001/* Long.java -- object wrapper for long
002   Copyright (C) 1998, 1999, 2001, 2002, 2004, 2005 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package java.lang;
040
041/**
042 * Instances of class <code>Long</code> represent primitive
043 * <code>long</code> values.
044 *
045 * Additionally, this class provides various helper functions and variables
046 * related to longs.
047 *
048 * @author Paul Fisher
049 * @author John Keiser
050 * @author Warren Levy
051 * @author Eric Blake (ebb9@email.byu.edu)
052 * @author Tom Tromey (tromey@redhat.com)
053 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
054 * @author Ian Rogers
055 * @since 1.0
056 * @status updated to 1.5
057 */
058public final class Long extends Number implements Comparable<Long>
059{
060  /**
061   * Compatible with JDK 1.0.2+.
062   */
063  private static final long serialVersionUID = 4290774380558885855L;
064
065  /**
066   * The minimum value a <code>long</code> can represent is
067   * -9223372036854775808L (or -2<sup>63</sup>).
068   */
069  public static final long MIN_VALUE = 0x8000000000000000L;
070
071  /**
072   * The maximum value a <code>long</code> can represent is
073   * 9223372036854775807 (or 2<sup>63</sup> - 1).
074   */
075  public static final long MAX_VALUE = 0x7fffffffffffffffL;
076
077  /**
078   * The primitive type <code>long</code> is represented by this
079   * <code>Class</code> object.
080   * @since 1.1
081   */
082  public static final Class<Long> TYPE = (Class<Long>) VMClassLoader.getPrimitiveClass ('J');
083
084  /**
085   * The number of bits needed to represent a <code>long</code>.
086   * @since 1.5
087   */
088  public static final int SIZE = 64;
089
090  // This caches some Long values, and is used by boxing
091  // conversions via valueOf().  We cache at least -128..127;
092  // these constants control how much we actually cache.
093  private static final int MIN_CACHE = -128;
094  private static final int MAX_CACHE = 127;
095  private static final Long[] longCache = new Long[MAX_CACHE - MIN_CACHE + 1];
096  static
097  {
098    for (int i=MIN_CACHE; i <= MAX_CACHE; i++)
099      longCache[i - MIN_CACHE] = new Long(i);
100  }
101
102  /**
103   * The immutable value of this Long.
104   *
105   * @serial the wrapped long
106   */
107  private final long value;
108
109  /**
110   * Create a <code>Long</code> object representing the value of the
111   * <code>long</code> argument.
112   *
113   * @param value the value to use
114   */
115  public Long(long value)
116  {
117    this.value = value;
118  }
119
120  /**
121   * Create a <code>Long</code> object representing the value of the
122   * argument after conversion to a <code>long</code>.
123   *
124   * @param s the string to convert
125   * @throws NumberFormatException if the String does not contain a long
126   * @see #valueOf(String)
127   */
128  public Long(String s)
129  {
130    value = parseLong(s, 10, false);
131  }
132
133  /**
134   * Return the size of a string large enough to hold the given number
135   *
136   * @param num the number we want the string length for (must be positive)
137   * @param radix the radix (base) that will be used for the string
138   * @return a size sufficient for a string of num
139   */
140  private static int stringSize(long num, int radix) {
141    int exp;
142    if (radix < 4)
143      {
144        exp = 1;
145      }
146    else if (radix < 8)
147      {
148        exp = 2;
149      }
150    else if (radix < 16)
151      {
152        exp = 3;
153      }
154    else if (radix < 32)
155      {
156        exp = 4;
157      }
158    else
159      {
160        exp = 5;
161      }
162    int size=0;
163    do
164      {
165        num >>>= exp;
166        size++;
167      }
168    while(num != 0);
169    return size;
170  }
171
172  /**
173   * Converts the <code>long</code> to a <code>String</code> using
174   * the specified radix (base). If the radix exceeds
175   * <code>Character.MIN_RADIX</code> or <code>Character.MAX_RADIX</code>, 10
176   * is used instead. If the result is negative, the leading character is
177   * '-' ('\\u002D'). The remaining characters come from
178   * <code>Character.forDigit(digit, radix)</code> ('0'-'9','a'-'z').
