cache_modified_input_iterator.cuh

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 * Copyright (c) 2011, Duane Merrill.  All rights reserved.
 * Copyright (c) 2011-2018, NVIDIA CORPORATION.  All rights reserved.
 * 
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 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
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 *       names of its contributors may be used to endorse or promote products
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#pragma once

#include <iterator>
#include <iostream>

#include "../thread/thread_load.cuh"
#include "../thread/thread_store.cuh"
#include "../util_device.cuh"
#include "../util_namespace.cuh"

#if (THRUST_VERSION >= 100700)
    // This iterator is compatible with Thrust API 1.7 and newer
    #include <thrust/iterator/iterator_facade.h>
    #include <thrust/iterator/iterator_traits.h>
#endif // THRUST_VERSION


CUB_NS_PREFIX

namespace cub {



template <
    CacheLoadModifier   MODIFIER,
    typename            ValueType,
    typename            OffsetT = ptrdiff_t>
class CacheModifiedInputIterator
{
public:

    // Required iterator traits
    typedef CacheModifiedInputIterator          self_type;              
    typedef OffsetT                             difference_type;        
    typedef ValueType                           value_type;             
    typedef ValueType*                          pointer;                
    typedef ValueType                           reference;              

#if (THRUST_VERSION >= 100700)
    // Use Thrust's iterator categories so we can use these iterators in Thrust 1.7 (or newer) methods
    typedef typename thrust::detail::iterator_facade_category<
        thrust::device_system_tag,
        thrust::random_access_traversal_tag,
        value_type,
        reference
      >::type iterator_category;                                        
#else
    typedef std::random_access_iterator_tag     iterator_category;      
#endif  // THRUST_VERSION


public:

    ValueType* ptr;

    template <typename QualifiedValueType>
    __host__ __device__ __forceinline__ CacheModifiedInputIterator(
        QualifiedValueType* ptr)     
    :
        ptr(const_cast<typename RemoveQualifiers<QualifiedValueType>::Type *>(ptr))
    {}

    __host__ __device__ __forceinline__ self_type operator++(int)
    {
        self_type retval = *this;
        ptr++;
        return retval;
    }

    __host__ __device__ __forceinline__ self_type operator++()
    {
        ptr++;
        return *this;
    }

    __device__ __forceinline__ reference operator*() const
    {
        return ThreadLoad<MODIFIER>(ptr);
    }

    template <typename Distance>
    __host__ __device__ __forceinline__ self_type operator+(Distance n) const
    {
        self_type retval(ptr + n);
        return retval;
    }

    template <typename Distance>
    __host__ __device__ __forceinline__ self_type& operator+=(Distance n)
    {
        ptr += n;
        return *this;
    }

    template <typename Distance>
    __host__ __device__ __forceinline__ self_type operator-(Distance n) const
    {
        self_type retval(ptr - n);
        return retval;
    }

    template <typename Distance>
    __host__ __device__ __forceinline__ self_type& operator-=(Distance n)
    {
        ptr -= n;
        return *this;
    }

    __host__ __device__ __forceinline__ difference_type operator-(self_type other) const
    {
        return ptr - other.ptr;
    }

    template <typename Distance>
    __device__ __forceinline__ reference operator[](Distance n) const
    {
        return ThreadLoad<MODIFIER>(ptr + n);
    }

    __device__ __forceinline__ pointer operator->()
    {
        return &ThreadLoad<MODIFIER>(ptr);
    }

    __host__ __device__ __forceinline__ bool operator==(const self_type& rhs)
    {
        return (ptr == rhs.ptr);
    }

    __host__ __device__ __forceinline__ bool operator!=(const self_type& rhs)
    {
        return (ptr != rhs.ptr);
    }

    friend std::ostream& operator<<(std::ostream& os, const self_type& /*itr*/)
    {
        return os;
    }
};


       // end group UtilIterator

}               // CUB namespace
CUB_NS_POSTFIX  // Optional outer namespace(s)