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1   /*
2    * Copyright  2000-2004 The Apache Software Foundation
3    *
4    *  Licensed under the Apache License, Version 2.0 (the "License"); 
5    *  you may not use this file except in compliance with the License.
6    *  You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   *  Unless required by applicable law or agreed to in writing, software
11   *  distributed under the License is distributed on an "AS IS" BASIS,
12   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   *  See the License for the specific language governing permissions and
14   *  limitations under the License. 
15   *
16   */
17  package org.apache.bcel.classfile;
18  
19  import java.io.ByteArrayInputStream;
20  import java.io.ByteArrayOutputStream;
21  import java.io.CharArrayReader;
22  import java.io.CharArrayWriter;
23  import java.io.FilterReader;
24  import java.io.FilterWriter;
25  import java.io.IOException;
26  import java.io.PrintStream;
27  import java.io.PrintWriter;
28  import java.io.Reader;
29  import java.io.Writer;
30  import java.util.ArrayList;
31  import java.util.List;
32  import java.util.Locale;
33  import java.util.zip.GZIPInputStream;
34  import java.util.zip.GZIPOutputStream;
35  import org.apache.bcel.Constants;
36  import org.apache.bcel.util.ByteSequence;
37  
38  /***
39   * Utility functions that do not really belong to any class in particular.
40   *
41   * @version $Id: Utility.java 386056 2006-03-15 11:31:56Z tcurdt $
42   * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
43   */
44  public abstract class Utility {
45  
46      private static int unwrap( ThreadLocal tl ) {
47          return ((Integer) tl.get()).intValue();
48      }
49  
50  
51      private static void wrap( ThreadLocal tl, int value ) {
52          tl.set(new Integer(value));
53      }
54  
55      private static ThreadLocal consumed_chars = new ThreadLocal() {
56  
57          protected Object initialValue() {
58              return new Integer(0);
59          }
60      };/* How many chars have been consumed
61       * during parsing in signatureToString().
62       * Read by methodSignatureToString().
63       * Set by side effect,but only internally.
64       */
65      private static boolean wide = false; /* The `WIDE' instruction is used in the
66       * byte code to allow 16-bit wide indices
67       * for local variables. This opcode
68       * precedes an `ILOAD', e.g.. The opcode
69       * immediately following takes an extra
70       * byte which is combined with the
71       * following byte to form a
72       * 16-bit value.
73       */
74  
75  
76      /***
77       * Convert bit field of flags into string such as `static final'.
78       *
79       * @param  access_flags Access flags
80       * @return String representation of flags
81       */
82      public static final String accessToString( int access_flags ) {
83          return accessToString(access_flags, false);
84      }
85  
86  
87      /***
88       * Convert bit field of flags into string such as `static final'.
89       *
90       * Special case: Classes compiled with new compilers and with the
91       * `ACC_SUPER' flag would be said to be "synchronized". This is
92       * because SUN used the same value for the flags `ACC_SUPER' and
93       * `ACC_SYNCHRONIZED'. 
94       *
95       * @param  access_flags Access flags
96       * @param  for_class access flags are for class qualifiers ?
97       * @return String representation of flags
98       */
99      public static final String accessToString( int access_flags, boolean for_class ) {
100         StringBuffer buf = new StringBuffer();
101         int p = 0;
102         for (int i = 0; p < Constants.MAX_ACC_FLAG; i++) { // Loop through known flags
103             p = pow2(i);
104             if ((access_flags & p) != 0) {
105                 /* Special case: Classes compiled with new compilers and with the
106                  * `ACC_SUPER' flag would be said to be "synchronized". This is
107                  * because SUN used the same value for the flags `ACC_SUPER' and
108                  * `ACC_SYNCHRONIZED'.
109                  */
110                 if (for_class && ((p == Constants.ACC_SUPER) || (p == Constants.ACC_INTERFACE))) {
111                     continue;
112                 }
113                 buf.append(Constants.ACCESS_NAMES[i]).append(" ");
114             }
115         }
116         return buf.toString().trim();
117     }
118 
119 
120     /***
121      * @return "class" or "interface", depending on the ACC_INTERFACE flag
122      */
123     public static final String classOrInterface( int access_flags ) {
124         return ((access_flags & Constants.ACC_INTERFACE) != 0) ? "interface" : "class";
125     }
126 
127 
128     /***
129      * Disassemble a byte array of JVM byte codes starting from code line 
130      * `index' and return the disassembled string representation. Decode only
131      * `num' opcodes (including their operands), use -1 if you want to
132      * decompile everything.
133      *
134      * @param  code byte code array
135      * @param  constant_pool Array of constants
136      * @param  index offset in `code' array
137      * <EM>(number of opcodes, not bytes!)</EM>
138      * @param  length number of opcodes to decompile, -1 for all
139      * @param  verbose be verbose, e.g. print constant pool index
140      * @return String representation of byte codes
141      */
142     public static final String codeToString( byte[] code, ConstantPool constant_pool, int index,
143             int length, boolean verbose ) {
144         StringBuffer buf = new StringBuffer(code.length * 20); // Should be sufficient
145         ByteSequence stream = new ByteSequence(code);
146         try {
147             for (int i = 0; i < index; i++) {
148                 codeToString(stream, constant_pool, verbose);
149             }
150             for (int i = 0; stream.available() > 0; i++) {
151                 if ((length < 0) || (i < length)) {
152                     String indices = fillup(stream.getIndex() + ":", 6, true, ' ');
153                     buf.append(indices).append(codeToString(stream, constant_pool, verbose))
154                             .append('\n');
155                 }
156             }
157         } catch (IOException e) {
158             System.out.println(buf.toString());
159             e.printStackTrace();
160             throw new ClassFormatException("Byte code error: " + e);
161         }
162         return buf.toString();
163     }
164 
165 
166     public static final String codeToString( byte[] code, ConstantPool constant_pool, int index,
167             int length ) {
168         return codeToString(code, constant_pool, index, length, true);
169     }
170 
171 
172     /***
173      * Disassemble a stream of byte codes and return the
174      * string representation.
