f55750d05a
Removes the use of shared character array buffers by String along with the two fields needed to support the use of shared buffers. Reviewed-by: alanb, mduigou, forax, briangoetz
1497 lines
57 KiB
Java
1497 lines
57 KiB
Java
/*
|
|
* Copyright (c) 1994, 2012, Oracle and/or its affiliates. All rights reserved.
|
|
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
|
|
*
|
|
* This code is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 only, as
|
|
* published by the Free Software Foundation. Oracle designates this
|
|
* particular file as subject to the "Classpath" exception as provided
|
|
* by Oracle in the LICENSE file that accompanied this code.
|
|
*
|
|
* This code is distributed in the hope that it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* version 2 for more details (a copy is included in the LICENSE file that
|
|
* accompanied this code).
|
|
*
|
|
* You should have received a copy of the GNU General Public License version
|
|
* 2 along with this work; if not, write to the Free Software Foundation,
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*
|
|
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
|
|
* or visit www.oracle.com if you need additional information or have any
|
|
* questions.
|
|
*/
|
|
|
|
package java.lang;
|
|
|
|
import java.util.Properties;
|
|
|
|
/**
|
|
* The {@code Integer} class wraps a value of the primitive type
|
|
* {@code int} in an object. An object of type {@code Integer}
|
|
* contains a single field whose type is {@code int}.
|
|
*
|
|
* <p>In addition, this class provides several methods for converting
|
|
* an {@code int} to a {@code String} and a {@code String} to an
|
|
* {@code int}, as well as other constants and methods useful when
|
|
* dealing with an {@code int}.
|
|
*
|
|
* <p>Implementation note: The implementations of the "bit twiddling"
|
|
* methods (such as {@link #highestOneBit(int) highestOneBit} and
|
|
* {@link #numberOfTrailingZeros(int) numberOfTrailingZeros}) are
|
|
* based on material from Henry S. Warren, Jr.'s <i>Hacker's
|
|
* Delight</i>, (Addison Wesley, 2002).
|
|
*
|
|
* @author Lee Boynton
|
|
* @author Arthur van Hoff
|
|
* @author Josh Bloch
|
|
* @author Joseph D. Darcy
|
|
* @since JDK1.0
|
|
*/
|
|
public final class Integer extends Number implements Comparable<Integer> {
|
|
/**
|
|
* A constant holding the minimum value an {@code int} can
|
|
* have, -2<sup>31</sup>.
|
|
*/
|
|
public static final int MIN_VALUE = 0x80000000;
|
|
|
|
/**
|
|
* A constant holding the maximum value an {@code int} can
|
|
* have, 2<sup>31</sup>-1.
|
|
*/
|
|
public static final int MAX_VALUE = 0x7fffffff;
|
|
|
|
/**
|
|
* The {@code Class} instance representing the primitive type
|
|
* {@code int}.
|
|
*
|
|
* @since JDK1.1
|
|
*/
|
|
@SuppressWarnings("unchecked")
|
|
public static final Class<Integer> TYPE = (Class<Integer>) Class.getPrimitiveClass("int");
|
|
|
|
/**
|
|
* All possible chars for representing a number as a String
|
|
*/
|
|
final static char[] digits = {
|
|
'0' , '1' , '2' , '3' , '4' , '5' ,
|
|
'6' , '7' , '8' , '9' , 'a' , 'b' ,
|
|
'c' , 'd' , 'e' , 'f' , 'g' , 'h' ,
|
|
'i' , 'j' , 'k' , 'l' , 'm' , 'n' ,
|
|
'o' , 'p' , 'q' , 'r' , 's' , 't' ,
|
|
'u' , 'v' , 'w' , 'x' , 'y' , 'z'
|
|
};
|
|
|
|
/**
|
|
* Returns a string representation of the first argument in the
|
|
* radix specified by the second argument.
|
|
*
|
|
* <p>If the radix is smaller than {@code Character.MIN_RADIX}
|
|
* or larger than {@code Character.MAX_RADIX}, then the radix
|
|
* {@code 10} is used instead.
|
|
*
|
|
* <p>If the first argument is negative, the first element of the
|
|
* result is the ASCII minus character {@code '-'}
|
|
* ({@code '\u005Cu002D'}). If the first argument is not
|
|
* negative, no sign character appears in the result.
|
|
*
|
|
* <p>The remaining characters of the result represent the magnitude
|
|
* of the first argument. If the magnitude is zero, it is
|
|
* represented by a single zero character {@code '0'}
|
|
* ({@code '\u005Cu0030'}); otherwise, the first character of
|
|
* the representation of the magnitude will not be the zero
|
|
* character. The following ASCII characters are used as digits:
|
|
*
|
|
* <blockquote>
|
|
* {@code 0123456789abcdefghijklmnopqrstuvwxyz}
|
|
* </blockquote>
|
|
*
|
|
* These are {@code '\u005Cu0030'} through
|
|
* {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
|
|
* {@code '\u005Cu007A'}. If {@code radix} is
|
|
* <var>N</var>, then the first <var>N</var> of these characters
|
|
* are used as radix-<var>N</var> digits in the order shown. Thus,
|
|
* the digits for hexadecimal (radix 16) are
|
|
* {@code 0123456789abcdef}. If uppercase letters are
|
|
* desired, the {@link java.lang.String#toUpperCase()} method may
|
|
* be called on the result:
|
|
*
|
|
* <blockquote>
|
|
* {@code Integer.toString(n, 16).toUpperCase()}
|
|
* </blockquote>
|
|
*
|
|
* @param i an integer to be converted to a string.
|
|
* @param radix the radix to use in the string representation.
|
|
* @return a string representation of the argument in the specified radix.
|
|
* @see java.lang.Character#MAX_RADIX
|
|
* @see java.lang.Character#MIN_RADIX
|
|
*/
|
|
public static String toString(int i, int radix) {
|
|
if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
|
|
radix = 10;
|
|
|
|
/* Use the faster version */
|
|
if (radix == 10) {
|
|
return toString(i);
|
|
}
|
|
|
|
char buf[] = new char[33];
|
|
boolean negative = (i < 0);
|
|
int charPos = 32;
|
|
|
|
if (!negative) {
|
|
i = -i;
|
|
}
|
|
|
|
while (i <= -radix) {
|
|
buf[charPos--] = digits[-(i % radix)];
|
|
i = i / radix;
|
|
}
|
|
buf[charPos] = digits[-i];
|
|
|
|
if (negative) {
|
|
buf[--charPos] = '-';
|
|
}
|
|
|
|
return new String(buf, charPos, (33 - charPos));
|
|
}
|
|
|
|
/**
|
|
* Returns a string representation of the first argument as an
|
|
* unsigned integer value in the radix specified by the second
|
|
* argument.
|
|
*
|
|
* <p>If the radix is smaller than {@code Character.MIN_RADIX}
|
|
* or larger than {@code Character.MAX_RADIX}, then the radix
|
|
* {@code 10} is used instead.
|
|
*
|
|
* <p>Note that since the first argument is treated as an unsigned
|
|
* value, no leading sign character is printed.
|
|
*
|
|
* <p>If the magnitude is zero, it is represented by a single zero
|
|
* character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
|
|
* the first character of the representation of the magnitude will
|
|
* not be the zero character.
|
|
*
|
|
* <p>The behavior of radixes and the characters used as digits
|
|
* are the same as {@link #toString(int, int) toString}.
|
|
*
|
|
* @param i an integer to be converted to an unsigned string.
|
|
* @param radix the radix to use in the string representation.
