/*
//@HEADER
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//
//                        Kokkos v. 2.0
//              Copyright (2014) Sandia Corporation
//
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
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*/

#ifndef KOKKOS_ARRAY_HPP
#define KOKKOS_ARRAY_HPP

#include <Kokkos_Macros.hpp>
#include <impl/Kokkos_Error.hpp>

#include <type_traits>
#include <algorithm>
#include <limits>
#include <cstddef>
#include <string>

namespace Kokkos {

#ifdef KOKKOS_ENABLE_DEBUG_BOUNDS_CHECK
namespace Impl {
template <typename Integral, bool Signed = std::is_signed<Integral>::value>
struct ArrayBoundsCheck;

template <typename Integral>
struct ArrayBoundsCheck<Integral, true> {
  KOKKOS_INLINE_FUNCTION
  ArrayBoundsCheck(Integral i, size_t N) {
    if (i < 0) {
#ifdef KOKKOS_ACTIVE_EXECUTION_MEMORY_SPACE_HOST
      std::string s = "Kokkos::Array: index ";
      s += std::to_string(i);
      s += " < 0";
      Kokkos::Impl::throw_runtime_exception(s);
#else
      Kokkos::abort("Kokkos::Array: negative index in device code");
#endif
    }
    ArrayBoundsCheck<Integral, false>(i, N);
  }
};

template <typename Integral>
struct ArrayBoundsCheck<Integral, false> {
  KOKKOS_INLINE_FUNCTION
  ArrayBoundsCheck(Integral i, size_t N) {
    if ( size_t(i) >= N) {
#ifdef KOKKOS_ACTIVE_EXECUTION_MEMORY_SPACE_HOST
      std::string s = "Kokkos::Array: index ";
      s += std::to_string(i);
      s += " >= ";
      s += std::to_string(N);
      Kokkos::Impl::throw_runtime_exception(s);
#else
      Kokkos::abort("Kokkos::Array: index >= size");
#endif
    }
  }
};
} // end namespace Impl

#define KOKKOS_ARRAY_BOUNDS_CHECK(i, N) \
  Kokkos::Impl::ArrayBoundsCheck<decltype(i)>(i, N)

#else  // !defined( KOKKOS_ENABLE_DEBUG_BOUNDS_CHECK )

#define KOKKOS_ARRAY_BOUNDS_CHECK(i, N) (void)0

#endif // !defined( KOKKOS_ENABLE_DEBUG_BOUNDS_CHECK )

/**\brief  Derived from the C++17 'std::array'.
 *         Dropping the iterator interface.
 */
template< class T      = void
        , size_t N     =KOKKOS_INVALID_INDEX
        , class Proxy  = void
        >
struct Array {
public:
  /**
   * The elements of this C array shall not be accessed directly. The data
   * member has to be declared public to enable aggregate initialization as for
   * std::array. We mark it as private in the documentation.
   * @private
   */
  T m_internal_implementation_private_member_data[N];
public:

  typedef T &                                 reference ;
  typedef typename std::add_const<T>::type &  const_reference ;
  typedef size_t                              size_type ;
  typedef ptrdiff_t                           difference_type ;
  typedef T                                   value_type ;
  typedef T *                                 pointer ;
  typedef typename std::add_const<T>::type *  const_pointer ;

  KOKKOS_INLINE_FUNCTION static constexpr size_type size() { return N ; }
  KOKKOS_INLINE_FUNCTION static constexpr bool      empty(){ return false ; }
  KOKKOS_INLINE_FUNCTION constexpr size_type max_size() const { return N ; }

  template< typename iType >
  KOKKOS_INLINE_FUNCTION
  reference operator[]( const iType & i )
    {
      static_assert( ( std::is_integral<iType>::value || std::is_enum<iType>::value ) , "Must be integral argument" );
      KOKKOS_ARRAY_BOUNDS_CHECK(i, N);
      return m_internal_implementation_private_member_data[i];
    }

  template< typename iType >
  KOKKOS_INLINE_FUNCTION
  const_reference operator[]( const iType & i ) const
    {
      static_assert( ( std::is_integral<iType>::value || std::is_enum<iType>::value ) , "Must be integral argument" );
      KOKKOS_ARRAY_BOUNDS_CHECK(i, N);
      return m_internal_implementation_private_member_data[i];
    }

  KOKKOS_INLINE_FUNCTION pointer       data()
    {
      return & m_internal_implementation_private_member_data[0];
    }
  KOKKOS_INLINE_FUNCTION const_pointer data() const
    {
      return & m_internal_implementation_private_member_data[0];
    }