175      *
176      * @param  bytes stream of bytes
177      * @param  constant_pool Array of constants
178      * @param  verbose be verbose, e.g. print constant pool index
179      * @return String representation of byte code
180      */
181     public static final String codeToString( ByteSequence bytes, ConstantPool constant_pool,
182             boolean verbose ) throws IOException {
183         short opcode = (short) bytes.readUnsignedByte();
184         int default_offset = 0, low, high, npairs;
185         int index, vindex, constant;
186         int[] match, jump_table;
187         int no_pad_bytes = 0, offset;
188         StringBuffer buf = new StringBuffer(Constants.OPCODE_NAMES[opcode]);
189         /* Special case: Skip (0-3) padding bytes, i.e., the
190          * following bytes are 4-byte-aligned
191          */
192         if ((opcode == Constants.TABLESWITCH) || (opcode == Constants.LOOKUPSWITCH)) {
193             int remainder = bytes.getIndex() % 4;
194             no_pad_bytes = (remainder == 0) ? 0 : 4 - remainder;
195             for (int i = 0; i < no_pad_bytes; i++) {
196                 byte b;
197                 if ((b = bytes.readByte()) != 0) {
198                     System.err.println("Warning: Padding byte != 0 in "
199                             + Constants.OPCODE_NAMES[opcode] + ":" + b);
200                 }
201             }
202             // Both cases have a field default_offset in common
203             default_offset = bytes.readInt();
204         }
205         switch (opcode) {
206             /* Table switch has variable length arguments.
207              */
208             case Constants.TABLESWITCH:
209                 low = bytes.readInt();
210                 high = bytes.readInt();
211                 offset = bytes.getIndex() - 12 - no_pad_bytes - 1;
212                 default_offset += offset;
213                 buf.append("\tdefault = ").append(default_offset).append(", low = ").append(low)
214                         .append(", high = ").append(high).append("(");
215                 jump_table = new int[high - low + 1];
216                 for (int i = 0; i < jump_table.length; i++) {
217                     jump_table[i] = offset + bytes.readInt();
218                     buf.append(jump_table[i]);
219                     if (i < jump_table.length - 1) {
220                         buf.append(", ");
221                     }
222                 }
223                 buf.append(")");
224                 break;
225             /* Lookup switch has variable length arguments.
226              */
227             case Constants.LOOKUPSWITCH: {
228                 npairs = bytes.readInt();
229                 offset = bytes.getIndex() - 8 - no_pad_bytes - 1;
230                 match = new int[npairs];
231                 jump_table = new int[npairs];
232                 default_offset += offset;
233                 buf.append("\tdefault = ").append(default_offset).append(", npairs = ").append(
234                         npairs).append(" (");
235                 for (int i = 0; i < npairs; i++) {
236                     match[i] = bytes.readInt();
237                     jump_table[i] = offset + bytes.readInt();
238                     buf.append("(").append(match[i]).append(", ").append(jump_table[i]).append(")");
239                     if (i < npairs - 1) {
240                         buf.append(", ");
241                     }
242                 }
243                 buf.append(")");
244             }
245                 break;
246             /* Two address bytes + offset from start of byte stream form the
247              * jump target
248              */
249             case Constants.GOTO:
250             case Constants.IFEQ:
251             case Constants.IFGE:
252             case Constants.IFGT:
253             case Constants.IFLE:
254             case Constants.IFLT:
255             case Constants.JSR:
256             case Constants.IFNE:
257             case Constants.IFNONNULL:
258             case Constants.IFNULL:
259             case Constants.IF_ACMPEQ:
260             case Constants.IF_ACMPNE:
261             case Constants.IF_ICMPEQ:
262             case Constants.IF_ICMPGE:
263             case Constants.IF_ICMPGT:
264             case Constants.IF_ICMPLE:
265             case Constants.IF_ICMPLT:
266             case Constants.IF_ICMPNE:
267                 buf.append("\t\t#").append((bytes.getIndex() - 1) + bytes.readShort());
268                 break;
269             /* 32-bit wide jumps
270              */
271             case Constants.GOTO_W:
272             case Constants.JSR_W:
273                 buf.append("\t\t#").append(((bytes.getIndex() - 1) + bytes.readInt()));
274                 break;
275             /* Index byte references local variable (register)
276              */
277             case Constants.ALOAD:
278             case Constants.ASTORE:
279             case Constants.DLOAD:
280             case Constants.DSTORE:
281             case Constants.FLOAD:
282             case Constants.FSTORE:
283             case Constants.ILOAD:
284             case Constants.ISTORE:
285             case Constants.LLOAD:
286             case Constants.LSTORE:
287             case Constants.RET:
288                 if (wide) {
289                     vindex = bytes.readUnsignedShort();
290                     wide = false; // Clear flag
291                 } else {
292                     vindex = bytes.readUnsignedByte();
293                 }
294                 buf.append("\t\t%").append(vindex);
295                 break;
296             /*
297              * Remember wide byte which is used to form a 16-bit address in the
298              * following instruction. Relies on that the method is called again with
299              * the following opcode.
300              */
301             case Constants.WIDE:
302                 wide = true;
303                 buf.append("\t(wide)");
304                 break;
305             /* Array of basic type.
306              */
307             case Constants.NEWARRAY:
308                 buf.append("\t\t<").append(Constants.TYPE_NAMES[bytes.readByte()]).append(">");
309                 break;
310             /* Access object/class fields.
