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/* |
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* Copyright (c) 1994, 2021, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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|
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package java.lang; |
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|
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import java.lang.annotation.Native; |
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import java.lang.invoke.MethodHandles; |
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import java.lang.constant.Constable; |
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import java.lang.constant.ConstantDesc; |
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import java.math.*; |
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import java.util.Objects; |
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import java.util.Optional; |
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import jdk.internal.misc.CDS; |
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import jdk.internal.vm.annotation.IntrinsicCandidate; |
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import static java.lang.String.COMPACT_STRINGS; |
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import static java.lang.String.LATIN1; |
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import static java.lang.String.UTF16; |
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|
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/** |
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* The {@code Long} class wraps a value of the primitive type {@code |
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* long} in an object. An object of type {@code Long} contains a |
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* single field whose type is {@code long}. |
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* |
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* <p> In addition, this class provides several methods for converting |
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* a {@code long} to a {@code String} and a {@code String} to a {@code |
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* long}, as well as other constants and methods useful when dealing |
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* with a {@code long}. |
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* |
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* <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a> |
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* class; programmers should treat instances that are |
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* {@linkplain #equals(Object) equal} as interchangeable and should not |
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* use instances for synchronization, or unpredictable behavior may |
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* occur. For example, in a future release, synchronization may fail. |
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* |
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* <p>Implementation note: The implementations of the "bit twiddling" |
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* methods (such as {@link #highestOneBit(long) highestOneBit} and |
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* {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are |
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* based on material from Henry S. Warren, Jr.'s <i>Hacker's |
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* Delight</i>, (Addison Wesley, 2002). |
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* |
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* @author Lee Boynton |
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* @author Arthur van Hoff |
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* @author Josh Bloch |
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* @author Joseph D. Darcy |
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* @since 1.0 |
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*/ |
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@jdk.internal.ValueBased |
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public final class Long extends Number |
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implements Comparable<Long>, Constable, ConstantDesc { |
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/** |
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* A constant holding the minimum value a {@code long} can |
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* have, -2<sup>63</sup>. |
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*/ |
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@Native public static final long MIN_VALUE = 0x8000000000000000L; |
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/** |
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* A constant holding the maximum value a {@code long} can |
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* have, 2<sup>63</sup>-1. |
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*/ |
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@Native public static final long MAX_VALUE = 0x7fffffffffffffffL; |
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/** |
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* The {@code Class} instance representing the primitive type |
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* {@code long}. |
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* |
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* @since 1.1 |
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*/ |
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@SuppressWarnings("unchecked") |
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public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long"); |
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/** |
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* Returns a string representation of the first argument in the |
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* radix specified by the second argument. |
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* |
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* <p>If the radix is smaller than {@code Character.MIN_RADIX} |
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* or larger than {@code Character.MAX_RADIX}, then the radix |
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* {@code 10} is used instead. |
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* |
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* <p>If the first argument is negative, the first element of the |
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* result is the ASCII minus sign {@code '-'} |
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* ({@code '\u005Cu002d'}). If the first argument is not |
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* negative, no sign character appears in the result. |
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* |
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* <p>The remaining characters of the result represent the magnitude |
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* of the first argument. If the magnitude is zero, it is |
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* represented by a single zero character {@code '0'} |
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* ({@code '\u005Cu0030'}); otherwise, the first character of |
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* the representation of the magnitude will not be the zero |
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* character. The following ASCII characters are used as digits: |
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* |
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* <blockquote> |
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* {@code 0123456789abcdefghijklmnopqrstuvwxyz} |
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* </blockquote> |
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* |
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* These are {@code '\u005Cu0030'} through |
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* {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through |
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* {@code '\u005Cu007a'}. If {@code radix} is |
