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 */
044// @since 6.0 methods are no longer final
045public abstract class Utility {
046
047    private static int unwrap( final ThreadLocal<Integer> tl ) {
048        return tl.get().intValue();
049    }
050
051    private static void wrap( final ThreadLocal<Integer> tl, final int value ) {
052        tl.set(Integer.valueOf(value));
053    }
054
055    /* How many chars have been consumed
056     * during parsing in typeSignatureToString().
057     * Read by methodSignatureToString().
058     * Set by side effect, but only internally.
059     */
060    private static ThreadLocal<Integer> consumed_chars = new ThreadLocal<Integer>() {
061        @Override
062        protected Integer initialValue() {
063            return Integer.valueOf(0);
064        }
065    };
066
067    /* The `WIDE' instruction is used in the
068     * byte code to allow 16-bit wide indices
069     * for local variables. This opcode
070     * precedes an `ILOAD', e.g.. The opcode
071     * immediately following takes an extra
072     * byte which is combined with the
073     * following byte to form a
074     * 16-bit value.
075     */
076    private static boolean wide = false;
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; 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 names, <em>java/lang/String</em> becomes
470     * <em>java.lang.String</em>,
471     * e.g.. If <em>chopit</em> is <em>true</em> the prefix <em>java.lang</em>
472     * is also removed.
473     *
474     * @param str The long class name
475     * @param chopit flag that determines whether chopping is executed or not
476     * @return Compacted class name
477     */
478    public static String compactClassName( final String str, final boolean chopit ) {
479        return compactClassName(str, "java.lang.", chopit);
480    }
481
482
483    /**
484     * Shorten long class name <em>str</em>, i.e., chop off the <em>prefix</em>,
485     * if the
486     * class name starts with this string and the flag <em>chopit</em> is true.
487     * Slashes <em>/</em> are converted to dots <em>.</em>.
488     *
489     * @param str The long class name
490     * @param prefix The prefix the get rid off
491     * @param chopit flag that determines whether chopping is executed or not
492     * @return Compacted class name
493     */
494    public static String compactClassName( String str, final String prefix, final boolean chopit ) {
495        final int len = prefix.length();
496        str = str.replace('/', '.'); // Is `/' on all systems, even DOS
497        if (chopit) {
498            // If string starts with `prefix' and contains no further dots
499            if (str.startsWith(prefix) && (str.substring(len).indexOf('.') == -1)) {
500                str = str.substring(len);
501            }
502        }
503        return str;
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     * Converts argument list portion of method signature to string with all class names compacted.
563     *
564     * @param  signature    Method signature
565     * @return String Array of argument types
566     * @throws ClassFormatException
567     */
568    public static String[] methodSignatureArgumentTypes( final String signature )
569            throws ClassFormatException {
570        return methodSignatureArgumentTypes(signature, true);
571    }
572
573
574    /**
575     * Converts argument list portion of method signature to string.
576     *
577     * @param  signature    Method signature
578     * @param  chopit flag that determines whether chopping is executed or not
579     * @return String Array of argument types
580     * @throws ClassFormatException
581     */
582    public static String[] methodSignatureArgumentTypes( final String signature, final boolean chopit )
583            throws ClassFormatException {
584        final List<String> vec = new ArrayList<>();
585        int index;
586        try {
587            // Skip any type arguments to read argument declarations between `(' and `)'
588            index = signature.indexOf('(') + 1;
589            if (index <= 0) {
590                throw new ClassFormatException("Invalid method signature: " + signature);
591            }
592            while (signature.charAt(index) != ')') {
593                vec.add(typeSignatureToString(signature.substring(index), chopit));
594                //corrected concurrent private static field acess
595                index += unwrap(consumed_chars); // update position
596            }
597        } catch (final StringIndexOutOfBoundsException e) { // Should never occur
598            throw new ClassFormatException("Invalid method signature: " + signature, e);
599        }
600        return vec.toArray(new String[vec.size()]);
601    }
602
603
604    /**
605     * Converts return type portion of method signature to string with all class names compacted.
606     *
607     * @param  signature    Method signature
608     * @return String representation of method return type
609     * @throws ClassFormatException
610     */
611    public static String methodSignatureReturnType( final String signature ) throws ClassFormatException {
612        return methodSignatureReturnType(signature, true);
613    }
614
615
616    /**
617     * Converts return type portion of method signature to string.
618     *
619     * @param  signature    Method signature
620     * @param  chopit flag that determines whether chopping is executed or not
621     * @return String representation of method return type
622     * @throws ClassFormatException
623     */
624    public static String methodSignatureReturnType( final String signature, final boolean chopit ) throws ClassFormatException {
625        int index;
626        String type;
627        try {
628            // Read return type after `)'
629            index = signature.lastIndexOf(')') + 1;
630            if (index <= 0) {
631                throw new ClassFormatException("Invalid method signature: " + signature);
632            }
633            type = typeSignatureToString(signature.substring(index), chopit);
634        } catch (final StringIndexOutOfBoundsException e) { // Should never occur
635            throw new ClassFormatException("Invalid method signature: " + signature, e);
636        }
637        return type;
638    }
639
640
641    /**
642     * Converts method signature to string with all class names compacted.
