X-Git-Url: https://git.dogcows.com/gitweb?p=chaz%2Fyoink;a=blobdiff_plain;f=src%2Fcml%2Fquaternion%2Fquaternion_comparison.h;fp=src%2Fcml%2Fquaternion%2Fquaternion_comparison.h;h=c1e6d0c5bfefca3b1cfdf03ec3e898839a64a822;hp=0000000000000000000000000000000000000000;hb=0fffd0097d7b496454413e57b398c903ecc252e4;hpb=79becf045222f385da5a1b9eb79081f6f5266c86

diff --git a/src/cml/quaternion/quaternion_comparison.h b/src/cml/quaternion/quaternion_comparison.h
new file mode 100644
index 0000000..c1e6d0c
--- /dev/null
+++ b/src/cml/quaternion/quaternion_comparison.h
@@ -0,0 +1,216 @@
+/* -*- 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 quaternion_comparison_h
+#define quaternion_comparison_h
+
+#include <cml/core/cml_assert.h>
+#include <cml/et/scalar_ops.h>
+
+/* This is used below to create a more meaningful compile-time error when
+ * quaternion_comparison is not provided with quaternion or QuaternionExpr arguments:
+ */
+struct quaternion_comparison_expects_quaternion_args_error;
+
+#define CML_QUAT_QUAT_ORDER(_order_, _op_, _OpT_)                       \
+template<                                                               \
+    typename E1, class AT1, typename E2, class AT2, class O, class C >  \
+inline bool                                                             \
+_op_ (                                                                  \
+        const quaternion<E1,AT1,O,C>& left,                             \
+        const quaternion<E2,AT2,O,C>& right)                            \
+{                                                                       \
+    return detail::quaternion_##_order_ (left, right, _OpT_ <E1,E2>()); \
+}
+
+#define CML_QUAT_QUATXPR_ORDER(_order_, _op_, _OpT_)                    \
+template<typename E, class AT, class O, class C, class XprT>            \
+inline bool                                                             \
+_op_ (                                                                  \
+        const quaternion<E,AT,O,C>& left,                               \
+        QUATXPR_ARG_TYPE right)                                         \
+{                                                                       \
+    return detail::quaternion_##_order_ (left, right,                   \
+            _OpT_ <E, typename XprT::value_type>());                    \
+}
+
+#define CML_QUATXPR_QUAT_ORDER(_order_, _op_, _OpT_)                    \
+template<class XprT, typename E, class AT, class O, class C >           \
+inline bool                                                             \
+_op_ (                                                                  \
+        QUATXPR_ARG_TYPE left,                                          \
+        const quaternion<E,AT,O,C>& right)                              \
+{                                                                       \
+    return detail::quaternion_##_order_ (left, right,                   \
+            _OpT_ <typename XprT::value_type, E>());                    \
+}
+
+#define CML_QUATXPR_QUATXPR_ORDER(_order_, _op_, _OpT_)                 \
+template<class XprT1, class XprT2>                                      \
+inline bool                                                             \
+_op_ (                                                                  \
+        QUATXPR_ARG_TYPE_N(1) left,                                     \
+        QUATXPR_ARG_TYPE_N(2) right)                                    \
+{                                                                       \
+    return detail::quaternion_##_order_ (left, right,                   \
+            _OpT_ <                                                     \
+                typename XprT1::value_type,                             \
+                typename XprT2::value_type>());                         \
+}
+
+
+namespace cml {
+namespace detail {
+
+/** Quaternion strict weak ordering relationship.
+ *
+ * OpT must implement a strict weak order on the quaternion element type.
+ * operator< and operator> on integer and floating-point types are
+ * examples.