311              */
312             case Constants.GETFIELD:
313             case Constants.GETSTATIC:
314             case Constants.PUTFIELD:
315             case Constants.PUTSTATIC:
316                 index = bytes.readUnsignedShort();
317                 buf.append("\t\t").append(
318                         constant_pool.constantToString(index, Constants.CONSTANT_Fieldref)).append(
319                         (verbose ? " (" + index + ")" : ""));
320                 break;
321             /* Operands are references to classes in constant pool
322              */
323             case Constants.NEW:
324             case Constants.CHECKCAST:
325                 buf.append("\t");
326             case Constants.INSTANCEOF:
327                 index = bytes.readUnsignedShort();
328                 buf.append("\t<").append(
329                         constant_pool.constantToString(index, Constants.CONSTANT_Class))
330                         .append(">").append((verbose ? " (" + index + ")" : ""));
331                 break;
332             /* Operands are references to methods in constant pool
333              */
334             case Constants.INVOKESPECIAL:
335             case Constants.INVOKESTATIC:
336             case Constants.INVOKEVIRTUAL:
337                 index = bytes.readUnsignedShort();
338                 buf.append("\t").append(
339                         constant_pool.constantToString(index, Constants.CONSTANT_Methodref))
340                         .append((verbose ? " (" + index + ")" : ""));
341                 break;
342             case Constants.INVOKEINTERFACE:
343                 index = bytes.readUnsignedShort();
344                 int nargs = bytes.readUnsignedByte(); // historical, redundant
345                 buf.append("\t").append(
346                         constant_pool
347                                 .constantToString(index, Constants.CONSTANT_InterfaceMethodref))
348                         .append(verbose ? " (" + index + ")\t" : "").append(nargs).append("\t")
349                         .append(bytes.readUnsignedByte()); // Last byte is a reserved space
350                 break;
351             /* Operands are references to items in constant pool
352              */
353             case Constants.LDC_W:
354             case Constants.LDC2_W:
355                 index = bytes.readUnsignedShort();
356                 buf.append("\t\t").append(
357                         constant_pool.constantToString(index, constant_pool.getConstant(index)
358                                 .getTag())).append((verbose ? " (" + index + ")" : ""));
359                 break;
360             case Constants.LDC:
361                 index = bytes.readUnsignedByte();
362                 buf.append("\t\t").append(
363                         constant_pool.constantToString(index, constant_pool.getConstant(index)
364                                 .getTag())).append((verbose ? " (" + index + ")" : ""));
365                 break;
366             /* Array of references.
367              */
368             case Constants.ANEWARRAY:
369                 index = bytes.readUnsignedShort();
370                 buf.append("\t\t<").append(
371                         compactClassName(constant_pool.getConstantString(index,
372                                 Constants.CONSTANT_Class), false)).append(">").append(
373                         (verbose ? " (" + index + ")" : ""));
374                 break;
375             /* Multidimensional array of references.
376              */
377             case Constants.MULTIANEWARRAY: {
378                 index = bytes.readUnsignedShort();
379                 int dimensions = bytes.readUnsignedByte();
380                 buf.append("\t<").append(
381                         compactClassName(constant_pool.getConstantString(index,
382                                 Constants.CONSTANT_Class), false)).append(">\t").append(dimensions)
383                         .append((verbose ? " (" + index + ")" : ""));
384             }
385                 break;
386             /* Increment local variable.
387              */
388             case Constants.IINC:
389                 if (wide) {
390                     vindex = bytes.readUnsignedShort();
391                     constant = bytes.readShort();
392                     wide = false;
393                 } else {
394                     vindex = bytes.readUnsignedByte();
395                     constant = bytes.readByte();
396                 }
397                 buf.append("\t\t%").append(vindex).append("\t").append(constant);
398                 break;
399             default:
400                 if (Constants.NO_OF_OPERANDS[opcode] > 0) {
401                     for (int i = 0; i < Constants.TYPE_OF_OPERANDS[opcode].length; i++) {
402                         buf.append("\t\t");
403                         switch (Constants.TYPE_OF_OPERANDS[opcode][i]) {
404                             case Constants.T_BYTE:
405                                 buf.append(bytes.readByte());
406                                 break;
407                             case Constants.T_SHORT:
408                                 buf.append(bytes.readShort());
409                                 break;
410                             case Constants.T_INT:
411                                 buf.append(bytes.readInt());
412                                 break;
413                             default: // Never reached
414                                 System.err.println("Unreachable default case reached!");
415                                 System.exit(-1);
416                         }
417                     }
418                 }
419         }
420         return buf.toString();
421     }
422 
423 
424     public static final String codeToString( ByteSequence bytes, ConstantPool constant_pool )
425             throws IOException {
426         return codeToString(bytes, constant_pool, true);
427     }
428 
429 
430     /***
431      * Shorten long class names, <em>java/lang/String</em> becomes 
432      * <em>String</em>.
433      *
434      * @param str The long class name
435      * @return Compacted class name
436      */
437     public static final String compactClassName( String str ) {
438         return compactClassName(str, true);
439     }
440 
441 
442     /***
443      * Shorten long class name <em>str</em>, i.e., chop off the <em>prefix</em>,
444      * if the
445      * class name starts with this string and the flag <em>chopit</em> is true.
446      * Slashes <em>/</em> are converted to dots <em>.</em>.
447      *
448      * @param str The long class name
449      * @param prefix The prefix the get rid off
450      * @param chopit Flag that determines whether chopping is executed or not
451      * @return Compacted class name
452      */
453     public static final String compactClassName( String str, String prefix, boolean chopit ) {
454         int len = prefix.length();
455         str = str.replace('/', '.'); // Is `/' on all systems, even DOS
456         if (chopit) {
457             // If string starts with `prefix' and contains no further dots
458             if (str.startsWith(prefix) && (str.substring(len).indexOf('.') == -1)) {
459                 str = str.substring(len);
460             }
461         }
462         return str;
463     }
464 
465 
466     /***
467      * Shorten long class names, <em>java/lang/String</em> becomes 
468      * <em>java.lang.String</em>,
469      * e.g.. If <em>chopit</em> is <em>true</em> the prefix <em>java.lang</em>
470      * is also removed.