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* <var>N</var>, then the first <var>N</var> of these characters |
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* are used as radix-<var>N</var> digits in the order shown. Thus, |
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* the digits for hexadecimal (radix 16) are |
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* {@code 0123456789abcdef}. If uppercase letters are |
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* desired, the {@link java.lang.String#toUpperCase()} method may |
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* be called on the result: |
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* |
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* <blockquote> |
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* {@code Long.toString(n, 16).toUpperCase()} |
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* </blockquote> |
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* |
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* @param i a {@code long} to be converted to a string. |
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* @param radix the radix to use in the string representation. |
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* @return a string representation of the argument in the specified radix. |
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* @see java.lang.Character#MAX_RADIX |
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* @see java.lang.Character#MIN_RADIX |
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*/ |
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public static String toString(long i, int radix) { |
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if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX) |
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radix = 10; |
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if (radix == 10) |
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return toString(i); |
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|
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if (COMPACT_STRINGS) { |
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byte[] buf = new byte[65]; |
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int charPos = 64; |
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boolean negative = (i < 0); |
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if (!negative) { |
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i = -i; |
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} |
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while (i <= -radix) { |
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buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))]; |
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i = i / radix; |
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} |
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buf[charPos] = (byte)Integer.digits[(int)(-i)]; |
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if (negative) { |
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buf[--charPos] = '-'; |
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} |
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return StringLatin1.newString(buf, charPos, (65 - charPos)); |
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} |
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return toStringUTF16(i, radix); |
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} |
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private static String toStringUTF16(long i, int radix) { |
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byte[] buf = new byte[65 * 2]; |
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int charPos = 64; |
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boolean negative = (i < 0); |
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if (!negative) { |
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i = -i; |
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} |
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while (i <= -radix) { |
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StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]); |
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i = i / radix; |
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} |
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StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]); |
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if (negative) { |
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StringUTF16.putChar(buf, --charPos, '-'); |
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} |
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return StringUTF16.newString(buf, charPos, (65 - charPos)); |
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} |
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/** |
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* Returns a string representation of the first argument as an |
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* unsigned integer value in the radix specified by the second |
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* argument. |
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* |
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* <p>If the radix is smaller than {@code Character.MIN_RADIX} |
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* or larger than {@code Character.MAX_RADIX}, then the radix |
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* {@code 10} is used instead. |
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* |
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* <p>Note that since the first argument is treated as an unsigned |
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* value, no leading sign character is printed. |
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* |
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* <p>If the magnitude is zero, it is represented by a single zero |
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* character {@code '0'} ({@code '\u005Cu0030'}); otherwise, |
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* the first character of the representation of the magnitude will |
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* not be the zero character. |
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* |
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* <p>The behavior of radixes and the characters used as digits |
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* are the same as {@link #toString(long, int) toString}. |
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* |
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* @param i an integer to be converted to an unsigned string. |
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* @param radix the radix to use in the string representation. |
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* @return an unsigned string representation of the argument in the specified radix. |
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* @see #toString(long, int) |
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* @since 1.8 |
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*/ |
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public static String toUnsignedString(long i, int radix) { |
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if (i >= 0) |
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return toString(i, radix); |
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else { |
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return switch (radix) { |
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case 2 -> toBinaryString(i); |
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case 4 -> toUnsignedString0(i, 2); |
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case 8 -> toOctalString(i); |
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case 10 -> { |
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/* |
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* We can get the effect of an unsigned division by 10 |
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* on a long value by first shifting right, yielding a |
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* positive value, and then dividing by 5. This |
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* allows the last digit and preceding digits to be |
