stub constraint-based packer for canvas

libs/canvas/kiwi/expression.h

@@ -0,0 +1,52 @@
+/*-----------------------------------------------------------------------------
+| Copyright (c) 2013-2017, Nucleic Development Team.
+|
+| Distributed under the terms of the Modified BSD License.
+|
+| The full license is in the file LICENSE, distributed with this software.
+|----------------------------------------------------------------------------*/
+#pragma once
+#include <vector>
+#include "term.h"
+
+namespace kiwi
+{
+
+class Expression
+{
+
+public:
+    Expression(double constant = 0.0) : m_constant(constant) {}
+
+    Expression(const Term &term, double constant = 0.0) : m_terms(1, term), m_constant(constant) {}
+
+    Expression(const std::vector<Term> &terms, double constant = 0.0) : m_terms(terms), m_constant(constant) {}
+
+    ~Expression() {}
+
+    const std::vector<Term> &terms() const
+    {
+        return m_terms;
+    }
+
+    double constant() const
+    {
+        return m_constant;
+    }
+
+    double value() const
+    {
+        typedef std::vector<Term>::const_iterator iter_t;
+        double result = m_constant;
+        iter_t end = m_terms.end();
+        for (iter_t it = m_terms.begin(); it != end; ++it)
+            result += it->value();
+        return result;
+    }
+
+private:
+    std::vector<Term> m_terms;
+    double m_constant;
+};
+
+} // namespace kiwi