|
|
* @return an unsigned string representation of the argument in the specified radix.
|
|
* @see #toString(int, int)
|
|
* @since 1.8
|
|
*/
|
|
public static String toUnsignedString(int i, int radix) {
|
|
return Long.toString(toUnsignedLong(i), radix);
|
|
}
|
|
|
|
/**
|
|
* Returns a string representation of the integer argument as an
|
|
* unsigned integer in base 16.
|
|
*
|
|
* <p>The unsigned integer value is the argument plus 2<sup>32</sup>
|
|
* if the argument is negative; otherwise, it is equal to the
|
|
* argument. This value is converted to a string of ASCII digits
|
|
* in hexadecimal (base 16) with no extra leading
|
|
* {@code 0}s.
|
|
*
|
|
* <p>The value of the argument can be recovered from the returned
|
|
* string {@code s} by calling {@link
|
|
* Integer#parseUnsignedInt(String, int)
|
|
* Integer.parseUnsignedInt(s, 16)}.
|
|
*
|
|
* <p>If the unsigned magnitude is zero, it is represented by a
|
|
* single zero character {@code '0'} ({@code '\u005Cu0030'});
|
|
* otherwise, the first character of the representation of the
|
|
* unsigned magnitude will not be the zero character. The
|
|
* following characters are used as hexadecimal digits:
|
|
*
|
|
* <blockquote>
|
|
* {@code 0123456789abcdef}
|
|
* </blockquote>
|
|
*
|
|
* These are the characters {@code '\u005Cu0030'} through
|
|
* {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
|
|
* {@code '\u005Cu0066'}. If uppercase letters are
|
|
* desired, the {@link java.lang.String#toUpperCase()} method may
|
|
* be called on the result:
|
|
*
|
|
* <blockquote>
|
|
* {@code Integer.toHexString(n).toUpperCase()}
|
|
* </blockquote>
|
|
*
|
|
* @param i an integer to be converted to a string.
|
|
* @return the string representation of the unsigned integer value
|
|
* represented by the argument in hexadecimal (base 16).
|
|
* @see #parseUnsignedInt(String, int)
|
|
* @see #toUnsignedString(int, int)
|
|
* @since JDK1.0.2
|
|
*/
|
|
public static String toHexString(int i) {
|
|
return toUnsignedString0(i, 4);
|
|
}
|
|
|
|
/**
|
|
* Returns a string representation of the integer argument as an
|
|
* unsigned integer in base 8.
|
|
*
|
|
* <p>The unsigned integer value is the argument plus 2<sup>32</sup>
|
|
* if the argument is negative; otherwise, it is equal to the
|
|
* argument. This value is converted to a string of ASCII digits
|
|
* in octal (base 8) with no extra leading {@code 0}s.
|
|
*
|
|
* <p>The value of the argument can be recovered from the returned
|
|
* string {@code s} by calling {@link
|
|
* Integer#parseUnsignedInt(String, int)
|
|
* Integer.parseUnsignedInt(s, 8)}.
|
|
*
|
|
* <p>If the unsigned magnitude is zero, it is represented by a
|
|
* single zero character {@code '0'} ({@code '\u005Cu0030'});
|
|
* otherwise, the first character of the representation of the
|
|
* unsigned magnitude will not be the zero character. The
|
|
* following characters are used as octal digits:
|
|
*
|
|
* <blockquote>
|
|
* {@code 01234567}
|
|
* </blockquote>
|
|
*
|
|
* These are the characters {@code '\u005Cu0030'} through
|
|
* {@code '\u005Cu0037'}.
|
|
*
|
|
* @param i an integer to be converted to a string.
|
|
* @return the string representation of the unsigned integer value
|
|
* represented by the argument in octal (base 8).
|
|
* @see #parseUnsignedInt(String, int)
|
|
* @see #toUnsignedString(int, int)
|
|
* @since JDK1.0.2
|
|
*/
|
|
public static String toOctalString(int i) {
|
|
return toUnsignedString0(i, 3);
|
|
}
|
|
|
|
/**
|
|
* Returns a string representation of the integer argument as an
|
|
* unsigned integer in base 2.
|
|
*
|
|
* <p>The unsigned integer value is the argument plus 2<sup>32</sup>
|
|
* if the argument is negative; otherwise it is equal to the
|
|
* argument. This value is converted to a string of ASCII digits
|
|
* in binary (base 2) with no extra leading {@code 0}s.
|
|
*
|
|
* <p>The value of the argument can be recovered from the returned
|
|
* string {@code s} by calling {@link
|
|
* Integer#parseUnsignedInt(String, int)
|
|
* Integer.parseUnsignedInt(s, 2)}.
|
|
*
|
|
* <p>If the unsigned magnitude is zero, it is represented by a
|
|
* single zero character {@code '0'} ({@code '\u005Cu0030'});
|
|
* otherwise, the first character of the representation of the
|
|
* unsigned magnitude will not be the zero character. The
|
|
* characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
|
|
* '1'} ({@code '\u005Cu0031'}) are used as binary digits.
|
|
*
|
|
* @param i an integer to be converted to a string.
|
|
* @return the string representation of the unsigned integer value
|
|
* represented by the argument in binary (base 2).
|
|
* @see #parseUnsignedInt(String, int)
|
|
* @see #toUnsignedString(int, int)
|
|
* @since JDK1.0.2
|
|
*/
|
|
public static String toBinaryString(int i) {
|
|
return toUnsignedString0(i, 1);
|
|
}
|
|
|
|
/**
|
|
* Convert the integer to an unsigned number.
|
|
*/
|
|
private static String toUnsignedString0(int i, int shift) {
|
|
char[] buf = new char[32];
|
|
int charPos = 32;
|
|
int radix = 1 << shift;
|
|
int mask = radix - 1;
|
|
do {
|
|
buf[--charPos] = digits[i & mask];
|
|
i >>>= shift;
|
|
} while (i != 0);
|
|
|
|
return new String(buf, charPos, (32 - charPos));
|
|
}
|
|
|
|
|
|
final static char [] DigitTens = {
|
|
'0', '0', '0', '0', '0', '0', '0', '0', '0', '0',
|
|
'1', '1', '1', '1', '1', '1', '1', '1', '1', '1',
|
|
'2', '2', '2', '2', '2', '2', '2', '2', '2', '2',
|
|
'3', '3', '3', '3', '3', '3', '3', '3', '3', '3',
|
|
'4', '4', '4', '4', '4', '4', '4', '4', '4', '4',
|
|
'5', '5', '5', '5', '5', '5', '5', '5', '5', '5',
|
|
'6', '6', '6', '6', '6', '6', '6', '6', '6', '6',
|
|
'7', '7', '7', '7', '7', '7', '7', '7', '7', '7',
|
|
'8', '8', '8', '8', '8', '8', '8', '8', '8', '8',
|
|
'9', '9', '9', '9', '9', '9', '9', '9', '9', '9',
|
|
} ;
|
|
|
|
final static char [] DigitOnes = {
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
|
|
} ;
|
|
|
|
// I use the "invariant division by multiplication" trick to
|
|
// accelerate Integer.toString. In particular we want to
|
|
// avoid division by 10.
|
|
//
|
|
// The "trick" has roughly the same performance characteristics
|
|
// as the "classic" Integer.toString code on a non-JIT VM.
|
|
// The trick avoids .rem and .div calls but has a longer code
|
|
// path and is thus dominated by dispatch overhead. In the
|
|
// JIT case the dispatch overhead doesn't exist and the
|
|
// "trick" is considerably faster than the classic code.
