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