eoScalarFitness, 'envelope class' for making minimizing/maximizing fitness

eo/src/eoScalarFitness.h

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+/* -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
+
+  -----------------------------------------------------------------------------
+  eoScalarFitness.h
+
+ (c) Maarten Keijzer (mkeijzer@mad.scientist.com) and GeNeura Team, 1999, 2000
+ 
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    Contact: todos@geneura.ugr.es, http://geneura.ugr.es
+ */
+
+
+#ifndef eoScalarFitness_h
+#define eoScalarFitness_h
+
+/**
+ * eoScalarFitness<ScalarType, Compare = less<ScalarType> >:
+ * Wraps a scalar fitness values such as a double or int, with the option of 
+ * maximizing (using less<ScalarType>) or miniziming (using greater<ScalarType>)
+ * this quantity in EO. 
+ *
+ * It overrides operator<() to use the Compare template argument
+ *
+ * Suitable constructors and assignments and casts are defined to work 
+ * with this quantity as if it were a ScalarType.
+*/
+
+template <class ScalarType, class Compare = less<ScalarType> > 
+class eoScalarFitness
+{
+    public :
+
+    eoScalarFitness() : value() {}
+    eoScalarFitness(const eoScalarFitness& other) : value(other.value) {}
+    eoScalarFitness(const ScalarType& v) : value(v) {}
+
+    eoScalarFitness& operator=(const eoScalarFitness& other)
+    { value = other.value; return *this; }
+    eoScalarFitness& operator=(const ScalarType& v)
+    { value = v; return *this; }
+
+    operator ScalarType(void) const { return value; }
+
+    // Comparison, using less by default
+    bool operator<(const eoScalarFitness& other) const 
+    { return Compare()(this->value, other.value); }
+
+    private :
+        ScalarType value;
+};
+
+template <class F, class Cmp>
+std::ostream& operator<<(std::ostream& os, const eoScalarFitness<F, Cmp>&
+f)
+{
+    os << (F) f;
+    return os;
+}
+
+template <class F, class Cmp>
+std::istream& operator>>(istream& is, eoScalarFitness<F, Cmp>& f)
+{
+    F value;
+    is >> value;
+    f = value;
+    return is;
+}
+
+#endif