643     *
644     * @param  signature to convert
645     * @param  name of method
646     * @param  access flags of method
647     * @return Human readable signature
648     */
649    public static String methodSignatureToString( final String signature, final String name, final String access ) {
650        return methodSignatureToString(signature, name, access, true);
651    }
652
653
654    /**
655     * Converts method signature to string.
656     *
657     * @param  signature to convert
658     * @param  name of method
659     * @param  access flags of method
660     * @param  chopit flag that determines whether chopping is executed or not
661     * @return Human readable signature
662     */
663    public static String methodSignatureToString( final String signature, final String name, final String access, final boolean chopit ) {
664        return methodSignatureToString(signature, name, access, chopit, null);
665    }
666
667
668    /**
669     * This method converts a method signature string into a Java type declaration like
670     * `void main(String[])' and throws a `ClassFormatException' when the parsed
671     * type is invalid.
672     *
673     * @param  signature    Method signature
674     * @param  name         Method name
675     * @param  access       Method access rights
676     * @param  chopit flag that determines whether chopping is executed or not
677     * @param  vars the LocalVariableTable for the method
678     * @return Java type declaration
679     * @throws ClassFormatException
680     */
681    public static String methodSignatureToString( final String signature, final String name,
682            final String access, final boolean chopit, final LocalVariableTable vars ) throws ClassFormatException {
683        final StringBuilder buf = new StringBuilder("(");
684        String type;
685        int index;
686        int var_index = access.contains("static") ? 0 : 1;
687        try {
688            // Skip any type arguments to read argument declarations between `(' and `)'
689            index = signature.indexOf('(') + 1;
690            if (index <= 0) {
691                throw new ClassFormatException("Invalid method signature: " + signature);
692            }
693            while (signature.charAt(index) != ')') {
694                final String param_type = typeSignatureToString(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 = typeSignatureToString(signature.substring(index), chopit);
716        } catch (final StringIndexOutOfBoundsException e) { // Should never occur
717            throw new ClassFormatException("Invalid method signature: " + signature, e);
718        }
719        // ignore any throws information in the signature
720        if (buf.length() > 1) {
721            buf.setLength(buf.length() - 2);
722        }
723        buf.append(")");
724        return access + ((access.length() > 0) ? " " : "") + // May be an empty string
725                type + " " + name + buf.toString();
726    }
727
728
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     * WARNING:
767     *
768     * There is some nomenclature confusion through much of the BCEL code base with
769     * respect to the terms Descriptor and Signature.  For the offical definitions see:
770     *
771     * @see <a href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.3">
772     * Descriptors in The Java Virtual Machine Specification</a>
773     *
774     * @see <a href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.9.1">
775     * Signatures in The Java Virtual Machine Specification</a>
776     *
777     * In brief, a descriptor is a string representing the type of a field or method.
778     * Signatures are similar, but more complex.  Signatures are used to encode declarations
779     * written in the Java programming language that use types outside the type system of the
780     * Java Virtual Machine.  They are used to describe the type of any class, interface,
781     * constructor, method or field whose declaration uses type variables or parameterized types.
782     *
783     * To parse a descriptor, call typeSignatureToString.
784     * To parse a signature, call signatureToString.
785     *
786     * Note that if the signature string is a single, non-generic item, the call to
787     * signatureToString reduces to a call to typeSignatureToString.
788     * Also note, that if you only wish to parse the first item in a longer signature
789     * string, you should call typeSignatureToString directly.
790     */
791
792
793    /**
794     * Converts a signature to a string with all class names compacted.
795     * Class, Method and Type signatures are supported.
796     * Enum and Interface signatures are not supported.
797     *
798     * @param  signature signature to convert
799     * @return String containg human readable signature
800     */
801    public static String signatureToString( final String signature ) {
802        return signatureToString(signature, true);
803    }
804
805
806    /**
807     * Converts a signature to a string.
808     * Class, Method and Type signatures are supported.
809     * Enum and Interface signatures are not supported.
810     *
811     * @param  signature signature to convert
812     * @param  chopit flag that determines whether chopping is executed or not
813     * @return String containg human readable signature
814     */
815    public static String signatureToString( final String signature, final boolean chopit ) {
816        String type = "";
817        String typeParams = "";
818        int index = 0;
819        if (signature.charAt(0) == '<') {
820            // we have type paramters
821            typeParams = typeParamTypesToString(signature, chopit);
822            index += unwrap(consumed_chars); // update position
823        }
824        if (signature.charAt(index) == '(') {
825            // We have a Method signature.