471      *
472      * @param str The long class name
473      * @param chopit Flag that determines whether chopping is executed or not
474      * @return Compacted class name
475      */
476     public static final String compactClassName( String str, boolean chopit ) {
477         return compactClassName(str, "java.lang.", chopit);
478     }
479 
480 
481     /***
482      * @return `flag' with bit `i' set to 1
483      */
484     public static final int setBit( int flag, int i ) {
485         return flag | pow2(i);
486     }
487 
488 
489     /***
490      * @return `flag' with bit `i' set to 0
491      */
492     public static final int clearBit( int flag, int i ) {
493         int bit = pow2(i);
494         return (flag & bit) == 0 ? flag : flag ^ bit;
495     }
496 
497 
498     /***
499      * @return true, if bit `i' in `flag' is set
500      */
501     public static final boolean isSet( int flag, int i ) {
502         return (flag & pow2(i)) != 0;
503     }
504 
505 
506     /***
507      * Converts string containing the method return and argument types 
508      * to a byte code method signature.
509      *
510      * @param  ret Return type of method
511      * @param  argv Types of method arguments
512      * @return Byte code representation of method signature
513      */
514     public final static String methodTypeToSignature( String ret, String[] argv )
515             throws ClassFormatException {
516         StringBuffer buf = new StringBuffer("(");
517         String str;
518         if (argv != null) {
519             for (int i = 0; i < argv.length; i++) {
520                 str = getSignature(argv[i]);
521                 if (str.endsWith("V")) {
522                     throw new ClassFormatException("Invalid type: " + argv[i]);
523                 }
524                 buf.append(str);
525             }
526         }
527         str = getSignature(ret);
528         buf.append(")").append(str);
529         return buf.toString();
530     }
531 
532 
533     /***
534      * @param  signature    Method signature
535      * @return Array of argument types
536      * @throws  ClassFormatException  
537      */
538     public static final String[] methodSignatureArgumentTypes( String signature )
539             throws ClassFormatException {
540         return methodSignatureArgumentTypes(signature, true);
541     }
542 
543 
544     /***
545      * @param  signature    Method signature
546      * @param chopit Shorten class names ?
547      * @return Array of argument types
548      * @throws  ClassFormatException  
549      */
550     public static final String[] methodSignatureArgumentTypes( String signature, boolean chopit )
551             throws ClassFormatException {
552         List vec = new ArrayList();
553         int index;
554         try { // Read all declarations between for `(' and `)'
555             if (signature.charAt(0) != '(') {
556                 throw new ClassFormatException("Invalid method signature: " + signature);
557             }
558             index = 1; // current string position
559             while (signature.charAt(index) != ')') {
560                 vec.add(signatureToString(signature.substring(index), chopit));
561                 //corrected concurrent private static field acess
562                 index += unwrap(consumed_chars); // update position
563             }
564         } catch (StringIndexOutOfBoundsException e) { // Should never occur
565             throw new ClassFormatException("Invalid method signature: " + signature);
566         }
567         return (String[]) vec.toArray(new String[vec.size()]);
568     }
569 
570 
571     /***
572      * @param  signature    Method signature
573      * @return return type of method
574      * @throws  ClassFormatException  
575      */
576     public static final String methodSignatureReturnType( String signature )
577             throws ClassFormatException {
578         return methodSignatureReturnType(signature, true);
579     }
580 
581 
582     /***
583      * @param  signature    Method signature
584      * @param chopit Shorten class names ?
585      * @return return type of method
586      * @throws  ClassFormatException  
587      */
588     public static final String methodSignatureReturnType( String signature, boolean chopit )
589             throws ClassFormatException {
590         int index;
591         String type;
592         try {
593             // Read return type after `)'
594             index = signature.lastIndexOf(')') + 1;
595             type = signatureToString(signature.substring(index), chopit);
596         } catch (StringIndexOutOfBoundsException e) { // Should never occur
597             throw new ClassFormatException("Invalid method signature: " + signature);
598         }
599         return type;
600     }
601 
602 
603     /***
604      * Converts method signature to string with all class names compacted.
605      *
606      * @param signature to convert
607      * @param name of method
608      * @param access flags of method
609      * @return Human readable signature
610      */
611     public static final String methodSignatureToString( String signature, String name, String access ) {
612         return methodSignatureToString(signature, name, access, true);
613     }
614 
615 
616     public static final String methodSignatureToString( String signature, String name,
617             String access, boolean chopit ) {
618         return methodSignatureToString(signature, name, access, chopit, null);
619     }
620 
621 
622     /***
623      * A return?type signature represents the return value from a method.
624      * It is a series of bytes in the following grammar:
625      *
626      * <return_signature> ::= <field_type> | V
627      *
628      * The character V indicates that the method returns no value. Otherwise, the
629      * signature indicates the type of the return value.
630      * An argument signature represents an argument passed to a method:
631      *
632      * <argument_signature> ::= <field_type>
633      *
634      * A method signature represents the arguments that the method expects, and
635      * the value that it returns.
636      * <method_signature> ::= (<arguments_signature>) <return_signature>
637      * <arguments_signature>::= <argument_signature>*
638      *
639      * This method converts such a string into a Java type declaration like
640      * `void main(String[])' and throws a `ClassFormatException' when the parsed 
641      * type is invalid.
