text: /* -*- C++ -*- ------------------------------------------------------------
   
  Copyright (c) 2007 Jesse Anders and Demian Nave http://cmldev.net/
  
  The Configurable Math Library (CML) is distributed under the terms of the
  Boost Software License, v1.0 (see cml/LICENSE for details).
  
   *-----------------------------------------------------------------------*/
  /** @file
   *  @brief
   */
  
  #ifndef fixed_2D_h
  #define fixed_2D_h
  
  #include <cml/core/common.h>
  #include <cml/core/fixed_1D.h>
  
  /* This is used below to create a more meaningful compile-time error when
   * an unknown layout argument is given:
   */
  struct invalid_layout_type_error;
  
  /* This is used below to create a more meaningful compile-time error when
   * a negative size is given.
   */
  struct negative_array_size_error;
  
  namespace cml {
  
  /** The internal statically-allocated 2D-array implementation class.
   *
   * This uses an internal class to setup the data matrix with the proper
   * layout.  The alternative is to use a 1D array with size Rows*Cols and a
   * multiplication to dereference an element, but it seems that compilers
   * better optimize 2D array dereferences.  This is different from
   * dynamic_2D<>, which must use the 1D array method.
   *
   * @sa cml::fixed
   *
   * @note This class is designed to have the same size as a C array with the
   * same dimensions.  It's therefore possible (but not recommended!) to coerce
   * a normal C array into a fixed_2D<> like this:
   *
   * typedef fixed_2D<double,10,10,row_major> array;
   * double c_array[10][10];
   * array& array_object = *((array*)&c_array);
   * double e11 = array_object[1][1];
   *
   * It's also possible to do this with a pointer to an array of values (e.g. a
   * double*), whether or not it was actually declared as a fixed C array.  This
   * is HIGHLY DISCOURAGED, though, since it's relatively straightforward to
   * implement a separate class to take a C array (or pointer) and turn it into
   * an array object.
   *
   * @internal Do <em>not</em> add the empty constructor and destructor; at
   * least one compiler (Intel C++ 9.0) fails to optimize them away, and they
   * aren't needed anyway here.
   */
  template<typename Element, int Rows, int Cols, typename Layout>
  class fixed_2D
  {
    public:
  
      /* Require Rows > 0, Cols > 0: */
      CML_STATIC_REQUIRE_M(
              (Rows > 0) && (Cols > 0),
              negative_array_size_error);
  
      /* Require Layout to be row_major or col_major: */
      CML_STATIC_REQUIRE_M(
              (same_type<Layout,row_major>::is_true
               || same_type<Layout,col_major>::is_true),
              invalid_layout_type_error);
  
  
      /* Record the generator: */
      typedef fixed<Rows,Cols> generator_type;
  
      /* Standard: */
      typedef Element value_type;
      typedef Element* pointer;
      typedef Element& reference;
      typedef const Element& const_reference;
      typedef const Element* const_pointer;
  
      /* For matching by memory layout: */
      typedef Layout layout;
  
      /* For matching by memory type: */
      typedef fixed_memory_tag memory_tag;
  
      /* For matching by size type: */
      typedef fixed_size_tag size_tag;
  
      /* For matching by resizability: */
      typedef not_resizable_tag resizing_tag;
  
      /* For matching by dimensions: */
      typedef twod_tag dimension_tag;
  
      /* To simplify the matrix transpose operator: */
      typedef fixed_2D<Element,Cols,Rows,Layout> transposed_type;
  
      /* To simplify the matrix row and column operators: */
      typedef fixed_1D<Element,Rows> row_array_type;
      typedef fixed_1D<Element,Cols> col_array_type;
  
  
    public:
  
      enum { array_rows = Rows, array_cols = Cols };
  
  
    public:
  
      /** Return the number of rows in the array. */
      size_t rows() const { return size_t(array_rows); }
  
      /** Return the number of cols in the array. */
      size_t cols() const { return size_t(array_cols); }
  
  
    public:
  
      /** Access element (row,col) of the matrix.
       *
       * @param row row of element.
       * @param col column of element.
       * @returns mutable reference.
       *
       * @note This function does not range-check the arguments.
       */
      reference operator()(size_t row, size_t col) {
          /* Dispatch to the right function based on layout: */
          return get_element(row,col,layout());
      }
  
      /** Const access element (row,col) of the matrix.
       *
       * @param row row of element.
       * @param col column of element.
       * @returns const reference.
       *
       * @note This function does not range-check the arguments.
       */
      const_reference operator()(size_t row, size_t col) const {
          /* Dispatch to the right function based on layout: */
          return get_element(row,col,layout());
      }
  
      /** Return access to the data as a raw pointer. */
      pointer data() { return &m_data[0][0]; }
  
      /** Return access to the data as a raw pointer. */
      const_pointer data() const { return &m_data[0][0]; }
  
  
    public:
  
      fixed_2D() {}
  
  
    protected:
  
      reference get_element(size_t row, size_t col, row_major) {
          return m_data[row][col];
      }
  
      const_reference get_element(size_t row, size_t col, row_major) const {
          return m_data[row][col];
      }
  
      reference get_element(size_t row, size_t col, col_major) {
          return m_data[col][row];
      }
  
      const_reference get_element(size_t row, size_t col, col_major) const {
          return m_data[col][row];
      }
  
  
    protected:
  
      /* Typedef the possible layouts: */
      typedef Element row_major_array[Rows][Cols];
      typedef Element col_major_array[Cols][Rows];
  
      /* Now, select the right layout for the current matrix: */
      typedef typename select_switch<
          Layout, row_major, row_major_array,     /* Case 1 */
                  col_major, col_major_array      /* Case 2 */
          >::result array_data;
  
      /* Declare the data array: */
      array_data                  m_data;
  };
  
  } // namespace cml
  
  #endif
  
  // -------------------------------------------------------------------------
  // vim:ft=cpp
  