Integer.java revision 4008
2362N/A * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved. 0N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 0N/A * This code is free software; you can redistribute it and/or modify it 0N/A * under the terms of the GNU General Public License version 2 only, as 2362N/A * published by the Free Software Foundation. Oracle designates this 0N/A * particular file as subject to the "Classpath" exception as provided 2362N/A * by Oracle in the LICENSE file that accompanied this code. 0N/A * This code is distributed in the hope that it will be useful, but WITHOUT 0N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 0N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 0N/A * version 2 for more details (a copy is included in the LICENSE file that 0N/A * accompanied this code). 0N/A * You should have received a copy of the GNU General Public License version 0N/A * 2 along with this work; if not, write to the Free Software Foundation, 0N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 2362N/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2362N/A * or visit www.oracle.com if you need additional information or have any 0N/A * The {@code Integer} class wraps a value of the primitive type 0N/A * {@code int} in an object. An object of type {@code Integer} 0N/A * contains a single field whose type is {@code int}. 0N/A * <p>In addition, this class provides several methods for converting 0N/A * an {@code int} to a {@code String} and a {@code String} to an 0N/A * {@code int}, as well as other constants and methods useful when 0N/A * dealing with an {@code int}. 0N/A * <p>Implementation note: The implementations of the "bit twiddling" 0N/A * methods (such as {@link #highestOneBit(int) highestOneBit} and 0N/A * {@link #numberOfTrailingZeros(int) numberOfTrailingZeros}) are 0N/A * based on material from Henry S. Warren, Jr.'s <i>Hacker's 0N/A * Delight</i>, (Addison Wesley, 2002). 0N/A * @author Lee Boynton 0N/A * @author Arthur van Hoff 0N/A * @author Josh Bloch 0N/A * @author Joseph D. Darcy 0N/A * A constant holding the minimum value an {@code int} can 0N/A * have, -2<sup>31</sup>. 0N/A * A constant holding the maximum value an {@code int} can 0N/A * have, 2<sup>31</sup>-1. 0N/A * The {@code Class} instance representing the primitive type 0N/A * All possible chars for representing a number as a String 0N/A '0' ,
'1' ,
'2' ,
'3' ,
'4' ,
'5' ,
0N/A '6' ,
'7' ,
'8' ,
'9' ,
'a' ,
'b' ,
0N/A 'c' ,
'd' ,
'e' ,
'f' ,
'g' ,
'h' ,
0N/A 'i' ,
'j' ,
'k' ,
'l' ,
'm' ,
'n' ,
0N/A 'o' ,
'p' ,
'q' ,
'r' ,
's' ,
't' ,
0N/A 'u' ,
'v' ,
'w' ,
'x' ,
'y' ,
'z' 0N/A * Returns a string representation of the first argument in the 0N/A * radix specified by the second argument. 0N/A * <p>If the radix is smaller than {@code Character.MIN_RADIX} 0N/A * or larger than {@code Character.MAX_RADIX}, then the radix 0N/A * {@code 10} is used instead. 0N/A * <p>If the first argument is negative, the first element of the 0N/A * result is the ASCII minus character {@code '-'} 0N/A * (<code>'\u002D'</code>). If the first argument is not 0N/A * negative, no sign character appears in the result. 0N/A * <p>The remaining characters of the result represent the magnitude 0N/A * of the first argument. If the magnitude is zero, it is 0N/A * represented by a single zero character {@code '0'} 0N/A * (<code>'\u0030'</code>); otherwise, the first character of 0N/A * the representation of the magnitude will not be the zero 0N/A * character. The following ASCII characters are used as digits: 0N/A * {@code 0123456789abcdefghijklmnopqrstuvwxyz} 0N/A * These are <code>'\u0030'</code> through 0N/A * <code>'\u0039'</code> and <code>'\u0061'</code> through 0N/A * <code>'\u007A'</code>. If {@code radix} is 0N/A * <var>N</var>, then the first <var>N</var> of these characters 0N/A * are used as radix-<var>N</var> digits in the order shown. Thus, 0N/A * 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: * {@code Integer.toString(n, 16).toUpperCase()} * @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 /* Use the faster version */ char buf[] =
new char[
33];
* 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. If the unsigned magnitude is zero, it is * represented by a single zero character {@code '0'} * (<code>'\u0030'</code>); otherwise, the first character of * the representation of the unsigned magnitude will not be the * zero character. The following characters are used as * {@code 0123456789abcdef} * These are the characters <code>'\u0030'</code> through * <code>'\u0039'</code> and <code>'\u0061'</code> through * <code>'\u0066'</code>. If uppercase letters are * desired, the {@link java.lang.String#toUpperCase()} method may * be called on the result: * {@code Integer.toHexString(n).toUpperCase()} * @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). * 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>If the unsigned magnitude is zero, it is represented by a * single zero character {@code '0'} * (<code>'\u0030'</code>); otherwise, the first character of * the representation of the unsigned magnitude will not be the * zero character. The following characters are used as octal * These are the characters <code>'\u0030'</code> through * <code>'\u0037'</code>. * @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). * 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. * If the unsigned magnitude is zero, it is represented by a * single zero character {@code '0'} * (<code>'\u0030'</code>); otherwise, the first character of * the representation of the unsigned magnitude will not be the * zero character. The characters {@code '0'} * (<code>'\u0030'</code>) and {@code '1'} * (<code>'\u0031'</code>) 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). * Convert the integer to an unsigned number. char[]
buf =
new char[
32];
'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',
'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 // 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 // RE: Division by Invariant Integers using Multiplication // T Gralund, P Montgomery * 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. * 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 * Will fail if i == Integer.MIN_VALUE // Generate two digits per iteration // really: r = i - (q * 100); r = i - ((q <<
6) + (q <<
5) + (q <<
2));
// Fall thru to fast mode for smaller numbers // assert(i <= 65536, i); q = (i *
52429) >>> (
16+
3);
r = i - ((q <<
3) + (q <<
1));
// r = i-(q*10) ... final static int []
sizeTable = {
9,
99,
999,
9999,
99999,
999999,
9999999,