642      *
643      * @param  signature    Method signature
644      * @param  name         Method name
645      * @param  access       Method access rights
646      * @return Java type declaration
647      * @throws  ClassFormatException  
648      */
649     public static final String methodSignatureToString( String signature, String name,
650             String access, boolean chopit, LocalVariableTable vars ) throws ClassFormatException {
651         StringBuffer buf = new StringBuffer("(");
652         String type;
653         int index;
654         int var_index = (access.indexOf("static") >= 0) ? 0 : 1;
655         try { // Read all declarations between for `(' and `)'
656             if (signature.charAt(0) != '(') {
657                 throw new ClassFormatException("Invalid method signature: " + signature);
658             }
659             index = 1; // current string position
660             while (signature.charAt(index) != ')') {
661                 String param_type = signatureToString(signature.substring(index), chopit);
662                 buf.append(param_type);
663                 if (vars != null) {
664                     LocalVariable l = vars.getLocalVariable(var_index);
665                     if (l != null) {
666                         buf.append(" ").append(l.getName());
667                     }
668                 } else {
669                     buf.append(" arg").append(var_index);
670                 }
671                 if ("double".equals(param_type) || "long".equals(param_type)) {
672                     var_index += 2;
673                 } else {
674                     var_index++;
675                 }
676                 buf.append(", ");
677                 //corrected concurrent private static field acess
678                 index += unwrap(consumed_chars); // update position
679             }
680             index++; // update position
681             // Read return type after `)'
682             type = signatureToString(signature.substring(index), chopit);
683         } catch (StringIndexOutOfBoundsException e) { // Should never occur
684             throw new ClassFormatException("Invalid method signature: " + signature);
685         }
686         if (buf.length() > 1) {
687             buf.setLength(buf.length() - 2);
688         }
689         buf.append(")");
690         return access + ((access.length() > 0) ? " " : "") + // May be an empty string
691                 type + " " + name + buf.toString();
692     }
693 
694 
695     // Guess what this does
696     private static final int pow2( int n ) {
697         return 1 << n;
698     }
699 
700 
701     /***
702      * Replace all occurences of <em>old</em> in <em>str</em> with <em>new</em>.
703      *
704      * @param str String to permute
705      * @param old String to be replaced
706      * @param new_ Replacement string
707      * @return new String object
708      */
709     public static final String replace( String str, String old, String new_ ) {
710         int index, old_index;
711         StringBuffer buf = new StringBuffer();
712         try {
713             if ((index = str.indexOf(old)) != -1) { // `old' found in str
714                 old_index = 0; // String start offset
715                 // While we have something to replace
716                 while ((index = str.indexOf(old, old_index)) != -1) {
717                     buf.append(str.substring(old_index, index)); // append prefix
718                     buf.append(new_); // append replacement
719                     old_index = index + old.length(); // Skip `old'.length chars
720                 }
721                 buf.append(str.substring(old_index)); // append rest of string
722                 str = buf.toString();
723             }
724         } catch (StringIndexOutOfBoundsException e) { // Should not occur
725             System.err.println(e);
726         }
727         return str;
728     }
729 
730 
731     /***
732      * Converts signature to string with all class names compacted.
733      *
734      * @param signature to convert
735      * @return Human readable signature
736      */
737     public static final String signatureToString( String signature ) {
738         return signatureToString(signature, true);
739     }
740 
741 
742     /***
743      * The field signature represents the value of an argument to a function or 
744      * the value of a variable. It is a series of bytes generated by the 
745      * following grammar:
746      *
747      * <PRE>
748      * <field_signature> ::= <field_type>
749      * <field_type>      ::= <base_type>|<object_type>|<array_type>
750      * <base_type>       ::= B|C|D|F|I|J|S|Z
751      * <object_type>     ::= L<fullclassname>;
752      * <array_type>      ::= [<field_type>
753      *
754      * The meaning of the base types is as follows:
755      * B byte signed byte
756      * C char character
757      * D double double precision IEEE float
758      * F float single precision IEEE float
759      * I int integer
760      * J long long integer
761      * L<fullclassname>; ... an object of the given class
762      * S short signed short
763      * Z boolean true or false
764      * [<field sig> ... array
765      * </PRE>
766      *
767      * This method converts this string into a Java type declaration such as
768      * `String[]' and throws a `ClassFormatException' when the parsed type is 
769      * invalid.
770      *
771      * @param  signature  Class signature
772      * @param chopit Flag that determines whether chopping is executed or not
773      * @return Java type declaration
774      * @throws ClassFormatException
775      */
776     public static final String signatureToString( String signature, boolean chopit ) {
777         //corrected concurrent private static field acess
778         wrap(consumed_chars, 1); // This is the default, read just one char like `B'
779         try {
780             switch (signature.charAt(0)) {
781                 case 'B':
782                     return "byte";
783                 case 'C':
784                     return "char";
785                 case 'D':
786                     return "double";
787                 case 'F':
788                     return "float";
789                 case 'I':
790                     return "int";
791                 case 'J':
792                     return "long";
793                 case 'L': { // Full class name
794                     int index = signature.indexOf(';'); // Look for closing `;'
795                     if (index < 0) {
796                         throw new ClassFormatException("Invalid signature: " + signature);
797                     }
798                     //corrected concurrent private static field acess
799                     wrap(consumed_chars, index + 1); // "Lblabla;" `L' and `;' are removed
800                     return compactClassName(signature.substring(1, index), chopit);
801                 }
802                 case 'S':
803                     return "short";
804                 case 'Z':
805                     return "boolean";
806                 case '[': { // Array declaration
807                     int n;
808                     StringBuffer brackets;
809                     String type;
810                     int consumed_chars; // Shadows global var
811                     brackets = new StringBuffer(); // Accumulate []'s
812                     // Count opening brackets and look for optional size argument
813                     for (n = 0; signature.charAt(n) == '['; n++) {
814                         brackets.append("[]");
815                     }
816                     consumed_chars = n; // Remember value
817                     // The rest of the string denotes a `<field_type>'
818                     type = signatureToString(signature.substring(n), chopit);
819                     //corrected concurrent private static field acess
820                     //Utility.consumed_chars += consumed_chars; is replaced by:
821                     int _temp = unwrap(Utility.consumed_chars) + consumed_chars;
822                     wrap(Utility.consumed_chars, _temp);
823                     return type + brackets.toString();
824                 }
825                 case 'V':
826                     return "void";
827                 default:
828                     throw new ClassFormatException("Invalid signature: `" + signature + "'");
829             }
830         } catch (StringIndexOutOfBoundsException e) { // Should never occur
831             throw new ClassFormatException("Invalid signature: " + e + ":" + signature);
832         }
833     }
834 
835 
836     /*** Parse Java type such as "char", or "java.lang.String[]" and return the
837      * signature in byte code format, e.g. "C" or "[Ljava/lang/String;" respectively.