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* isolated more quickly than by an initial conversion |
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* to BigInteger. |
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*/ |
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long quot = (i >>> 1) / 5; |
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long rem = i - quot * 10; |
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yield toString(quot) + rem; |
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} |
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case 16 -> toHexString(i); |
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case 32 -> toUnsignedString0(i, 5); |
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default -> toUnsignedBigInteger(i).toString(radix); |
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}; |
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} |
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} |
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/** |
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* Return a BigInteger equal to the unsigned value of the |
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* argument. |
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*/ |
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private static BigInteger toUnsignedBigInteger(long i) { |
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if (i >= 0L) |
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return BigInteger.valueOf(i); |
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else { |
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int upper = (int) (i >>> 32); |
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int lower = (int) i; |
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|
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// return (upper << 32) + lower |
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return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32). |
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add(BigInteger.valueOf(Integer.toUnsignedLong(lower))); |
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} |
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} |
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/** |
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* Returns a string representation of the {@code long} |
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* argument as an unsigned integer in base 16. |
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* |
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* <p>The unsigned {@code long} value is the argument plus |
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* 2<sup>64</sup> if the argument is negative; otherwise, it is |
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* equal to the argument. This value is converted to a string of |
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* ASCII digits in hexadecimal (base 16) with no extra |
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* leading {@code 0}s. |
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* |
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* <p>The value of the argument can be recovered from the returned |
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* string {@code s} by calling {@link |
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* Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, |
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* 16)}. |
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* |
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* <p>If the unsigned magnitude is zero, it is represented by a |
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* single zero character {@code '0'} ({@code '\u005Cu0030'}); |
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* otherwise, the first character of the representation of the |
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* unsigned magnitude will not be the zero character. The |
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* following characters are used as hexadecimal digits: |
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* |
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* <blockquote> |
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* {@code 0123456789abcdef} |
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* </blockquote> |
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* |
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* These are the characters {@code '\u005Cu0030'} through |
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* {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through |
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* {@code '\u005Cu0066'}. If uppercase letters are desired, |
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* the {@link java.lang.String#toUpperCase()} method may be called |
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* on the result: |
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* |
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* <blockquote> |
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* {@code Long.toHexString(n).toUpperCase()} |
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* </blockquote> |
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* |
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* @apiNote |
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* The {@link java.util.HexFormat} class provides formatting and parsing |
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* of byte arrays and primitives to return a string or adding to an {@link Appendable}. |
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* {@code HexFormat} formats and parses uppercase or lowercase hexadecimal characters, |
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* with leading zeros and for byte arrays includes for each byte |
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* a delimiter, prefix, and suffix. |
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* |
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* @param i a {@code long} to be converted to a string. |
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* @return the string representation of the unsigned {@code long} |
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* value represented by the argument in hexadecimal |
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* (base 16). |
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* @see java.util.HexFormat |
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* @see #parseUnsignedLong(String, int) |
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* @see #toUnsignedString(long, int) |
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* @since 1.0.2 |
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*/ |
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public static String toHexString(long i) { |
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return toUnsignedString0(i, 4); |
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} |
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|
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/** |
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* Returns a string representation of the {@code long} |
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* argument as an unsigned integer in base 8. |
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* |
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* <p>The unsigned {@code long} value is the argument plus |
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* 2<sup>64</sup> if the argument is negative; otherwise, it is |
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* equal to the argument. This value is converted to a string of |
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* ASCII digits in octal (base 8) with no extra leading |
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* {@code 0}s. |
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* |
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* <p>The value of the argument can be recovered from the returned |
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* string {@code s} by calling {@link |
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* Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, |