* 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>'\u002D'</code>) to * indicate a negative value or an ASCII plus sign {@code '+'} * (<code>'\u002B'</code>) 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: * <li>The first argument is {@code null} or is a string of * <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>'\u002D'</code>) or plus sign * {@code '+'} (<code>'\u002B'</code>) provided that the * string is longer than length 1. * <li>The value represented by the string is not a value of type * 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 * @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 * @exception NumberFormatException if the {@code String} * does not contain a parsable {@code int}. * WARNING: This method may be invoked early during VM initialization * before IntegerCache is initialized. Care must be taken to not use " less than Character.MIN_RADIX");
" greater than Character.MAX_RADIX");
if (
firstChar <
'0') {
// Possible leading "+" or "-" if (
len ==
1)
// Cannot have lone "+" or "-" // Accumulating negatively avoids surprises near MAX_VALUE * 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>'\u002D'</code>) to indicate a negative value or an * ASCII plus sign {@code '+'} (<code>'\u002B'</code>) 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, * @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 * 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: * {@code new Integer(Integer.parseInt(s, radix))} * @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 * @exception NumberFormatException if the {@code String} * does not contain a parsable {@code int}. * 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: * {@code new Integer(Integer.parseInt(s))} * @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 * 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 static final int low = -
128;
// high value may be configured by property // Maximum array size is Integer.MAX_VALUE * 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}. * The value of the {@code Integer}. * 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. * 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 * @exception NumberFormatException if the {@code String} does not * contain a parsable integer. * @see java.lang.Integer#parseInt(java.lang.String, int) * Returns the value of this {@code Integer} as a * Returns the value of this {@code Integer} as a * Returns the value of this {@code Integer} as an * Returns the value of this {@code Integer} as a * Returns the value of this {@code Integer} as a * Returns the value of this {@code Integer} as a * 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 * 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. * 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. * Determines the integer value of the system property with the * <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 and an {@code Integer} object representing this value is * returned. Details of possible numeric formats can be found with * the definition of {@code getProperty}. * <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: * {@code getInteger(nm, null)} * @param nm property name. * @return the {@code Integer} value of the property. * @see java.lang.System#getProperty(java.lang.String) * @see java.lang.System#getProperty(java.lang.String, java.lang.String) * Determines the integer value of the system property with the * <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 and an {@code Integer} object representing this value is * returned. Details of possible numeric formats can be found with * the definition of {@code getProperty}. * <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 * <p>In other words, this method returns an {@code Integer} object * {@code getInteger(nm, new Integer(val))} * but in practice it may be implemented in a manner such as: * Integer result = getInteger(nm, null); * return (result == null) ? new Integer(val) : result; * 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. * @see java.lang.System#getProperty(java.lang.String) * @see java.lang.System#getProperty(java.lang.String, java.lang.String) * 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 {@code Integer.decode} method, * and an {@code Integer} object representing this value is * <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)} * <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. * @see java.lang.System#getProperty(java.lang.String) * @see java.lang.System#getProperty(java.lang.String, java.lang.String) * @see java.lang.Integer#decode * Decodes a {@code String} into an {@code Integer}. * Accepts decimal, hexadecimal, and octal numbers given * by the following grammar: * <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> * <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) // Handle sign, if present // Handle radix specifier, if present // 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 * 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 * Compares two {@code int} values numerically. * The value returned is identical to what would be returned by: * Integer.valueOf(x).compareTo(Integer.valueOf(y)) * @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} public static int compare(
int x,
int y) {
return (x < y) ? -
1 : ((x == y) ?
0 :
1);
* The number of bits used to represent an {@code int} value in two's * complement binary form. 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 * @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. * 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 * @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. * 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: * <li>floor(log<sub>2</sub>(x)) = {@code 31 - numberOfLeadingZeros(x)} * <li>ceil(log<sub>2</sub>(x)) = {@code 32 - numberOfLeadingZeros(x - 1)} * @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 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; }
* 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 * @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 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. i = i - ((i >>>
1) &
0x55555555);
i = (i &
0x33333333) + ((i >>>
2) &
0x33333333);
i = (i + (i >>>
4)) &
0x0f0f0f0f;
* 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. * 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. * Returns the value obtained by reversing the order of the bits in the * two's complement binary representation of the specified {@code int} * @return the value obtained by reversing order of the bits in the * specified {@code int} value. 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);
* 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. public static int signum(
int i) {
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 /** use serialVersionUID from JDK 1.0.2 for interoperability */