gecko-dev/js/rhino/org/mozilla/javascript/Label.java
1999-04-19 20:43:53 +00:00

88 lines
2.6 KiB
Java

/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1997-1999 Netscape Communications Corporation. All Rights
* Reserved.
*/
package org.mozilla.javascript;
public class Label {
private static final int FIXUPTABLE_SIZE = 8;
private static final boolean DEBUG = true;
public Label()
{
itsPC = -1;
}
public short getPC()
{
return itsPC;
}
public void fixGotos(byte theCodeBuffer[])
{
if (DEBUG) {
if ((itsPC == -1) && (itsFixupTable != null))
throw new RuntimeException("Unlocated label");
}
if (itsFixupTable != null) {
for (int i = 0; i < itsFixupTableTop; i++) {
int fixupSite = itsFixupTable[i];
// -1 to get delta from instruction start
short offset = (short)(itsPC - (fixupSite - 1));
theCodeBuffer[fixupSite++] = (byte)(offset >> 8);
theCodeBuffer[fixupSite] = (byte)offset;
}
}
itsFixupTable = null;
}
public void setPC(short thePC)
{
if (DEBUG) {
if ((itsPC != -1) && (itsPC != thePC))
throw new RuntimeException("Duplicate label");
}
itsPC = thePC;
}
public void addFixup(int fixupSite)
{
if (itsFixupTable == null) {
itsFixupTableTop = 1;
itsFixupTable = new int[FIXUPTABLE_SIZE];
itsFixupTable[0] = fixupSite;
}
else {
if (itsFixupTableTop == itsFixupTable.length) {
int oldLength = itsFixupTable.length;
int newTable[] = new int[oldLength + FIXUPTABLE_SIZE];
System.arraycopy(itsFixupTable, 0, newTable, 0, oldLength);
itsFixupTable = newTable;
}
itsFixupTable[itsFixupTableTop++] = fixupSite;
}
}
private short itsPC;
private int itsFixupTable[];
private int itsFixupTableTop;
}