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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   */
17  
18  package org.apache.bcel.classfile;
19  
20  import java.io.ByteArrayInputStream;
21  import java.io.ByteArrayOutputStream;
22  import java.io.CharArrayReader;
23  import java.io.CharArrayWriter;
24  import java.io.FilterReader;
25  import java.io.FilterWriter;
26  import java.io.IOException;
27  import java.io.PrintStream;
28  import java.io.PrintWriter;
29  import java.io.Reader;
30  import java.io.Writer;
31  import java.util.ArrayList;
32  import java.util.List;
33  import java.util.Locale;
34  import java.util.zip.GZIPInputStream;
35  import java.util.zip.GZIPOutputStream;
36  
37  import org.apache.bcel.Const;
38  import org.apache.bcel.util.ByteSequence;
39  
40  /**
41   * Utility functions that do not really belong to any class in particular.
42   *
43   * @version $Id: Utility.html 1018313 2017-09-18 09:03:04Z britter $
44   */
45  // @since 6.0 methods are no longer final
46  public abstract class Utility {
47  
48      private static int unwrap( final ThreadLocal<Integer> tl ) {
49          return tl.get().intValue();
50      }
51  
52  
53      private static void wrap( final ThreadLocal<Integer> tl, final int value ) {
54          tl.set(Integer.valueOf(value));
55      }
56  
57      private static ThreadLocal<Integer> consumed_chars = new ThreadLocal<Integer>() {
58  
59          @Override
60          protected Integer initialValue() {
61              return Integer.valueOf(0);
62          }
63      };/* How many chars have been consumed
64       * during parsing in signatureToString().
65       * Read by methodSignatureToString().
66       * Set by side effect,but only internally.
67       */
68      private static boolean wide = false; /* The `WIDE' instruction is used in the
69       * byte code to allow 16-bit wide indices
70       * for local variables. This opcode
71       * precedes an `ILOAD', e.g.. The opcode
72       * immediately following takes an extra
73       * byte which is combined with the
74       * following byte to form a
75       * 16-bit value.
76       */
77  
78  
79      /**
80       * Convert bit field of flags into string such as `static final'.
81       *
82       * @param  access_flags Access flags
83       * @return String representation of flags
84       */
85      public static String accessToString( final int access_flags ) {
86          return accessToString(access_flags, false);
87      }
88  
89  
90      /**
91       * Convert bit field of flags into string such as `static final'.
92       *
93       * Special case: Classes compiled with new compilers and with the
94       * `ACC_SUPER' flag would be said to be "synchronized". This is
95       * because SUN used the same value for the flags `ACC_SUPER' and
96       * `ACC_SYNCHRONIZED'.
97       *
98       * @param  access_flags Access flags
99       * @param  for_class access flags are for class qualifiers ?
100      * @return String representation of flags
101      */
102     public static String accessToString( final int access_flags, final boolean for_class ) {
103         final StringBuilder buf = new StringBuilder();
104         int p = 0;
105         for (int i = 0; p < Const.MAX_ACC_FLAG; i++) { // Loop through known flags
106             p = pow2(i);
107             if ((access_flags & p) != 0) {
108                 /* Special case: Classes compiled with new compilers and with the
109                  * `ACC_SUPER' flag would be said to be "synchronized". This is
110                  * because SUN used the same value for the flags `ACC_SUPER' and
111                  * `ACC_SYNCHRONIZED'.
112                  */
113                 if (for_class && ((p == Const.ACC_SUPER) || (p == Const.ACC_INTERFACE))) {
114                     continue;
115                 }
116                 buf.append(Const.getAccessName(i)).append(" ");
117             }
118         }
119         return buf.toString().trim();
120     }
121 
122 
123     /**
124      * @param access_flags the class flags
125      *
126      * @return "class" or "interface", depending on the ACC_INTERFACE flag
127      */
128     public static String classOrInterface( final int access_flags ) {
129         return ((access_flags & Const.ACC_INTERFACE) != 0) ? "interface" : "class";
130     }
131 
132 
133     /**
134      * Disassemble a byte array of JVM byte codes starting from code line
135      * `index' and return the disassembled string representation. Decode only
136      * `num' opcodes (including their operands), use -1 if you want to
137      * decompile everything.
138      *
139      * @param  code byte code array
140      * @param  constant_pool Array of constants
141      * @param  index offset in `code' array
142      * <EM>(number of opcodes, not bytes!)</EM>
143      * @param  length number of opcodes to decompile, -1 for all
144      * @param  verbose be verbose, e.g. print constant pool index
145      * @return String representation of byte codes
146      */
147     public static String codeToString( final byte[] code, final ConstantPool constant_pool, final int index,
148             final int length, final boolean verbose ) {
149         final StringBuilder buf = new StringBuilder(code.length * 20); // Should be sufficient // CHECKSTYLE IGNORE MagicNumber
150         try (ByteSequence stream = new ByteSequence(code)) {
151             for (int i = 0; i < index; i++) {
152                 codeToString(stream, constant_pool, verbose);
153             }
154             for (int i = 0; stream.available() > 0; i++) {
155                 if ((length < 0) || (i < length)) {
156                     final String indices = fillup(stream.getIndex() + ":", 6, true, ' ');
157                     buf.append(indices).append(codeToString(stream, constant_pool, verbose)).append('\n');
158                 }
159             }
160         } catch (final IOException e) {
161             throw new ClassFormatException("Byte code error: " + buf.toString(), e);
162         }
163         return buf.toString();
164     }
165 
166 
167     public static String codeToString( final byte[] code, final ConstantPool constant_pool, final int index, final 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      * @throws IOException if a failure from reading from the bytes argument occurs
182      */
183     public static String codeToString( final ByteSequence bytes, final ConstantPool constant_pool,
184             final boolean verbose ) throws IOException {
185         final short opcode = (short) bytes.readUnsignedByte();
186         int default_offset = 0;
187         int low;
188         int high;
189         int npairs;
190         int index;
191         int vindex;
192         int constant;
193         int[] match;
194         int[] jump_table;
195         int no_pad_bytes = 0;
196         int offset;
197         final StringBuilder buf = new StringBuilder(Const.getOpcodeName(opcode));
198         /* Special case: Skip (0-3) padding bytes, i.e., the
199          * following bytes are 4-byte-aligned
200          */
201         if ((opcode == Const.TABLESWITCH) || (opcode == Const.LOOKUPSWITCH)) {
202             final int remainder = bytes.getIndex() % 4;
203             no_pad_bytes = (remainder == 0) ? 0 : 4 - remainder;
204             for (int i = 0; i < no_pad_bytes; i++) {
205                 byte b;
206                 if ((b = bytes.readByte()) != 0) {
207                     System.err.println("Warning: Padding byte != 0 in "
208                             + Const.getOpcodeName(opcode) + ":" + b);
209                 }
210             }
211             // Both cases have a field default_offset in common
212             default_offset = bytes.readInt();
213         }
214         switch (opcode) {
215             /* Table switch has variable length arguments.