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* 8)}. |
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* |
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* <p>If the unsigned magnitude is zero, it is represented by a |
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* single zero character {@code '0'} ({@code '\u005Cu0030'}); |
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* otherwise, the first character of the representation of the |
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* unsigned magnitude will not be the zero character. The |
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* following characters are used as octal digits: |
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* |
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* <blockquote> |
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* {@code 01234567} |
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* </blockquote> |
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* |
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* These are the characters {@code '\u005Cu0030'} through |
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* {@code '\u005Cu0037'}. |
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* |
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* @param i a {@code long} to be converted to a string. |
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* @return the string representation of the unsigned {@code long} |
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* value represented by the argument in octal (base 8). |
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* @see #parseUnsignedLong(String, int) |
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* @see #toUnsignedString(long, int) |
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* @since 1.0.2 |
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*/ |
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public static String toOctalString(long i) { |
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return toUnsignedString0(i, 3); |
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} |
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|
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/** |
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* Returns a string representation of the {@code long} |
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* argument as an unsigned integer in base 2. |
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* |
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* <p>The unsigned {@code long} value is the argument plus |
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* 2<sup>64</sup> if the argument is negative; otherwise, it is |
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* equal to the argument. This value is converted to a string of |
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* ASCII digits in binary (base 2) with no extra leading |
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* {@code 0}s. |
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* |
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* <p>The value of the argument can be recovered from the returned |
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* string {@code s} by calling {@link |
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* Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, |
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* 2)}. |
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* |
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* <p>If the unsigned magnitude is zero, it is represented by a |
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* single zero character {@code '0'} ({@code '\u005Cu0030'}); |
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* otherwise, the first character of the representation of the |
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* unsigned magnitude will not be the zero character. The |
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* characters {@code '0'} ({@code '\u005Cu0030'}) and {@code |
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* '1'} ({@code '\u005Cu0031'}) are used as binary digits. |
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* |
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* @param i a {@code long} to be converted to a string. |
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* @return the string representation of the unsigned {@code long} |
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* value represented by the argument in binary (base 2). |
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* @see #parseUnsignedLong(String, int) |
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* @see #toUnsignedString(long, int) |
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* @since 1.0.2 |
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*/ |
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public static String toBinaryString(long i) { |
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return toUnsignedString0(i, 1); |
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} |
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|
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/** |
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* Format a long (treated as unsigned) into a String. |
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* @param val the value to format |
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* @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) |
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*/ |
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static String toUnsignedString0(long val, int shift) { |
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// assert shift > 0 && shift <=5 : "Illegal shift value"; |
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int mag = Long.SIZE - Long.numberOfLeadingZeros(val); |
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int chars = Math.max(((mag + (shift - 1)) / shift), 1); |
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if (COMPACT_STRINGS) { |
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byte[] buf = new byte[chars]; |
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formatUnsignedLong0(val, shift, buf, 0, chars); |
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return new String(buf, LATIN1); |
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} else { |
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byte[] buf = new byte[chars * 2]; |
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formatUnsignedLong0UTF16(val, shift, buf, 0, chars); |
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return new String(buf, UTF16); |
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} |
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} |
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|
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/** |
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* Format a long (treated as unsigned) into a byte buffer (LATIN1 version). If |
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* {@code len} exceeds the formatted ASCII representation of {@code val}, |
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* {@code buf} will be padded with leading zeroes. |
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* |
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* @param val the unsigned long to format |
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* @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) |
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* @param buf the byte buffer to write to |
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* @param offset the offset in the destination buffer to start at |
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* @param len the number of characters to write |
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*/ |
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private static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) { |
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int charPos = offset + len; |
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int radix = 1 << shift; |
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int mask = radix - 1; |
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do { |