179   *
180   * @param num the <code>long</code> to convert to <code>String</code>
181   * @param radix the radix (base) to use in the conversion
182   * @return the <code>String</code> representation of the argument
183   */
184  public static String toString(long num, int radix)
185  {
186    if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
187      radix = 10;
188
189    // Is the value negative?
190    boolean isNeg = num < 0;
191
192    // Is the string a single character?
193    if (!isNeg && num < radix)
194      return new String(digits, (int)num, 1, true);
195
196    // Compute string size and allocate buffer
197    // account for a leading '-' if the value is negative
198    int size;
199    int i;
200    char[] buffer;
201    if (isNeg)
202      {
203        num = -num;
204
205        // When the value is MIN_VALUE, it overflows when made positive
206        if (num < 0)
207          {
208            i = size = stringSize(MAX_VALUE, radix) + 2;
209            buffer = new char[size];
210            buffer[--i] = digits[(int) (-(num + radix) % radix)];
211            num = -(num / radix);
212          }
213        else
214          {
215            i = size = stringSize(num, radix) + 1;
216            buffer = new char[size];
217          }
218      }
219    else
220      {
221        i = size = stringSize(num, radix);
222        buffer = new char[size];
223      }
224
225    do
226      {
227        buffer[--i] = digits[(int) (num % radix)];
228        num /= radix;
229      }
230    while (num > 0);
231
232    if (isNeg)
233      buffer[--i] = '-';
234
235    // Package constructor avoids an array copy.
236    return new String(buffer, i, size - i, true);
237  }
238
239  /**
240   * Converts the <code>long</code> to a <code>String</code> assuming it is
241   * unsigned in base 16.
242   *
243   * @param l the <code>long</code> to convert to <code>String</code>
244   * @return the <code>String</code> representation of the argument
245   */
246  public static String toHexString(long l)
247  {
248    return toUnsignedString(l, 4);
249  }
250
251  /**
252   * Converts the <code>long</code> to a <code>String</code> assuming it is
253   * unsigned in base 8.
254   *
255   * @param l the <code>long</code> to convert to <code>String</code>
256   * @return the <code>String</code> representation of the argument
257   */
258  public static String toOctalString(long l)
259  {
260    return toUnsignedString(l, 3);
261  }
262
263  /**
264   * Converts the <code>long</code> to a <code>String</code> assuming it is
265   * unsigned in base 2.
266   *
267   * @param l the <code>long</code> to convert to <code>String</code>
268   * @return the <code>String</code> representation of the argument
269   */
270  public static String toBinaryString(long l)
271  {
272    return toUnsignedString(l, 1);
273  }
274
275  /**
276   * Converts the <code>long</code> to a <code>String</code> and assumes
277   * a radix of 10.
278   *
279   * @param num the <code>long</code> to convert to <code>String</code>
280   * @return the <code>String</code> representation of the argument
281   * @see #toString(long, int)
282   */
283  public static String toString(long num)
284  {
285    return toString(num, 10);
286  }
287
288  /**
289   * Converts the specified <code>String</code> into an <code>int</code>
290   * using the specified radix (base). The string must not be <code>null</code>
291   * or empty. It may begin with an optional '-', which will negate the answer,
292   * provided that there are also valid digits. Each digit is parsed as if by
293   * <code>Character.digit(d, radix)</code>, and must be in the range
294   * <code>0</code> to <code>radix - 1</code>. Finally, the result must be
295   * within <code>MIN_VALUE</code> to <code>MAX_VALUE</code>, inclusive.
296   * Unlike Double.parseDouble, you may not have a leading '+'; and 'l' or
297   * 'L' as the last character is only valid in radices 22 or greater, where
298   * it is a digit and not a type indicator.
