;

            template <int I>
            static
            BOOST_QVM_INLINE_CRITICAL
            scalar_type
            read_element( this_vector const & x )
                {
                BOOST_QVM_STATIC_ASSERT(I>=0);
                BOOST_QVM_STATIC_ASSERT(I<dim);
                int const idx=qvm_detail::swizzle<SwizzleList,I>::value;
                BOOST_QVM_STATIC_ASSERT(idx<vec_traits<OriginalVector>::dim);
                return idx>=0?
                    vec_traits<OriginalVector>::template read_element<qvm_detail::neg_zero<idx>::value>(reinterpret_cast<OriginalVector const &>(x)) :
                    qvm_detail::const_value<this_vector,idx>::value();
                }

            template <int I>
            static
            BOOST_QVM_INLINE_CRITICAL
            scalar_type &
            write_element( this_vector & x )
                {
                BOOST_QVM_STATIC_ASSERT(I>=0);
                BOOST_QVM_STATIC_ASSERT(I<dim);
                int const idx=qvm_detail::swizzle<SwizzleList,I>::value;
                BOOST_QVM_STATIC_ASSERT(idx>=0);
                BOOST_QVM_STATIC_ASSERT(idx<vec_traits<OriginalVector>::dim);
                return vec_traits<OriginalVector>::template write_element<idx>(reinterpret_cast<OriginalVector &>(x));
                }
            };

        template <class SwizzleList>
        struct
        vec_traits<qvm_detail::sw01_<SwizzleList> >
            {
            typedef qvm_detail::sw01_<SwizzleList> this_vector;
            typedef int scalar_type;
            static int const dim=qvm_detail::swizzle_list_length<SwizzleList>::value;

            template <int I>
            static
            BOOST_QVM_INLINE_CRITICAL
            scalar_type
            read_element( this_vector const & )
                {
                BOOST_QVM_STATIC_ASSERT(I>=0);
                BOOST_QVM_STATIC_ASSERT(I<dim);
                int const idx=qvm_detail::swizzle<SwizzleList,I>::value;
                BOOST_QVM_STATIC_ASSERT(idx<0);
                return qvm_detail::const_value<this_vector,idx>::value();
                }
            };

        template <class OriginalScalar,class SwizzleList>
        struct
        vec_traits<qvm_detail::sws_<OriginalScalar,SwizzleList> >
            {
            typedef qvm_detail::sws_<OriginalScalar,SwizzleList> this_vector;
            typedef OriginalScalar scalar_type;
            static int const dim=qvm_detail::swizzle_list_length<SwizzleList>::value;

            template <int I>
            static
            BOOST_QVM_INLINE_CRITICAL
            scalar_type
            read_element( this_vector const & x )
                {
                BOOST_QVM_STATIC_ASSERT(I>=0);
                BOOST_QVM_STATIC_ASSERT(I<dim);
                int const idx=qvm_detail::swizzle<SwizzleList,I>::value;
                BOOST_QVM_STATIC_ASSERT(idx<1);
                return idx==0?
                    reinterpret_cast<OriginalScalar const &>(x) :
                    qvm_detail::const_value<this_vector,idx>::value();
                }

            template <int I>
            static
            BOOST_QVM_INLINE_CRITICAL
            scalar_type &
            write_element( this_vector & x )
                {
                BOOST_QVM_STATIC_ASSERT(I>=0);
                BOOST_QVM_STATIC_ASSERT(I<dim);
                int const idx=qvm_detail::swizzle<SwizzleList,I>::value;
                BOOST_QVM_STATIC_ASSERT(idx==0);
                return reinterpret_cast<OriginalScalar &>(x);
                }
            };

        template <class OriginalVector,class SwizzleList,int D>
        struct
        deduce_vec<qvm_detail::sw_<OriginalVector,SwizzleList>,D>
            {
            typedef vec<typename vec_traits<OriginalVector>::scalar_type,D> type;
            };

        template <class OriginalVector,class SwizzleList,int D>
        struct
        deduce_vec2<qvm_detail::sw_<OriginalVector,SwizzleList>,qvm_detail::sw_<OriginalVector,SwizzleList>,D>
            {
            typedef vec<typename vec_traits<OriginalVector>::scalar_type,D> type;
            };

        template <class Scalar,class SwizzleList,int D>
        struct
        deduce_vec<qvm_detail::sws_<Scalar,SwizzleList>,D>
            {
            typedef vec<Scalar,D> type;
            };

        template <class Scalar,class SwizzleList,int D>
        struct
        deduce_vec2<qvm_detail::sws_<Scalar,SwizzleList>,qvm_detail::sws_<Scalar,SwizzleList>,D>
            {
            typedef vec<Scalar,D> type;
            };
        }
    }

#endif