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buf[--charPos] = (byte)Integer.digits[((int) val) & mask]; |
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val >>>= shift; |
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} while (charPos > offset); |
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} |
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|
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/** |
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* Format a long (treated as unsigned) into a byte buffer (UTF16 version). If |
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* {@code len} exceeds the formatted ASCII representation of {@code val}, |
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* {@code buf} will be padded with leading zeroes. |
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* |
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* @param val the unsigned long to format |
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* @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) |
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* @param buf the byte buffer to write to |
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* @param offset the offset in the destination buffer to start at |
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* @param len the number of characters to write |
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*/ |
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private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) { |
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int charPos = offset + len; |
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int radix = 1 << shift; |
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int mask = radix - 1; |
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do { |
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StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]); |
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val >>>= shift; |
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} while (charPos > offset); |
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} |
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|
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static String fastUUID(long lsb, long msb) { |
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if (COMPACT_STRINGS) { |
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byte[] buf = new byte[36]; |
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formatUnsignedLong0(lsb, 4, buf, 24, 12); |
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formatUnsignedLong0(lsb >>> 48, 4, buf, 19, 4); |
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formatUnsignedLong0(msb, 4, buf, 14, 4); |
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formatUnsignedLong0(msb >>> 16, 4, buf, 9, 4); |
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formatUnsignedLong0(msb >>> 32, 4, buf, 0, 8); |
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|
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buf[23] = '-'; |
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buf[18] = '-'; |
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buf[13] = '-'; |
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buf[8] = '-'; |
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|
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return new String(buf, LATIN1); |
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} else { |
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byte[] buf = new byte[72]; |
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|
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formatUnsignedLong0UTF16(lsb, 4, buf, 24, 12); |
|
formatUnsignedLong0UTF16(lsb >>> 48, 4, buf, 19, 4); |
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formatUnsignedLong0UTF16(msb, 4, buf, 14, 4); |
|
formatUnsignedLong0UTF16(msb >>> 16, 4, buf, 9, 4); |
|
formatUnsignedLong0UTF16(msb >>> 32, 4, buf, 0, 8); |
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|
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StringUTF16.putChar(buf, 23, '-'); |
|
StringUTF16.putChar(buf, 18, '-'); |
|
StringUTF16.putChar(buf, 13, '-'); |
|
StringUTF16.putChar(buf, 8, '-'); |
|
|
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return new String(buf, UTF16); |
|
} |
|
} |
|
|
|
/** |
|
* Returns a {@code String} object representing the specified |
|
* {@code long}. The argument is converted to signed decimal |
|
* representation and returned as a string, exactly as if the |
|
* argument and the radix 10 were given as arguments to the {@link |
|
* #toString(long, int)} method. |
|
* |
|
* @param i a {@code long} to be converted. |
|
* @return a string representation of the argument in base 10. |
|
*/ |
|
public static String toString(long i) { |
|
int size = stringSize(i); |
|
if (COMPACT_STRINGS) { |
|
byte[] buf = new byte[size]; |
|
getChars(i, size, buf); |
|
return new String(buf, LATIN1); |
|
} else { |
|
byte[] buf = new byte[size * 2]; |
|
StringUTF16.getChars(i, size, buf); |
|
return new String(buf, UTF16); |
|
} |
|
} |
|
|
|
/** |
|
* 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(long, |
|
* int)} method. |
|
* |
|
* @param i an integer to be converted to an unsigned string. |
|
* @return an unsigned string representation of the argument. |
|
* @see #toUnsignedString(long, int) |
|
* @since 1.8 |
|
*/ |
|
public static String toUnsignedString(long i) { |
|
return toUnsignedString(i, 10); |
|
} |
|
|
|
/** |
|
* Places characters representing the long 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. |
|
* |
|
* @implNote This method converts positive inputs into negative |
|
* values, to cover the Long.MIN_VALUE case. Converting otherwise |
|
* (negative to positive) will expose -Long.MIN_VALUE that overflows |
|
* long. |
|
* |
|
* @param i value to convert |
|
* @param index next index, after the least significant digit |
|
* @param buf target buffer, Latin1-encoded |
|
* @return index of the most significant digit or minus sign, if present |
|
*/ |
|
static int getChars(long i, int index, byte[] buf) { |
|
long q; |
|
int r; |
|
int charPos = index; |
|
|
|
boolean negative = (i < 0); |
|
if (!negative) { |
|
i = -i; |
|
} |
|
|
|
// Get 2 digits/iteration using longs until quotient fits into an int |
|
while (i <= Integer.MIN_VALUE) { |
|
q = i / 100; |
|
r = (int)((q * 100) - i); |
|
i = q; |
|
buf[--charPos] = Integer.DigitOnes[r]; |
|
buf[--charPos] = Integer.DigitTens[r]; |
|
} |
|
|
|
// Get 2 digits/iteration using ints |
|
int q2; |
|
int i2 = (int)i; |
|
while (i2 <= -100) { |
|
q2 = i2 / 100; |
|
r = (q2 * 100) - i2; |
|
i2 = q2; |
|
buf[--charPos] = Integer.DigitOnes[r]; |
|
buf[--charPos] = Integer.DigitTens[r]; |
|
} |
|
|
|
// We know there are at most two digits left at this point. |
|
q2 = i2 / 10; |
|
r = (q2 * 10) - i2; |
|
buf[--charPos] = (byte)('0' + r); |
|
|
|
// Whatever left is the remaining digit. |
|
if (q2 < 0) { |
|
buf[--charPos] = (byte)('0' - q2); |
|
} |
|
|
|
if (negative) { |
|
buf[--charPos] = (byte)'-'; |
|
} |
|
return charPos; |
|
} |
|
|
|
/** |
|
* Returns the string representation size for a given long value. |
|
* |
|
* @param x long value |
|
* @return string size |
|
* |
|
* @implNote There are other ways to compute this: e.g. binary search, |
|
* but values are biased heavily towards zero, and therefore linear search |
|
* wins. The iteration results are also routinely inlined in the generated |
|
* code after loop unrolling. |
|
*/ |
|
static int stringSize(long x) { |
|
int d = 1; |
|
if (x >= 0) { |
|
d = 0; |
|
x = -x; |
|
} |
|
long p = -10; |
|
for (int i = 1; i < 19; i++) { |
|
if (x > p) |
|
return i + d; |
|
p = 10 * p; |
|
} |
|
return 19 + d; |
|
} |
|
|
|
/** |
|
* Parses the string argument as a signed {@code long} 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 {@code long} value is returned. |
|
* |
|
* <p>Note that neither the character {@code L} |
|
* ({@code '\u005Cu004C'}) nor {@code l} |
|
* ({@code '\u005Cu006C'}) is permitted to appear at the end |
|
* of the string as a type indicator, as would be permitted in |
|
* Java programming language source code - except that either |
|
* {@code L} or {@code l} may appear as a digit for a |
|
* radix greater than or equal to 22. |
|
* |
|
* <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 {@code 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 long}. |
|
* </ul> |
|
* |
|
* <p>Examples: |
|