+ */
+template<typename LeftT, typename RightT, typename OpT>
+inline bool
+quaternion_weak_order(const LeftT& left, const RightT& right, OpT)
+{
+    /* Shorthand: */
+    typedef et::ExprTraits<LeftT> left_traits;
+    typedef et::ExprTraits<RightT> right_traits;
+
+    /* quaternion_comparison() requires quaternion expressions: */
+    CML_STATIC_REQUIRE_M(
+            (et::QuaternionExpressions<LeftT,RightT>::is_true),
+            quaternion_comparison_expects_quaternion_args_error);
+    /* Note: parens are required here so that the preprocessor ignores the
+     * commas:
+     */
+
+    typedef typename et::QuaternionPromote<
+        typename left_traits::result_type,
+        typename right_traits::result_type
+    >::type result_type;
+
+    for(ssize_t i = 0; i < result_type::array_size; ++ i) {
+
+        if(OpT().apply(
+                    left_traits().get(left,i),
+                    right_traits().get(right,i)
+                    ))
+        {
+            /* If weak order (a < b) is satisfied, return true: */
+            return true;
+        } else if(OpT().apply(
+                    right_traits().get(right,i),
+                    left_traits().get(left,i)
+                    ))
+        {
+            /* If !(b < a), then return false: */
+            return false;
+        } else {
+
+            /* Have !(a < b) && !(b < a) <=> (a >= b && b >= a) <=> (a == b).
+             * so need to test next element:
+             */
+            continue;
+        }
+    }
+    /* XXX Can this be unrolled in any reasonable way? */
+
+    /* If we get here, then left == right: */
+    return false;
+}
+
+/** Quaternion total order relationship.
+ *
+ * OpT must implement a total order on the quaternion element type.  operator<=
+ * and operator>= on integer and floating-point types are examples.
+ */
+template<typename LeftT, typename RightT, typename OpT>
+inline bool
+quaternion_total_order(const LeftT& left, const RightT& right, OpT)
+{
+    /* Shorthand: */
+    typedef et::ExprTraits<LeftT> left_traits;
+    typedef et::ExprTraits<RightT> right_traits;
+
+    /* quaternion_comparison() requires quaternion expressions: */
+    CML_STATIC_REQUIRE_M(
+            (et::QuaternionExpressions<LeftT,RightT>::is_true),
+            quaternion_comparison_expects_quaternion_args_error);
+    /* Note: parens are required here so that the preprocessor ignores the
+     * commas:
+     */
+
+    typedef typename et::QuaternionPromote<
+        typename left_traits::result_type,
+        typename right_traits::result_type
+    >::type result_type;
+
+    for(ssize_t i = 0; i < result_type::array_size; ++ i) {
+
+        /* Test total order: */
+        if(OpT().apply(
+                    left_traits().get(left,i),
+                    right_traits().get(right,i)
+		    ))
+        {
+            /* Automatically true if weak order (a <= b) && !(b <= a) <=>
+             * (a <= b) && (b > a) <=> (a < b) is satisfied:
+             */
+            if(!OpT().apply(
+                        right_traits().get(right,i),
+                        left_traits().get(left,i)
+                        ))
+                return true;
+
+            /* Otherwise, have equality (a <= b) && (b <= a), so continue
+             * to next element:
+             */
+            else
+                continue;
+
+        } else {
+            
+            /* Total order isn't satisfied (a > b), so return false: */
+            return false;
+        }
+    }
+    /* XXX Can this be unrolled in any reasonable way? */
+
+    /* Total (==) or weak (<) order was satisfied, so return true: */
+    return true;
+}
+
+}
+
+/* XXX There is a better way to handle these with operator traits... */
+
+CML_QUAT_QUAT_ORDER(       total_order, operator==, et::OpEqual)
+CML_QUATXPR_QUAT_ORDER(    total_order, operator==, et::OpEqual)
+CML_QUAT_QUATXPR_ORDER(    total_order, operator==, et::OpEqual)
+CML_QUATXPR_QUATXPR_ORDER( total_order, operator==, et::OpEqual)
+
+CML_QUAT_QUAT_ORDER(       weak_order, operator!=, et::OpNotEqual)
+CML_QUATXPR_QUAT_ORDER(    weak_order, operator!=, et::OpNotEqual)
+CML_QUAT_QUATXPR_ORDER(    weak_order, operator!=, et::OpNotEqual)
+CML_QUATXPR_QUATXPR_ORDER( weak_order, operator!=, et::OpNotEqual)
+
+CML_QUAT_QUAT_ORDER(       weak_order, operator<, et::OpLess)
+CML_QUATXPR_QUAT_ORDER(    weak_order, operator<, et::OpLess)
+CML_QUAT_QUATXPR_ORDER(    weak_order, operator<, et::OpLess)
+CML_QUATXPR_QUATXPR_ORDER( weak_order, operator<, et::OpLess)
+
+} // namespace cml
+
+#endif
+
+// -------------------------------------------------------------------------
+// vim:ft=cpp