EVOLUTION-MANAGER

Edit File: permutation_input_iterator.h

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
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http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
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==============================================================================*/

#ifndef TENSORFLOW_CORE_UTIL_PERMUTATION_INPUT_ITERATOR_H_
#define TENSORFLOW_CORE_UTIL_PERMUTATION_INPUT_ITERATOR_H_

#include <iostream>
#include <iterator>

namespace tensorflow {

template <typename ValueType, typename InputIteratorT, typename IndexIteratorT,
          typename OffsetT = ptrdiff_t>
class PermutationInputIterator {
 public:
  // Required iterator traits
  typedef PermutationInputIterator self_type;  ///< My own type
  typedef OffsetT difference_type;  ///< Type to express the result of
                                    ///< subtracting one iterator from another
  typedef ValueType
      value_type;  ///< The type of the element the iterator can point to
  typedef ValueType* pointer;   ///< The type of a pointer to an element the
                                ///< iterator can point to
  typedef ValueType reference;  ///< The type of a reference to an element the
                                ///< iterator can point to

typedef std::random_access_iterator_tag
      iterator_category;  ///< The iterator category

private:
  InputIteratorT input_itr;
  IndexIteratorT index_itr;

public:
  /// Constructor
  __host__ __device__ __forceinline__ PermutationInputIterator(
      InputIteratorT input_itr,  ///< Input iterator to wrap
      IndexIteratorT index_itr)  ///< Conversion functor to wrap
      : input_itr(input_itr), index_itr(index_itr) {}

/// Postfix increment
  __host__ __device__ __forceinline__ self_type operator++(int) {
    self_type retval = *this;
    index_itr++;
    return retval;
  }

/// Prefix increment
  __host__ __device__ __forceinline__ self_type operator++() {
    index_itr++;
    return *this;
  }

/// Indirection
  __host__ __device__ __forceinline__ reference operator*() const {
    return input_itr[*index_itr];
  }

/// Addition
  template <typename Distance>
  __host__ __device__ __forceinline__ self_type operator+(Distance n) const {
    self_type retval(input_itr, index_itr + n);
    return retval;
  }

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

/// Subtraction
  template <typename Distance>
  __host__ __device__ __forceinline__ self_type operator-(Distance n) const {
    self_type retval(input_itr, index_itr - n);
    return retval;
  }

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

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

/// Array subscript
  template <typename Distance>
  __host__ __device__ __forceinline__ reference operator[](Distance n) const {
    return input_itr[index_itr[n]];
  }

/// Structure dereference
  __host__ __device__ __forceinline__ pointer operator->() {
    return input_itr + *index_itr;
  }

/// Equal to
  __host__ __device__ __forceinline__ bool operator==(const self_type& rhs) {
    return (index_itr == rhs.index_itr && input_itr == rhs.input_itr);
  }

/// Not equal to
  __host__ __device__ __forceinline__ bool operator!=(const self_type& rhs) {
    return !(*this == rhs);
  }

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

}  // end namespace tensorflow

#endif  // TENSORFLOW_CORE_UTIL_PERMUTATION_INPUT_ITERATOR_H_