216              */
217             case Const.TABLESWITCH:
218                 low = bytes.readInt();
219                 high = bytes.readInt();
220                 offset = bytes.getIndex() - 12 - no_pad_bytes - 1;
221                 default_offset += offset;
222                 buf.append("\tdefault = ").append(default_offset).append(", low = ").append(low)
223                         .append(", high = ").append(high).append("(");
224                 jump_table = new int[high - low + 1];
225                 for (int i = 0; i < jump_table.length; i++) {
226                     jump_table[i] = offset + bytes.readInt();
227                     buf.append(jump_table[i]);
228                     if (i < jump_table.length - 1) {
229                         buf.append(", ");
230                     }
231                 }
232                 buf.append(")");
233                 break;
234             /* Lookup switch has variable length arguments.
235              */
236             case Const.LOOKUPSWITCH: {
237                 npairs = bytes.readInt();
238                 offset = bytes.getIndex() - 8 - no_pad_bytes - 1;
239                 match = new int[npairs];
240                 jump_table = new int[npairs];
241                 default_offset += offset;
242                 buf.append("\tdefault = ").append(default_offset).append(", npairs = ").append(
243                         npairs).append(" (");
244                 for (int i = 0; i < npairs; i++) {
245                     match[i] = bytes.readInt();
246                     jump_table[i] = offset + bytes.readInt();
247                     buf.append("(").append(match[i]).append(", ").append(jump_table[i]).append(")");
248                     if (i < npairs - 1) {
249                         buf.append(", ");
250                     }
251                 }
252                 buf.append(")");
253             }
254                 break;
255             /* Two address bytes + offset from start of byte stream form the
256              * jump target
257              */
258             case Const.GOTO:
259             case Const.IFEQ:
260             case Const.IFGE:
261             case Const.IFGT:
262             case Const.IFLE:
263             case Const.IFLT:
264             case Const.JSR:
265             case Const.IFNE:
266             case Const.IFNONNULL:
267             case Const.IFNULL:
268             case Const.IF_ACMPEQ:
269             case Const.IF_ACMPNE:
270             case Const.IF_ICMPEQ:
271             case Const.IF_ICMPGE:
272             case Const.IF_ICMPGT:
273             case Const.IF_ICMPLE:
274             case Const.IF_ICMPLT:
275             case Const.IF_ICMPNE:
276                 buf.append("\t\t#").append((bytes.getIndex() - 1) + bytes.readShort());
277                 break;
278             /* 32-bit wide jumps
279              */
280             case Const.GOTO_W:
281             case Const.JSR_W:
282                 buf.append("\t\t#").append((bytes.getIndex() - 1) + bytes.readInt());
283                 break;
284             /* Index byte references local variable (register)
285              */
286             case Const.ALOAD:
287             case Const.ASTORE:
288             case Const.DLOAD:
289             case Const.DSTORE:
290             case Const.FLOAD:
291             case Const.FSTORE:
292             case Const.ILOAD:
293             case Const.ISTORE:
294             case Const.LLOAD:
295             case Const.LSTORE:
296             case Const.RET:
297                 if (wide) {
298                     vindex = bytes.readUnsignedShort();
299                     wide = false; // Clear flag
300                 } else {
301                     vindex = bytes.readUnsignedByte();
302                 }
303                 buf.append("\t\t%").append(vindex);
304                 break;
305             /*
306              * Remember wide byte which is used to form a 16-bit address in the
307              * following instruction. Relies on that the method is called again with
308              * the following opcode.
309              */
310             case Const.WIDE:
311                 wide = true;
312                 buf.append("\t(wide)");
313                 break;
314             /* Array of basic type.
315              */
316             case Const.NEWARRAY:
317                 buf.append("\t\t<").append(Const.getTypeName(bytes.readByte())).append(">");
318                 break;
319             /* Access object/class fields.
320              */
321             case Const.GETFIELD:
322             case Const.GETSTATIC:
323             case Const.PUTFIELD:
324             case Const.PUTSTATIC:
325                 index = bytes.readUnsignedShort();
326                 buf.append("\t\t").append(
327                         constant_pool.constantToString(index, Const.CONSTANT_Fieldref)).append(
328                         verbose ? " (" + index + ")" : "");
329                 break;
330             /* Operands are references to classes in constant pool
331              */
332             case Const.NEW:
333             case Const.CHECKCAST:
334                 buf.append("\t");
335                 //$FALL-THROUGH$
336             case Const.INSTANCEOF:
337                 index = bytes.readUnsignedShort();
338                 buf.append("\t<").append(
339                         constant_pool.constantToString(index, Const.CONSTANT_Class))
340                         .append(">").append(verbose ? " (" + index + ")" : "");
341                 break;
342             /* Operands are references to methods in constant pool
343              */
344             case Const.INVOKESPECIAL:
345             case Const.INVOKESTATIC:
346                 index = bytes.readUnsignedShort();
347                 final Constant c = constant_pool.getConstant(index);
348                 // With Java8 operand may be either a CONSTANT_Methodref
349                 // or a CONSTANT_InterfaceMethodref.   (markro)
350                 buf.append("\t").append(
351                         constant_pool.constantToString(index, c.getTag()))
352                         .append(verbose ? " (" + index + ")" : "");
353                 break;
354             case Const.INVOKEVIRTUAL:
355                 index = bytes.readUnsignedShort();
356                 buf.append("\t").append(
357                         constant_pool.constantToString(index, Const.CONSTANT_Methodref))
358                         .append(verbose ? " (" + index + ")" : "");
359                 break;
360             case Const.INVOKEINTERFACE:
361                 index = bytes.readUnsignedShort();
362                 final int nargs = bytes.readUnsignedByte(); // historical, redundant
363                 buf.append("\t").append(
364                         constant_pool
365                                 .constantToString(index, Const.CONSTANT_InterfaceMethodref))
366                         .append(verbose ? " (" + index + ")\t" : "").append(nargs).append("\t")
367                         .append(bytes.readUnsignedByte()); // Last byte is a reserved space
368                 break;
369             case Const.INVOKEDYNAMIC:
370                 index = bytes.readUnsignedShort();
371                 buf.append("\t").append(
372                         constant_pool
373                                 .constantToString(index, Const.CONSTANT_InvokeDynamic))
374                         .append(verbose ? " (" + index + ")\t" : "")
375                         .append(bytes.readUnsignedByte())  // Thrid byte is a reserved space
376                         .append(bytes.readUnsignedByte()); // Last byte is a reserved space
377                 break;
378             /* Operands are references to items in constant pool
379              */
380             case Const.LDC_W:
381             case Const.LDC2_W:
382                 index = bytes.readUnsignedShort();
383                 buf.append("\t\t").append(
384                         constant_pool.constantToString(index, constant_pool.getConstant(index)
385                                 .getTag())).append(verbose ? " (" + index + ")" : "");
386                 break;
387             case Const.LDC:
388                 index = bytes.readUnsignedByte();
389                 buf.append("\t\t").append(
390                         constant_pool.constantToString(index, constant_pool.getConstant(index)
391                                 .getTag())).append(verbose ? " (" + index + ")" : "");
392                 break;
393             /* Array of references.
