Add a multidimensional wrapper around c-array

src/common/CArray.hpp

@@ -0,0 +1,184 @@
+/**
+ * @file CArray.hpp
+ * @brief This file contains the implementation of the CArray class.
+ */
+
+#pragma once
+
+
+#include "common/ShivaMacros.hpp"
+
+#include "CArrayHelper.hpp"
+
+#include <utility>
+
+
+
+namespace shiva
+{
+
+
+
+/**
+ * @struct CArray
+ * @brief This struct provides a compile-time dimesion multidimensional array.
+ * @tparam T This is the type of the data stored in the array.
+ * @tparam DIMS These are the dimensions of the array.
+ */
+template< typename T, typename DATA_BUFFER, int ... DIMS >
+struct CArray
+{
+  /// The type of the an element in the array.
+  using element_type = T;
+
+  /// The type of the data stored in the array.
+  using value_type = std::remove_cv_t< T >;
+
+  /// The type of the indices used to access the array.
+  using index_type = int;
+
+  /// The number of dimensions in the array.
+  static inline constexpr int rank() { return sizeof ... ( DIMS ); }
+
+  /// The dimensions of the array.
+  template< int INDEX >
+  static inline constexpr int extent() { return CArrayHelper::get< INDEX, DIMS ... >(); }
+
+  /// The size of the data in array...i.e. the product of the dimensions.
+  static inline constexpr int size() { return ( DIMS * ... ); }
+
+  /**
+   * @brief Constructor for wrapping a pointer to data
+   * @tparam U Type to used to check if the data is a pointer for SFINAE.
+   * @tparam ENABLE SFINAE parameter.
+   * @param buffer data that the view will point to.
+   */
+  template< typename U = DATA_BUFFER,
+            std::enable_if_t< std::is_pointer_v< U >, int > ENABLE = 0 >
+  constexpr explicit CArray( T const (&buffer)[ CArrayHelper::size< DIMS... >() ] ):
+    m_data( buffer )
+  {}
+
+  /**
+   * @copydoc CArray
+   */
+  template< typename U = DATA_BUFFER,
+            std::enable_if_t< std::is_pointer_v< U >, int > = 0 >
+  constexpr explicit CArray( std::remove_const_t< T >(&buffer)[ CArrayHelper::size< DIMS... >() ] ):
+    m_data( buffer )
+  {}
+
+  /**
+   * @brief Constructor for list initialization.
+   * @tparam ...U the type of the arguments.
+   * @param ...args the data to initialize the array with.
+   */
+  template< typename ... U >
+  constexpr CArray( U ... args ): m_data{ args ... }
+  {}
+
+  /**
+   * @brief accessor for m_data
+   * @return reference to m_data
+   */
+  DATA_BUFFER & data() { return m_data; }
+
+  /**
+   * @brief const accessor for m_data
+   * @return reference to const m_data
+   */
+  DATA_BUFFER const & data() const { return m_data; }
+
+  /**
+   * @brief Templated operator() to access the data in the array.
+   * @tparam ...INDICES The indices that specify the data to access.
+   * @return A reference to the data at the specified indices.
+   */
+  template< int... INDICES >
+  SHIVA_CONSTEXPR_HOSTDEVICE_FORCEINLINE