299   *
300   * @param str the <code>String</code> to convert
301   * @param radix the radix (base) to use in the conversion
302   * @return the <code>String</code> argument converted to <code>long</code>
303   * @throws NumberFormatException if <code>s</code> cannot be parsed as a
304   *         <code>long</code>
305   */
306  public static long parseLong(String str, int radix)
307  {
308    return parseLong(str, radix, false);
309  }
310
311  /**
312   * Converts the specified <code>String</code> into a <code>long</code>.
313   * This function assumes a radix of 10.
314   *
315   * @param s the <code>String</code> to convert
316   * @return the <code>int</code> value of <code>s</code>
317   * @throws NumberFormatException if <code>s</code> cannot be parsed as a
318   *         <code>long</code>
319   * @see #parseLong(String, int)
320   */
321  public static long parseLong(String s)
322  {
323    return parseLong(s, 10, false);
324  }
325
326  /**
327   * Creates a new <code>Long</code> object using the <code>String</code>
328   * and specified radix (base).
329   *
330   * @param s the <code>String</code> to convert
331   * @param radix the radix (base) to convert with
332   * @return the new <code>Long</code>
333   * @throws NumberFormatException if <code>s</code> cannot be parsed as a
334   *         <code>long</code>
335   * @see #parseLong(String, int)
336   */
337  public static Long valueOf(String s, int radix)
338  {
339    return valueOf(parseLong(s, radix, false));
340  }
341
342  /**
343   * Creates a new <code>Long</code> object using the <code>String</code>,
344   * assuming a radix of 10.
345   *
346   * @param s the <code>String</code> to convert
347   * @return the new <code>Long</code>
348   * @throws NumberFormatException if <code>s</code> cannot be parsed as a
349   *         <code>long</code>
350   * @see #Long(String)
351   * @see #parseLong(String)
352   */
353  public static Long valueOf(String s)
354  {
355    return valueOf(parseLong(s, 10, false));
356  }
357
358  /**
359   * Returns a <code>Long</code> object wrapping the value.
360   *
361   * @param val the value to wrap
362   * @return the <code>Long</code>
363   * @since 1.5
364   */
365  public static Long valueOf(long val)
366  {
367    if (val < MIN_CACHE || val > MAX_CACHE)
368      return new Long(val);
369    else
370      return longCache[((int)val) - MIN_CACHE];
371  }
372
373  /**
374   * Convert the specified <code>String</code> into a <code>Long</code>.
375   * The <code>String</code> may represent decimal, hexadecimal, or
376   * octal numbers.
377   *
378   * <p>The extended BNF grammar is as follows:<br>
379   * <pre>
380   * <em>DecodableString</em>:
381   *      ( [ <code>-</code> ] <em>DecimalNumber</em> )
382   *    | ( [ <code>-</code> ] ( <code>0x</code> | <code>0X</code>
383   *              | <code>#</code> ) <em>HexDigit</em> { <em>HexDigit</em> } )
384   *    | ( [ <code>-</code> ] <code>0</code> { <em>OctalDigit</em> } )
385   * <em>DecimalNumber</em>:
386   *        <em>DecimalDigit except '0'</em> { <em>DecimalDigit</em> }
387   * <em>DecimalDigit</em>:
388   *        <em>Character.digit(d, 10) has value 0 to 9</em>
389   * <em>OctalDigit</em>:
390   *        <em>Character.digit(d, 8) has value 0 to 7</em>
391   * <em>DecimalDigit</em>:
392   *        <em>Character.digit(d, 16) has value 0 to 15</em>
393   * </pre>
394   * Finally, the value must be in the range <code>MIN_VALUE</code> to
395   * <code>MAX_VALUE</code>, or an exception is thrown. Note that you cannot
396   * use a trailing 'l' or 'L', unlike in Java source code.
397   *
398   * @param str the <code>String</code> to interpret
399   * @return the value of the String as a <code>Long</code>
400   * @throws NumberFormatException if <code>s</code> cannot be parsed as a
401   *         <code>long</code>
402   * @throws NullPointerException if <code>s</code> is null
403   * @since 1.2
404   */
405  public static Long decode(String str)
406  {
407    return valueOf(parseLong(str, 10, true));
408  }
409
410  /**
411   * Return the value of this <code>Long</code> as a <code>byte</code>.