394              */
395             case Const.ANEWARRAY:
396                 index = bytes.readUnsignedShort();
397                 buf.append("\t\t<").append(
398                         compactClassName(constant_pool.getConstantString(index,
399                                 Const.CONSTANT_Class), false)).append(">").append(
400                         verbose ? " (" + index + ")" : "");
401                 break;
402             /* Multidimensional array of references.
403              */
404             case Const.MULTIANEWARRAY: {
405                 index = bytes.readUnsignedShort();
406                 final int dimensions = bytes.readUnsignedByte();
407                 buf.append("\t<").append(
408                         compactClassName(constant_pool.getConstantString(index,
409                                 Const.CONSTANT_Class), false)).append(">\t").append(dimensions)
410                         .append(verbose ? " (" + index + ")" : "");
411             }
412                 break;
413             /* Increment local variable.
414              */
415             case Const.IINC:
416                 if (wide) {
417                     vindex = bytes.readUnsignedShort();
418                     constant = bytes.readShort();
419                     wide = false;
420                 } else {
421                     vindex = bytes.readUnsignedByte();
422                     constant = bytes.readByte();
423                 }
424                 buf.append("\t\t%").append(vindex).append("\t").append(constant);
425                 break;
426             default:
427                 if (Const.getNoOfOperands(opcode) > 0) {
428                     for (int i = 0; i < Const.getOperandTypeCount(opcode); i++) {
429                         buf.append("\t\t");
430                         switch (Const.getOperandType(opcode, i)) {
431                             case Const.T_BYTE:
432                                 buf.append(bytes.readByte());
433                                 break;
434                             case Const.T_SHORT:
435                                 buf.append(bytes.readShort());
436                                 break;
437                             case Const.T_INT:
438                                 buf.append(bytes.readInt());
439                                 break;
440                             default: // Never reached
441                                 throw new IllegalStateException("Unreachable default case reached!");
442                         }
443                     }
444                 }
445         }
446         return buf.toString();
447     }
448 
449 
450     public static String codeToString( final ByteSequence bytes, final ConstantPool constant_pool )
451             throws IOException {
452         return codeToString(bytes, constant_pool, true);
453     }
454 
455 
456     /**
457      * Shorten long class names, <em>java/lang/String</em> becomes
458      * <em>String</em>.
459      *
460      * @param str The long class name
461      * @return Compacted class name
462      */
463     public static String compactClassName( final String str ) {
464         return compactClassName(str, true);
465     }
466 
467 
468     /**
469      * Shorten long class name <em>str</em>, i.e., chop off the <em>prefix</em>,
470      * if the
471      * class name starts with this string and the flag <em>chopit</em> is true.
472      * Slashes <em>/</em> are converted to dots <em>.</em>.
473      *
474      * @param str The long class name
475      * @param prefix The prefix the get rid off
476      * @param chopit Flag that determines whether chopping is executed or not
477      * @return Compacted class name
478      */
479     public static String compactClassName( String str, final String prefix, final boolean chopit ) {
480         final int len = prefix.length();
481         str = str.replace('/', '.'); // Is `/' on all systems, even DOS
482         if (chopit) {
483             // If string starts with `prefix' and contains no further dots
484             if (str.startsWith(prefix) && (str.substring(len).indexOf('.') == -1)) {
485                 str = str.substring(len);
486             }
487         }
488         return str;
489     }
490 
491 
492     /**
493      * Shorten long class names, <em>java/lang/String</em> becomes
494      * <em>java.lang.String</em>,
495      * e.g.. If <em>chopit</em> is <em>true</em> the prefix <em>java.lang</em>
496      * is also removed.
497      *
498      * @param str The long class name
499      * @param chopit Flag that determines whether chopping is executed or not
500      * @return Compacted class name
501      */
502     public static String compactClassName( final String str, final boolean chopit ) {
503         return compactClassName(str, "java.lang.", chopit);
504     }
505 
506 
507     /**
508      * @return `flag' with bit `i' set to 1
509      */
510     public static int setBit( final int flag, final int i ) {
511         return flag | pow2(i);
512     }
513 
514 
515     /**
516      * @return `flag' with bit `i' set to 0
517      */
518     public static int clearBit( final int flag, final int i ) {
519         final int bit = pow2(i);
520         return (flag & bit) == 0 ? flag : flag ^ bit;
521     }
522 
523 
524     /**
525      * @return true, if bit `i' in `flag' is set
526      */
527     public static boolean isSet( final int flag, final int i ) {
528         return (flag & pow2(i)) != 0;
529     }
530 
531 
532     /**
533      * Converts string containing the method return and argument types
534      * to a byte code method signature.
535      *
536      * @param  ret Return type of method
537      * @param  argv Types of method arguments
538      * @return Byte code representation of method signature
539      *
540      * @throws ClassFormatException if the signature is for Void
541      */
542     public static String methodTypeToSignature( final String ret, final String[] argv )
543             throws ClassFormatException {
544         final StringBuilder buf = new StringBuilder("(");
545         String str;
546         if (argv != null) {
547             for (final String element : argv) {
548                 str = getSignature(element);
549                 if (str.endsWith("V")) {
550                     throw new ClassFormatException("Invalid type: " + element);
551                 }
552                 buf.append(str);
553             }
554         }
555         str = getSignature(ret);
556         buf.append(")").append(str);
557         return buf.toString();
558     }
559 
560 
561     /**
562      * @param  signature    Method signature
563      * @return Array of argument types
564      * @throws  ClassFormatException
565      */
566     public static String[] methodSignatureArgumentTypes( final String signature )
567             throws ClassFormatException {
568         return methodSignatureArgumentTypes(signature, true);
569     }
570 
571 
572     /**
573      * @param  signature    Method signature
574      * @param chopit Shorten class names ?
