- /*
- * Copyright 2001-2004 The Apache Software Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- /*
- * $Id: SlotAllocator.java,v 1.6 2004/02/16 22:26:44 minchau Exp $
- */
-
- package com.sun.org.apache.xalan.internal.xsltc.compiler.util;
-
- import com.sun.org.apache.bcel.internal.generic.LocalVariableGen;
- import com.sun.org.apache.bcel.internal.generic.Type;
-
- /**
- * @author Jacek Ambroziak
- */
- final class SlotAllocator {
-
- private int _firstAvailableSlot;
- private int _size = 8;
- private int _free = 0;
- private int[] _slotsTaken = new int[_size];
-
- public void initialize(LocalVariableGen[] vars) {
- final int length = vars.length;
- int slot = 0, size, index;
-
- for (int i = 0; i < length; i++) {
- size = vars[i].getType().getSize();
- index = vars[i].getIndex();
- slot = Math.max(slot, index + size);
- }
- _firstAvailableSlot = slot;
- }
-
- public int allocateSlot(Type type) {
- final int size = type.getSize();
- final int limit = _free;
- int slot = _firstAvailableSlot, where = 0;
-
- if (_free + size > _size) {
- final int[] array = new int[_size *= 2];
- for (int j = 0; j < limit; j++)
- array[j] = _slotsTaken[j];
- _slotsTaken = array;
- }
-
- while (where < limit) {
- if (slot + size <= _slotsTaken[where]) {
- // insert
- for (int j = limit - 1; j >= where; j--)
- _slotsTaken[j + size] = _slotsTaken[j];
- break;
- }
- else {
- slot = _slotsTaken[where++] + 1;
- }
- }
-
- for (int j = 0; j < size; j++)
- _slotsTaken[where + j] = slot + j;
-
- _free += size;
- return slot;
- }
-
- public void releaseSlot(LocalVariableGen lvg) {
- final int size = lvg.getType().getSize();
- final int slot = lvg.getIndex();
- final int limit = _free;
-
- for (int i = 0; i < limit; i++) {
- if (_slotsTaken[i] == slot) {
- int j = i + size;
- while (j < limit) {
- _slotsTaken[i++] = _slotsTaken[j++];
- }
- _free -= size;
- return;
- }
- }
- String state = "Variable slot allocation error"+
- "(size="+size+", slot="+slot+", limit="+limit+")";
- ErrorMsg err = new ErrorMsg(ErrorMsg.INTERNAL_ERR, state);
- throw new Error(err.toString());
- }
- }