* <blockquote><pre> |
|
* parseLong("0", 10) returns 0L |
|
* parseLong("473", 10) returns 473L |
|
* parseLong("+42", 10) returns 42L |
|
* parseLong("-0", 10) returns 0L |
|
* parseLong("-FF", 16) returns -255L |
|
* parseLong("1100110", 2) returns 102L |
|
* parseLong("99", 8) throws a NumberFormatException |
|
* parseLong("Hazelnut", 10) throws a NumberFormatException |
|
* parseLong("Hazelnut", 36) returns 1356099454469L |
|
* </pre></blockquote> |
|
* |
|
* @param s the {@code String} containing the |
|
* {@code long} representation to be parsed. |
|
* @param radix the radix to be used while parsing {@code s}. |
|
* @return the {@code long} represented by the string argument in |
|
* the specified radix. |
|
* @throws NumberFormatException if the string does not contain a |
|
* parsable {@code long}. |
|
*/ |
|
public static long parseLong(String s, int radix) |
|
throws NumberFormatException |
|
{ |
|
if (s == null) { |
|
throw new NumberFormatException("Cannot parse null string"); |
|
} |
|
|
|
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"); |
|
} |
|
|
|
boolean negative = false; |
|
int i = 0, len = s.length(); |
|
long limit = -Long.MAX_VALUE; |
|
|
|
if (len > 0) { |
|
char firstChar = s.charAt(0); |
|
if (firstChar < '0') { // Possible leading "+" or "-" |
|
if (firstChar == '-') { |
|
negative = true; |
|
limit = Long.MIN_VALUE; |
|
} else if (firstChar != '+') { |
|
throw NumberFormatException.forInputString(s, radix); |
|
} |
|
|
|
if (len == 1) { // Cannot have lone "+" or "-" |
|
throw NumberFormatException.forInputString(s, radix); |
|
} |
|
i++; |
|
} |
|
long multmin = limit / radix; |
|
long result = 0; |
|
while (i < len) { |
|
// Accumulating negatively avoids surprises near MAX_VALUE |
|
int digit = Character.digit(s.charAt(i++),radix); |
|
if (digit < 0 || result < multmin) { |
|
throw NumberFormatException.forInputString(s, radix); |
|
} |
|
result *= radix; |
|
if (result < limit + digit) { |
|
throw NumberFormatException.forInputString(s, radix); |
|
} |
|
result -= digit; |
|
} |
|
return negative ? result : -result; |
|
} else { |
|
throw NumberFormatException.forInputString(s, radix); |
|
} |
|
} |
|
|
|
/** |
|
* Parses the {@link CharSequence} argument as a signed {@code long} in |
|
* the specified {@code radix}, beginning at the specified |
|
* {@code beginIndex} and extending to {@code endIndex - 1}. |
|
* |
|
* <p>The method does not take steps to guard against the |
|
* {@code CharSequence} being mutated while parsing. |
|
* |
|
* @param s the {@code CharSequence} containing the {@code long} |
|
* representation to be parsed |
|
* @param beginIndex the beginning index, inclusive. |
|
* @param endIndex the ending index, exclusive. |
|
* @param radix the radix to be used while parsing {@code s}. |
|
* @return the signed {@code long} represented by the subsequence in |
|
* the specified radix. |
|
* @throws NullPointerException if {@code s} is null. |
|
* @throws IndexOutOfBoundsException if {@code beginIndex} is |
|
* negative, or if {@code beginIndex} is greater than |
|
* {@code endIndex} or if {@code endIndex} is greater than |
|
* {@code s.length()}. |
|
* @throws NumberFormatException if the {@code CharSequence} does not |
|
* contain a parsable {@code long} in the specified |
|
* {@code radix}, or if {@code radix} is either smaller than |
|
* {@link java.lang.Character#MIN_RADIX} or larger than |
|
* {@link java.lang.Character#MAX_RADIX}. |
|
* @since 9 |
|
*/ |
|
public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix) |
|
throws NumberFormatException { |
|
Objects.requireNonNull(s); |
|
|
|
if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) { |
|
throw new IndexOutOfBoundsException(); |
|
} |
|
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"); |
|
} |
|
|
|
boolean negative = false; |
|
int i = beginIndex; |
|
long limit = -Long.MAX_VALUE; |
|
|
|
if (i < endIndex) { |
|
char firstChar = s.charAt(i); |
|
if (firstChar < '0') { // Possible leading "+" or "-" |
|
if (firstChar == '-') { |
|
negative = true; |
|
limit = Long.MIN_VALUE; |
|
} else if (firstChar != '+') { |
|
throw NumberFormatException.forCharSequence(s, beginIndex, |
|
endIndex, i); |
|
} |
|
i++; |
|
} |
|
if (i >= endIndex) { // Cannot have lone "+", "-" or "" |
|
throw NumberFormatException.forCharSequence(s, beginIndex, |
|
endIndex, i); |
|
} |
|
long multmin = limit / radix; |
|
long result = 0; |
|
while (i < endIndex) { |
|
// Accumulating negatively avoids surprises near MAX_VALUE |
|
int digit = Character.digit(s.charAt(i), radix); |
|
if (digit < 0 || result < multmin) { |
|
throw NumberFormatException.forCharSequence(s, beginIndex, |
|
endIndex, i); |
|
} |
|
result *= radix; |
|
if (result < limit + digit) { |
|
throw NumberFormatException.forCharSequence(s, beginIndex, |
|
endIndex, i); |
|
} |
|
i++; |
|
result -= digit; |
|
} |
|
return negative ? result : -result; |
|
} else { |
|
throw new NumberFormatException(""); |
|
} |
|
} |
|
|
|
/** |
|
* Parses the string argument as a signed decimal {@code long}. |
|
* 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 {@code long} value is |
|
* returned, exactly as if the argument and the radix {@code 10} |
|
* were given as arguments to the {@link |
|
* #parseLong(java.lang.String, int)} method. |
|
* |
|
* <p>Note that neither the character {@code L} |
|
* ({@code '\u005Cu004C'}) nor {@code l} |
|
* ({@code '\u005Cu006C'}) is permitted to appear at the end |
|
* of the string as a type indicator, as would be permitted in |
|
* Java programming language source code. |
|
* |
|
* @param s a {@code String} containing the {@code long} |
|
* representation to be parsed |
|
* @return the {@code long} represented by the argument in |
|
* decimal. |
|
* @throws NumberFormatException if the string does not contain a |
|
* parsable {@code long}. |
|
*/ |
|
public static long parseLong(String s) throws NumberFormatException { |
|
return parseLong(s, 10); |
|
} |
|
|
|
/** |
|
* Parses the string argument as an unsigned {@code long} 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 long}, 2<sup>64</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 unsigned {@code long} represented by the string |
|
* argument in the specified radix. |
|
* @throws NumberFormatException if the {@code String} |
|
* does not contain a parsable {@code long}. |
|
* @since 1.8 |
|
*/ |
|
public static long parseUnsignedLong(String s, int radix) |
|
throws NumberFormatException { |
|
if (s == null) { |
|
throw new NumberFormatException("Cannot parse null string"); |
|
} |
|
|
|
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 <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits |
|
(radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits |
|
return parseLong(s, radix); |
|
} |
|
|
|
// No need for range checks on len due to testing above. |
|
long first = parseLong(s, 0, len - 1, radix); |
|
int second = Character.digit(s.charAt(len - 1), radix); |
|
if (second < 0) { |
|
throw new NumberFormatException("Bad digit at end of " + s); |
|
} |
|
long result = first * radix + second; |
|
|
|
/* |
|
* Test leftmost bits of multiprecision extension of first*radix |
|
* for overflow. The number of bits needed is defined by |
|
* GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then |
|
* int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and |
|
* overflow is tested by splitting guard in the ranges |
|
* guard < 92, 92 <= guard < 128, and 128 <= guard, where |
|
* 92 = 128 - Character.MAX_RADIX. Note that guard cannot take |
|
* on a value which does not include a prime factor in the legal |
|
* radix range. |
|
*/ |
|
int guard = radix * (int) (first >>> 57); |
|
if (guard >= 128 || |
|
(result >= 0 && guard >= 128 - Character.MAX_RADIX)) { |
|
/* |
|
* For purposes of exposition, the programmatic statements |
|
* below should be taken to be multi-precision, i.e., not |
|
* subject to overflow. |
|
* |
|
* A) Condition guard >= 128: |
|
* If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64 |
|
* hence always overflow. |
|
* |
|
* B) Condition guard < 92: |
|
* Define left7 = first >>> 57. |
|
* Given first = (left7 * 2^57) + (first & (2^57 - 1)) then |
|
* result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second. |
|
* Thus if radix*left7 < 92, radix <= 36, and second < 36, |
|
* then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence |
|
* never overflow. |
|
* |
|
* C) Condition 92 <= guard < 128: |
|
* first*radix + second >= radix*left7*2^57 + second |
|