575      * @return Array of argument types
576      * @throws  ClassFormatException
577      */
578     public static String[] methodSignatureArgumentTypes( final String signature, final boolean chopit )
579             throws ClassFormatException {
580         final List<String> vec = new ArrayList<>();
581         int index;
582         try { // Read all declarations between for `(' and `)'
583             if (signature.charAt(0) != '(') {
584                 throw new ClassFormatException("Invalid method signature: " + signature);
585             }
586             index = 1; // current string position
587             while (signature.charAt(index) != ')') {
588                 vec.add(signatureToString(signature.substring(index), chopit));
589                 //corrected concurrent private static field acess
590                 index += unwrap(consumed_chars); // update position
591             }
592         } catch (final StringIndexOutOfBoundsException e) { // Should never occur
593             throw new ClassFormatException("Invalid method signature: " + signature, e);
594         }
595         return vec.toArray(new String[vec.size()]);
596     }
597 
598 
599     /**
600      * @param  signature    Method signature
601      * @return return type of method
602      * @throws  ClassFormatException
603      */
604     public static String methodSignatureReturnType( final String signature ) throws ClassFormatException {
605         return methodSignatureReturnType(signature, true);
606     }
607 
608 
609     /**
610      * @param  signature    Method signature
611      * @param chopit Shorten class names ?
612      * @return return type of method
613      * @throws  ClassFormatException
614      */
615     public static String methodSignatureReturnType( final String signature, final boolean chopit ) throws ClassFormatException {
616         int index;
617         String type;
618         try {
619             // Read return type after `)'
620             index = signature.lastIndexOf(')') + 1;
621             type = signatureToString(signature.substring(index), chopit);
622         } catch (final StringIndexOutOfBoundsException e) { // Should never occur
623             throw new ClassFormatException("Invalid method signature: " + signature, e);
624         }
625         return type;
626     }
627 
628 
629     /**
630      * Converts method signature to string with all class names compacted.
631      *
632      * @param signature to convert
633      * @param name of method
634      * @param access flags of method
635      * @return Human readable signature
636      */
637     public static String methodSignatureToString( final String signature, final String name, final String access ) {
638         return methodSignatureToString(signature, name, access, true);
639     }
640 
641 
642     public static String methodSignatureToString( final String signature, final String name, final String access, final boolean chopit ) {
643         return methodSignatureToString(signature, name, access, chopit, null);
644     }
645 
646 
647     /**
648      * A returntype signature represents the return value from a method.
649      * It is a series of bytes in the following grammar:
650      *
651      * <pre>
652      * &lt;return_signature&gt; ::= &lt;field_type&gt; | V
653      * </pre>
654      *
655      * The character V indicates that the method returns no value. Otherwise, the
656      * signature indicates the type of the return value.
657      * An argument signature represents an argument passed to a method:
658      *
659      * <pre>
660      * &lt;argument_signature&gt; ::= &lt;field_type&gt;
661      * </pre>
662      *
663      * A method signature represents the arguments that the method expects, and
664      * the value that it returns.
665      * <pre>
666      * &lt;method_signature&gt; ::= (&lt;arguments_signature&gt;) &lt;return_signature&gt;
667      * &lt;arguments_signature&gt;::= &lt;argument_signature&gt;*
668      * </pre>
669      *
670      * This method converts such a string into a Java type declaration like
671      * `void main(String[])' and throws a `ClassFormatException' when the parsed
672      * type is invalid.
673      *
674      * @param  signature    Method signature
675      * @param  name         Method name
676      * @param  access       Method access rights
677      * @param chopit
678      * @param vars
679      * @return Java type declaration
680      * @throws  ClassFormatException
681      */
682     public static String methodSignatureToString( final String signature, final String name,
683             final String access, final boolean chopit, final LocalVariableTable vars ) throws ClassFormatException {
684         final StringBuilder buf = new StringBuilder("(");
685         String type;
686         int index;
687         int var_index = access.contains("static") ? 0 : 1;
688         try { // Read all declarations between for `(' and `)'
689             if (signature.charAt(0) != '(') {
690                 throw new ClassFormatException("Invalid method signature: " + signature);
691             }
692             index = 1; // current string position
693             while (signature.charAt(index) != ')') {
694                 final String param_type = signatureToString(signature.substring(index), chopit);
695                 buf.append(param_type);
696                 if (vars != null) {
697                     final LocalVariable l = vars.getLocalVariable(var_index, 0);
698                     if (l != null) {
699                         buf.append(" ").append(l.getName());
700                     }
701                 } else {
702                     buf.append(" arg").append(var_index);
703                 }
704                 if ("double".equals(param_type) || "long".equals(param_type)) {
705                     var_index += 2;
706                 } else {
707                     var_index++;
708                 }
709                 buf.append(", ");
710                 //corrected concurrent private static field acess
711                 index += unwrap(consumed_chars); // update position
712             }
713             index++; // update position
714             // Read return type after `)'
715             type = signatureToString(signature.substring(index), chopit);
716         } catch (final StringIndexOutOfBoundsException e) { // Should never occur
717             throw new ClassFormatException("Invalid method signature: " + signature, e);
718         }
719         if (buf.length() > 1) {
720             buf.setLength(buf.length() - 2);
721         }
722         buf.append(")");
723         return access + ((access.length() > 0) ? " " : "") + // May be an empty string
724                 type + " " + name + buf.toString();
725     }
726 
727 
728     // Guess what this does
729     private static int pow2( final int n ) {
730         return 1 << n;
731     }
732 
733 
734     /**
735      * Replace all occurrences of <em>old</em> in <em>str</em> with <em>new</em>.
736      *
737      * @param str String to permute
738      * @param old String to be replaced
739      * @param new_ Replacement string
740      * @return new String object
741      */
742     public static String replace( String str, final String old, final String new_ ) {
743         int index;
744         int old_index;
745         try {
746             if (str.contains(old)) { // `old' found in str
747                 final StringBuilder buf = new StringBuilder();
748                 old_index = 0; // String start offset
749                 // While we have something to replace
750                 while ((index = str.indexOf(old, old_index)) != -1) {
751                     buf.append(str.substring(old_index, index)); // append prefix
752                     buf.append(new_); // append replacement
753                     old_index = index + old.length(); // Skip `old'.length chars
754                 }
755                 buf.append(str.substring(old_index)); // append rest of string
756                 str = buf.toString();
757             }
758         } catch (final StringIndexOutOfBoundsException e) { // Should not occur
759             System.err.println(e);
760         }
761         return str;
762     }
763 
764 
765     /**
766      * Converts signature to string with all class names compacted.