412   *
413   * @return the byte value
414   */
415  public byte byteValue()
416  {
417    return (byte) value;
418  }
419
420  /**
421   * Return the value of this <code>Long</code> as a <code>short</code>.
422   *
423   * @return the short value
424   */
425  public short shortValue()
426  {
427    return (short) value;
428  }
429
430  /**
431   * Return the value of this <code>Long</code> as an <code>int</code>.
432   *
433   * @return the int value
434   */
435  public int intValue()
436  {
437    return (int) value;
438  }
439
440  /**
441   * Return the value of this <code>Long</code>.
442   *
443   * @return the long value
444   */
445  public long longValue()
446  {
447    return value;
448  }
449
450  /**
451   * Return the value of this <code>Long</code> as a <code>float</code>.
452   *
453   * @return the float value
454   */
455  public float floatValue()
456  {
457    return value;
458  }
459
460  /**
461   * Return the value of this <code>Long</code> as a <code>double</code>.
462   *
463   * @return the double value
464   */
465  public double doubleValue()
466  {
467    return value;
468  }
469
470  /**
471   * Converts the <code>Long</code> value to a <code>String</code> and
472   * assumes a radix of 10.
473   *
474   * @return the <code>String</code> representation
475   */
476  public String toString()
477  {
478    return toString(value, 10);
479  }
480
481  /**
482   * Return a hashcode representing this Object. <code>Long</code>'s hash
483   * code is calculated by <code>(int) (value ^ (value &gt;&gt; 32))</code>.
484   *
485   * @return this Object's hash code
486   */
487  public int hashCode()
488  {
489    return (int) (value ^ (value >>> 32));
490  }
491
492  /**
493   * Returns <code>true</code> if <code>obj</code> is an instance of
494   * <code>Long</code> and represents the same long value.
495   *
496   * @param obj the object to compare
497   * @return whether these Objects are semantically equal
498   */
499  public boolean equals(Object obj)
500  {
501    return obj instanceof Long && value == ((Long) obj).value;
502  }
503
504  /**
505   * Get the specified system property as a <code>Long</code>. The
506   * <code>decode()</code> method will be used to interpret the value of
507   * the property.
508   *
509   * @param nm the name of the system property
510   * @return the system property as a <code>Long</code>, or null if the
511   *         property is not found or cannot be decoded
512   * @throws SecurityException if accessing the system property is forbidden
513   * @see System#getProperty(String)
514   * @see #decode(String)
515   */
516  public static Long getLong(String nm)
517  {
518    return getLong(nm, null);
519  }
520
521  /**
522   * Get the specified system property as a <code>Long</code>, or use a
523   * default <code>long</code> value if the property is not found or is not
524   * decodable. The <code>decode()</code> method will be used to interpret
525   * the value of the property.
526   *
527   * @param nm the name of the system property
528   * @param val the default value
529   * @return the value of the system property, or the default
530   * @throws SecurityException if accessing the system property is forbidden
531   * @see System#getProperty(String)
532   * @see #decode(String)
533   */
534  public static Long getLong(String nm, long val)
535  {
536    Long result = getLong(nm, null);
537    return result == null ? valueOf(val) : result;
538  }
539
540  /**
541   * Get the specified system property as a <code>Long</code>, or use a
542   * default <code>Long</code> value if the property is not found or is
543   * not decodable. The <code>decode()</code> method will be used to
544   * interpret the value of the property.
545   *
546   * @param nm the name of the system property
547   * @param def the default value
548   * @return the value of the system property, or the default
549   * @throws SecurityException if accessing the system property is forbidden
550   * @see System#getProperty(String)
551   * @see #decode(String)
552   */
553  public static Long getLong(String nm, Long def)
554  {
555    if (nm == null || "".equals(nm))
556      return def;
557    nm = System.getProperty(nm);
558    if (nm == null)
559      return def;
560    try
561      {
562        return decode(nm);
563      }
564    catch (NumberFormatException e)
565      {
566        return def;
567      }
568  }
569
570  /**
571   * Compare two Longs numerically by comparing their <code>long</code>
572   * values. The result is positive if the first is greater, negative if the
573   * second is greater, and 0 if the two are equal.
