- package com.sun.org.apache.bcel.internal.generic;
-
- /* ====================================================================
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 2001 The Apache Software Foundation. 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 end-user documentation included with the redistribution,
- * if any, must include the following acknowledgment:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowledgment may appear in the software itself,
- * if and wherever such third-party acknowledgments normally appear.
- *
- * 4. The names "Apache" and "Apache Software Foundation" and
- * "Apache BCEL" must not be used to endorse or promote products
- * derived from this software without prior written permission. For
- * written permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache",
- * "Apache BCEL", nor may "Apache" appear in their name, without
- * prior written permission of the Apache Software Foundation.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
- * ITS 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.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation. For more
- * information on the Apache Software Foundation, please see
- * <http://www.apache.org/>.
- */
-
- /**
- * SWITCH - Branch depending on int value, generates either LOOKUPSWITCH or
- * TABLESWITCH instruction, depending on whether the match values (int[]) can be
- * sorted with no gaps between the numbers.
- *
- * @version $Id: SWITCH.java,v 1.1.1.1 2001/10/29 20:00:27 jvanzyl Exp $
- * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
- */
- public final class SWITCH implements CompoundInstruction {
- private int[] match;
- private InstructionHandle[] targets;
- private Select instruction;
- private int match_length;
-
- /**
- * Template for switch() constructs. If the match array can be
- * sorted in ascending order with gaps no larger than max_gap
- * between the numbers, a TABLESWITCH instruction is generated, and
- * a LOOKUPSWITCH otherwise. The former may be more efficient, but
- * needs more space.
- *
- * Note, that the key array always will be sorted, though we leave
- * the original arrays unaltered.
- *
- * @param match array of match values (case 2: ... case 7: ..., etc.)
- * @param targets the instructions to be branched to for each case
- * @param target the default target
- * @param max_gap maximum gap that may between case branches
- */
- public SWITCH(int[] match, InstructionHandle[] targets,
- InstructionHandle target, int max_gap) {
- this.match = (int[])match.clone();
- this.targets = (InstructionHandle[])targets.clone();
-
- if((match_length = match.length) < 2) // (almost) empty switch, or just default
- instruction = new TABLESWITCH(match, targets, target);
- else {
- sort(0, match_length - 1);
-
- if(matchIsOrdered(max_gap)) {
- fillup(max_gap, target);
-
- instruction = new TABLESWITCH(this.match, this.targets, target);
- }
- else
- instruction = new LOOKUPSWITCH(this.match, this.targets, target);
- }
- }
-
- public SWITCH(int[] match, InstructionHandle[] targets,
- InstructionHandle target) {
- this(match, targets, target, 1);
- }
-
- private final void fillup(int max_gap, InstructionHandle target) {
- int max_size = match_length + match_length * max_gap;
- int[] m_vec = new int[max_size];
- InstructionHandle[] t_vec = new InstructionHandle[max_size];
- int count = 1;
-
- m_vec[0] = match[0];
- t_vec[0] = targets[0];
-
- for(int i=1; i < match_length; i++) {
- int prev = match[i-1];
- int gap = match[i] - prev;
-
- for(int j=1; j < gap; j++) {
- m_vec[count] = prev + j;
- t_vec[count] = target;
- count++;
- }
-
- m_vec[count] = match[i];
- t_vec[count] = targets[i];
- count++;
- }
-
- match = new int[count];
- targets = new InstructionHandle[count];
-
- System.arraycopy(m_vec, 0, match, 0, count);
- System.arraycopy(t_vec, 0, targets, 0, count);
- }
-
- /**
- * Sort match and targets array with QuickSort.
- */
- private final void sort(int l, int r) {
- int i = l, j = r;
- int h, m = match[(l + r) / 2];
- InstructionHandle h2;
-
- do {
- while(match[i] < m) i++;
- while(m < match[j]) j--;
-
- if(i <= j) {
- h=match[i]; match[i]=match[j]; match[j]=h; // Swap elements
- h2=targets[i]; targets[i]=targets[j]; targets[j]=h2; // Swap instructions, too
- i++; j--;
- }
- } while(i <= j);
-
- if(l < j) sort(l, j);
- if(i < r) sort(i, r);
- }
-
- /**
- * @return match is sorted in ascending order with no gap bigger than max_gap?
- */
- private final boolean matchIsOrdered(int max_gap) {
- for(int i=1; i < match_length; i++)
- if(match[i] - match[i-1] > max_gap)
- return false;
-
- return true;
- }
-
- public final InstructionList getInstructionList() {
- return new InstructionList(instruction);
- }
-
- public final Instruction getInstruction() {
- return instruction;
- }
- }