* so that first*radix + second >= 92*2^57 + 0 > 2^63 |
|
* |
|
* D) Condition guard < 128: |
|
* radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1) |
|
* so |
|
* radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36 |
|
* thus |
|
* radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36 |
|
* whence |
|
* radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63 |
|
* |
|
* E) Conditions C, D, and result >= 0: |
|
* C and D combined imply the mathematical result |
|
* 2^63 < first*radix + second < 2^64 + 2^63. The lower |
|
* bound is therefore negative as a signed long, but the |
|
* upper bound is too small to overflow again after the |
|
* signed long overflows to positive above 2^64 - 1. Hence |
|
* result >= 0 implies overflow given C and D. |
|
*/ |
|
throw new NumberFormatException(String.format("String value %s exceeds " + |
|
"range of unsigned long.", s)); |
|
} |
|
return result; |
|
} |
|
} else { |
|
throw NumberFormatException.forInputString(s, radix); |
|
} |
|
} |
|
|
|
/** |
|
* Parses the {@link CharSequence} argument as an unsigned {@code long} in |
|
* the specified {@code radix}, beginning at the specified |
|
* {@code beginIndex} and extending to {@code endIndex - 1}. |
|
* |
|
* <p>The method does not take steps to guard against the |
|
* {@code CharSequence} being mutated while parsing. |
|
* |
|
* @param s the {@code CharSequence} containing the unsigned |
|
* {@code long} representation to be parsed |
|
* @param beginIndex the beginning index, inclusive. |
|
* @param endIndex the ending index, exclusive. |
|
* @param radix the radix to be used while parsing {@code s}. |
|
* @return the unsigned {@code long} represented by the subsequence in |
|
* the specified radix. |
|
* @throws NullPointerException if {@code s} is null. |
|
* @throws IndexOutOfBoundsException if {@code beginIndex} is |
|
* negative, or if {@code beginIndex} is greater than |
|
* {@code endIndex} or if {@code endIndex} is greater than |
|
* {@code s.length()}. |
|
* @throws NumberFormatException if the {@code CharSequence} does not |
|
* contain a parsable unsigned {@code long} in the specified |
|
* {@code radix}, or if {@code radix} is either smaller than |
|
* {@link java.lang.Character#MIN_RADIX} or larger than |
|
* {@link java.lang.Character#MAX_RADIX}. |
|
* @since 9 |
|
*/ |
|
public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix) |
|
throws NumberFormatException { |
|
Objects.requireNonNull(s); |
|
|
|
if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) { |
|
throw new IndexOutOfBoundsException(); |
|
} |
|
int start = beginIndex, len = endIndex - beginIndex; |
|
|
|
if (len > 0) { |
|
char firstChar = s.charAt(start); |
|
if (firstChar == '-') { |
|
throw new NumberFormatException(String.format("Illegal leading minus sign " + |
|
"on unsigned string %s.", s.subSequence(start, start + len))); |
|
} else { |
|
if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits |
|
(radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits |
|
return parseLong(s, start, start + len, radix); |
|
} |
|
|
|
// No need for range checks on end due to testing above. |
|
long first = parseLong(s, start, start + len - 1, radix); |
|
int second = Character.digit(s.charAt(start + len - 1), radix); |
|
if (second < 0) { |
|
throw new NumberFormatException("Bad digit at end of " + |
|
s.subSequence(start, start + len)); |
|
} |
|
long result = first * radix + second; |
|
|
|
/* |
|
* Test leftmost bits of multiprecision extension of first*radix |
|
* for overflow. The number of bits needed is defined by |
|
* GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then |
|
* int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and |
|
* overflow is tested by splitting guard in the ranges |
|
* guard < 92, 92 <= guard < 128, and 128 <= guard, where |
|
* 92 = 128 - Character.MAX_RADIX. Note that guard cannot take |
|
* on a value which does not include a prime factor in the legal |
|
* radix range. |
|
*/ |
|
int guard = radix * (int) (first >>> 57); |
|
if (guard >= 128 || |
|
(result >= 0 && guard >= 128 - Character.MAX_RADIX)) { |
|
/* |
|
* For purposes of exposition, the programmatic statements |
|
* below should be taken to be multi-precision, i.e., not |
|
* subject to overflow. |
|
* |
|
* A) Condition guard >= 128: |
|
* If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64 |
|
* hence always overflow. |
|
* |
|
* B) Condition guard < 92: |
|
* Define left7 = first >>> 57. |
|
* Given first = (left7 * 2^57) + (first & (2^57 - 1)) then |
|
* result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second. |
|
* Thus if radix*left7 < 92, radix <= 36, and second < 36, |
|
* then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence |
|
* never overflow. |
|
* |
|
* C) Condition 92 <= guard < 128: |
|
* first*radix + second >= radix*left7*2^57 + second |
|
* so that first*radix + second >= 92*2^57 + 0 > 2^63 |
|
* |
|
* D) Condition guard < 128: |
|
* radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1) |
|
* so |
|
* radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36 |
|
* thus |
|
* radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36 |
|
* whence |
|
* radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63 |
|
* |
|
* E) Conditions C, D, and result >= 0: |
|
* C and D combined imply the mathematical result |
|
* 2^63 < first*radix + second < 2^64 + 2^63. The lower |
|
* bound is therefore negative as a signed long, but the |
|
* upper bound is too small to overflow again after the |
|
* signed long overflows to positive above 2^64 - 1. Hence |
|
* result >= 0 implies overflow given C and D. |
|
*/ |
|
throw new NumberFormatException(String.format("String value %s exceeds " + |
|
"range of unsigned long.", s.subSequence(start, start + len))); |
|
} |
|
return result; |
|
} |
|
} else { |
|
throw NumberFormatException.forInputString("", radix); |
|
} |
|
} |
|
|
|
/** |
|
* Parses the string argument as an unsigned decimal {@code long}. The |
|
* characters in the string must all be decimal digits, except |
|
* that the first character may be 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 |
|
* #parseUnsignedLong(java.lang.String, int)} method. |
|
* |
|
* @param s a {@code String} containing the unsigned {@code long} |
|
* representation to be parsed |
|
* @return the unsigned {@code long} value represented by the decimal string argument |
|
* @throws NumberFormatException if the string does not contain a |
|
* parsable unsigned integer. |
|
* @since 1.8 |
|
*/ |
|
public static long parseUnsignedLong(String s) throws NumberFormatException { |
|
return parseUnsignedLong(s, 10); |
|
} |
|
|
|
/** |
|
* Returns a {@code Long} 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 |
|
* {@code long} in the radix specified by the second |
|
* argument, exactly as if the arguments were given to the {@link |
|
* #parseLong(java.lang.String, int)} method. The result is a |
|
* {@code Long} object that represents the {@code long} |
|
* value specified by the string. |
|
* |
|
* <p>In other words, this method returns a {@code Long} object equal |
|
* to the value of: |
|
* |
|
* <blockquote> |
|
* {@code new Long(Long.parseLong(s, radix))} |
|
* </blockquote> |
|
* |
|
* @param s the string to be parsed |
|
* @param radix the radix to be used in interpreting {@code s} |
|
* @return a {@code Long} object holding the value |
|
* represented by the string argument in the specified |
|
* radix. |
|
* @throws NumberFormatException If the {@code String} does not |
|
* contain a parsable {@code long}. |
|
*/ |
|
public static Long valueOf(String s, int radix) throws NumberFormatException { |
|
return Long.valueOf(parseLong(s, radix)); |
|
} |
|
|
|
/** |
|
* Returns a {@code Long} object holding the value |
|
* of the specified {@code String}. The argument is |
|
* interpreted as representing a signed decimal {@code long}, |
|
* exactly as if the argument were given to the {@link |
|
* #parseLong(java.lang.String)} method. The result is a |
|
* {@code Long} object that represents the integer value |
|
* specified by the string. |
|
* |
|
* <p>In other words, this method returns a {@code Long} object |
|
* equal to the value of: |
|
* |
|
* <blockquote> |
|
* {@code new Long(Long.parseLong(s))} |
|
* </blockquote> |
|
* |
|
* @param s the string to be parsed. |
|
* @return a {@code Long} object holding the value |
|
* represented by the string argument. |
|
* @throws NumberFormatException If the string cannot be parsed |
|
* as a {@code long}. |
|