826            // add types of arguments
827            type = typeParams + typeSignaturesToString(signature.substring(index), chopit, ')');
828            index += unwrap(consumed_chars); // update position
829            // add return type
830            type = type + typeSignatureToString(signature.substring(index), chopit);
831            index += unwrap(consumed_chars); // update position
832            // ignore any throws information in the signature
833            return type;
834        }
835        // Could be Class or Type...
836        type = typeSignatureToString(signature.substring(index), chopit);
837        index += unwrap(consumed_chars); // update position
838        if ((typeParams.length() == 0) && (index == signature.length())) {
839            // We have a Type signature.
840            return type;
841        }
842        // We have a Class signature.
843        final StringBuilder typeClass = new StringBuilder(typeParams);
844        typeClass.append(" extends ");
845        typeClass.append(type);
846        if (index < signature.length()) {
847            typeClass.append(" implements ");
848            typeClass.append(typeSignatureToString(signature.substring(index), chopit));
849            index += unwrap(consumed_chars); // update position
850        }
851        while (index < signature.length()) {
852            typeClass.append(", ");
853            typeClass.append(typeSignatureToString(signature.substring(index), chopit));
854            index += unwrap(consumed_chars); // update position
855        }
856        return typeClass.toString();
857    }
858
859
860    /**
861     * Converts a type parameter list signature to a string.
862     *
863     * @param  signature signature to convert
864     * @param  chopit flag that determines whether chopping is executed or not
865     * @return String containg human readable signature
866     */
867    private static String typeParamTypesToString( final String signature, final boolean chopit ) {
868        // The first character is guranteed to be '<'
869        final StringBuilder typeParams = new StringBuilder("<");
870        int index = 1;  // skip the '<'
871        // get the first TypeParameter
872        typeParams.append(typeParamTypeToString(signature.substring(index), chopit));
873        index += unwrap(consumed_chars); // update position
874        // are there more TypeParameters?
875        while (signature.charAt(index) != '>') {
876            typeParams.append(", ");
877            typeParams.append(typeParamTypeToString(signature.substring(index), chopit));
878            index += unwrap(consumed_chars); // update position
879        }
880        wrap(consumed_chars, index + 1); // account for the '>' char
881        return typeParams.append(">").toString();
882    }
883
884
885    /**
886     * Converts a type parameter signature to a string.
887     *
888     * @param  signature signature to convert
889     * @param  chopit flag that determines whether chopping is executed or not
890     * @return String containg human readable signature
891     */
892    private static String typeParamTypeToString( final String signature, final boolean chopit ) {
893        int index = signature.indexOf(':');
894        if (index <= 0) {
895            throw new ClassFormatException("Invalid type parameter signature: " + signature);
896        }
897        // get the TypeParameter identifier
898        final StringBuilder typeParam = new StringBuilder(signature.substring(0, index));
899        index++;  // account for the ':'
900        if (signature.charAt(index) != ':') {
901            // we have a class bound
902            typeParam.append(" extends ");
903            typeParam.append(typeSignatureToString(signature.substring(index), chopit));
904            index += unwrap(consumed_chars); // update position
905        }
906        // look for interface bounds
907        while (signature.charAt(index) == ':') {
908            index++;  // skip over the ':'
909            typeParam.append(" & ");
910            typeParam.append(typeSignatureToString(signature.substring(index), chopit));
911            index += unwrap(consumed_chars); // update position
912        }
913        wrap(consumed_chars, index);
914        return typeParam.toString();
915    }
916
917
918    /**
919     * Converts a list of type signatures to a string.
920     *
921     * @param  signature signature to convert
922     * @param  chopit flag that determines whether chopping is executed or not
923     * @param  term character indicating the end of the list
924     * @return String containg human readable signature
925     */
926    private static String typeSignaturesToString( final String signature, final boolean chopit, final char term ) {
927        // The first character will be an 'open' that matches the 'close' contained in term.
928        final StringBuilder typeList = new StringBuilder(signature.substring(0, 1));
929        int index = 1;  // skip the 'open' character
930        // get the first Type in the list
931        if (signature.charAt(index) != term) {
932            typeList.append(typeSignatureToString(signature.substring(index), chopit));
933            index += unwrap(consumed_chars); // update position
934        }
935        // are there more types in the list?
936        while (signature.charAt(index) != term) {
937            typeList.append(", ");
938            typeList.append(typeSignatureToString(signature.substring(index), chopit));
939            index += unwrap(consumed_chars); // update position
940        }
941        wrap(consumed_chars, index + 1); // account for the term char
942        return typeList.append(term).toString();
943    }
944
945
946    /**
947     *
948     * This method converts a type signature string into a Java type declaration such as
949     * `String[]' and throws a `ClassFormatException' when the parsed type is invalid.