|
|
//
|
|
// TODO-FIXME: convert (x * 52429) into the equiv shift-add
|
|
// sequence.
|
|
//
|
|
// RE: Division by Invariant Integers using Multiplication
|
|
// T Gralund, P Montgomery
|
|
// ACM PLDI 1994
|
|
//
|
|
|
|
/**
|
|
* Returns a {@code String} object representing the
|
|
* specified integer. The argument is converted to signed decimal
|
|
* representation and returned as a string, exactly as if the
|
|
* argument and radix 10 were given as arguments to the {@link
|
|
* #toString(int, int)} method.
|
|
*
|
|
* @param i an integer to be converted.
|
|
* @return a string representation of the argument in base 10.
|
|
*/
|
|
public static String toString(int i) {
|
|
if (i == Integer.MIN_VALUE)
|
|
return "-2147483648";
|
|
int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
|
|
char[] buf = new char[size];
|
|
getChars(i, size, buf);
|
|
return new String(buf, true);
|
|
}
|
|
|
|
/**
|
|
* Returns a string representation of the argument as an unsigned
|
|
* decimal value.
|
|
*
|
|
* The argument is converted to unsigned decimal representation
|
|
* and returned as a string exactly as if the argument and radix
|
|
* 10 were given as arguments to the {@link #toUnsignedString(int,
|
|
* int)} method.
|
|
*
|
|
* @param i an integer to be converted to an unsigned string.
|
|
* @return an unsigned string representation of the argument.
|
|
* @see #toUnsignedString(int, int)
|
|
* @since 1.8
|
|
*/
|
|
public static String toUnsignedString(int i) {
|
|
return Long.toString(toUnsignedLong(i));
|
|
}
|
|
|
|
/**
|
|
* Places characters representing the integer i into the
|
|
* character array buf. The characters are placed into
|
|
* the buffer backwards starting with the least significant
|
|
* digit at the specified index (exclusive), and working
|
|
* backwards from there.
|
|
*
|
|
* Will fail if i == Integer.MIN_VALUE
|
|
*/
|
|
static void getChars(int i, int index, char[] buf) {
|
|
int q, r;
|
|
int charPos = index;
|
|
char sign = 0;
|
|
|
|
if (i < 0) {
|
|
sign = '-';
|
|
i = -i;
|
|
}
|
|
|
|
// Generate two digits per iteration
|
|
while (i >= 65536) {
|
|
q = i / 100;
|
|
// really: r = i - (q * 100);
|
|
r = i - ((q << 6) + (q << 5) + (q << 2));
|
|
i = q;
|
|
buf [--charPos] = DigitOnes[r];
|
|
buf [--charPos] = DigitTens[r];
|
|
}
|
|
|
|
// Fall thru to fast mode for smaller numbers
|
|
// assert(i <= 65536, i);
|
|
for (;;) {
|
|
q = (i * 52429) >>> (16+3);
|
|
r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
|
|
buf [--charPos] = digits [r];
|
|
i = q;
|
|
if (i == 0) break;
|
|
}
|
|
if (sign != 0) {
|
|
buf [--charPos] = sign;
|
|
}
|
|
}
|
|
|
|
final static int [] sizeTable = { 9, 99, 999, 9999, 99999, 999999, 9999999,
|
|
99999999, 999999999, Integer.MAX_VALUE };
|
|
|
|
// Requires positive x
|
|
static int stringSize(int x) {
|
|
for (int i=0; ; i++)
|
|
if (x <= sizeTable[i])
|
|
return i+1;
|
|
}
|
|
|
|
/**
|
|
* Parses the string argument as a signed integer in the radix
|
|
* specified by the second argument. The characters in the string
|
|
* must all be digits of the specified radix (as determined by
|
|
* whether {@link java.lang.Character#digit(char, int)} returns a
|
|
* nonnegative value), except that the first character may be an
|
|
* ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
|
|
* indicate a negative value or an ASCII plus sign {@code '+'}
|
|
* ({@code '\u005Cu002B'}) to indicate a positive value. The
|
|
* resulting integer value is returned.
|
|
*
|
|
* <p>An exception of type {@code NumberFormatException} is
|
|
* thrown if any of the following situations occurs:
|
|
* <ul>
|
|
* <li>The first argument is {@code null} or is a string of
|
|
* length zero.
|
|
*
|
|
* <li>The radix is either smaller than
|
|
* {@link java.lang.Character#MIN_RADIX} or
|
|
* larger than {@link java.lang.Character#MAX_RADIX}.
|
|
*
|
|
* <li>Any character of the string is not a digit of the specified
|
|
* radix, except that the first character may be a minus sign
|
|
* {@code '-'} ({@code '\u005Cu002D'}) or plus sign
|
|
* {@code '+'} ({@code '\u005Cu002B'}) provided that the
|
|
* string is longer than length 1.
|
|
*
|
|
* <li>The value represented by the string is not a value of type
|
|
* {@code int}.
|
|
* </ul>
|
|
*
|
|
* <p>Examples:
|
|
* <blockquote><pre>
|
|
* parseInt("0", 10) returns 0
|
|
* parseInt("473", 10) returns 473
|
|
* parseInt("+42", 10) returns 42
|
|
* parseInt("-0", 10) returns 0
|
|
* parseInt("-FF", 16) returns -255
|
|
* parseInt("1100110", 2) returns 102
|
|
* parseInt("2147483647", 10) returns 2147483647
|
|
* parseInt("-2147483648", 10) returns -2147483648
|
|
* parseInt("2147483648", 10) throws a NumberFormatException
|
|
* parseInt("99", 8) throws a NumberFormatException
|
|
* parseInt("Kona", 10) throws a NumberFormatException
|
|
* parseInt("Kona", 27) returns 411787
|
|
* </pre></blockquote>
|
|
*
|
|
* @param s the {@code String} containing the integer
|
|
* representation to be parsed
|
|
* @param radix the radix to be used while parsing {@code s}.
|
|
* @return the integer represented by the string argument in the
|
|
* specified radix.
|
|
* @exception NumberFormatException if the {@code String}
|
|
* does not contain a parsable {@code int}.
|
|
*/
|
|
public static int parseInt(String s, int radix)
|
|
throws NumberFormatException
|
|
{
|
|
/*
|
|
* WARNING: This method may be invoked early during VM initialization
|
|
* before IntegerCache is initialized. Care must be taken to not use
|
|
* the valueOf method.