838      *
839      * @param  type Java type
840      * @return byte code signature
841      */
842     public static String getSignature( String type ) {
843         StringBuffer buf = new StringBuffer();
844         char[] chars = type.toCharArray();
845         boolean char_found = false, delim = false;
846         int index = -1;
847         loop: for (int i = 0; i < chars.length; i++) {
848             switch (chars[i]) {
849                 case ' ':
850                 case '\t':
851                 case '\n':
852                 case '\r':
853                 case '\f':
854                     if (char_found) {
855                         delim = true;
856                     }
857                     break;
858                 case '[':
859                     if (!char_found) {
860                         throw new RuntimeException("Illegal type: " + type);
861                     }
862                     index = i;
863                     break loop;
864                 default:
865                     char_found = true;
866                     if (!delim) {
867                         buf.append(chars[i]);
868                     }
869             }
870         }
871         int brackets = 0;
872         if (index > 0) {
873             brackets = countBrackets(type.substring(index));
874         }
875         type = buf.toString();
876         buf.setLength(0);
877         for (int i = 0; i < brackets; i++) {
878             buf.append('[');
879         }
880         boolean found = false;
881         for (int i = Constants.T_BOOLEAN; (i <= Constants.T_VOID) && !found; i++) {
882             if (Constants.TYPE_NAMES[i].equals(type)) {
883                 found = true;
884                 buf.append(Constants.SHORT_TYPE_NAMES[i]);
885             }
886         }
887         if (!found) {
888             buf.append('L').append(type.replace('.', '/')).append(';');
889         }
890         return buf.toString();
891     }
892 
893 
894     private static int countBrackets( String brackets ) {
895         char[] chars = brackets.toCharArray();
896         int count = 0;
897         boolean open = false;
898         for (int i = 0; i < chars.length; i++) {
899             switch (chars[i]) {
900                 case '[':
901                     if (open) {
902                         throw new RuntimeException("Illegally nested brackets:" + brackets);
903                     }
904                     open = true;
905                     break;
906                 case ']':
907                     if (!open) {
908                         throw new RuntimeException("Illegally nested brackets:" + brackets);
909                     }
910                     open = false;
911                     count++;
912                     break;
913                 default:
914                     // Don't care
915             }
916         }
917         if (open) {
918             throw new RuntimeException("Illegally nested brackets:" + brackets);
919         }
920         return count;
921     }
922 
923 
924     /***
925      * Return type of method signature as a byte value as defined in <em>Constants</em>
926      *
927      * @param  signature in format described above
928      * @return type of method signature
929      * @see    Constants
930      */
931     public static final byte typeOfMethodSignature( String signature ) throws ClassFormatException {
932         int index;
933         try {
934             if (signature.charAt(0) != '(') {
935                 throw new ClassFormatException("Invalid method signature: " + signature);
936             }
937             index = signature.lastIndexOf(')') + 1;
938             return typeOfSignature(signature.substring(index));
939         } catch (StringIndexOutOfBoundsException e) {
940             throw new ClassFormatException("Invalid method signature: " + signature);
941         }
942     }
943 
944 
945     /***
946      * Return type of signature as a byte value as defined in <em>Constants</em>
947      *
948      * @param  signature in format described above
949      * @return type of signature
950      * @see    Constants
951      */
952     public static final byte typeOfSignature( String signature ) throws ClassFormatException {
953         try {
954             switch (signature.charAt(0)) {
955                 case 'B':
956                     return Constants.T_BYTE;
957                 case 'C':
958                     return Constants.T_CHAR;
959                 case 'D':
960                     return Constants.T_DOUBLE;
961                 case 'F':
962                     return Constants.T_FLOAT;
963                 case 'I':
964                     return Constants.T_INT;
965                 case 'J':
966                     return Constants.T_LONG;
967                 case 'L':
968                     return Constants.T_REFERENCE;
969                 case '[':
970                     return Constants.T_ARRAY;
971                 case 'V':
972                     return Constants.T_VOID;
973                 case 'Z':
974                     return Constants.T_BOOLEAN;
975                 case 'S':
976                     return Constants.T_SHORT;
977                 default:
978                     throw new ClassFormatException("Invalid method signature: " + signature);
979             }
980         } catch (StringIndexOutOfBoundsException e) {
981             throw new ClassFormatException("Invalid method signature: " + signature);
982         }
983     }
984 
985 
986     /*** Map opcode names to opcode numbers. E.g., return Constants.ALOAD for "aload"
987      */
988     public static short searchOpcode( String name ) {
989         name = name.toLowerCase(Locale.ENGLISH);
990         for (short i = 0; i < Constants.OPCODE_NAMES.length; i++) {
991             if (Constants.OPCODE_NAMES[i].equals(name)) {
992                 return i;
993             }
994         }
995         return -1;
996     }
997 
998 
999     /***
1000      * Convert (signed) byte to (unsigned) short value, i.e., all negative
1001      * values become positive.
