striding_ptr.hpp

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/*
Copyright (c) 2014-2016, Scott Zuyderduyn
All rights reserved.

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*/

//----------------------------------------------------------------------------
// ptr/striding_ptr.hpp
//
// A pointer specialization that describes device memory where elements are
// stored with a constant spacing in-between (hence incrementing/decrementing
// the pointer involves "striding" between elements).
//
// Author: Scott D. Zuyderduyn, Ph.D. (scott.zuyderduyn@utoronto.ca)
//----------------------------------------------------------------------------

#ifndef ECUDA_PTR_STRIDING_PTR_HPP
#define ECUDA_PTR_STRIDING_PTR_HPP

#include <iostream>

#include "../global.hpp"
#include "../type_traits.hpp"
#include "../utility.hpp"
#include "common.hpp"

namespace ecuda {

template<typename T,typename P=typename ecuda::add_pointer<T>::type>
class striding_ptr
{

public:
    typedef T              element_type;
    typedef P              pointer;
    typedef T&             reference;
    typedef const T&       const_reference;
    typedef std::size_t    size_type;
    typedef std::ptrdiff_t difference_type;

private:
    pointer ptr;      
    size_type stride; 

    template<typename U,typename Q> friend class striding_ptr;

public:
    __HOST__ __DEVICE__ striding_ptr( pointer ptr = pointer(), size_type stride = 0 ) : ptr(ptr), stride(stride) {}

    __HOST__ __DEVICE__ striding_ptr( const striding_ptr& src ) : ptr(src.ptr), stride(src.stride) {}

        template<typename U,typename Q>
        __HOST__ __DEVICE__ striding_ptr( const striding_ptr<U,Q>& src ) : ptr(src.ptr), stride(src.stride) {}

    #ifdef ECUDA_CPP11_AVAILABLE
    __HOST__ __DEVICE__ striding_ptr( striding_ptr&& src ) : ptr(std::move(src.ptr)), stride(std::move(src.stride)) {}

    __HOST__ __DEVICE__ striding_ptr& operator=( striding_ptr&& src )
    {
        ptr = std::move(src.ptr);
        stride = std::move(src.stride);
        return *this;
    }
    #endif

    __HOST__ __DEVICE__ inline pointer get() const { return ptr; }

    __HOST__ __DEVICE__ inline size_type get_stride() const { return stride; }

    __DEVICE__ inline reference       operator*()                       { return *ptr; }
    __DEVICE__ inline const_reference operator*() const                 { return *ptr; }
    __DEVICE__ inline pointer         operator->() const                { return ptr; }
    __DEVICE__ inline reference       operator[]( std::size_t i )       { return striding_ptr(*this).operator+=(i).operator*(); }
    __DEVICE__ inline const_reference operator[]( std::size_t i ) const { return striding_ptr(*this).operator+=(i).operator*(); }

    __HOST__ __DEVICE__ inline striding_ptr& operator++()      { ptr += stride; return *this; }
    __HOST__ __DEVICE__ inline striding_ptr& operator--()      { ptr -= stride; return *this; }
    __HOST__ __DEVICE__ inline striding_ptr  operator++( int ) { striding_ptr tmp(*this); ++(*this); return tmp; }
    __HOST__ __DEVICE__ inline striding_ptr  operator--( int ) { striding_ptr tmp(*this); --(*this); return tmp; }

    __HOST__ __DEVICE__ inline striding_ptr& operator+=( int x ) { ptr += x*stride; return *this; }
    __HOST__ __DEVICE__ inline striding_ptr& operator-=( int x ) { ptr -= x*stride; return *this; }

    __HOST__ __DEVICE__ inline striding_ptr operator+( int x ) const { striding_ptr tmp(*this); tmp += x; return tmp; }
    __HOST__ __DEVICE__ inline striding_ptr operator-( int x ) const { striding_ptr tmp(*this); tmp -= x; return tmp; }

    template<typename T2,typename P2> __HOST__ __DEVICE__ inline bool operator==( const striding_ptr<T2,P2>& other ) const { return ptr == other.ptr; }
    template<typename T2,typename P2> __HOST__ __DEVICE__ inline bool operator!=( const striding_ptr<T2,P2>& other ) const { return ptr != other.ptr; }
    template<typename T2,typename P2> __HOST__ __DEVICE__ inline bool operator< ( const striding_ptr<T2,P2>& other ) const { return ptr <  other.ptr; }
    template<typename T2,typename P2> __HOST__ __DEVICE__ inline bool operator> ( const striding_ptr<T2,P2>& other ) const { return ptr >  other.ptr; }
    template<typename T2,typename P2> __HOST__ __DEVICE__ inline bool operator<=( const striding_ptr<T2,P2>& other ) const { return ptr <= other.ptr; }
    template<typename T2,typename P2> __HOST__ __DEVICE__ inline bool operator>=( const striding_ptr<T2,P2>& other ) const { return ptr >= other.ptr; }

    template<typename U,typename V>
    friend std::basic_ostream<U,V>& operator<<( std::basic_ostream<U,V>& out, const striding_ptr& ptr )
    {
        out << "striding_ptr(ptr=" << ptr.ptr << ";stride=" << ptr.stride << ")";
        return out;
    }

};

} // namespace ecuda

#endif