|
|
*/
|
|
|
|
if (s == null) {
|
|
throw new NumberFormatException("null");
|
|
}
|
|
|
|
if (radix < Character.MIN_RADIX) {
|
|
throw new NumberFormatException("radix " + radix +
|
|
" less than Character.MIN_RADIX");
|
|
}
|
|
|
|
if (radix > Character.MAX_RADIX) {
|
|
throw new NumberFormatException("radix " + radix +
|
|
" greater than Character.MAX_RADIX");
|
|
}
|
|
|
|
int result = 0;
|
|
boolean negative = false;
|
|
int i = 0, len = s.length();
|
|
int limit = -Integer.MAX_VALUE;
|
|
int multmin;
|
|
int digit;
|
|
|
|
if (len > 0) {
|
|
char firstChar = s.charAt(0);
|
|
if (firstChar < '0') { // Possible leading "+" or "-"
|
|
if (firstChar == '-') {
|
|
negative = true;
|
|
limit = Integer.MIN_VALUE;
|
|
} else if (firstChar != '+')
|
|
throw NumberFormatException.forInputString(s);
|
|
|
|
if (len == 1) // Cannot have lone "+" or "-"
|
|
throw NumberFormatException.forInputString(s);
|
|
i++;
|
|
}
|
|
multmin = limit / radix;
|
|
while (i < len) {
|
|
// Accumulating negatively avoids surprises near MAX_VALUE
|
|
digit = Character.digit(s.charAt(i++),radix);
|
|
if (digit < 0) {
|
|
throw NumberFormatException.forInputString(s);
|
|
}
|
|
if (result < multmin) {
|
|
throw NumberFormatException.forInputString(s);
|
|
}
|
|
result *= radix;
|
|
if (result < limit + digit) {
|
|
throw NumberFormatException.forInputString(s);
|
|
}
|
|
result -= digit;
|
|
}
|
|
} else {
|
|
throw NumberFormatException.forInputString(s);
|
|
}
|
|
return negative ? result : -result;
|
|
}
|
|
|
|
/**
|
|
* Parses the string argument as a signed decimal integer. The
|
|
* characters in the string must all be decimal digits, except
|
|
* that the first character may be an ASCII minus sign {@code '-'}
|
|
* ({@code '\u005Cu002D'}) to indicate a negative value or an
|
|
* ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
|
|
* indicate a positive value. The resulting integer value is
|
|
* returned, exactly as if the argument and the radix 10 were
|
|
* given as arguments to the {@link #parseInt(java.lang.String,
|
|
* int)} method.
|
|
*
|
|
* @param s a {@code String} containing the {@code int}
|
|
* representation to be parsed
|
|
* @return the integer value represented by the argument in decimal.
|
|
* @exception NumberFormatException if the string does not contain a
|
|
* parsable integer.
|
|
*/
|
|
public static int parseInt(String s) throws NumberFormatException {
|
|
return parseInt(s,10);
|
|
}
|
|
|
|
/**
|
|
* Parses the string argument as an unsigned integer in the radix
|
|
* specified by the second argument. An unsigned integer maps the
|
|
* values usually associated with negative numbers to positive
|
|
* numbers larger than {@code MAX_VALUE}.
|
|
*
|
|
* The characters in the string must all be digits of the
|
|
* specified radix (as determined by whether {@link
|
|
* java.lang.Character#digit(char, int)} returns a nonnegative
|
|
* value), except that the first character may be an ASCII plus
|
|
* sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
|
|
* integer value is returned.
|
|
*
|
|
* <p>An exception of type {@code NumberFormatException} is
|
|
* thrown if any of the following situations occurs:
|
|
* <ul>
|
|
* <li>The first argument is {@code null} or is a string of
|
|
* length zero.
|
|
*
|
|
* <li>The radix is either smaller than
|
|
* {@link java.lang.Character#MIN_RADIX} or
|
|
* larger than {@link java.lang.Character#MAX_RADIX}.
|
|
*
|
|
* <li>Any character of the string is not a digit of the specified
|
|
* radix, except that the first character may be a plus sign
|
|
* {@code '+'} ({@code '\u005Cu002B'}) provided that the
|
|
* string is longer than length 1.
|
|
*
|
|
* <li>The value represented by the string is larger than the
|
|
* largest unsigned {@code int}, 2<sup>32</sup>-1.
|
|
*
|
|
* </ul>
|
|
*
|
|
*
|
|
* @param s the {@code String} containing the unsigned integer
|
|
* representation to be parsed
|
|
* @param radix the radix to be used while parsing {@code s}.
|
|
* @return the integer represented by the string argument in the
|
|
* specified radix.
|
|
* @throws NumberFormatException if the {@code String}
|
|
* does not contain a parsable {@code int}.
|
|
* @since 1.8
|
|
*/
|
|
public static int parseUnsignedInt(String s, int radix)
|
|
throws NumberFormatException {
|
|
if (s == null) {
|
|
throw new NumberFormatException("null");
|
|
}
|
|
|
|
int len = s.length();
|
|
if (len > 0) {
|
|
char firstChar = s.charAt(0);
|
|
if (firstChar == '-') {
|
|
throw new
|
|
NumberFormatException(String.format("Illegal leading minus sign " +
|
|
"on unsigned string %s.", s));
|
|
} else {
|
|
if (len <= 5 || // Integer.MAX_VALUE in Character.MAX_RADIX is 6 digits
|
|
(radix == 10 && len <= 9) ) { // Integer.MAX_VALUE in base 10 is 10 digits
|
|
return parseInt(s, radix);
|
|
} else {
|
|
long ell = Long.parseLong(s, radix);
|
|
if ((ell & 0xffff_ffff_0000_0000L) == 0) {
|
|
return (int) ell;
|
|
} else {
|
|
throw new
|
|
NumberFormatException(String.format("String value %s exceeds " +
|
|
"range of unsigned int.", s));
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
throw NumberFormatException.forInputString(s);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Parses the string argument as an unsigned decimal integer. The
|
|
* characters in the string must all be decimal digits, except
|
|
* that the first character may be an an ASCII plus sign {@code
|
|
* '+'} ({@code '\u005Cu002B'}). The resulting integer value
|
|
* is returned, exactly as if the argument and the radix 10 were
|
|
* given as arguments to the {@link
|
|
* #parseUnsignedInt(java.lang.String, int)} method.
|
|
*
|
|
* @param s a {@code String} containing the unsigned {@code int}
|
|
* representation to be parsed
|
|
* @return the unsigned integer value represented by the argument in decimal.
|
|
* @throws NumberFormatException if the string does not contain a
|
|
* parsable unsigned integer.
|
|
* @since 1.8
|
|
*/
|
|
public static int parseUnsignedInt(String s) throws NumberFormatException {
|
|
return parseUnsignedInt(s, 10);
|
|
}
|
|
|
|
/**
|
|
* Returns an {@code Integer} object holding the value
|
|
* extracted from the specified {@code String} when parsed
|
|
* with the radix given by the second argument. The first argument
|
|
* is interpreted as representing a signed integer in the radix
|
|
* specified by the second argument, exactly as if the arguments
|
|
* were given to the {@link #parseInt(java.lang.String, int)}
|
|
* method. The result is an {@code Integer} object that
|
|
* represents the integer value specified by the string.
|
|
*
|
|
* <p>In other words, this method returns an {@code Integer}
|
|
* object equal to the value of:
|
|
*
|
|
* <blockquote>
|
|
* {@code new Integer(Integer.parseInt(s, radix))}
|
|
* </blockquote>
|
|
*
|
|
* @param s the string to be parsed.
|
|
* @param radix the radix to be used in interpreting {@code s}
|
|
* @return an {@code Integer} object holding the value
|
|
* represented by the string argument in the specified
|
|
* radix.
|
|
* @exception NumberFormatException if the {@code String}
|
|
* does not contain a parsable {@code int}.
|
|
*/
|
|
public static Integer valueOf(String s, int radix) throws NumberFormatException {
|
|
return Integer.valueOf(parseInt(s,radix));
|
|
}
|
|
|
|
/**
|
|
* Returns an {@code Integer} object holding the
|
|
* value of the specified {@code String}. The argument is
|
|
* interpreted as representing a signed decimal integer, exactly
|
|
* as if the argument were given to the {@link
|
|
* #parseInt(java.lang.String)} method. The result is an
|
|
* {@code Integer} object that represents the integer value
|
|
* specified by the string.
|
|
*
|
|
* <p>In other words, this method returns an {@code Integer}
|
|
* object equal to the value of:
|
|
*
|
|
* <blockquote>
|
|
* {@code new Integer(Integer.parseInt(s))}
|
|
* </blockquote>
|
|
*
|
|
* @param s the string to be parsed.