  #ifdef KOKKOS_IMPL_ROCM_CLANG_WORKAROUND
  // Do not default unless move and move-assignment are also defined
  KOKKOS_INLINE_FUNCTION
  ~Array() = default ;
  Array() = default ;
  Array( const Array & ) = default ;
  Array & operator = ( const Array & ) = default ;

  // Some supported compilers are not sufficiently C++11 compliant
  // for default move constructor and move assignment operator.
  Array( Array && ) = default ;
  Array & operator = ( Array && ) = default ;
 
  KOKKOS_INLINE_FUNCTION
  Array(const std::initializer_list<T>& vals) {
    for(int i=0; i<N; i++) {
      m_internal_implementation_private_member_data[i] = vals.begin()[i];
    }
  }
  #endif
};


template< class T , class Proxy >
struct Array<T,0,Proxy> {
public:

  typedef typename std::add_const<T>::type &  reference ;
  typedef typename std::add_const<T>::type &  const_reference ;
  typedef size_t                              size_type ;
  typedef ptrdiff_t                           difference_type ;
  typedef typename std::add_const<T>::type    value_type ;
  typedef typename std::add_const<T>::type *  pointer ;
  typedef typename std::add_const<T>::type *  const_pointer ;

  KOKKOS_INLINE_FUNCTION static constexpr size_type size()  { return 0 ; }
  KOKKOS_INLINE_FUNCTION static constexpr bool      empty() { return true ; }
  KOKKOS_INLINE_FUNCTION constexpr size_type max_size() const { return 0 ; }

  template< typename iType >
  KOKKOS_INLINE_FUNCTION
  value_type operator[]( const iType & )
    {
      static_assert( ( std::is_integral<iType>::value || std::is_enum<iType>::value ) , "Must be integer argument" );
      return value_type();
    }

  template< typename iType >
  KOKKOS_INLINE_FUNCTION
  value_type operator[]( const iType & ) const
    {
      static_assert( ( std::is_integral<iType>::value || std::is_enum<iType>::value ) , "Must be integer argument" );
      return value_type();
    }

  KOKKOS_INLINE_FUNCTION pointer       data()       { return pointer(0) ; }
  KOKKOS_INLINE_FUNCTION const_pointer data() const { return const_pointer(0); }

#ifdef KOKKOS_CUDA_9_DEFAULTED_BUG_WORKAROUND
  KOKKOS_INLINE_FUNCTION ~Array() {}
  KOKKOS_INLINE_FUNCTION Array() {}
  KOKKOS_INLINE_FUNCTION Array( const Array & ) {}
  KOKKOS_INLINE_FUNCTION Array & operator = ( const Array & ) {}
#else
  KOKKOS_INLINE_FUNCTION ~Array() = default;
  KOKKOS_INLINE_FUNCTION Array() = default;
  KOKKOS_INLINE_FUNCTION Array( const Array & ) = default;
  KOKKOS_INLINE_FUNCTION Array & operator = ( const Array & ) = default;
#endif

  // Some supported compilers are not sufficiently C++11 compliant
  // for default move constructor and move assignment operator.
  // Array( Array && ) = default ;
  // Array & operator = ( Array && ) = default ;
};


template<>
struct Array<void,KOKKOS_INVALID_INDEX,void>
{
  struct contiguous {};
  struct strided {};
};

template< class T >
struct Array< T ,KOKKOS_INVALID_INDEX , Array<>::contiguous >
{
private:
  T *    m_elem ;
  size_t m_size ;
public:

  typedef T &                                 reference ;
  typedef typename std::add_const<T>::type &  const_reference ;
  typedef size_t                              size_type ;
  typedef ptrdiff_t                           difference_type ;
  typedef T                                   value_type ;
  typedef T *                                 pointer ;
  typedef typename std::add_const<T>::type *  const_pointer ;

  KOKKOS_INLINE_FUNCTION constexpr size_type size()  const { return m_size ; }
  KOKKOS_INLINE_FUNCTION constexpr bool      empty() const { return 0 != m_size ; }
  KOKKOS_INLINE_FUNCTION constexpr size_type max_size() const { return m_size ; }

  template< typename iType >
  KOKKOS_INLINE_FUNCTION
  reference operator[]( const iType & i )
    {
      static_assert( ( std::is_integral<iType>::value || std::is_enum<iType>::value ) , "Must be integral argument" );
      KOKKOS_ARRAY_BOUNDS_CHECK(i, m_size);
      return m_elem[i];
    }

  template< typename iType >
  KOKKOS_INLINE_FUNCTION
  const_reference operator[]( const iType & i ) const
    {
      static_assert( ( std::is_integral<iType>::value || std::is_enum<iType>::value ) , "Must be integral argument" );
      KOKKOS_ARRAY_BOUNDS_CHECK(i, m_size);
      return m_elem[i];
    }