950     *
951     * @param  signature type signature
952     * @param  chopit flag that determines whether chopping is executed or not
953     * @return string containing human readable type signature
954     * @throws ClassFormatException
955     * @since 6.4.0
956     */
957    public static String typeSignatureToString( final String signature, final boolean chopit ) throws ClassFormatException {
958        //corrected concurrent private static field acess
959        wrap(consumed_chars, 1); // This is the default, read just one char like `B'
960        try {
961            switch (signature.charAt(0)) {
962                case 'B':
963                    return "byte";
964                case 'C':
965                    return "char";
966                case 'D':
967                    return "double";
968                case 'F':
969                    return "float";
970                case 'I':
971                    return "int";
972                case 'J':
973                    return "long";
974                case 'T': { // TypeVariableSignature
975                    final int index = signature.indexOf(';'); // Look for closing `;'
976                    if (index < 0) {
977                        throw new ClassFormatException("Invalid type variable signature: " + signature);
978                    }
979                    //corrected concurrent private static field acess
980                    wrap(consumed_chars, index + 1); // "Tblabla;" `T' and `;' are removed
981                    return compactClassName(signature.substring(1, index), chopit);
982                }
983                case 'L': { // Full class name
984                    // should this be a while loop? can there be more than
985                    // one generic clause?  (markro)
986                    int fromIndex = signature.indexOf('<'); // generic type?
987                    if (fromIndex < 0) {
988                        fromIndex = 0;
989                    } else {
990                        fromIndex = signature.indexOf('>', fromIndex);
991                        if (fromIndex < 0) {
992                            throw new ClassFormatException("Invalid signature: " + signature);
993                        }
994                    }
995                    final int index = signature.indexOf(';', fromIndex); // Look for closing `;'
996                    if (index < 0) {
997                        throw new ClassFormatException("Invalid signature: " + signature);
998                    }
999
1000                    // check to see if there are any TypeArguments
1001                    final int bracketIndex = signature.substring(0, index).indexOf('<');
1002                    if (bracketIndex < 0) {
1003                        // just a class identifier
1004                        wrap(consumed_chars, index + 1); // "Lblabla;" `L' and `;' are removed
1005                        return compactClassName(signature.substring(1, index), chopit);
1006                    }
1007                    // but make sure we are not looking past the end of the current item
1008                    fromIndex = signature.indexOf(';');
1009                    if (fromIndex < 0) {
1010                        throw new ClassFormatException("Invalid signature: " + signature);
1011                    }
1012                    if (fromIndex < bracketIndex) {
1013                        // just a class identifier
1014                        wrap(consumed_chars, fromIndex + 1); // "Lblabla;" `L' and `;' are removed
1015                        return compactClassName(signature.substring(1, fromIndex), chopit);
1016                    }
1017
1018                    // we have TypeArguments; build up partial result
1019                    // as we recurse for each TypeArgument
1020                    final StringBuilder type = new StringBuilder(compactClassName(signature.substring(1, bracketIndex), chopit)).append("<");
1021                    int consumed_chars = bracketIndex + 1; // Shadows global var
1022
1023                    // check for wildcards
1024                    if (signature.charAt(consumed_chars) == '+') {
1025                        type.append("? extends ");
1026                        consumed_chars++;
1027                    } else if (signature.charAt(consumed_chars) == '-') {
1028                        type.append("? super ");
1029                        consumed_chars++;
1030                    }
1031
1032                    // get the first TypeArgument
1033                    if (signature.charAt(consumed_chars) == '*') {
1034                        type.append("?");
1035                        consumed_chars++;
1036                    } else {
1037                        type.append(typeSignatureToString(signature.substring(consumed_chars), chopit));
1038                        // update our consumed count by the number of characters the for type argument
1039                        consumed_chars = unwrap(Utility.consumed_chars) + consumed_chars;
1040                        wrap(Utility.consumed_chars, consumed_chars);
1041                    }
1042
1043                    // are there more TypeArguments?