1002      */
1003     private static final short byteToShort( byte b ) {
1004         return (b < 0) ? (short) (256 + b) : (short) b;
1005     }
1006 
1007 
1008     /*** Convert bytes into hexidecimal string
1009      *
1010      * @return bytes as hexidecimal string, e.g. 00 FA 12 ...
1011      */
1012     public static final String toHexString( byte[] bytes ) {
1013         StringBuffer buf = new StringBuffer();
1014         for (int i = 0; i < bytes.length; i++) {
1015             short b = byteToShort(bytes[i]);
1016             String hex = Integer.toString(b, 0x10);
1017             if (b < 0x10) {
1018                 buf.append('0');
1019             }
1020             buf.append(hex);
1021             if (i < bytes.length - 1) {
1022                 buf.append(' ');
1023             }
1024         }
1025         return buf.toString();
1026     }
1027 
1028 
1029     /***
1030      * Return a string for an integer justified left or right and filled up with
1031      * `fill' characters if necessary.
1032      *
1033      * @param i integer to format
1034      * @param length length of desired string
1035      * @param left_justify format left or right
1036      * @param fill fill character
1037      * @return formatted int
1038      */
1039     public static final String format( int i, int length, boolean left_justify, char fill ) {
1040         return fillup(Integer.toString(i), length, left_justify, fill);
1041     }
1042 
1043 
1044     /***
1045      * Fillup char with up to length characters with char `fill' and justify it left or right.
1046      *
1047      * @param str string to format
1048      * @param length length of desired string
1049      * @param left_justify format left or right
1050      * @param fill fill character
1051      * @return formatted string
1052      */
1053     public static final String fillup( String str, int length, boolean left_justify, char fill ) {
1054         int len = length - str.length();
1055         char[] buf = new char[(len < 0) ? 0 : len];
1056         for (int j = 0; j < buf.length; j++) {
1057             buf[j] = fill;
1058         }
1059         if (left_justify) {
1060             return str + new String(buf);
1061         }
1062         return new String(buf) + str;
1063     }
1064 
1065 
1066     static final boolean equals( byte[] a, byte[] b ) {
1067         int size;
1068         if ((size = a.length) != b.length) {
1069             return false;
1070         }
1071         for (int i = 0; i < size; i++) {
1072             if (a[i] != b[i]) {
1073                 return false;
1074             }
1075         }
1076         return true;
1077     }
1078 
1079 
1080     public static final void printArray( PrintStream out, Object[] obj ) {
1081         out.println(printArray(obj, true));
1082     }
1083 
1084 
1085     public static final void printArray( PrintWriter out, Object[] obj ) {
1086         out.println(printArray(obj, true));
1087     }
1088 
1089 
1090     public static final String printArray( Object[] obj ) {
1091         return printArray(obj, true);
1092     }
1093 
1094 
1095     public static final String printArray( Object[] obj, boolean braces ) {
1096         return printArray(obj, braces, false);
1097     }
1098 
1099 
1100     public static final String printArray( Object[] obj, boolean braces, boolean quote ) {
1101         if (obj == null) {
1102             return null;
1103         }
1104         StringBuffer buf = new StringBuffer();
1105         if (braces) {
1106             buf.append('{');
1107         }
1108         for (int i = 0; i < obj.length; i++) {
1109             if (obj[i] != null) {
1110                 buf.append((quote ? "\"" : "")).append(obj[i].toString()).append(
1111                         (quote ? "\"" : ""));
1112             } else {
1113                 buf.append("null");
1114             }
1115             if (i < obj.length - 1) {
1116                 buf.append(", ");
1117             }
1118         }
1119         if (braces) {
1120             buf.append('}');
1121         }
1122         return buf.toString();
1123     }
1124 
1125 
1126     /*** @return true, if character is one of (a, ... z, A, ... Z, 0, ... 9, _)
1127      */
1128     public static boolean isJavaIdentifierPart( char ch ) {
1129         return ((ch >= 'a') && (ch <= 'z')) || ((ch >= 'A') && (ch <= 'Z'))
1130                 || ((ch >= '0') && (ch <= '9')) || (ch == '_');
1131     }
1132 
1133 
1134     /*** Encode byte array it into Java identifier string, i.e., a string
1135      * that only contains the following characters: (a, ... z, A, ... Z,
1136      * 0, ... 9, _, $).  The encoding algorithm itself is not too
1137      * clever: if the current byte's ASCII value already is a valid Java
1138      * identifier part, leave it as it is. Otherwise it writes the
1139      * escape character($) followed by <p><ul><li> the ASCII value as a
1140      * hexadecimal string, if the value is not in the range
1141      * 200..247</li> <li>a Java identifier char not used in a lowercase
1142      * hexadecimal string, if the value is in the range
1143      * 200..247</li><ul></p>
1144      *
1145      * <p>This operation inflates the original byte array by roughly 40-50%</p>
1146      *
1147      * @param bytes the byte array to convert
1148      * @param compress use gzip to minimize string
1149      */
1150     public static String encode( byte[] bytes, boolean compress ) throws IOException {
1151         if (compress) {
1152             ByteArrayOutputStream baos = new ByteArrayOutputStream();
1153             GZIPOutputStream gos = new GZIPOutputStream(baos);
1154             gos.write(bytes, 0, bytes.length);
1155             gos.close();
1156             baos.close();
1157             bytes = baos.toByteArray();
1158         }
1159         CharArrayWriter caw = new CharArrayWriter();
1160         JavaWriter jw = new JavaWriter(caw);
1161         for (int i = 0; i < bytes.length; i++) {
1162             int in = bytes[i] & 0x000000ff; // Normalize to unsigned
1163             jw.write(in);
1164         }
1165         return caw.toString();
1166     }
1167 
1168 
1169     /*** Decode a string back to a byte array.