  KOKKOS_INLINE_FUNCTION pointer       data()       { return m_elem ; }
  KOKKOS_INLINE_FUNCTION const_pointer data() const { return m_elem ; }

#ifdef KOKKOS_CUDA_9_DEFAULTED_BUG_WORKAROUND
  KOKKOS_INLINE_FUNCTION ~Array() {}
#else
  KOKKOS_INLINE_FUNCTION ~Array() = default;
#endif
  Array() = delete ;
  Array( const Array & rhs ) = delete ;

  // Some supported compilers are not sufficiently C++11 compliant
  // for default move constructor and move assignment operator.
  // Array( Array && rhs ) = default ;
  // Array & operator = ( Array && rhs ) = delete ;

  KOKKOS_INLINE_FUNCTION
  Array & operator = ( const Array & rhs )
    {
      const size_t n = std::min( m_size , rhs.size() );
      for ( size_t i = 0 ; i < n ; ++i ) m_elem[i] = rhs[i] ;
      return *this ;
    }

  template< size_t N , class P >
  KOKKOS_INLINE_FUNCTION
  Array & operator = ( const Array<T,N,P> & rhs )
    {
      const size_t n = std::min( m_size , rhs.size() );
      for ( size_t i = 0 ; i < n ; ++i ) m_elem[i] = rhs[i] ;
      return *this ;
    }

  KOKKOS_INLINE_FUNCTION constexpr Array( pointer arg_ptr , size_type arg_size , size_type = 0 )
    : m_elem(arg_ptr), m_size(arg_size) {}
};

template< class T >
struct Array< T ,KOKKOS_INVALID_INDEX , Array<>::strided >
{
private:
  T *    m_elem ;
  size_t m_size ;
  size_t m_stride ;
public:

  typedef T &                                 reference ;
  typedef typename std::add_const<T>::type &  const_reference ;
  typedef size_t                              size_type ;
  typedef ptrdiff_t                           difference_type ;
  typedef T                                   value_type ;
  typedef T *                                 pointer ;
  typedef typename std::add_const<T>::type *  const_pointer ;

  KOKKOS_INLINE_FUNCTION constexpr size_type size()  const { return m_size ; }
  KOKKOS_INLINE_FUNCTION constexpr bool      empty() const { return 0 != m_size ; }
  KOKKOS_INLINE_FUNCTION constexpr size_type max_size() const { return m_size ; }

  template< typename iType >
  KOKKOS_INLINE_FUNCTION
  reference operator[]( const iType & i )
    {
      static_assert( ( std::is_integral<iType>::value || std::is_enum<iType>::value ) , "Must be integral argument" );
      KOKKOS_ARRAY_BOUNDS_CHECK(i, m_size);
      return m_elem[i*m_stride];
    }

  template< typename iType >
  KOKKOS_INLINE_FUNCTION
  const_reference operator[]( const iType & i ) const
    {
      static_assert( ( std::is_integral<iType>::value || std::is_enum<iType>::value ) , "Must be integral argument" );
      KOKKOS_ARRAY_BOUNDS_CHECK(i, m_size);
      return m_elem[i*m_stride];
    }

  KOKKOS_INLINE_FUNCTION pointer       data()       { return m_elem ; }
  KOKKOS_INLINE_FUNCTION const_pointer data() const { return m_elem ; }

#ifdef KOKKOS_CUDA_9_DEFAULTED_BUG_WORKAROUND
  KOKKOS_INLINE_FUNCTION ~Array() {}
#else
  KOKKOS_INLINE_FUNCTION ~Array() = default;
#endif
  Array()  = delete ;
  Array( const Array & ) = delete ;


  // Some supported compilers are not sufficiently C++11 compliant
  // for default move constructor and move assignment operator.
  // Array( Array && rhs ) = default ;
  // Array & operator = ( Array && rhs ) = delete ;

  KOKKOS_INLINE_FUNCTION
  Array & operator = ( const Array & rhs )
    {
      const size_t n = std::min( m_size , rhs.size() );
      for ( size_t i = 0 ; i < n ; ++i ) m_elem[i] = rhs[i] ;
      return *this ;
    }

  template< size_t N , class P >
  KOKKOS_INLINE_FUNCTION
  Array & operator = ( const Array<T,N,P> & rhs )
    {
      const size_t n = std::min( m_size , rhs.size() );
      for ( size_t i = 0 ; i < n ; ++i ) m_elem[i] = rhs[i] ;
      return *this ;
    }

  KOKKOS_INLINE_FUNCTION constexpr Array( pointer arg_ptr , size_type arg_size , size_type arg_stride )
    : m_elem(arg_ptr), m_size(arg_size), m_stride(arg_stride) {}
};

} // namespace Kokkos

#endif /* #ifndef KOKKOS_ARRAY_HPP */