1044                    while (signature.charAt(consumed_chars) != '>') {
1045                        type.append(", ");
1046                        // check for wildcards
1047                        if (signature.charAt(consumed_chars) == '+') {
1048                            type.append("? extends ");
1049                            consumed_chars++;
1050                        } else if (signature.charAt(consumed_chars) == '-') {
1051                            type.append("? super ");
1052                            consumed_chars++;
1053                        }
1054                        if (signature.charAt(consumed_chars) == '*') {
1055                            type.append("?");
1056                            consumed_chars++;
1057                        } else {
1058                            type.append(typeSignatureToString(signature.substring(consumed_chars), chopit));
1059                            // update our consumed count by the number of characters the for type argument
1060                            consumed_chars = unwrap(Utility.consumed_chars) + consumed_chars;
1061                            wrap(Utility.consumed_chars, consumed_chars);
1062                        }
1063                    }
1064
1065                    // process the closing ">"
1066                    consumed_chars++;
1067                    type.append(">");
1068
1069                    if (signature.charAt(consumed_chars) == '.') {
1070                        // we have a ClassTypeSignatureSuffix
1071                        type.append(".");
1072                        // convert SimpleClassTypeSignature to fake ClassTypeSignature
1073                        // and then recurse to parse it
1074                        type.append(typeSignatureToString("L" + signature.substring(consumed_chars+1), chopit));
1075                        // update our consumed count by the number of characters the for type argument
1076                        // note that this count includes the "L" we added, but that is ok
1077                        // as it accounts for the "." we didn't consume
1078                        consumed_chars = unwrap(Utility.consumed_chars) + consumed_chars;
1079                        wrap(Utility.consumed_chars, consumed_chars);
1080                        return type.toString();
1081                    }
1082                    if (signature.charAt(consumed_chars) != ';') {
1083                        throw new ClassFormatException("Invalid signature: " + signature);
1084                    }
1085                    wrap(Utility.consumed_chars, consumed_chars + 1); // remove final ";"
1086                    return type.toString();
1087                }
1088                case 'S':
1089                    return "short";
1090                case 'Z':
1091                    return "boolean";
1092                case '[': { // Array declaration
1093                    int n;
1094                    StringBuilder brackets;
1095                    String type;
1096                    int consumed_chars; // Shadows global var
1097                    brackets = new StringBuilder(); // Accumulate []'s
1098                    // Count opening brackets and look for optional size argument
1099                    for (n = 0; signature.charAt(n) == '['; n++) {
1100                        brackets.append("[]");
1101                    }
1102                    consumed_chars = n; // Remember value
1103                    // The rest of the string denotes a `<field_type>'
1104                    type = typeSignatureToString(signature.substring(n), chopit);
1105                    //corrected concurrent private static field acess
1106                    //Utility.consumed_chars += consumed_chars; is replaced by:
1107                    final int _temp = unwrap(Utility.consumed_chars) + consumed_chars;
1108                    wrap(Utility.consumed_chars, _temp);
1109                    return type + brackets.toString();
1110                }
1111                case 'V':
1112                    return "void";
1113                default:
1114                    throw new ClassFormatException("Invalid signature: `" + signature + "'");
1115            }
1116        } catch (final StringIndexOutOfBoundsException e) { // Should never occur
1117            throw new ClassFormatException("Invalid signature: " + signature, e);
1118        }
1119    }
1120
1121
1122    /** Parse Java type such as "char", or "java.lang.String[]" and return the
1123     * signature in byte code format, e.g. "C" or "[Ljava/lang/String;" respectively.
1124     *
1125     * @param  type Java type
1126     * @return byte code signature
1127     */
1128    public static String getSignature( String type ) {
1129        final StringBuilder buf = new StringBuilder();
1130        final char[] chars = type.toCharArray();
1131        boolean char_found = false;
1132        boolean delim = false;
1133        int index = -1;
1134        loop: for (int i = 0; i < chars.length; i++) {
1135            switch (chars[i]) {
1136                case ' ':
1137                case '\t':
1138                case '\n':
1139                case '\r':
1140                case '\f':
1141                    if (char_found) {
1142                        delim = true;
1143                    }
1144                    break;
1145                case '[':
1146                    if (!char_found) {
1147                        throw new IllegalArgumentException("Illegal type: " + type);
1148                    }
1149                    index = i;
1150                    break loop;
1151                default:
1152                    char_found = true;
1153                    if (!delim) {
1154                        buf.append(chars[i]);
1155                    }
1156            }
1157        }
1158        int brackets = 0;
1159        if (index > 0) {
1160            brackets = countBrackets(type.substring(index));
1161        }
1162        type = buf.toString();
1163        buf.setLength(0);
1164        for (int i = 0; i < brackets; i++) {
1165            buf.append('[');
1166        }
1167        boolean found = false;
1168        for (int i = Const.T_BOOLEAN; (i <= Const.T_VOID) && !found; i++) {
1169            if (Const.getTypeName(i).equals(type)) {
1170                found = true;
1171                buf.append(Const.getShortTypeName(i));