767      *
768      * @param signature to convert
769      * @return Human readable signature
770      */
771     public static String signatureToString( final String signature ) {
772         return signatureToString(signature, true);
773     }
774 
775 
776     /**
777      * The field signature represents the value of an argument to a function or
778      * the value of a variable. It is a series of bytes generated by the
779      * following grammar:
780      *
781      * <PRE>
782      * &lt;field_signature&gt; ::= &lt;field_type&gt;
783      * &lt;field_type&gt;      ::= &lt;base_type&gt;|&lt;object_type&gt;|&lt;array_type&gt;
784      * &lt;base_type&gt;       ::= B|C|D|F|I|J|S|Z
785      * &lt;object_type&gt;     ::= L&lt;fullclassname&gt;;
786      * &lt;array_type&gt;      ::= [&lt;field_type&gt;
787      *
788      * The meaning of the base types is as follows:
789      * B byte signed byte
790      * C char character
791      * D double double precision IEEE float
792      * F float single precision IEEE float
793      * I int integer
794      * J long long integer
795      * L&lt;fullclassname&gt;; ... an object of the given class
796      * S short signed short
797      * Z boolean true or false
798      * [&lt;field sig&gt; ... array
799      * </PRE>
800      *
801      * This method converts this string into a Java type declaration such as
802      * `String[]' and throws a `ClassFormatException' when the parsed type is
803      * invalid.
804      *
805      * @param  signature  Class signature
806      * @param chopit Flag that determines whether chopping is executed or not
807      * @return Java type declaration
808      * @throws ClassFormatException
809      */
810     public static String signatureToString( final String signature, final boolean chopit ) {
811         //corrected concurrent private static field acess
812         wrap(consumed_chars, 1); // This is the default, read just one char like `B'
813         try {
814             switch (signature.charAt(0)) {
815                 case 'B':
816                     return "byte";
817                 case 'C':
818                     return "char";
819                 case 'D':
820                     return "double";
821                 case 'F':
822                     return "float";
823                 case 'I':
824                     return "int";
825                 case 'J':
826                     return "long";
827                 case 'T': { // TypeVariableSignature
828                     final int index = signature.indexOf(';'); // Look for closing `;'
829                     if (index < 0) {
830                         throw new ClassFormatException("Invalid signature: " + signature);
831                     }
832                     //corrected concurrent private static field acess
833                     wrap(consumed_chars, index + 1); // "Tblabla;" `T' and `;' are removed
834                     return compactClassName(signature.substring(1, index), chopit);
835                 }
836                 case 'L': { // Full class name
837                     // should this be a while loop? can there be more than
838                     // one generic clause?  (markro)
839                     int fromIndex = signature.indexOf('<'); // generic type?
840                     if (fromIndex < 0) {
841                         fromIndex = 0;
842                     } else {
843                         fromIndex = signature.indexOf('>', fromIndex);
844                         if (fromIndex < 0) {
845                             throw new ClassFormatException("Invalid signature: " + signature);
846                         }
847                     }
848                     final int index = signature.indexOf(';', fromIndex); // Look for closing `;'
849                     if (index < 0) {
850                         throw new ClassFormatException("Invalid signature: " + signature);
851                     }
852 
853                     // check to see if there are any TypeArguments
854                     final int bracketIndex = signature.substring(0, index).indexOf('<');
855                     if (bracketIndex < 0) {
856                         // just a class identifier
857                         wrap(consumed_chars, index + 1); // "Lblabla;" `L' and `;' are removed
858                         return compactClassName(signature.substring(1, index), chopit);
859                     }
860                     // but make sure we are not looking past the end of the current item
861                     fromIndex = signature.indexOf(';');
862                     if (fromIndex < 0) {
863                         throw new ClassFormatException("Invalid signature: " + signature);
864                     }
865                     if (fromIndex < bracketIndex) {
866                         // just a class identifier
867                         wrap(consumed_chars, fromIndex + 1); // "Lblabla;" `L' and `;' are removed
868                         return compactClassName(signature.substring(1, fromIndex), chopit);
869                     }
870 
871                     // we have TypeArguments; build up partial result
872                     // as we recurse for each TypeArgument
873                     final StringBuilder type = new StringBuilder(compactClassName(signature.substring(1, bracketIndex), chopit)).append("<");
874                     int consumed_chars = bracketIndex + 1; // Shadows global var
875 
876                     // check for wildcards
877                     if (signature.charAt(consumed_chars) == '+') {
878                         type.append("? extends ");
879                         consumed_chars++;
880                     } else if (signature.charAt(consumed_chars) == '-') {
881                         type.append("? super ");
882                         consumed_chars++;
883                     }
884 
885                     // get the first TypeArgument
886                     if (signature.charAt(consumed_chars) == '*') {
887                         type.append("?");
888                         consumed_chars++;
889                     } else {
890                         type.append(signatureToString(signature.substring(consumed_chars), chopit));
891                         // update our consumed count by the number of characters the for type argument
892                         consumed_chars = unwrap(Utility.consumed_chars) + consumed_chars;
893                         wrap(Utility.consumed_chars, consumed_chars);
894                     }
895 
896                     // are there more TypeArguments?
