Dogcows Code - chaz/yoink/blob - et/traits.h

   1 /* -*- C++ -*- ------------------------------------------------------------
   2
   3 Copyright (c) 2007 Jesse Anders and Demian Nave http://cmldev.net/
   4
   5 The Configurable Math Library (CML) is distributed under the terms of the
   6 Boost Software License, v1.0 (see cml/LICENSE for details).
   7
   8  *-----------------------------------------------------------------------*/
   9 /** @file
  10  *  @brief
  11  */
  12
  13 #ifndef traits_h
  14 #define traits_h
  15
  16 #include <cml/et/tags.h>
  17
  18 /* XXX This is here temporarily, should be rolled into the traits classes
  19  * once it's clear how to best specify scalar args
  20  */
  21 //#define SCALAR_ARG_TYPE const ScalarT&
  22 //#define ELEMENT_ARG_TYPE const Element&
  23 #define SCALAR_ARG_TYPE ScalarT
  24 #define ELEMENT_ARG_TYPE Element
  25
  26 namespace cml {
  27 namespace et {
  28
  29 /** The expression traits class.
  30  *
  31  * The traits class is used to provide uniform access to expression
  32  * objects, including scalars, when used in vector and matrix expressions.
  33  * One especially useful property for scalars is that scalars are
  34  * implicitly "promoted" to vectors or scalars as necessary via the
  35  * ExprTraits's get() method.  Without this functionality, a separate
  36  * expression tree node would be needed to hold a scalar, which would
  37  * adversely affect performance.
  38  *
  39  * @internal This is also currently used for determining traits of scalar
  40  * types from the scalar operators (+,-,etc.).  Really, a separate traits
  41  * class should probably be used for this (e.g. ScalarTraits).
  42  */
  43 template<typename T> struct ExprTraits
  44 #if defined(CML_NO_DEFAULT_EXPR_TRAITS)
  45 /* For testing, don't default to scalar traits: */
  46 #else
  47 {
  48     /* Standard: */
  49     typedef T expr_type;
  50     typedef T value_type;
  51     typedef T& reference;
  52     typedef T const_reference;
  53     typedef scalar_result_tag result_tag;
  54     typedef fixed_memory_tag memory_tag;
  55     typedef unit_size_tag size_tag;
  56     typedef expr_type result_type;
  57     typedef expr_leaf_tag node_tag;
  58
  59     /** Vector-like access, just returns the value. */
  60     value_type get(const_reference v, size_t) const { return v; }
  61
  62     /** Matrix-like access, just returns the value. */
  63     value_type get(const_reference v, size_t, size_t) const { return v; }
  64
  65     /** Size is always 1. */
  66     size_t size(const_reference) const { return 1; }
  67
  68     /** Size is always 1. */
  69     size_t rows(double) const { return 1; }
  70
  71     /** Size is always 1. */
  72     size_t cols(double) const { return 1; }
  73 }
  74 #endif
  75 ;
  76
  77 #if defined(CML_NO_DEFAULT_EXPR_TRAITS)
  78 template<> struct ExprTraits<double>
  79 {
  80     /* Standard: */
  81     typedef double expr_type;
  82     typedef double value_type;
  83     typedef double& reference;
  84     typedef double const_reference;
  85     typedef scalar_result_tag result_tag;
  86     typedef fixed_memory_tag memory_tag;
  87     typedef unit_size_tag size_tag;
  88     typedef double result_type;
  89     typedef expr_leaf_tag node_tag;
  90
  91     /** Vector-like access, just returns the value. */
  92     value_type get(double v, size_t) const { return v; }
  93
  94     /** Matrix-like access, just returns the value. */
  95     value_type get(double v, size_t, size_t) const { return v; }
  96
  97     /** Size is always 1. */
  98     size_t size(double) const { return 1; }
  99
 100     /** Size is always 1. */
 101     size_t rows(double) const { return 1; }
 102
 103     /** Size is always 1. */
 104     size_t cols(double) const { return 1; }
 105 };
 106
 107 template<> struct ExprTraits<float>
 108 {
 109     /* Standard: */
 110     typedef float expr_type;
 111     typedef float value_type;
 112     typedef float& reference;
 113     typedef float const_reference;
 114     typedef scalar_result_tag result_tag;
 115     typedef fixed_memory_tag memory_tag;
 116     typedef unit_size_tag size_tag;
 117     typedef float result_type;
 118     typedef expr_leaf_tag node_tag;
 119
 120     /** Vector-like access, just returns the value. */
 121     value_type get(float v, size_t) const { return v; }
 122
 123     /** Matrix-like access, just returns the value. */
 124     value_type get(float v, size_t, size_t) const { return v; }
 125
 126     /** Size is always 1. */
 127     size_t size(float) const { return 1; }
 128
 129     /** Size is always 1. */
 130     size_t rows(float) const { return 1; }
 131
 132     /** Size is always 1. */
 133     size_t cols(float) const { return 1; }
 134 };
 135 #endif
 136
 137 } // namespace et
 138 } // namespace cml
 139
 140 #endif
 141
 142 // -------------------------------------------------------------------------
 143 // vim:ft=cpp