Move ConstantTermNormalizer

Library-SMTLIB/src/de/uni_freiburg/informatik/ultimate/util/ConstantTermNormalizer.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2009-2012 University of Freiburg
+ *
+ * This file is part of SMTInterpol.
+ *
+ * SMTInterpol 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * SMTInterpol 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 SMTInterpol.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.uni_freiburg.informatik.ultimate.util;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+import de.uni_freiburg.informatik.ultimate.logic.ConstantTerm;
+import de.uni_freiburg.informatik.ultimate.logic.Rational;
+import de.uni_freiburg.informatik.ultimate.logic.Term;
+import de.uni_freiburg.informatik.ultimate.logic.TermTransformer;
+
+/**
+ * {@link ConstantTerm}s that have numeric sort (Int, Real) can represent their
+ * value either as {@link BigInteger}, {@link BigDecimal}, or {@link Rational}.
+ * This class helps us to establish a normal form in which values are always
+ * represented by {@link Rational}s.
+ *
+ * @author Matthias Heizmann ([email protected]>)
+ *
+ */
+public class ConstantTermNormalizer extends TermTransformer {
+
+	@Override
+	protected void convert(final Term term) {
+		if (term instanceof ConstantTerm) {
+			final Term res;
+			final ConstantTerm ct = (ConstantTerm) term;
+			res = convertConstantTerm(ct);
+			setResult(res);
+		} else {
+			super.convert(term);
+		}
+	}
+
+	private static Term convertConstantTerm(final ConstantTerm ct) {
+		if (!ct.getSort().isNumericSort()) {
+			// do nothing, only applicable to numeric sorts
+			return ct;
+		}
+		if (ct.getValue() instanceof BigInteger) {
+			final Rational rat = Rational.valueOf((BigInteger) ct.getValue(), BigInteger.ONE);
+			return rat.toTerm(ct.getSort());
+		} else if (ct.getValue() instanceof BigDecimal) {
+			final BigDecimal decimal = (BigDecimal) ct.getValue();
+			Rational rat;
+			if (decimal.scale() <= 0) {
+				final BigInteger num = decimal.toBigInteger();
+				rat = Rational.valueOf(num, BigInteger.ONE);
+			} else {
+				final BigInteger num = decimal.unscaledValue();
+				final BigInteger denom = BigInteger.TEN.pow(decimal.scale());
+				rat = Rational.valueOf(num, denom);
+			}
+			return rat.toTerm(ct.getSort());
+		} else if (ct.getValue() instanceof Rational) {
+			// do nothing, already in normal form
+			return ct;
+		} else {
+			throw new AssertionError("Value has to be either BigInteger, Decimal, or Rational");
+		}
+	}
+
+}