897                     while (signature.charAt(consumed_chars) != '>') {
898                         type.append(", ");
899                         // check for wildcards
900                         if (signature.charAt(consumed_chars) == '+') {
901                             type.append("? extends ");
902                             consumed_chars++;
903                         } else if (signature.charAt(consumed_chars) == '-') {
904                             type.append("? super ");
905                             consumed_chars++;
906                         }
907                         if (signature.charAt(consumed_chars) == '*') {
908                             type.append("?");
909                             consumed_chars++;
910                         } else {
911                             type.append(signatureToString(signature.substring(consumed_chars), chopit));
912                             // update our consumed count by the number of characters the for type argument
913                             consumed_chars = unwrap(Utility.consumed_chars) + consumed_chars;
914                             wrap(Utility.consumed_chars, consumed_chars);
915                         }
916                     }
917 
918                     // process the closing ">"
919                     consumed_chars++;
920                     type.append(">");
921 
922                     if (signature.charAt(consumed_chars) == '.') {
923                         // we have a ClassTypeSignatureSuffix
924                         type.append(".");
925                         // convert SimpleClassTypeSignature to fake ClassTypeSignature
926                         // and then recurse to parse it
927                         type.append(signatureToString("L" + signature.substring(consumed_chars+1), chopit));
928                         // update our consumed count by the number of characters the for type argument
929                         // note that this count includes the "L" we added, but that is ok
930                         // as it accounts for the "." we didn't consume
931                         consumed_chars = unwrap(Utility.consumed_chars) + consumed_chars;
932                         wrap(Utility.consumed_chars, consumed_chars);
933                         return type.toString();
934                     }
935                     if (signature.charAt(consumed_chars) != ';') {
936                         throw new ClassFormatException("Invalid signature: " + signature);
937                     }
938                     wrap(Utility.consumed_chars, consumed_chars + 1); // remove final ";"
939                     return type.toString();
940                 }
941                 case 'S':
942                     return "short";
943                 case 'Z':
944                     return "boolean";
945                 case '[': { // Array declaration
946                     int n;
947                     StringBuilder brackets;
948                     String type;
949                     int consumed_chars; // Shadows global var
950                     brackets = new StringBuilder(); // Accumulate []'s
951                     // Count opening brackets and look for optional size argument
952                     for (n = 0; signature.charAt(n) == '['; n++) {
953                         brackets.append("[]");
954                     }
955                     consumed_chars = n; // Remember value
956                     // The rest of the string denotes a `<field_type>'
957                     type = signatureToString(signature.substring(n), chopit);
958                     //corrected concurrent private static field acess
959                     //Utility.consumed_chars += consumed_chars; is replaced by:
960                     final int _temp = unwrap(Utility.consumed_chars) + consumed_chars;
961                     wrap(Utility.consumed_chars, _temp);
962                     return type + brackets.toString();
963                 }
964                 case 'V':
965                     return "void";
966                 default:
967                     throw new ClassFormatException("Invalid signature: `" + signature + "'");
968             }
969         } catch (final StringIndexOutOfBoundsException e) { // Should never occur
970             throw new ClassFormatException("Invalid signature: " + signature, e);
971         }
972     }
973 
974 
975     /** Parse Java type such as "char", or "java.lang.String[]" and return the
976      * signature in byte code format, e.g. "C" or "[Ljava/lang/String;" respectively.
977      *
978      * @param  type Java type
979      * @return byte code signature
980      */
981     public static String getSignature( String type ) {
982         final StringBuilder buf = new StringBuilder();
983         final char[] chars = type.toCharArray();
984         boolean char_found = false;
985         boolean delim = false;
986         int index = -1;
987         loop: for (int i = 0; i < chars.length; i++) {
988             switch (chars[i]) {
989                 case ' ':
990                 case '\t':
991                 case '\n':
992                 case '\r':
993                 case '\f':
994                     if (char_found) {
995                         delim = true;
996                     }
997                     break;
998                 case '[':
999                     if (!char_found) {
1000                         throw new RuntimeException("Illegal type: " + type);
1001                     }
1002                     index = i;
1003                     break loop;
1004                 default:
1005                     char_found = true;
1006                     if (!delim) {
1007                         buf.append(chars[i]);
1008                     }
1009             }
1010         }
1011         int brackets = 0;
1012         if (index > 0) {
1013             brackets = countBrackets(type.substring(index));
1014         }
1015         type = buf.toString();
1016         buf.setLength(0);
1017         for (int i = 0; i < brackets; i++) {
1018             buf.append('[');
1019         }
1020         boolean found = false;
1021         for (int i = Const.T_BOOLEAN; (i <= Const.T_VOID) && !found; i++) {
1022             if (Const.getTypeName(i).equals(type)) {
1023                 found = true;
1024                 buf.append(Const.getShortTypeName(i));
1025             }
1026         }
1027         if (!found) {
1028             buf.append('L').append(type.replace('.', '/')).append(';');
1029         }
1030         return buf.toString();
1031     }
1032 
1033 
1034     private static int countBrackets( final String brackets ) {
1035         final char[] chars = brackets.toCharArray();
1036         int count = 0;
1037         boolean open = false;
1038         for (final char c : chars) {
1039             switch (c) {
1040                 case '[':
1041                     if (open) {
1042                         throw new RuntimeException("Illegally nested brackets:" + brackets);
1043                     }
1044                     open = true;
1045                     break;
1046                 case ']':
1047                     if (!open) {
1048                         throw new RuntimeException("Illegally nested brackets:" + brackets);
1049                     }
1050                     open = false;
1051                     count++;
1052                     break;
1053                 default:
1054                     // Don't care
1055                     break;
1056             }
1057         }
1058         if (open) {
1059             throw new RuntimeException("Illegally nested brackets:" + brackets);
1060         }
1061         return count;
1062     }
1063 
1064 
1065     /**
1066      * Return type of method signature as a byte value as defined in <em>Constants</em>
1067      *
1068      * @param  signature in format described above
1069      * @return type of method signature
1070      * @see    Const
1071      *
1072      * @throws ClassFormatException if signature is not a method signature
1073      */
1074     public static byte typeOfMethodSignature( final String signature ) throws ClassFormatException {
1075         int index;
1076         try {
1077             if (signature.charAt(0) != '(') {
1078                 throw new ClassFormatException("Invalid method signature: " + signature);
1079             }
1080             index = signature.lastIndexOf(')') + 1;
1081             return typeOfSignature(signature.substring(index));
1082         } catch (final StringIndexOutOfBoundsException e) {
1083             throw new ClassFormatException("Invalid method signature: " + signature, e);
1084         }
1085     }
1086 
1087 
1088     /**
1089      * Return type of signature as a byte value as defined in <em>Constants</em>
1090      *
1091      * @param  signature in format described above
1092      * @return type of signature
1093      * @see    Const
1094      *
1095      * @throws ClassFormatException if signature isn't a known type
1096      */
1097     public static byte typeOfSignature( final String signature ) throws ClassFormatException {
1098         try {
1099             switch (signature.charAt(0)) {
1100                 case 'B':
1101                     return Const.T_BYTE;
1102                 case 'C':
1103                     return Const.T_CHAR;
1104                 case 'D':
1105                     return Const.T_DOUBLE;
1106                 case 'F':
1107                     return Const.T_FLOAT;
1108                 case 'I':
1109                     return Const.T_INT;
1110                 case 'J':
1111                     return Const.T_LONG;
1112                 case 'L':
1113                 case 'T':
1114                     return Const.T_REFERENCE;
1115                 case '[':
1116                     return Const.T_ARRAY;
1117                 case 'V':
1118                     return Const.T_VOID;
1119                 case 'Z':
1120                     return Const.T_BOOLEAN;
1121                 case 'S':
1122                     return Const.T_SHORT;
1123                 case '!':
1124                 case '+':
1125                 case '*':
1126                     return typeOfSignature(signature.substring(1));
1127                 default:
1128                     throw new ClassFormatException("Invalid method signature: " + signature);
1129             }
1130         } catch (final StringIndexOutOfBoundsException e) {
1131             throw new ClassFormatException("Invalid method signature: " + signature, e);
1132         }
1133     }
1134 
1135 
1136     /** Map opcode names to opcode numbers. E.g., return Constants.ALOAD for "aload"
1137      */
1138     public static short searchOpcode( String name ) {
1139         name = name.toLowerCase(Locale.ENGLISH);
1140         for (short i = 0; i < Const.OPCODE_NAMES_LENGTH; i++) {
1141             if (Const.getOpcodeName(i).equals(name)) {
1142                 return i;
1143             }
1144         }
1145         return -1;
1146     }
1147 
1148 
1149     /**
1150      * Convert (signed) byte to (unsigned) short value, i.e., all negative
1151      * values become positive.