574   *
575   * @param l the Long to compare
576   * @return the comparison
577   * @since 1.2
578   */
579  public int compareTo(Long l)
580  {
581    if (value == l.value)
582      return 0;
583    // Returns just -1 or 1 on inequality; doing math might overflow the long.
584    return value > l.value ? 1 : -1;
585  }
586
587  /**
588   * Compares two unboxed long values.
589   * The result is positive if the first is greater, negative if the second
590   * is greater, and 0 if the two are equal.
591   *
592   * @param x First value to compare.
593   * @param y Second value to compare.
594   *
595   * @return positive int if the first value is greater, negative if the second
596   * is greater, and 0 if the two are equal.
597   * @since 1.7
598   */
599  public static int compare(long x, long y)
600  {
601    return Long.valueOf(x).compareTo(Long.valueOf(y));
602  }
603
604  /**
605   * Return the number of bits set in x.
606   * @param x value to examine
607   * @since 1.5
608   */
609  public static int bitCount(long x)
610  {
611    // Successively collapse alternating bit groups into a sum.
612    x = ((x >> 1) & 0x5555555555555555L) + (x & 0x5555555555555555L);
613    x = ((x >> 2) & 0x3333333333333333L) + (x & 0x3333333333333333L);
614    int v = (int) ((x >>> 32) + x);
615    v = ((v >> 4) & 0x0f0f0f0f) + (v & 0x0f0f0f0f);
616    v = ((v >> 8) & 0x00ff00ff) + (v & 0x00ff00ff);
617    return ((v >> 16) & 0x0000ffff) + (v & 0x0000ffff);
618  }
619
620  /**
621   * Rotate x to the left by distance bits.
622   * @param x the value to rotate
623   * @param distance the number of bits by which to rotate
624   * @since 1.5
625   */
626  public static long rotateLeft(long x, int distance)
627  {
628    // This trick works because the shift operators implicitly mask
629    // the shift count.
630    return (x << distance) | (x >>> - distance);
631  }
632
633  /**
634   * Rotate x to the right by distance bits.
635   * @param x the value to rotate
636   * @param distance the number of bits by which to rotate
637   * @since 1.5
638   */
639  public static long rotateRight(long x, int distance)
640  {
641    // This trick works because the shift operators implicitly mask
642    // the shift count.
643    return (x << - distance) | (x >>> distance);
644  }
645
646  /**
647   * Find the highest set bit in value, and return a new value
648   * with only that bit set.
649   * @param value the value to examine
650   * @since 1.5
651   */
652  public static long highestOneBit(long value)
653  {
654    value |= value >>> 1;
655    value |= value >>> 2;
656    value |= value >>> 4;
657    value |= value >>> 8;
658    value |= value >>> 16;
659    value |= value >>> 32;
660    return value ^ (value >>> 1);
661  }
662
663  /**
664   * Return the number of leading zeros in value.
665   * @param value the value to examine
666   * @since 1.5
667   */
668  public static int numberOfLeadingZeros(long value)
669  {
670    value |= value >>> 1;
671    value |= value >>> 2;
672    value |= value >>> 4;
673    value |= value >>> 8;
674    value |= value >>> 16;
675    value |= value >>> 32;
676    return bitCount(~value);
677  }
678
679  /**
680   * Find the lowest set bit in value, and return a new value
681   * with only that bit set.
682   * @param value the value to examine
683   * @since 1.5
684   */
685  public static long lowestOneBit(long value)
686  {
687    // Classic assembly trick.
688    return value & - value;
689  }
690
691  /**
692   * Find the number of trailing zeros in value.
693   * @param value the value to examine
694   * @since 1.5
695   */
696  public static int numberOfTrailingZeros(long value)
697  {
698    return bitCount((value & -value) - 1);
699  }
700
701  /**
702   * Return 1 if x is positive, -1 if it is negative, and 0 if it is
703   * zero.