+  T& operator()( )
+  {
+    static_assert( sizeof...(INDICES) == sizeof...(DIMS), "Incorrect number of indices" );
+    return m_data[ CArrayHelper::linearIndexHelper< DIMS... >::template eval< INDICES... >() ];
+  }
+
+  /**
+   * @brief const operator() to access the data in the array.
+   * @tparam ...INDICES The indices that specify the data to access.
+   * @return A reference to the data at the specified indices.
+   */
+  template< int... INDICES >
+  SHIVA_CONSTEXPR_HOSTDEVICE_FORCEINLINE
+  std::add_const_t< T >& operator()( ) const
+  {
+    static_assert( sizeof...(INDICES) == sizeof...(DIMS), "Incorrect number of indices" );
+    return m_data[ CArrayHelper::linearIndexHelper< DIMS... >::template eval< INDICES... >() ];
+  }
+
+  /**
+   * @brief parentheses operator accessor to data in the array.
+   * @tparam ...INDICES The type of the indices that specify the data to access.
+   * @param ...indices The pack of indices that specify the data to access.
+   * @return A reference to the data at the specified indices.
+   */
+  template< typename ... INDICES >
+  SHIVA_CONSTEXPR_HOSTDEVICE_FORCEINLINE
+  T& operator()( INDICES... indices )
+  {
+    static_assert( sizeof...(INDICES) == sizeof...(DIMS), "Incorrect number of indices" );
+    return m_data[ CArrayHelper::linearIndexHelper< DIMS... >::eval( indices ... ) ];
+  }
+
+  /**
+   * @brief const parentheses operator accessor to data in the array.
+   * @tparam ...INDICES The type of the indices that specify the data to access.
+   * @param ...indices The pack of indices that specify the data to access.
+   * @return A reference to the data at the specified indices.
+   */
+  template< typename ... INDICES >
+  SHIVA_CONSTEXPR_HOSTDEVICE_FORCEINLINE
+  std::add_const_t< T >& operator()( INDICES... indices ) const
+  {
+    static_assert( sizeof...(INDICES) == sizeof...(DIMS), "Incorrect number of indices" );
+    return m_data[ CArrayHelper::linearIndexHelper< DIMS... >::eval( indices ... ) ];
+  }
+
+private:
+  /// The data in the array.
+  DATA_BUFFER m_data;
+};
+
+/**
+ * @brief Alias for a scalar.
+ * @tparam T Type held in the scalar
+ */
+template< typename T >
+using Scalar = CArray< T, T[1], 1 >;
+
+/**
+ * @brief Alias for a N-d array.
+ * @tparam T Type held in the array.
+ * @tparam DIMS The dimensions of the array.
+ */
+template< typename T, int ... DIMS >
+using CArrayNd = CArray< T, T[CArrayHelper::size< DIMS ... >()], DIMS ... >;
+
+
+/**
+ * @brief Alias for a scalar view.
+ * @tparam T Type held in the scalar
+ */
+template< typename T >
+using ScalarView = CArray< T, T, 1 >;
+
+/**
+ * @brief Alias for a N-d array view.
+ * @tparam T Type held in the array.
+ * @tparam DIMS The dimensions of the array.
+ */
+template< typename T, int ... DIMS >
+using CArrayViewNd = CArray< T, T * const, DIMS ... >;
+
+
+
+} // namespace shiva