|
|
* @return an {@code Integer} object holding the value
|
|
* represented by the string argument.
|
|
* @exception NumberFormatException if the string cannot be parsed
|
|
* as an integer.
|
|
*/
|
|
public static Integer valueOf(String s) throws NumberFormatException {
|
|
return Integer.valueOf(parseInt(s, 10));
|
|
}
|
|
|
|
/**
|
|
* Cache to support the object identity semantics of autoboxing for values between
|
|
* -128 and 127 (inclusive) as required by JLS.
|
|
*
|
|
* The cache is initialized on first usage. The size of the cache
|
|
* may be controlled by the -XX:AutoBoxCacheMax=<size> option.
|
|
* During VM initialization, java.lang.Integer.IntegerCache.high property
|
|
* may be set and saved in the private system properties in the
|
|
* sun.misc.VM class.
|
|
*/
|
|
|
|
private static class IntegerCache {
|
|
static final int low = -128;
|
|
static final int high;
|
|
static final Integer cache[];
|
|
|
|
static {
|
|
// high value may be configured by property
|
|
int h = 127;
|
|
String integerCacheHighPropValue =
|
|
sun.misc.VM.getSavedProperty("java.lang.Integer.IntegerCache.high");
|
|
if (integerCacheHighPropValue != null) {
|
|
int i = parseInt(integerCacheHighPropValue);
|
|
i = Math.max(i, 127);
|
|
// Maximum array size is Integer.MAX_VALUE
|
|
h = Math.min(i, Integer.MAX_VALUE - (-low));
|
|
}
|
|
high = h;
|
|
|
|
cache = new Integer[(high - low) + 1];
|
|
int j = low;
|
|
for(int k = 0; k < cache.length; k++)
|
|
cache[k] = new Integer(j++);
|
|
|
|
// range [-128, 127] must be interned (JLS7 5.1.7)
|
|
assert IntegerCache.high >= 127;
|
|
}
|
|
|
|
private IntegerCache() {}
|
|
}
|
|
|
|
/**
|
|
* Returns an {@code Integer} instance representing the specified
|
|
* {@code int} value. If a new {@code Integer} instance is not
|
|
* required, this method should generally be used in preference to
|
|
* the constructor {@link #Integer(int)}, as this method is likely
|
|
* to yield significantly better space and time performance by
|
|
* caching frequently requested values.
|
|
*
|
|
* This method will always cache values in the range -128 to 127,
|
|
* inclusive, and may cache other values outside of this range.
|
|
*
|
|
* @param i an {@code int} value.
|
|
* @return an {@code Integer} instance representing {@code i}.
|
|
* @since 1.5
|
|
*/
|
|
public static Integer valueOf(int i) {
|
|
if (i >= IntegerCache.low && i <= IntegerCache.high)
|
|
return IntegerCache.cache[i + (-IntegerCache.low)];
|
|
return new Integer(i);
|
|
}
|
|
|
|
/**
|
|
* The value of the {@code Integer}.
|
|
*
|
|
* @serial
|
|
*/
|
|
private final int value;
|
|
|
|
/**
|
|
* Constructs a newly allocated {@code Integer} object that
|
|
* represents the specified {@code int} value.
|
|
*
|
|
* @param value the value to be represented by the
|
|
* {@code Integer} object.
|
|
*/
|
|
public Integer(int value) {
|
|
this.value = value;
|
|
}
|
|
|
|
/**
|
|
* Constructs a newly allocated {@code Integer} object that
|
|
* represents the {@code int} value indicated by the
|
|
* {@code String} parameter. The string is converted to an
|
|
* {@code int} value in exactly the manner used by the
|
|
* {@code parseInt} method for radix 10.
|
|
*
|
|
* @param s the {@code String} to be converted to an
|
|
* {@code Integer}.
|
|
* @exception NumberFormatException if the {@code String} does not
|
|
* contain a parsable integer.
|
|
* @see java.lang.Integer#parseInt(java.lang.String, int)
|
|
*/
|
|
public Integer(String s) throws NumberFormatException {
|
|
this.value = parseInt(s, 10);
|
|
}
|
|
|
|
/**
|
|
* Returns the value of this {@code Integer} as a {@code byte}
|
|
* after a narrowing primitive conversion.
|
|
* @jls 5.1.3 Narrowing Primitive Conversions
|
|
*/
|
|
public byte byteValue() {
|
|
return (byte)value;
|
|
}
|
|
|
|
/**
|
|
* Returns the value of this {@code Integer} as a {@code short}
|
|
* after a narrowing primitive conversion.
|
|
* @jls 5.1.3 Narrowing Primitive Conversions
|
|
*/
|
|
public short shortValue() {
|
|
return (short)value;
|
|
}
|
|
|
|
/**
|
|
* Returns the value of this {@code Integer} as an
|
|
* {@code int}.
|
|
*/
|
|
public int intValue() {
|
|
return value;
|
|
}
|
|
|
|
/**
|
|
* Returns the value of this {@code Integer} as a {@code long}
|
|
* after a widening primitive conversion.
|
|
* @jls 5.1.2 Widening Primitive Conversions
|
|
*/
|
|
public long longValue() {
|
|
return (long)value;
|
|
}
|
|
|
|
/**
|
|
* Returns the value of this {@code Integer} as a {@code float}
|
|
* after a widening primitive conversion.
|
|
* @jls 5.1.2 Widening Primitive Conversions
|
|
*/
|
|
public float floatValue() {
|
|
return (float)value;
|
|
}
|
|
|
|
/**
|
|
* Returns the value of this {@code Integer} as a {@code double}
|
|
* after a widening primitive conversion.
|
|
* @jls 5.1.2 Widening Primitive Conversions
|
|
*/
|
|
public double doubleValue() {
|
|
return (double)value;
|
|
}
|
|
|
|
/**
|
|
* Returns a {@code String} object representing this
|
|
* {@code Integer}'s value. The value is converted to signed
|
|
* decimal representation and returned as a string, exactly as if
|
|
* the integer value were given as an argument to the {@link
|
|
* java.lang.Integer#toString(int)} method.
|
|
*
|
|
* @return a string representation of the value of this object in
|
|
* base 10.
|
|
*/
|
|
public String toString() {
|
|
return toString(value);
|
|
}
|
|
|
|
/**
|
|
* Returns a hash code for this {@code Integer}.
|
|
*
|
|
* @return a hash code value for this object, equal to the
|
|
* primitive {@code int} value represented by this
|
|
* {@code Integer} object.
|
|
*/
|
|
public int hashCode() {
|
|
return value;
|
|
}
|
|
|
|
/**
|
|
* Compares this object to the specified object. The result is
|
|
* {@code true} if and only if the argument is not
|
|
* {@code null} and is an {@code Integer} object that
|
|
* contains the same {@code int} value as this object.
|
|
*
|
|
* @param obj the object to compare with.
|
|
* @return {@code true} if the objects are the same;
|
|
* {@code false} otherwise.
|
|
*/
|
|
public boolean equals(Object obj) {
|
|
if (obj instanceof Integer) {
|
|
return value == ((Integer)obj).intValue();
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Determines the integer value of the system property with the
|
|
* specified name.
|
|
*
|
|
* <p>The first argument is treated as the name of a system
|
|
* property. System properties are accessible through the {@link
|
|
* java.lang.System#getProperty(java.lang.String)} method. The
|
|
* string value of this property is then interpreted as an integer
|
|
* value using the grammar supported by {@link Integer#decode decode} and
|
|
* an {@code Integer} object representing this value is returned.