704   * @param x the value to examine
705   * @since 1.5
706   */
707  public static int signum(long x)
708  {
709    return (int) ((x >> 63) | (-x >>> 63));
710
711    // The LHS propagates the sign bit through every bit in the word;
712    // if X < 0, every bit is set to 1, else 0.  if X > 0, the RHS
713    // negates x and shifts the resulting 1 in the sign bit to the
714    // LSB, leaving every other bit 0.
715
716    // Hacker's Delight, Section 2-7
717  }
718
719  /**
720   * Reverse the bytes in val.
721   * @since 1.5
722   */
723  public static long reverseBytes(long val)
724  {
725    int hi = Integer.reverseBytes((int) val);
726    int lo = Integer.reverseBytes((int) (val >>> 32));
727    return (((long) hi) << 32) | lo;
728  }
729
730  /**
731   * Reverse the bits in val.
732   * @since 1.5
733   */
734  public static long reverse(long val)
735  {
736    long hi = Integer.reverse((int) val) & 0xffffffffL;
737    long lo = Integer.reverse((int) (val >>> 32)) & 0xffffffffL;
738    return (hi << 32) | lo;
739  }
740
741  /**
742   * Helper for converting unsigned numbers to String.
743   *
744   * @param num the number
745   * @param exp log2(digit) (ie. 1, 3, or 4 for binary, oct, hex)
746   */
747  private static String toUnsignedString(long num, int exp)
748  {
749    // Compute string length
750    int size = 1;
751    long copy = num >>> exp;
752    while (copy != 0)
753      {
754        size++;
755        copy >>>= exp;
756      }
757    // Quick path for single character strings
758    if (size == 1)
759      return new String(digits, (int)num, 1, true);
760
761    // Encode into buffer
762    int mask = (1 << exp) - 1;
763    char[] buffer = new char[size];
764    int i = size;
765    do
766      {
767        buffer[--i] = digits[(int) num & mask];
768        num >>>= exp;
769      }
770    while (num != 0);
771
772    // Package constructor avoids an array copy.
773    return new String(buffer, i, size - i, true);
774  }
775
776  /**
777   * Helper for parsing longs.
778   *
779   * @param str the string to parse
780   * @param radix the radix to use, must be 10 if decode is true
781   * @param decode if called from decode
782   * @return the parsed long value
783   * @throws NumberFormatException if there is an error
784   * @throws NullPointerException if decode is true and str is null
785   * @see #parseLong(String, int)
786   * @see #decode(String)
787   */
788  private static long parseLong(String str, int radix, boolean decode)
789  {
790    if (! decode && str == null)
791      throw new NumberFormatException();
792    int index = 0;
793    int len = str.length();
794    boolean isNeg = false;
795    if (len == 0)
796      throw new NumberFormatException();
797    int ch = str.charAt(index);
798    if (ch == '-')
799      {
800        if (len == 1)
801          throw new NumberFormatException();
802        isNeg = true;
803        ch = str.charAt(++index);
804      }
805    if (decode)
806      {
807        if (ch == '0')
808          {
809            if (++index == len)
810              return 0;
811            if ((str.charAt(index) & ~('x' ^ 'X')) == 'X')
812              {
813                radix = 16;
814                index++;
815              }
816            else
817              radix = 8;
818          }
819        else if (ch == '#')
820          {
821            radix = 16;
822            index++;
823          }
824      }
825    if (index == len)
826      throw new NumberFormatException();
827
828    long max = MAX_VALUE / radix;
829    // We can't directly write `max = (MAX_VALUE + 1) / radix'.
830    // So instead we fake it.
831    if (isNeg && MAX_VALUE % radix == radix - 1)
832      ++max;
833
834    long val = 0;
835    while (index < len)
836      {
837        if (val < 0 || val > max)
838          throw new NumberFormatException();
839
840        ch = Character.digit(str.charAt(index++), radix);
841        val = val * radix + ch;
842        if (ch < 0 || (val < 0 && (! isNeg || val != MIN_VALUE)))
843          throw new NumberFormatException();
844      }
845    return isNeg ? -val : val;
846  }
847}