1172            }
1173        }
1174        if (!found) {
1175            buf.append('L').append(type.replace('.', '/')).append(';');
1176        }
1177        return buf.toString();
1178    }
1179
1180
1181    private static int countBrackets( final String brackets ) {
1182        final char[] chars = brackets.toCharArray();
1183        int count = 0;
1184        boolean open = false;
1185        for (final char c : chars) {
1186            switch (c) {
1187                case '[':
1188                    if (open) {
1189                        throw new IllegalArgumentException("Illegally nested brackets:" + brackets);
1190                    }
1191                    open = true;
1192                    break;
1193                case ']':
1194                    if (!open) {
1195                        throw new IllegalArgumentException("Illegally nested brackets:" + brackets);
1196                    }
1197                    open = false;
1198                    count++;
1199                    break;
1200                default:
1201                    // Don't care
1202                    break;
1203            }
1204        }
1205        if (open) {
1206            throw new IllegalArgumentException("Illegally nested brackets:" + brackets);
1207        }
1208        return count;
1209    }
1210
1211
1212    /**
1213     * Return type of method signature as a byte value as defined in <em>Constants</em>
1214     *
1215     * @param  signature in format described above
1216     * @return type of method signature
1217     * @see    Const
1218     *
1219     * @throws ClassFormatException if signature is not a method signature
1220     */
1221    public static byte typeOfMethodSignature( final String signature ) throws ClassFormatException {
1222        int index;
1223        try {
1224            if (signature.charAt(0) != '(') {
1225                throw new ClassFormatException("Invalid method signature: " + signature);
1226            }
1227            index = signature.lastIndexOf(')') + 1;
1228            return typeOfSignature(signature.substring(index));
1229        } catch (final StringIndexOutOfBoundsException e) {
1230            throw new ClassFormatException("Invalid method signature: " + signature, e);
1231        }
1232    }
1233
1234
1235    /**
1236     * Return type of signature as a byte value as defined in <em>Constants</em>
1237     *
1238     * @param  signature in format described above
1239     * @return type of signature
1240     * @see    Const
1241     *
1242     * @throws ClassFormatException if signature isn't a known type
1243     */
1244    public static byte typeOfSignature( final String signature ) throws ClassFormatException {
1245        try {
1246            switch (signature.charAt(0)) {
1247                case 'B':
1248                    return Const.T_BYTE;
1249                case 'C':
1250                    return Const.T_CHAR;
1251                case 'D':
1252                    return Const.T_DOUBLE;
1253                case 'F':
1254                    return Const.T_FLOAT;
1255                case 'I':
1256                    return Const.T_INT;
1257                case 'J':
1258                    return Const.T_LONG;
1259                case 'L':
1260                case 'T':
1261                    return Const.T_REFERENCE;
1262                case '[':
1263                    return Const.T_ARRAY;
1264                case 'V':
1265                    return Const.T_VOID;
1266                case 'Z':
1267                    return Const.T_BOOLEAN;
1268                case 'S':
1269                    return Const.T_SHORT;
1270                case '!':
1271                case '+':
1272                case '*':
1273                    return typeOfSignature(signature.substring(1));
1274                default:
1275                    throw new ClassFormatException("Invalid method signature: " + signature);
1276            }
1277        } catch (final StringIndexOutOfBoundsException e) {
1278            throw new ClassFormatException("Invalid method signature: " + signature, e);
1279        }
1280    }
1281
1282
1283    /** Map opcode names to opcode numbers. E.g., return Constants.ALOAD for "aload"
1284     */
1285    public static short searchOpcode( String name ) {
1286        name = name.toLowerCase(Locale.ENGLISH);
1287        for (short i = 0; i < Const.OPCODE_NAMES_LENGTH; i++) {
1288            if (Const.getOpcodeName(i).equals(name)) {
1289                return i;
1290            }
1291        }
1292        return -1;
1293    }
1294
1295
1296    /**
1297     * Convert (signed) byte to (unsigned) short value, i.e., all negative
1298     * values become positive.
1299     */
1300    private static short byteToShort( final byte b ) {
1301        return (b < 0) ? (short) (256 + b) : (short) b;
1302    }
1303
1304
1305    /** Convert bytes into hexadecimal string
1306     *
1307     * @param bytes an array of bytes to convert to hexadecimal
1308     *
1309     * @return bytes as hexadecimal string, e.g. 00 fa 12 ...
1310     */
1311    public static String toHexString( final byte[] bytes ) {
1312        final StringBuilder buf = new StringBuilder();
1313        for (int i = 0; i < bytes.length; i++) {
1314            final short b = byteToShort(bytes[i]);
1315            final String hex = Integer.toHexString(b);
1316            if (b < 0x10) {
1317                buf.append('0');
1318            }
1319            buf.append(hex);
1320            if (i < bytes.length - 1) {
1321                buf.append(' ');
1322            }
1323        }
1324        return buf.toString();
1325    }
1326
1327
1328    /**
1329     * Return a string for an integer justified left or right and filled up with
1330     * `fill' characters if necessary.
1331     *
1332     * @param i integer to format
1333     * @param length length of desired string
1334     * @param left_justify format left or right
1335     * @param fill fill character
1336     * @return formatted int
1337     */
1338    public static String format( final int i, final int length, final boolean left_justify, final char fill ) {
1339        return fillup(Integer.toString(i), length, left_justify, fill);
1340    }
1341
1342
1343    /**
1344     * Fillup char with up to length characters with char `fill' and justify it left or right.