|
|
*
|
|
* <p>If there is no property with the specified name, if the
|
|
* specified name is empty or {@code null}, or if the property
|
|
* does not have the correct numeric format, then {@code null} is
|
|
* returned.
|
|
*
|
|
* <p>In other words, this method returns an {@code Integer}
|
|
* object equal to the value of:
|
|
*
|
|
* <blockquote>
|
|
* {@code getInteger(nm, null)}
|
|
* </blockquote>
|
|
*
|
|
* @param nm property name.
|
|
* @return the {@code Integer} value of the property.
|
|
* @throws SecurityException for the same reasons as
|
|
* {@link System#getProperty(String) System.getProperty}
|
|
* @see java.lang.System#getProperty(java.lang.String)
|
|
* @see java.lang.System#getProperty(java.lang.String, java.lang.String)
|
|
*/
|
|
public static Integer getInteger(String nm) {
|
|
return getInteger(nm, null);
|
|
}
|
|
|
|
/**
|
|
* Determines the integer value of the system property with the
|
|
* specified name.
|
|
*
|
|
* <p>The first argument is treated as the name of a system
|
|
* property. System properties are accessible through the {@link
|
|
* java.lang.System#getProperty(java.lang.String)} method. The
|
|
* string value of this property is then interpreted as an integer
|
|
* value using the grammar supported by {@link Integer#decode decode} and
|
|
* an {@code Integer} object representing this value is returned.
|
|
*
|
|
* <p>The second argument is the default value. An {@code Integer} object
|
|
* that represents the value of the second argument is returned if there
|
|
* is no property of the specified name, if the property does not have
|
|
* the correct numeric format, or if the specified name is empty or
|
|
* {@code null}.
|
|
*
|
|
* <p>In other words, this method returns an {@code Integer} object
|
|
* equal to the value of:
|
|
*
|
|
* <blockquote>
|
|
* {@code getInteger(nm, new Integer(val))}
|
|
* </blockquote>
|
|
*
|
|
* but in practice it may be implemented in a manner such as:
|
|
*
|
|
* <blockquote><pre>
|
|
* Integer result = getInteger(nm, null);
|
|
* return (result == null) ? new Integer(val) : result;
|
|
* </pre></blockquote>
|
|
*
|
|
* to avoid the unnecessary allocation of an {@code Integer}
|
|
* object when the default value is not needed.
|
|
*
|
|
* @param nm property name.
|
|
* @param val default value.
|
|
* @return the {@code Integer} value of the property.
|
|
* @throws SecurityException for the same reasons as
|
|
* {@link System#getProperty(String) System.getProperty}
|
|
* @see java.lang.System#getProperty(java.lang.String)
|
|
* @see java.lang.System#getProperty(java.lang.String, java.lang.String)
|
|
*/
|
|
public static Integer getInteger(String nm, int val) {
|
|
Integer result = getInteger(nm, null);
|
|
return (result == null) ? Integer.valueOf(val) : result;
|
|
}
|
|
|
|
/**
|
|
* Returns the integer value of the system property with the
|
|
* specified name. The first argument is treated as the name of a
|
|
* system property. System properties are accessible through the
|
|
* {@link java.lang.System#getProperty(java.lang.String)} method.
|
|
* The string value of this property is then interpreted as an
|
|
* integer value, as per the {@link Integer#decode decode} method,
|
|
* and an {@code Integer} object representing this value is
|
|
* returned; in summary:
|
|
*
|
|
* <ul><li>If the property value begins with the two ASCII characters
|
|
* {@code 0x} or the ASCII character {@code #}, not
|
|
* followed by a minus sign, then the rest of it is parsed as a
|
|
* hexadecimal integer exactly as by the method
|
|
* {@link #valueOf(java.lang.String, int)} with radix 16.
|
|
* <li>If the property value begins with the ASCII character
|
|
* {@code 0} followed by another character, it is parsed as an
|
|
* octal integer exactly as by the method
|
|
* {@link #valueOf(java.lang.String, int)} with radix 8.
|
|
* <li>Otherwise, the property value is parsed as a decimal integer
|
|
* exactly as by the method {@link #valueOf(java.lang.String, int)}
|
|
* with radix 10.
|
|
* </ul>
|
|
*
|
|
* <p>The second argument is the default value. The default value is
|
|
* returned if there is no property of the specified name, if the
|
|
* property does not have the correct numeric format, or if the
|
|
* specified name is empty or {@code null}.
|
|
*
|
|
* @param nm property name.
|
|
* @param val default value.
|
|
* @return the {@code Integer} value of the property.
|
|
* @throws SecurityException for the same reasons as
|
|
* {@link System#getProperty(String) System.getProperty}
|
|
* @see System#getProperty(java.lang.String)
|
|
* @see System#getProperty(java.lang.String, java.lang.String)
|
|
*/
|
|
public static Integer getInteger(String nm, Integer val) {
|
|
String v = null;
|
|
try {
|
|
v = System.getProperty(nm);
|
|
} catch (IllegalArgumentException | NullPointerException e) {
|
|
}
|
|
if (v != null) {
|
|
try {
|
|
return Integer.decode(v);
|
|
} catch (NumberFormatException e) {
|
|
}
|
|
}
|
|
return val;
|
|
}
|
|
|
|
/**
|
|
* Decodes a {@code String} into an {@code Integer}.
|
|
* Accepts decimal, hexadecimal, and octal numbers given
|
|
* by the following grammar:
|
|
*
|
|
* <blockquote>
|
|
* <dl>
|
|
* <dt><i>DecodableString:</i>
|
|
* <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
|
|
* <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
|
|
* <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
|
|
* <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
|
|
* <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
|
|
* <p>
|
|
* <dt><i>Sign:</i>
|
|
* <dd>{@code -}
|
|
* <dd>{@code +}
|
|
* </dl>
|
|
* </blockquote>
|
|
*
|
|
* <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
|
|
* are as defined in section 3.10.1 of
|
|
* <cite>The Java™ Language Specification</cite>,
|
|
* except that underscores are not accepted between digits.
|
|
*
|
|
* <p>The sequence of characters following an optional
|
|
* sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
|
|
* "{@code #}", or leading zero) is parsed as by the {@code
|
|
* Integer.parseInt} method with the indicated radix (10, 16, or
|
|
* 8). This sequence of characters must represent a positive
|
|
* value or a {@link NumberFormatException} will be thrown. The
|
|
* result is negated if first character of the specified {@code
|
|
* String} is the minus sign. No whitespace characters are
|
|
* permitted in the {@code String}.
|
|
*
|
|
* @param nm the {@code String} to decode.
|
|
* @return an {@code Integer} object holding the {@code int}
|
|
* value represented by {@code nm}
|
|
* @exception NumberFormatException if the {@code String} does not
|
|
* contain a parsable integer.
|
|
* @see java.lang.Integer#parseInt(java.lang.String, int)
|
|
*/
|
|
public static Integer decode(String nm) throws NumberFormatException {
|
|
int radix = 10;
|
|
int index = 0;
|
|
boolean negative = false;
|
|
Integer result;
|
|
|
|
if (nm.length() == 0)
|
|
throw new NumberFormatException("Zero length string");
|
|
char firstChar = nm.charAt(0);
|
|
// Handle sign, if present
|
|
if (firstChar == '-') {
|
|
negative = true;
|
|
index++;
|
|
} else if (firstChar == '+')
|
|
index++;
|
|
|
|
// Handle radix specifier, if present
|
|
if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
|
|
index += 2;
|
|
radix = 16;
|
|
}
|
|
else if (nm.startsWith("#", index)) {
|
|
index ++;
|
|
radix = 16;
|
|
}
|
|
else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
|
|
index ++;
|
|
radix = 8;
|
|
}
|
|
|
|
if (nm.startsWith("-", index) || nm.startsWith("+", index))
|
|
throw new NumberFormatException("Sign character in wrong position");
|
|
|
|
try {
|
|
result = Integer.valueOf(nm.substring(index), radix);
|
|
result = negative ? Integer.valueOf(-result.intValue()) : result;
|
|
} catch (NumberFormatException e) {
|
|
// If number is Integer.MIN_VALUE, we'll end up here. The next line
|
|
// handles this case, and causes any genuine format error to be
|
|
// rethrown.