1152      */
1153     private static short byteToShort( final byte b ) {
1154         return (b < 0) ? (short) (256 + b) : (short) b;
1155     }
1156 
1157 
1158     /** Convert bytes into hexadecimal string
1159      *
1160      * @param bytes an array of bytes to convert to hexadecimal
1161      *
1162      * @return bytes as hexadecimal string, e.g. 00 fa 12 ...
1163      */
1164     public static String toHexString( final byte[] bytes ) {
1165         final StringBuilder buf = new StringBuilder();
1166         for (int i = 0; i < bytes.length; i++) {
1167             final short b = byteToShort(bytes[i]);
1168             final String hex = Integer.toHexString(b);
1169             if (b < 0x10) {
1170                 buf.append('0');
1171             }
1172             buf.append(hex);
1173             if (i < bytes.length - 1) {
1174                 buf.append(' ');
1175             }
1176         }
1177         return buf.toString();
1178     }
1179 
1180 
1181     /**
1182      * Return a string for an integer justified left or right and filled up with
1183      * `fill' characters if necessary.
1184      *
1185      * @param i integer to format
1186      * @param length length of desired string
1187      * @param left_justify format left or right
1188      * @param fill fill character
1189      * @return formatted int
1190      */
1191     public static String format( final int i, final int length, final boolean left_justify, final char fill ) {
1192         return fillup(Integer.toString(i), length, left_justify, fill);
1193     }
1194 
1195 
1196     /**
1197      * Fillup char with up to length characters with char `fill' and justify it left or right.
1198      *
1199      * @param str string to format
1200      * @param length length of desired string
1201      * @param left_justify format left or right
1202      * @param fill fill character
1203      * @return formatted string
1204      */
1205     public static String fillup( final String str, final int length, final boolean left_justify, final char fill ) {
1206         final int len = length - str.length();
1207         final char[] buf = new char[(len < 0) ? 0 : len];
1208         for (int j = 0; j < buf.length; j++) {
1209             buf[j] = fill;
1210         }
1211         if (left_justify) {
1212             return str + new String(buf);
1213         }
1214         return new String(buf) + str;
1215     }
1216 
1217 
1218     static boolean equals( final byte[] a, final byte[] b ) {
1219         int size;
1220         if ((size = a.length) != b.length) {
1221             return false;
1222         }
1223         for (int i = 0; i < size; i++) {
1224             if (a[i] != b[i]) {
1225                 return false;
1226             }
1227         }
1228         return true;
1229     }
1230 
1231 
1232     public static void printArray( final PrintStream out, final Object[] obj ) {
1233         out.println(printArray(obj, true));
1234     }
1235 
1236 
1237     public static void printArray( final PrintWriter out, final Object[] obj ) {
1238         out.println(printArray(obj, true));
1239     }
1240 
1241 
1242     public static String printArray( final Object[] obj ) {
1243         return printArray(obj, true);
1244     }
1245 
1246 
1247     public static String printArray( final Object[] obj, final boolean braces ) {
1248         return printArray(obj, braces, false);
1249     }
1250 
1251 
1252     public static String printArray( final Object[] obj, final boolean braces, final boolean quote ) {
1253         if (obj == null) {
1254             return null;
1255         }
1256         final StringBuilder buf = new StringBuilder();
1257         if (braces) {
1258             buf.append('{');
1259         }
1260         for (int i = 0; i < obj.length; i++) {
1261             if (obj[i] != null) {
1262                 buf.append(quote ? "\"" : "").append(obj[i]).append(quote ? "\"" : "");
1263             } else {
1264                 buf.append("null");
1265             }
1266             if (i < obj.length - 1) {
1267                 buf.append(", ");
1268             }
1269         }
1270         if (braces) {
1271             buf.append('}');
1272         }
1273         return buf.toString();
1274     }
1275 
1276 
1277     /**
1278      * @param ch the character to test if it's part of an identifier
1279      *
1280      * @return true, if character is one of (a, ... z, A, ... Z, 0, ... 9, _)
1281      */
1282     public static boolean isJavaIdentifierPart( final char ch ) {
1283         return ((ch >= 'a') && (ch <= 'z')) || ((ch >= 'A') && (ch <= 'Z'))
1284                 || ((ch >= '0') && (ch <= '9')) || (ch == '_');
1285     }
1286 
1287 
1288     /**
1289      * Encode byte array it into Java identifier string, i.e., a string
1290      * that only contains the following characters: (a, ... z, A, ... Z,
1291      * 0, ... 9, _, $).  The encoding algorithm itself is not too
1292      * clever: if the current byte's ASCII value already is a valid Java
1293      * identifier part, leave it as it is. Otherwise it writes the
1294      * escape character($) followed by:
1295      *
1296      * <ul>
1297      *   <li> the ASCII value as a hexadecimal string, if the value is not in the range 200..247</li>
1298      *   <li>a Java identifier char not used in a lowercase hexadecimal string, if the value is in the range 200..247</li>
1299      * </ul>
1300      *
1301      * <p>This operation inflates the original byte array by roughly 40-50%</p>
1302      *
1303      * @param bytes the byte array to convert
1304      * @param compress use gzip to minimize string
1305      *
1306      * @throws IOException if there's a gzip exception
1307      */
1308     public static String encode(byte[] bytes, final boolean compress) throws IOException {
1309         if (compress) {
1310             try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
1311                     GZIPOutputStream gos = new GZIPOutputStream(baos)) {
1312                 gos.write(bytes, 0, bytes.length);
1313                 bytes = baos.toByteArray();
1314             }
1315         }
1316         final CharArrayWriter caw = new CharArrayWriter();
1317         try (JavaWriter jw = new JavaWriter(caw)) {
1318             for (final byte b : bytes) {
1319                 final int in = b & 0x000000ff; // Normalize to unsigned
1320                 jw.write(in);
1321             }
1322         }
1323         return caw.toString();
1324     }
1325 
1326 
1327     /**
1328      * Decode a string back to a byte array.
