1 /* 2 * Copyright (c) 2001, 2003, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 package sun.jvm.hotspot.interpreter; 26 27 import sun.jvm.hotspot.oops.*; 28 import sun.jvm.hotspot.utilities.*; 29 30 public class BytecodeTableswitch extends Bytecode { BytecodeTableswitch(Method method, int bci)31 BytecodeTableswitch(Method method, int bci) { 32 super(method, bci); 33 } 34 35 36 // Attributes defaultOffset()37 public int defaultOffset() { return javaSignedWordAt(alignedOffset(1 + 0*jintSize)); } lowKey()38 public int lowKey() { return javaSignedWordAt(alignedOffset(1 + 1*jintSize)); } highKey()39 public int highKey() { return javaSignedWordAt(alignedOffset(1 + 2*jintSize)); } length()40 public int length() { return highKey()-lowKey()+1; } destOffsetAt(int i)41 public int destOffsetAt(int i) { 42 int x2 = alignedOffset(1 + (3 + i)*jintSize); 43 int val = javaSignedWordAt(x2); 44 return javaSignedWordAt(alignedOffset(1 + (3 + i)*jintSize)); 45 } 46 verify()47 public void verify() { 48 if (Assert.ASSERTS_ENABLED) { 49 Assert.that(isValid(), "check tableswitch"); 50 } 51 } 52 isValid()53 public boolean isValid() { 54 boolean result = javaCode() == Bytecodes._tableswitch; 55 if (result == false) return false; 56 int lo = lowKey(); 57 int hi = highKey(); 58 if (hi < lo) // incorrect hi/lo values in tableswitch 59 return false; 60 61 int i = hi - lo - 1 ; 62 while (i-- > 0) { 63 // no special check needed 64 } 65 return true; 66 } 67 at(Method method, int bci)68 public static BytecodeTableswitch at(Method method, int bci) { 69 BytecodeTableswitch b = new BytecodeTableswitch(method, bci); 70 if (Assert.ASSERTS_ENABLED) { 71 b.verify(); 72 } 73 return b; 74 } 75 76 /** Like at, but returns null if the BCI is not at tableswitch */ atCheck(Method method, int bci)77 public static BytecodeTableswitch atCheck(Method method, int bci) { 78 BytecodeTableswitch b = new BytecodeTableswitch(method, bci); 79 return (b.isValid() ? b : null); 80 } 81 at(BytecodeStream bcs)82 public static BytecodeTableswitch at(BytecodeStream bcs) { 83 return new BytecodeTableswitch(bcs.method(), bcs.bci()); 84 } 85 toString()86 public String toString() { 87 StringBuffer buf = new StringBuffer(); 88 buf.append("tableswitch"); 89 buf.append(spaces); 90 buf.append("default: "); 91 buf.append(Integer.toString(bci() + defaultOffset())); 92 buf.append(comma); 93 int lo = lowKey(); 94 int hi = highKey(); 95 int i = hi - lo - 1 ; 96 while (i-- > 0) { 97 buf.append("case "); 98 buf.append(Integer.toString(lo + i)); 99 buf.append(':'); 100 buf.append(Integer.toString(bci() + destOffsetAt(i))); 101 buf.append(comma); 102 } 103 return buf.toString(); 104 } 105 } 106