|
|
String constant = negative ? ("-" + nm.substring(index))
|
|
: nm.substring(index);
|
|
result = Integer.valueOf(constant, radix);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* Compares two {@code Integer} objects numerically.
|
|
*
|
|
* @param anotherInteger the {@code Integer} to be compared.
|
|
* @return the value {@code 0} if this {@code Integer} is
|
|
* equal to the argument {@code Integer}; a value less than
|
|
* {@code 0} if this {@code Integer} is numerically less
|
|
* than the argument {@code Integer}; and a value greater
|
|
* than {@code 0} if this {@code Integer} is numerically
|
|
* greater than the argument {@code Integer} (signed
|
|
* comparison).
|
|
* @since 1.2
|
|
*/
|
|
public int compareTo(Integer anotherInteger) {
|
|
return compare(this.value, anotherInteger.value);
|
|
}
|
|
|
|
/**
|
|
* Compares two {@code int} values numerically.
|
|
* The value returned is identical to what would be returned by:
|
|
* <pre>
|
|
* Integer.valueOf(x).compareTo(Integer.valueOf(y))
|
|
* </pre>
|
|
*
|
|
* @param x the first {@code int} to compare
|
|
* @param y the second {@code int} to compare
|
|
* @return the value {@code 0} if {@code x == y};
|
|
* a value less than {@code 0} if {@code x < y}; and
|
|
* a value greater than {@code 0} if {@code x > y}
|
|
* @since 1.7
|
|
*/
|
|
public static int compare(int x, int y) {
|
|
return (x < y) ? -1 : ((x == y) ? 0 : 1);
|
|
}
|
|
|
|
/**
|
|
* Compares two {@code int} values numerically treating the values
|
|
* as unsigned.
|
|
*
|
|
* @param x the first {@code int} to compare
|
|
* @param y the second {@code int} to compare
|
|
* @return the value {@code 0} if {@code x == y}; a value less
|
|
* than {@code 0} if {@code x < y} as unsigned values; and
|
|
* a value greater than {@code 0} if {@code x > y} as
|
|
* unsigned values
|
|
* @since 1.8
|
|
*/
|
|
public static int compareUnsigned(int x, int y) {
|
|
return compare(x + MIN_VALUE, y + MIN_VALUE);
|
|
}
|
|
|
|
/**
|
|
* Converts the argument to a {@code long} by an unsigned
|
|
* conversion. In an unsigned conversion to a {@code long}, the
|
|
* high-order 32 bits of the {@code long} are zero and the
|
|
* low-order 32 bits are equal to the bits of the integer
|
|
* argument.
|
|
*
|
|
* Consequently, zero and positive {@code int} values are mapped
|
|
* to a numerically equal {@code long} value and negative {@code
|
|
* int} values are mapped to a {@code long} value equal to the
|
|
* input plus 2<sup>32</sup>.
|
|
*
|
|
* @param x the value to convert to an unsigned {@code long}
|
|
* @return the argument converted to {@code long} by an unsigned
|
|
* conversion
|
|
* @since 1.8
|
|
*/
|
|
public static long toUnsignedLong(int x) {
|
|
return ((long) x) & 0xffffffffL;
|
|
}
|
|
|
|
/**
|
|
* Returns the unsigned quotient of dividing the first argument by
|
|
* the second where each argument and the result is interpreted as
|
|
* an unsigned value.
|
|
*
|
|
* <p>Note that in two's complement arithmetic, the three other
|
|
* basic arithmetic operations of add, subtract, and multiply are
|
|
* bit-wise identical if the two operands are regarded as both
|
|
* being signed or both being unsigned. Therefore separate {@code
|
|
* addUnsigned}, etc. methods are not provided.
|
|
*
|
|
* @param dividend the value to be divided
|
|
* @param divisor the value doing the dividing
|
|
* @return the unsigned quotient of the first argument divided by
|
|
* the second argument
|
|
* @see #remainderUnsigned
|
|
* @since 1.8
|
|
*/
|
|
public static int divideUnsigned(int dividend, int divisor) {
|
|
// In lieu of tricky code, for now just use long arithmetic.
|
|
return (int)(toUnsignedLong(dividend) / toUnsignedLong(divisor));
|
|
}
|
|
|
|
/**
|
|
* Returns the unsigned remainder from dividing the first argument
|
|
* by the second where each argument and the result is interpreted
|
|
* as an unsigned value.
|
|
*
|
|
* @param dividend the value to be divided
|
|
* @param divisor the value doing the dividing
|
|
* @return the unsigned remainder of the first argument divided by
|
|
* the second argument
|
|
* @see #divideUnsigned
|
|
* @since 1.8
|
|
*/
|
|
public static int remainderUnsigned(int dividend, int divisor) {
|
|
// In lieu of tricky code, for now just use long arithmetic.
|
|
return (int)(toUnsignedLong(dividend) % toUnsignedLong(divisor));
|
|
}
|
|
|
|
|
|
// Bit twiddling
|
|
|
|
/**
|
|
* The number of bits used to represent an {@code int} value in two's
|
|
* complement binary form.
|
|
*
|
|
* @since 1.5
|
|
*/
|
|
public static final int SIZE = 32;
|
|
|
|
/**
|
|
* Returns an {@code int} value with at most a single one-bit, in the
|
|
* position of the highest-order ("leftmost") one-bit in the specified
|
|
* {@code int} value. Returns zero if the specified value has no
|
|
* one-bits in its two's complement binary representation, that is, if it
|
|
* is equal to zero.
|
|
*
|
|
* @return an {@code int} value with a single one-bit, in the position
|
|
* of the highest-order one-bit in the specified value, or zero if
|
|
* the specified value is itself equal to zero.
|
|
* @since 1.5
|
|
*/
|
|
public static int highestOneBit(int i) {
|
|
// HD, Figure 3-1
|
|
i |= (i >> 1);
|
|
i |= (i >> 2);
|
|
i |= (i >> 4);
|
|
i |= (i >> 8);
|
|
i |= (i >> 16);
|
|
return i - (i >>> 1);
|
|
}
|
|
|
|
/**
|
|
* Returns an {@code int} value with at most a single one-bit, in the
|
|
* position of the lowest-order ("rightmost") one-bit in the specified
|
|
* {@code int} value. Returns zero if the specified value has no
|
|
* one-bits in its two's complement binary representation, that is, if it
|
|
* is equal to zero.
|
|
*
|
|
* @return an {@code int} value with a single one-bit, in the position
|
|
* of the lowest-order one-bit in the specified value, or zero if
|
|
* the specified value is itself equal to zero.
|
|
* @since 1.5
|
|
*/
|
|
public static int lowestOneBit(int i) {
|
|
// HD, Section 2-1
|
|
return i & -i;
|
|
}
|
|
|
|
/**
|
|
* Returns the number of zero bits preceding the highest-order
|
|
* ("leftmost") one-bit in the two's complement binary representation
|
|
* of the specified {@code int} value. Returns 32 if the
|
|
* specified value has no one-bits in its two's complement representation,
|
|
* in other words if it is equal to zero.