1345     *
1346     * @param str string to format
1347     * @param length length of desired string
1348     * @param left_justify format left or right
1349     * @param fill fill character
1350     * @return formatted string
1351     */
1352    public static String fillup( final String str, final int length, final boolean left_justify, final char fill ) {
1353        final int len = length - str.length();
1354        final char[] buf = new char[(len < 0) ? 0 : len];
1355        for (int j = 0; j < buf.length; j++) {
1356            buf[j] = fill;
1357        }
1358        if (left_justify) {
1359            return str + new String(buf);
1360        }
1361        return new String(buf) + str;
1362    }
1363
1364
1365    static boolean equals( final byte[] a, final byte[] b ) {
1366        int size;
1367        if ((size = a.length) != b.length) {
1368            return false;
1369        }
1370        for (int i = 0; i < size; i++) {
1371            if (a[i] != b[i]) {
1372                return false;
1373            }
1374        }
1375        return true;
1376    }
1377
1378
1379    public static void printArray( final PrintStream out, final Object[] obj ) {
1380        out.println(printArray(obj, true));
1381    }
1382
1383
1384    public static void printArray( final PrintWriter out, final Object[] obj ) {
1385        out.println(printArray(obj, true));
1386    }
1387
1388
1389    public static String printArray( final Object[] obj ) {
1390        return printArray(obj, true);
1391    }
1392
1393
1394    public static String printArray( final Object[] obj, final boolean braces ) {
1395        return printArray(obj, braces, false);
1396    }
1397
1398
1399    public static String printArray( final Object[] obj, final boolean braces, final boolean quote ) {
1400        if (obj == null) {
1401            return null;
1402        }
1403        final StringBuilder buf = new StringBuilder();
1404        if (braces) {
1405            buf.append('{');
1406        }
1407        for (int i = 0; i < obj.length; i++) {
1408            if (obj[i] != null) {
1409                buf.append(quote ? "\"" : "").append(obj[i]).append(quote ? "\"" : "");
1410            } else {
1411                buf.append("null");
1412            }
1413            if (i < obj.length - 1) {
1414                buf.append(", ");
1415            }
1416        }
1417        if (braces) {
1418            buf.append('}');
1419        }
1420        return buf.toString();
1421    }
1422
1423
1424    /**
1425     * @param ch the character to test if it's part of an identifier
1426     *
1427     * @return true, if character is one of (a, ... z, A, ... Z, 0, ... 9, _)
1428     */
1429    public static boolean isJavaIdentifierPart( final char ch ) {
1430        return ((ch >= 'a') && (ch <= 'z')) || ((ch >= 'A') && (ch <= 'Z'))
1431                || ((ch >= '0') && (ch <= '9')) || (ch == '_');
1432    }
1433
1434
1435    /**
1436     * Encode byte array it into Java identifier string, i.e., a string
1437     * that only contains the following characters: (a, ... z, A, ... Z,
1438     * 0, ... 9, _, $).  The encoding algorithm itself is not too
1439     * clever: if the current byte's ASCII value already is a valid Java
1440     * identifier part, leave it as it is. Otherwise it writes the
1441     * escape character($) followed by:
1442     *
1443     * <ul>
1444     *   <li> the ASCII value as a hexadecimal string, if the value is not in the range 200..247</li>
1445     *   <li>a Java identifier char not used in a lowercase hexadecimal string, if the value is in the range 200..247</li>
1446     * </ul>
1447     *
1448     * <p>This operation inflates the original byte array by roughly 40-50%</p>
1449     *
1450     * @param bytes the byte array to convert
1451     * @param compress use gzip to minimize string
1452     *
1453     * @throws IOException if there's a gzip exception
1454     */
1455    public static String encode(byte[] bytes, final boolean compress) throws IOException {
1456        if (compress) {
1457            try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
1458                    GZIPOutputStream gos = new GZIPOutputStream(baos)) {
1459                gos.write(bytes, 0, bytes.length);
1460                bytes = baos.toByteArray();
1461            }
1462        }
1463        final CharArrayWriter caw = new CharArrayWriter();
1464        try (JavaWriter jw = new JavaWriter(caw)) {
1465            for (final byte b : bytes) {
1466                final int in = b & 0x000000ff; // Normalize to unsigned
1467                jw.write(in);
1468            }
1469        }
1470        return caw.toString();
1471    }
1472
1473
1474    /**
1475     * Decode a string back to a byte array.
