001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 */
017
018package org.apache.bcel.classfile;
019
020import java.io.ByteArrayInputStream;
021import java.io.ByteArrayOutputStream;
022import java.io.CharArrayReader;
023import java.io.CharArrayWriter;
024import java.io.FilterReader;
025import java.io.FilterWriter;
026import java.io.IOException;
027import java.io.PrintStream;
028import java.io.PrintWriter;
029import java.io.Reader;
030import java.io.Writer;
031import java.util.ArrayList;
032import java.util.List;
033import java.util.Locale;
034import java.util.zip.GZIPInputStream;
035import java.util.zip.GZIPOutputStream;
036
037import org.apache.bcel.Const;
038import org.apache.bcel.util.ByteSequence;
039
040/**
041 * Utility functions that do not really belong to any class in particular.
042 *
043 * @version $Id: Utility.java 1808131 2017-09-12 16:36:55Z britter $
044 */
045// @since 6.0 methods are no longer final
046public abstract class Utility {
047
048    private static int unwrap( final ThreadLocal<Integer> tl ) {
049        return tl.get().intValue();
050    }
051
052
053    private static void wrap( final ThreadLocal<Integer> tl, final int value ) {
054        tl.set(Integer.valueOf(value));
055    }
056
057    private static ThreadLocal<Integer> consumed_chars = new ThreadLocal<Integer>() {
058
059        @Override
060        protected Integer initialValue() {
061            return Integer.valueOf(0);
062        }
063    };/* How many chars have been consumed
064     * during parsing in signatureToString().
065     * Read by methodSignatureToString().
066     * Set by side effect,but only internally.
067     */
068    private static boolean wide = false; /* The `WIDE' instruction is used in the
069     * byte code to allow 16-bit wide indices
070     * for local variables. This opcode
071     * precedes an `ILOAD', e.g.. The opcode
072     * immediately following takes an extra
073     * byte which is combined with the
074     * following byte to form a
075     * 16-bit value.
076     */
077
078
079    /**
080     * Convert bit field of flags into string such as `static final'.
081     *
082     * @param  access_flags Access flags
083     * @return String representation of flags
084     */
085    public static String accessToString( final int access_flags ) {
086        return accessToString(access_flags, false);
087    }
088
089
090    /**
091     * Convert bit field of flags into string such as `static final'.
092     *
093     * Special case: Classes compiled with new compilers and with the
094     * `ACC_SUPER' flag would be said to be "synchronized". This is
095     * because SUN used the same value for the flags `ACC_SUPER' and
096     * `ACC_SYNCHRONIZED'.
097     *
098     * @param  access_flags Access flags
099     * @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}