1329      *
1330      * @param s the string to convert
1331      * @param uncompress use gzip to uncompress the stream of bytes
1332      *
1333      * @throws IOException if there's a gzip exception
1334      */
1335     public static byte[] decode(final String s, final boolean uncompress) throws IOException {
1336         byte[] bytes;
1337         try (JavaReader jr = new JavaReader(new CharArrayReader(s.toCharArray()));
1338                 ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
1339             int ch;
1340             while ((ch = jr.read()) >= 0) {
1341                 bos.write(ch);
1342             }
1343             bytes = bos.toByteArray();
1344         }
1345         if (uncompress) {
1346             final GZIPInputStream gis = new GZIPInputStream(new ByteArrayInputStream(bytes));
1347             final byte[] tmp = new byte[bytes.length * 3]; // Rough estimate
1348             int count = 0;
1349             int b;
1350             while ((b = gis.read()) >= 0) {
1351                 tmp[count++] = (byte) b;
1352             }
1353             bytes = new byte[count];
1354             System.arraycopy(tmp, 0, bytes, 0, count);
1355         }
1356         return bytes;
1357     }
1358 
1359     // A-Z, g-z, _, $
1360     private static final int FREE_CHARS = 48;
1361     private static int[] CHAR_MAP = new int[FREE_CHARS];
1362     private static int[] MAP_CHAR = new int[256]; // Reverse map
1363     private static final char ESCAPE_CHAR = '$';
1364     static {
1365         int j = 0;
1366         for (int i = 'A'; i <= 'Z'; i++) {
1367             CHAR_MAP[j] = i;
1368             MAP_CHAR[i] = j;
1369             j++;
1370         }
1371         for (int i = 'g'; i <= 'z'; i++) {
1372             CHAR_MAP[j] = i;
1373             MAP_CHAR[i] = j;
1374             j++;
1375         }
1376         CHAR_MAP[j] = '$';
1377         MAP_CHAR['$'] = j;
1378         j++;
1379         CHAR_MAP[j] = '_';
1380         MAP_CHAR['_'] = j;
1381     }
1382 
1383     /**
1384      * Decode characters into bytes.
1385      * Used by <a href="Utility.html#decode(java.lang.String, boolean)">decode()</a>
1386      */
1387     private static class JavaReader extends FilterReader {
1388 
1389         public JavaReader(final Reader in) {
1390             super(in);
1391         }
1392 
1393 
1394         @Override
1395         public int read() throws IOException {
1396             final int b = in.read();
1397             if (b != ESCAPE_CHAR) {
1398                 return b;
1399             }
1400             final int i = in.read();
1401             if (i < 0) {
1402                 return -1;
1403             }
1404             if (((i >= '0') && (i <= '9')) || ((i >= 'a') && (i <= 'f'))) { // Normal escape
1405                 final int j = in.read();
1406                 if (j < 0) {
1407                     return -1;
1408                 }
1409                 final char[] tmp = {
1410                         (char) i, (char) j
1411                 };
1412                 final int s = Integer.parseInt(new String(tmp), 16);
1413                 return s;
1414             }
1415             return MAP_CHAR[i];
1416         }
1417 
1418 
1419         @Override
1420         public int read( final char[] cbuf, final int off, final int len ) throws IOException {
1421             for (int i = 0; i < len; i++) {
1422                 cbuf[off + i] = (char) read();
1423             }
1424             return len;
1425         }
1426     }
1427 
1428     /**
1429      * Encode bytes into valid java identifier characters.
1430      * Used by <a href="Utility.html#encode(byte[], boolean)">encode()</a>
1431      */
1432     private static class JavaWriter extends FilterWriter {
1433 
1434         public JavaWriter(final Writer out) {
1435             super(out);
1436         }
1437 
1438 
1439         @Override
1440         public void write( final int b ) throws IOException {
1441             if (isJavaIdentifierPart((char) b) && (b != ESCAPE_CHAR)) {
1442                 out.write(b);
1443             } else {
1444                 out.write(ESCAPE_CHAR); // Escape character
1445                 // Special escape
1446                 if (b >= 0 && b < FREE_CHARS) {
1447                     out.write(CHAR_MAP[b]);
1448                 } else { // Normal escape
1449                     final char[] tmp = Integer.toHexString(b).toCharArray();
1450                     if (tmp.length == 1) {
1451                         out.write('0');
1452                         out.write(tmp[0]);
1453                     } else {
1454                         out.write(tmp[0]);
1455                         out.write(tmp[1]);
1456                     }
1457                 }
1458             }
1459         }
1460 
1461 
1462         @Override
1463         public void write( final char[] cbuf, final int off, final int len ) throws IOException {
1464             for (int i = 0; i < len; i++) {
1465                 write(cbuf[off + i]);
1466             }
1467         }
1468 
1469 
1470         @Override
1471         public void write( final String str, final int off, final int len ) throws IOException {
1472             write(str.toCharArray(), off, len);
1473         }
1474     }
1475 
1476 
1477     /**
1478      * Escape all occurences of newline chars '\n', quotes \", etc.
1479      */
1480     public static String convertString( final String label ) {
1481         final char[] ch = label.toCharArray();
1482         final StringBuilder buf = new StringBuilder();
1483         for (final char element : ch) {
1484             switch (element) {
1485                 case '\n':
1486                     buf.append("\\n");
1487                     break;
1488                 case '\r':
1489                     buf.append("\\r");
1490                     break;
1491                 case '\"':
1492                     buf.append("\\\"");
1493                     break;
1494                 case '\'':
1495                     buf.append("\\'");
1496                     break;
1497                 case '\\':
1498                     buf.append("\\\\");
1499                     break;
1500                 default:
1501                     buf.append(element);
1502                     break;
1503             }
1504         }
1505         return buf.toString();
1506     }
1507 
1508 }