1476     *
1477     * @param s the string to convert
1478     * @param uncompress use gzip to uncompress the stream of bytes
1479     *
1480     * @throws IOException if there's a gzip exception
1481     */
1482    public static byte[] decode(final String s, final boolean uncompress) throws IOException {
1483        byte[] bytes;
1484        try (JavaReader jr = new JavaReader(new CharArrayReader(s.toCharArray()));
1485                ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
1486            int ch;
1487            while ((ch = jr.read()) >= 0) {
1488                bos.write(ch);
1489            }
1490            bytes = bos.toByteArray();
1491        }
1492        if (uncompress) {
1493            final GZIPInputStream gis = new GZIPInputStream(new ByteArrayInputStream(bytes));
1494            final byte[] tmp = new byte[bytes.length * 3]; // Rough estimate
1495            int count = 0;
1496            int b;
1497            while ((b = gis.read()) >= 0) {
1498                tmp[count++] = (byte) b;
1499            }
1500            bytes = new byte[count];
1501            System.arraycopy(tmp, 0, bytes, 0, count);
1502        }
1503        return bytes;
1504    }
1505
1506    // A-Z, g-z, _, $
1507    private static final int FREE_CHARS = 48;
1508    private static int[] CHAR_MAP = new int[FREE_CHARS];
1509    private static int[] MAP_CHAR = new int[256]; // Reverse map
1510    private static final char ESCAPE_CHAR = '$';
1511    static {
1512        int j = 0;
1513        for (int i = 'A'; i <= 'Z'; i++) {
1514            CHAR_MAP[j] = i;
1515            MAP_CHAR[i] = j;
1516            j++;
1517        }
1518        for (int i = 'g'; i <= 'z'; i++) {
1519            CHAR_MAP[j] = i;
1520            MAP_CHAR[i] = j;
1521            j++;
1522        }
1523        CHAR_MAP[j] = '$';
1524        MAP_CHAR['$'] = j;
1525        j++;
1526        CHAR_MAP[j] = '_';
1527        MAP_CHAR['_'] = j;
1528    }
1529
1530    /**
1531     * Decode characters into bytes.
1532     * Used by <a href="Utility.html#decode(java.lang.String, boolean)">decode()</a>
1533     */
1534    private static class JavaReader extends FilterReader {
1535
1536        public JavaReader(final Reader in) {
1537            super(in);
1538        }
1539
1540
1541        @Override
1542        public int read() throws IOException {
1543            final int b = in.read();
1544            if (b != ESCAPE_CHAR) {
1545                return b;
1546            }
1547            final int i = in.read();
1548            if (i < 0) {
1549                return -1;
1550            }
1551            if (((i >= '0') && (i <= '9')) || ((i >= 'a') && (i <= 'f'))) { // Normal escape
1552                final int j = in.read();
1553                if (j < 0) {
1554                    return -1;
1555                }
1556                final char[] tmp = {
1557                        (char) i, (char) j
1558                };
1559                final int s = Integer.parseInt(new String(tmp), 16);
1560                return s;
1561            }
1562            return MAP_CHAR[i];
1563        }
1564
1565
1566        @Override
1567        public int read( final char[] cbuf, final int off, final int len ) throws IOException {
1568            for (int i = 0; i < len; i++) {
1569                cbuf[off + i] = (char) read();
1570            }
1571            return len;
1572        }
1573    }
1574
1575    /**
1576     * Encode bytes into valid java identifier characters.
1577     * Used by <a href="Utility.html#encode(byte[], boolean)">encode()</a>
1578     */
1579    private static class JavaWriter extends FilterWriter {
1580
1581        public JavaWriter(final Writer out) {
1582            super(out);
1583        }
1584
1585
1586        @Override
1587        public void write( final int b ) throws IOException {
1588            if (isJavaIdentifierPart((char) b) && (b != ESCAPE_CHAR)) {
1589                out.write(b);
1590            } else {
1591                out.write(ESCAPE_CHAR); // Escape character
1592                // Special escape
1593                if (b >= 0 && b < FREE_CHARS) {
1594                    out.write(CHAR_MAP[b]);
1595                } else { // Normal escape
1596                    final char[] tmp = Integer.toHexString(b).toCharArray();
1597                    if (tmp.length == 1) {
1598                        out.write('0');
1599                        out.write(tmp[0]);
1600                    } else {
1601                        out.write(tmp[0]);
1602                        out.write(tmp[1]);
1603                    }
1604                }
1605            }
1606        }
1607
1608
1609        @Override
1610        public void write( final char[] cbuf, final int off, final int len ) throws IOException {
1611            for (int i = 0; i < len; i++) {
1612                write(cbuf[off + i]);
1613            }
1614        }
1615
1616
1617        @Override
1618        public void write( final String str, final int off, final int len ) throws IOException {
1619            write(str.toCharArray(), off, len);
1620        }
1621    }
1622
1623
1624    /**
1625     * Escape all occurences of newline chars '\n', quotes \", etc.
1626     */
1627    public static String convertString( final String label ) {
1628        final char[] ch = label.toCharArray();
1629        final StringBuilder buf = new StringBuilder();
1630        for (final char element : ch) {
1631            switch (element) {
1632                case '\n':
1633                    buf.append("\\n");
1634                    break;
1635                case '\r':
1636                    buf.append("\\r");
1637                    break;
1638                case '\"':
1639                    buf.append("\\\"");
1640                    break;
1641                case '\'':
1642                    buf.append("\\'");
1643                    break;
1644                case '\\':
1645                    buf.append("\\\\");
1646                    break;
1647                default:
1648                    buf.append(element);
1649                    break;
1650            }
1651        }
1652        return buf.toString();
1653    }
1654
1655}