|
|
*
|
|
* <p>Note that this method is closely related to the logarithm base 2.
|
|
* For all positive {@code int} values x:
|
|
* <ul>
|
|
* <li>floor(log<sub>2</sub>(x)) = {@code 31 - numberOfLeadingZeros(x)}
|
|
* <li>ceil(log<sub>2</sub>(x)) = {@code 32 - numberOfLeadingZeros(x - 1)}
|
|
* </ul>
|
|
*
|
|
* @return the number of zero bits preceding the highest-order
|
|
* ("leftmost") one-bit in the two's complement binary representation
|
|
* of the specified {@code int} value, or 32 if the value
|
|
* is equal to zero.
|
|
* @since 1.5
|
|
*/
|
|
public static int numberOfLeadingZeros(int i) {
|
|
// HD, Figure 5-6
|
|
if (i == 0)
|
|
return 32;
|
|
int n = 1;
|
|
if (i >>> 16 == 0) { n += 16; i <<= 16; }
|
|
if (i >>> 24 == 0) { n += 8; i <<= 8; }
|
|
if (i >>> 28 == 0) { n += 4; i <<= 4; }
|
|
if (i >>> 30 == 0) { n += 2; i <<= 2; }
|
|
n -= i >>> 31;
|
|
return n;
|
|
}
|
|
|
|
/**
|
|
* Returns the number of zero bits following the lowest-order ("rightmost")
|
|
* one-bit in the two's complement binary representation of the specified
|
|
* {@code int} value. Returns 32 if the specified value has no
|
|
* one-bits in its two's complement representation, in other words if it is
|
|
* equal to zero.
|
|
*
|
|
* @return the number of zero bits following the lowest-order ("rightmost")
|
|
* one-bit in the two's complement binary representation of the
|
|
* specified {@code int} value, or 32 if the value is equal
|
|
* to zero.
|
|
* @since 1.5
|
|
*/
|
|
public static int numberOfTrailingZeros(int i) {
|
|
// HD, Figure 5-14
|
|
int y;
|
|
if (i == 0) return 32;
|
|
int n = 31;
|
|
y = i <<16; if (y != 0) { n = n -16; i = y; }
|
|
y = i << 8; if (y != 0) { n = n - 8; i = y; }
|
|
y = i << 4; if (y != 0) { n = n - 4; i = y; }
|
|
y = i << 2; if (y != 0) { n = n - 2; i = y; }
|
|
return n - ((i << 1) >>> 31);
|
|
}
|
|
|
|
/**
|
|
* Returns the number of one-bits in the two's complement binary
|
|
* representation of the specified {@code int} value. This function is
|
|
* sometimes referred to as the <i>population count</i>.
|
|
*
|
|
* @return the number of one-bits in the two's complement binary
|
|
* representation of the specified {@code int} value.
|
|
* @since 1.5
|
|
*/
|
|
public static int bitCount(int i) {
|
|
// HD, Figure 5-2
|
|
i = i - ((i >>> 1) & 0x55555555);
|
|
i = (i & 0x33333333) + ((i >>> 2) & 0x33333333);
|
|
i = (i + (i >>> 4)) & 0x0f0f0f0f;
|
|
i = i + (i >>> 8);
|
|
i = i + (i >>> 16);
|
|
return i & 0x3f;
|
|
}
|
|
|
|
/**
|
|
* Returns the value obtained by rotating the two's complement binary
|
|
* representation of the specified {@code int} value left by the
|
|
* specified number of bits. (Bits shifted out of the left hand, or
|
|
* high-order, side reenter on the right, or low-order.)
|
|
*
|
|
* <p>Note that left rotation with a negative distance is equivalent to
|
|
* right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
|
|
* distance)}. Note also that rotation by any multiple of 32 is a
|
|
* no-op, so all but the last five bits of the rotation distance can be
|
|
* ignored, even if the distance is negative: {@code rotateLeft(val,
|
|
* distance) == rotateLeft(val, distance & 0x1F)}.
|
|
*
|
|
* @return the value obtained by rotating the two's complement binary
|
|
* representation of the specified {@code int} value left by the
|
|
* specified number of bits.
|
|
* @since 1.5
|
|
*/
|
|
public static int rotateLeft(int i, int distance) {
|
|
return (i << distance) | (i >>> -distance);
|
|
}
|
|
|
|
/**
|
|
* Returns the value obtained by rotating the two's complement binary
|
|
* representation of the specified {@code int} value right by the
|
|
* specified number of bits. (Bits shifted out of the right hand, or
|
|
* low-order, side reenter on the left, or high-order.)
|
|
*
|
|
* <p>Note that right rotation with a negative distance is equivalent to
|
|
* left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
|
|
* distance)}. Note also that rotation by any multiple of 32 is a
|
|
* no-op, so all but the last five bits of the rotation distance can be
|
|
* ignored, even if the distance is negative: {@code rotateRight(val,
|
|
* distance) == rotateRight(val, distance & 0x1F)}.
|
|
*
|
|
* @return the value obtained by rotating the two's complement binary
|
|
* representation of the specified {@code int} value right by the
|
|
* specified number of bits.
|
|
* @since 1.5
|
|
*/
|
|
public static int rotateRight(int i, int distance) {
|
|
return (i >>> distance) | (i << -distance);
|
|
}
|
|
|
|
/**
|
|
* Returns the value obtained by reversing the order of the bits in the
|
|
* two's complement binary representation of the specified {@code int}
|
|
* value.
|
|
*
|
|
* @return the value obtained by reversing order of the bits in the
|
|
* specified {@code int} value.
|
|
* @since 1.5
|
|
*/
|
|
public static int reverse(int i) {
|
|
// HD, Figure 7-1
|
|
i = (i & 0x55555555) << 1 | (i >>> 1) & 0x55555555;
|
|
i = (i & 0x33333333) << 2 | (i >>> 2) & 0x33333333;
|
|
i = (i & 0x0f0f0f0f) << 4 | (i >>> 4) & 0x0f0f0f0f;
|
|
i = (i << 24) | ((i & 0xff00) << 8) |
|
|
((i >>> 8) & 0xff00) | (i >>> 24);
|
|
return i;
|
|
}
|
|
|
|
/**
|
|
* Returns the signum function of the specified {@code int} value. (The
|
|
* return value is -1 if the specified value is negative; 0 if the
|
|
* specified value is zero; and 1 if the specified value is positive.)
|
|
*
|
|
* @return the signum function of the specified {@code int} value.
|
|
* @since 1.5
|
|
*/
|
|
public static int signum(int i) {
|
|
// HD, Section 2-7
|
|
return (i >> 31) | (-i >>> 31);
|
|
}
|
|
|
|
/**
|
|
* Returns the value obtained by reversing the order of the bytes in the
|
|
* two's complement representation of the specified {@code int} value.
|
|
*
|
|
* @return the value obtained by reversing the bytes in the specified
|
|
* {@code int} value.
|
|
* @since 1.5
|
|
*/
|
|
public static int reverseBytes(int i) {
|
|
return ((i >>> 24) ) |
|
|
((i >> 8) & 0xFF00) |
|
|
((i << 8) & 0xFF0000) |
|
|
((i << 24));
|
|
}
|
|
|
|
/** use serialVersionUID from JDK 1.0.2 for interoperability */
|
|
private static final long serialVersionUID = 1360826667806852920L;
|
|
}
|