/******************************************************************************
* Copyright (c) 2002 - 2014 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*****************************************************************************/
/*
* Copyright (c) 2013,
* Tobias Blaschke <code@tobiasblaschke.de>
* All rights reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The names of the contributors may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package com.ibm.wala.util;
import com.ibm.wala.types.TypeReference;
import com.ibm.wala.types.TypeName;
import java.util.Map;
import java.util.EnumMap;
import java.util.HashMap;
/**
* Offers checks like ClassHierarchy.isAssignable but for primitives.
*
* This Class does not consider Boxing / Unboxing
*
* @author Tobias Blaschke <code@tobiasblaschke.de>
* @since 2013-11-21
*/
public class PrimitiveAssignability {
public static enum AssignabilityKind {
IDENTITY,
WIDENING,
NARROWING,
WIDENING_NARROWING,
UNASSIGNABLE
}
private static enum Primitive {
BOOLEAN,
CHAR,
BYTE,
SHORT,
INT,
LONG,
FLOAT,
DOUBLE
}
private static final Map<Primitive, Map<Primitive, AssignabilityKind>> assignability =
new EnumMap<Primitive, Map<Primitive, AssignabilityKind>>(Primitive.class);
static {
// fill assignability
for (final Primitive t : Primitive.values()) {
final Map<Primitive, AssignabilityKind> addendum = new EnumMap<Primitive, AssignabilityKind>(Primitive.class);
addendum.put(t, AssignabilityKind.IDENTITY);
assignability.put(t, addendum);
}
putWidening(Primitive.BYTE, Primitive.SHORT);
putWidening(Primitive.BYTE, Primitive.INT);
putWidening(Primitive.BYTE, Primitive.LONG);
putWidening(Primitive.BYTE, Primitive.FLOAT);
putWidening(Primitive.BYTE, Primitive.DOUBLE);
putWidening(Primitive.SHORT, Primitive.INT);
putWidening(Primitive.SHORT, Primitive.LONG);
putWidening(Primitive.SHORT, Primitive.FLOAT);
putWidening(Primitive.SHORT, Primitive.DOUBLE);
putWidening(Primitive.CHAR, Primitive.INT);
putWidening(Primitive.CHAR, Primitive.LONG);
putWidening(Primitive.CHAR, Primitive.FLOAT);
putWidening(Primitive.CHAR, Primitive.DOUBLE);
putWidening(Primitive.INT, Primitive.LONG);
putWidening(Primitive.INT, Primitive.FLOAT);
putWidening(Primitive.INT, Primitive.DOUBLE);
putWidening(Primitive.LONG, Primitive.FLOAT);
putWidening(Primitive.LONG, Primitive.DOUBLE);
putWidening(Primitive.FLOAT, Primitive.DOUBLE);
putNarrowing(Primitive.SHORT, Primitive.BYTE);
putNarrowing(Primitive.SHORT, Primitive.CHAR);
putNarrowing(Primitive.CHAR, Primitive.BYTE);
putNarrowing(Primitive.CHAR, Primitive.SHORT);
putNarrowing(Primitive.INT, Primitive.BYTE);
putNarrowing(Primitive.INT, Primitive.SHORT);
putNarrowing(Primitive.INT, Primitive.CHAR);
putNarrowing(Primitive.LONG, Primitive.BYTE);
putNarrowing(Primitive.LONG, Primitive.SHORT);
putNarrowing(Primitive.LONG, Primitive.CHAR);
putNarrowing(Primitive.LONG, Primitive.INT);
putNarrowing(Primitive.FLOAT, Primitive.BYTE);
putNarrowing(Primitive.FLOAT, Primitive.SHORT);
putNarrowing(Primitive.FLOAT, Primitive.CHAR);
putNarrowing(Primitive.FLOAT, Primitive.INT);
putNarrowing(Primitive.FLOAT, Primitive.LONG);
putNarrowing(Primitive.DOUBLE, Primitive.BYTE);
putNarrowing(Primitive.DOUBLE, Primitive.SHORT);
putNarrowing(Primitive.DOUBLE, Primitive.CHAR);
putNarrowing(Primitive.DOUBLE, Primitive.INT);
putNarrowing(Primitive.DOUBLE, Primitive.LONG);
putNarrowing(Primitive.DOUBLE, Primitive.FLOAT);
assignability.get(Primitive.BYTE).put(Primitive.CHAR, AssignabilityKind.WIDENING_NARROWING);
}
private static void putNarrowing(final Primitive from, final Primitive to) {
assert (! assignability.get(from).containsKey(to));
assignability.get(from).put(to, AssignabilityKind.NARROWING);
}
private static void putWidening(final Primitive from, final Primitive to) {
assert (! assignability.get(from).containsKey(to));
assignability.get(from).put(to, AssignabilityKind.WIDENING);
}
private static final Map<TypeName, Primitive> namePrimitiveMap = new HashMap<TypeName, Primitive>();
static {
// fill namePrimitiveMap
namePrimitiveMap.put(TypeReference.BooleanName, Primitive.BOOLEAN);
namePrimitiveMap.put(TypeReference.ByteName, Primitive.BYTE);
namePrimitiveMap.put(TypeReference.CharName, Primitive.CHAR);
namePrimitiveMap.put(TypeReference.DoubleName, Primitive.DOUBLE);
namePrimitiveMap.put(TypeReference.FloatName, Primitive.FLOAT);
namePrimitiveMap.put(TypeReference.IntName, Primitive.INT);
namePrimitiveMap.put(TypeReference.LongName, Primitive.LONG);
namePrimitiveMap.put(TypeReference.ShortName, Primitive.SHORT);
}
/**
* Is information lost on c1 x := c2 y?
*/
public static AssignabilityKind getAssignableFrom(TypeName from, TypeName to) {
final Primitive f = namePrimitiveMap.get(from);
final Primitive t = namePrimitiveMap.get(to);
if (assignability.get(f).containsKey(t)) {
return assignability.get(f).get(t);
} else {
return AssignabilityKind.UNASSIGNABLE;
}
}
/**
* Does an expression c1 x := c2 y typecheck?
*/
public static boolean isAssignableFrom(TypeName from, TypeName to) {
return getAssignableFrom(from, to) != AssignabilityKind.UNASSIGNABLE;
}
}