src/common/CArrayHelper.hpp

@@ -0,0 +1,184 @@
+/**
+ * @file CArrayHelper.hpp
+ * @brief This file contains the helper functions for the MultiDimensionalArray and MultiDimensionalSpan.
+ */
+
+#pragma once
+
+
+#include "common/ShivaMacros.hpp"
+#include <utility>
+
+
+
+namespace shiva
+{
+
+/**
+ * @namespace shiva::CArrayHelper
+ * @brief The CArrayHelper namespace contains some stride calculations and
+ * linearIndex calculations for the MultiDimensionalBase class.
+ */
+namespace CArrayHelper
+{
+
+
+/**
+ * @brief This recursive function helps to calculates the strides for
+ *   dimensions passed in as a template parameter pack.
+ * @tparam DIM This is the first dimension peeled off the parameter pack.
+ * @tparam DIMS These are the remaining dimensions of the pack.
+ * @return This returns the stride of the largest dimension in the pack.
+ */
+template< int DIM, int ... DIMS >
+SHIVA_STATIC_CONSTEXPR_HOSTDEVICE_FORCEINLINE int
+strideHelper()
+{
+  if constexpr ( sizeof ... ( DIMS ) == 0 )
+  {
+    return DIM;
+  }
+  else
+  {
+    return DIM * strideHelper< DIMS ... >();
+  }
+}
+
+/**
+ * @brief This function calculates the stride of the largest dimension in the
+ *   pack.
+ * @tparam DIM This is the first dimension peeled off the parameter pack.
+ * @tparam DIMS These are the remaining dimensions of the pack.
+ * @return This returns the stride of the largest dimension in the pack.
+ */
+template< int DIM, int ... DIMS >
+SHIVA_STATIC_CONSTEXPR_HOSTDEVICE_FORCEINLINE int
+stride()
+{
+  return strideHelper< DIMS ..., 1 >();
+}
+
+/**
+ * @struct linearIndexHelper
+ * @brief struct to facilitate the calculation of a linear index from a pack
+ * of dimensions by peeling the dimensions pack one at a time.
+ * @tparam DIM This is the first dimension peeled off the parameter pack.
+ * @tparam DIMS These are the remaining dimensions of the pack.
+ */
+template< int DIM, int ... DIMS >
+struct linearIndexHelper
+{
+  /**
+   * @brief This recursive function calculates the linear index from a pack
+   * of indices by peeling off the indices one at a time, and multiplying
+   * by the stride at that "level" of the product sum.
+   * @tparam INDEX This is the first index peeled off the parameter pack.
+   * @tparam INDICES These are the remaining indices of the pack.
+   * @return This returns the linear index.
+   */
+  template< int INDEX, int ... INDICES >
+  SHIVA_STATIC_CONSTEXPR_HOSTDEVICE_FORCEINLINE int
+  level()
+  {
+    constexpr int thisStride = strideHelper< DIMS ..., 1 >();
+    if constexpr ( sizeof ... ( DIMS ) == 0 )
+    {
+      return INDEX * thisStride;
+    }
+    else
+    {
+      return INDEX * thisStride + linearIndexHelper< DIMS ... >::template level< INDICES ... >();
+    }
+  }
+
+  /**
+   * @copydoc level()
+   */
+  template< typename INDEX_TYPE, typename ... INDICES_TYPE >
+  SHIVA_STATIC_CONSTEXPR_HOSTDEVICE_FORCEINLINE int
+  level( INDEX_TYPE const index, INDICES_TYPE const ... indices )
+  {
+    constexpr int thisStride = strideHelper< DIMS ..., 1 >();
+    if constexpr ( sizeof ... ( DIMS ) == 0 )
+    {
+      return index * thisStride;
+    }
+    else
+    {
+      return index * thisStride + linearIndexHelper< DIMS ... >::template level( std::forward< INDICES_TYPE const >( indices )... );
+    }
+  }
+
+  /**
+   * @brief This function calculates the linear index from a pack of indices.
+   * @tparam INDICES The indices to calculate the linear index from.
+   * @return This returns the linear index.
+   */
+  template< int ... INDICES >
+  SHIVA_STATIC_CONSTEXPR_HOSTDEVICE_FORCEINLINE int
+  eval()
+  {
+    return level< INDICES ... >();
+  }
+
+  /**
+   * @brief This function calculates the linear index from a pack of indices.
+   * @tparam INDEX_TYPE The type of the index.
+   * @param indices The indices to calculate the linear index from.
+   * @return This returns the linear index.
+   */
+  template< typename ... INDEX_TYPE >
+  SHIVA_STATIC_CONSTEXPR_HOSTDEVICE_FORCEINLINE int
+  eval( INDEX_TYPE ... indices )
+  {
+    return level( std::forward< INDEX_TYPE >( indices )... );
+  }
+};
+
+
+/**
+ * @brief function to get a specific value from a pack of indices.
+ * @tparam COUNT The index of the pack to return.
+ * @tparam INDEX The first index peeled off the pack.
+ * @tparam INDICES The remaining indices in the pack.
+ * @return The value of the INDICES pack at COUNT.
+ */
+template< int COUNT, int INDEX, int ... INDICES >
+SHIVA_STATIC_CONSTEXPR_HOSTDEVICE_FORCEINLINE int
+get()
+{
+  if constexpr ( COUNT == 0 )
+  {
+    return INDEX;
+  }
+  else
+  {
+    return get< COUNT - 1, INDICES ... >();
+  }
+}
+
+/**
+ * @brief function to get the product size of a pack of indices.
+ * @tparam INDICES The indices to get the aggregate length of.
+ */
+template< int ... DIMS >
+SHIVA_STATIC_CONSTEXPR_HOSTDEVICE_FORCEINLINE int
+size()
+{
+  return ( DIMS * ... );
+}
+
+/**
+ * @brief function to peel a value from a parameter pack.
+ * @tparam T The type of the first value in the pack.
+ * @tparam Ts The types of the remaining values in the pack.
+ */
+template< typename T, typename ... Ts >
+struct Peeler
+{
+  /// The type of the first value in the pack.
+  using type = T;
+};
+
+} // namespace CArrayHelper
+} // namespace shiva

src/common/CMakeLists.txt

@@ -1,5 +1,7 @@
 
 set( common_headers
+     CArray.hpp
+     CArrayHelper.hpp
      IndexTypes.hpp
      LinearIndex.hpp
      MathUtilities.hpp