1170      *
1171      * @param s the string to convert
1172      * @param uncompress use gzip to uncompress the stream of bytes
1173      */
1174     public static byte[] decode( String s, boolean uncompress ) throws IOException {
1175         char[] chars = s.toCharArray();
1176         CharArrayReader car = new CharArrayReader(chars);
1177         JavaReader jr = new JavaReader(car);
1178         ByteArrayOutputStream bos = new ByteArrayOutputStream();
1179         int ch;
1180         while ((ch = jr.read()) >= 0) {
1181             bos.write(ch);
1182         }
1183         bos.close();
1184         car.close();
1185         jr.close();
1186         byte[] bytes = bos.toByteArray();
1187         if (uncompress) {
1188             GZIPInputStream gis = new GZIPInputStream(new ByteArrayInputStream(bytes));
1189             byte[] tmp = new byte[bytes.length * 3]; // Rough estimate
1190             int count = 0;
1191             int b;
1192             while ((b = gis.read()) >= 0) {
1193                 tmp[count++] = (byte) b;
1194             }
1195             bytes = new byte[count];
1196             System.arraycopy(tmp, 0, bytes, 0, count);
1197         }
1198         return bytes;
1199     }
1200 
1201     // A-Z, g-z, _, $
1202     private static final int FREE_CHARS = 48;
1203     static int[] CHAR_MAP = new int[FREE_CHARS];
1204     static int[] MAP_CHAR = new int[256]; // Reverse map
1205     private static final char ESCAPE_CHAR = '$';
1206     static {
1207         int j = 0;
1208         for (int i = 'A'; i <= 'Z'; i++) {
1209             CHAR_MAP[j] = i;
1210             MAP_CHAR[i] = j;
1211             j++;
1212         }
1213         for (int i = 'g'; i <= 'z'; i++) {
1214             CHAR_MAP[j] = i;
1215             MAP_CHAR[i] = j;
1216             j++;
1217         }
1218         CHAR_MAP[j] = '$';
1219         MAP_CHAR['$'] = j;
1220         j++;
1221         CHAR_MAP[j] = '_';
1222         MAP_CHAR['_'] = j;
1223     }
1224 
1225     /*** Decode characters into bytes.
1226      * Used by <a href="Utility.html#decode(java.lang.String, boolean)">decode()</a>
1227      */
1228     private static class JavaReader extends FilterReader {
1229 
1230         public JavaReader(Reader in) {
1231             super(in);
1232         }
1233 
1234 
1235         public int read() throws IOException {
1236             int b = in.read();
1237             if (b != ESCAPE_CHAR) {
1238                 return b;
1239             }
1240             int i = in.read();
1241             if (i < 0) {
1242                 return -1;
1243             }
1244             if (((i >= '0') && (i <= '9')) || ((i >= 'a') && (i <= 'f'))) { // Normal escape
1245                 int j = in.read();
1246                 if (j < 0) {
1247                     return -1;
1248                 }
1249                 char[] tmp = {
1250                         (char) i, (char) j
1251                 };
1252                 int s = Integer.parseInt(new String(tmp), 16);
1253                 return s;
1254             }
1255             return MAP_CHAR[i];
1256         }
1257 
1258 
1259         public int read( char[] cbuf, int off, int len ) throws IOException {
1260             for (int i = 0; i < len; i++) {
1261                 cbuf[off + i] = (char) read();
1262             }
1263             return len;
1264         }
1265     }
1266 
1267     /*** Encode bytes into valid java identifier characters.
1268      * Used by <a href="Utility.html#encode(byte[], boolean)">encode()</a>
1269      */
1270     private static class JavaWriter extends FilterWriter {
1271 
1272         public JavaWriter(Writer out) {
1273             super(out);
1274         }
1275 
1276 
1277         public void write( int b ) throws IOException {
1278             if (isJavaIdentifierPart((char) b) && (b != ESCAPE_CHAR)) {
1279                 out.write(b);
1280             } else {
1281                 out.write(ESCAPE_CHAR); // Escape character
1282                 // Special escape
1283                 if (b >= 0 && b < FREE_CHARS) {
1284                     out.write(CHAR_MAP[b]);
1285                 } else { // Normal escape
1286                     char[] tmp = Integer.toHexString(b).toCharArray();
1287                     if (tmp.length == 1) {
1288                         out.write('0');
1289                         out.write(tmp[0]);
1290                     } else {
1291                         out.write(tmp[0]);
1292                         out.write(tmp[1]);
1293                     }
1294                 }
1295             }
1296         }
1297 
1298 
1299         public void write( char[] cbuf, int off, int len ) throws IOException {
1300             for (int i = 0; i < len; i++) {
1301                 write(cbuf[off + i]);
1302             }
1303         }
1304 
1305 
1306         public void write( String str, int off, int len ) throws IOException {
1307             write(str.toCharArray(), off, len);
1308         }
1309     }
1310 
1311 
1312     /***
1313      * Escape all occurences of newline chars '\n', quotes \", etc.
1314      */
1315     public static final String convertString( String label ) {
1316         char[] ch = label.toCharArray();
1317         StringBuffer buf = new StringBuffer();
1318         for (int i = 0; i < ch.length; i++) {
1319             switch (ch[i]) {
1320                 case '\n':
1321                     buf.append("//n");
1322                     break;
1323                 case '\r':
1324                     buf.append("//r");
1325                     break;
1326                 case '\"':
1327                     buf.append("//\"");
1328                     break;
1329                 case '\'':
1330                     buf.append("//'");
1331                     break;
1332                 case '//':
1333                     buf.append("////");
1334                     break;
1335                 default:
1336                     buf.append(ch[i]);
1337                     break;
1338             }
1339         }
1340         return buf.toString();
1341     }
1342 }