/*
* xtc - The eXTensible Compiler
* Copyright (C) 2006-2007 Robert Grimm
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*/
package xtc.type;
import java.io.IOException;
import java.math.BigInteger;
/**
* Representation of an index reference.
*
* @author Robert Grimm
* @version $Revision: 1.8 $
*/
public class IndexReference extends RelativeReference {
/** The index. */
final BigInteger index;
/**
* Create a new index reference.
*
* @param base The base reference.
* @param index The index.
*/
public IndexReference(Reference base, BigInteger index) {
super(base.type, base);
this.index = index;
}
/**
* Create a new index reference.
*
* @param type The type.
* @param base The base.
* @param index The index.
*/
IndexReference(Type type, Reference base, BigInteger index) {
super(type, base);
this.index = index;
}
public boolean isNull() {
return 0 == index.signum() ? base.isNull() : false;
}
public boolean hasIndex() {
return true;
}
public BigInteger getIndex() {
return index;
}
public boolean hasLocation() {
return base.hasLocation();
}
public BigInteger getLocation(C ops) {
if (! base.hasLocation()) throw new IllegalStateException();
return base.getLocation(ops).
add(index.multiply(BigInteger.valueOf(ops.getSize(type))));
}
public Reference add(BigInteger val) {
if (val.signum() == 0) {
return this;
} else {
return new IndexReference(type, base, index.add(val));
}
}
public Reference subtract(BigInteger val) {
if (val.signum() == 0) {
return this;
} else {
return new IndexReference(type, base, index.subtract(val));
}
}
public int hashCode() {
return index.hashCode();
}
public boolean equals(Object o) {
if (this == o) return true;
if (! (o instanceof IndexReference)) return false;
IndexReference other = (IndexReference)o;
return (this.index.equals(other.index) &&
this.base.equals(other.base) &&
this.type.equals(other.type));
}
/** The minimum limit for decimal printouts. */
private static final BigInteger MIN = BigInteger.valueOf(-255);
/** The maximum limit for decimal printouts. */
private static final BigInteger MAX = BigInteger.valueOf(255);
public void write(Appendable out) throws IOException {
if (base.isPrefix()) out.append('(');
base.write(out);
if (base.isPrefix()) out.append(')');
out.append('[');
if ((MIN.compareTo(index) <= 0) && (index.compareTo(MAX) <= 0)) {
out.append(index.toString());
} else if (-1 == index.signum()) {
out.append("-0x");
out.append(index.negate().toString(16));
} else {
out.append("0x");
out.append(index.toString(16));
}
out.append(']');
}
}