*/ |
|
public static Long valueOf(String s) throws NumberFormatException |
|
{ |
|
return Long.valueOf(parseLong(s, 10)); |
|
} |
|
|
|
private static class LongCache { |
|
private LongCache() {} |
|
|
|
static final Long[] cache; |
|
static Long[] archivedCache; |
|
|
|
static { |
|
int size = -(-128) + 127 + 1; |
|
|
|
// Load and use the archived cache if it exists |
|
CDS.initializeFromArchive(LongCache.class); |
|
if (archivedCache == null || archivedCache.length != size) { |
|
Long[] c = new Long[size]; |
|
long value = -128; |
|
for(int i = 0; i < size; i++) { |
|
c[i] = new Long(value++); |
|
} |
|
archivedCache = c; |
|
} |
|
cache = archivedCache; |
|
} |
|
} |
|
|
|
/** |
|
* Returns a {@code Long} instance representing the specified |
|
* {@code long} value. |
|
* If a new {@code Long} instance is not required, this method |
|
* should generally be used in preference to the constructor |
|
* {@link #Long(long)}, 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 l a long value. |
|
* @return a {@code Long} instance representing {@code l}. |
|
* @since 1.5 |
|
*/ |
|
@IntrinsicCandidate |
|
public static Long valueOf(long l) { |
|
final int offset = 128; |
|
if (l >= -128 && l <= 127) { // will cache |
|
return LongCache.cache[(int)l + offset]; |
|
} |
|
return new Long(l); |
|
} |
|
|
|
/** |
|
* Decodes a {@code String} into a {@code Long}. |
|
* 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> |
|
* |
|
* <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 {@jls 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 |
|
* Long.parseLong} 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 a {@code Long} object holding the {@code long} |
|
* value represented by {@code nm} |
|
* @throws NumberFormatException if the {@code String} does not |
|
* contain a parsable {@code long}. |
|
* @see java.lang.Long#parseLong(String, int) |
|
* @since 1.2 |
|
*/ |
|
public static Long decode(String nm) throws NumberFormatException { |
|
int radix = 10; |
|
int index = 0; |
|
boolean negative = false; |
|
Long result; |
|
|
|
if (nm.isEmpty()) |
|
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 = Long.valueOf(nm.substring(index), radix); |
|
result = negative ? Long.valueOf(-result.longValue()) : result; |
|
} catch (NumberFormatException e) { |
|
// If number is Long.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 = Long.valueOf(constant, radix); |
|
} |
|
return result; |
|
} |
|
|
|
/** |
|
* The value of the {@code Long}. |
|
* |
|
* @serial |
|
*/ |
|
private final long value; |
|
|
|
/** |
|
* Constructs a newly allocated {@code Long} object that |
|
* represents the specified {@code long} argument. |
|
* |
|
* @param value the value to be represented by the |
|
* {@code Long} object. |
|
* |
|
* @deprecated |
|
* It is rarely appropriate to use this constructor. The static factory |
|
* {@link #valueOf(long)} is generally a better choice, as it is |
|
* likely to yield significantly better space and time performance. |
|
*/ |
|
@Deprecated(since="9", forRemoval = true) |
|
public Long(long value) { |
|
this.value = value; |
|
} |
|
|
|
/** |
|
* Constructs a newly allocated {@code Long} object that |
|
* represents the {@code long} value indicated by the |
|
* {@code String} parameter. The string is converted to a |
|
* {@code long} value in exactly the manner used by the |
|
* {@code parseLong} method for radix 10. |
|
* |
|
* @param s the {@code String} to be converted to a |
|
* {@code Long}. |
|
* @throws NumberFormatException if the {@code String} does not |
|
* contain a parsable {@code long}. |
|
* |
|
* @deprecated |
|
* It is rarely appropriate to use this constructor. |
|
* Use {@link #parseLong(String)} to convert a string to a |
|
* {@code long} primitive, or use {@link #valueOf(String)} |
|
* to convert a string to a {@code Long} object. |
|
*/ |
|
@Deprecated(since="9", forRemoval = true) |
|
public Long(String s) throws NumberFormatException { |
|
this.value = parseLong(s, 10); |
|
} |
|
|
|
/** |
|
* Returns the value of this {@code Long} as a {@code byte} after |
|
* a narrowing primitive conversion. |
|
* @jls 5.1.3 Narrowing Primitive Conversion |
|
*/ |
|
public byte byteValue() { |
|
return (byte)value; |
|
} |
|
|
|
/** |
|
* Returns the value of this {@code Long} as a {@code short} after |
|
* a narrowing primitive conversion. |
|
* @jls 5.1.3 Narrowing Primitive Conversion |
|
*/ |
|
public short shortValue() { |
|
return (short)value; |
|
} |
|
|
|
/** |
|
* Returns the value of this {@code Long} as an {@code int} after |
|
* a narrowing primitive conversion. |
|
* @jls 5.1.3 Narrowing Primitive Conversion |
|
*/ |
|
public int intValue() { |
|
return (int)value; |
|
} |
|
|
|
/** |
|
* Returns the value of this {@code Long} as a |
|
* {@code long} value. |
|
*/ |
|
@IntrinsicCandidate |
|
public long longValue() { |
|
return value; |
|
} |
|
|
|
/** |
|
* Returns the value of this {@code Long} as a {@code float} after |
|
* a widening primitive conversion. |
|
* @jls 5.1.2 Widening Primitive Conversion |
|
*/ |
|
public float floatValue() { |
|
return (float)value; |
|
} |
|
|
|
/** |
|
* Returns the value of this {@code Long} as a {@code double} |
|
* after a widening primitive conversion. |
|
* @jls 5.1.2 Widening Primitive Conversion |
|
*/ |
|
public double doubleValue() { |
|
return (double)value; |
|
} |
|
|
|
/** |
|
* Returns a {@code String} object representing this |
|
* {@code Long}'s value. The value is converted to signed |
|
* decimal representation and returned as a string, exactly as if |
|
* the {@code long} value were given as an argument to the |
|
* {@link java.lang.Long#toString(long)} 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 Long}. The result is |
|
* the exclusive OR of the two halves of the primitive |
|
* {@code long} value held by this {@code Long} |
|
* object. That is, the hashcode is the value of the expression: |
|
* |
|
* <blockquote> |
|
* {@code (int)(this.longValue()^(this.longValue()>>>32))} |
|
* </blockquote> |
|
* |
|
* @return a hash code value for this object. |
|
*/ |
|
@Override |
|
public int hashCode() { |
|
return Long.hashCode(value); |
|
} |
|
|
|
/** |
|
* Returns a hash code for a {@code long} value; compatible with |
|
* {@code Long.hashCode()}. |
|
* |
|
* @param value the value to hash |
|
* @return a hash code value for a {@code long} value. |
|
* @since 1.8 |
|
*/ |
|
public static int hashCode(long value) { |
|
return (int)(value ^ (value >>> 32)); |
|
} |
|
|
|
/** |
|
* Compares this object to the specified object. The result is |
|
* {@code true} if and only if the argument is not |
|
* {@code null} and is a {@code Long} object that |
|
* contains the same {@code long} 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 Long) { |
|
return value == ((Long)obj).longValue(); |
|
} |
|
return false; |
|
} |
|
|
|
/** |
|
* Determines the {@code long} 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 a {@code |
|
* long} value using the grammar supported by {@link Long#decode decode} |
|
* and a {@code Long} 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 a {@code Long} object |
|
* equal to the value of: |
|
* |
|
* <blockquote> |
|
* {@code getLong(nm, null)} |
|
* </blockquote> |
|
* |
|
* @param nm property name. |
|
* @return the {@code Long} 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 Long getLong(String nm) { |
|
return getLong(nm, null); |
|
} |
|
|
|
/** |
|
* Determines the {@code long} 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 a {@code |
|
* long} value using the grammar supported by {@link Long#decode decode} |
|
* and a {@code Long} object representing this value is returned. |
|
* |
|
* <p>The second argument is the default value. A {@code Long} 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 null. |
|
* |
|
* <p>In other words, this method returns a {@code Long} object equal |
|
* to the value of: |
|
* |
|
* <blockquote> |
|
* {@code getLong(nm, new Long(val))} |
|
* </blockquote> |
|
* |
|
* but in practice it may be implemented in a manner such as: |
|
* |
|
* <blockquote><pre> |
|
* Long result = getLong(nm, null); |
|
* return (result == null) ? new Long(val) : result; |
|
* </pre></blockquote> |
|
* |
|
* to avoid the unnecessary allocation of a {@code Long} object when |
|
* the default value is not needed. |
|
* |
|
* @param nm property name. |
|
* @param val default value. |
|
* @return the {@code Long} 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 Long getLong(String nm, long val) { |
|
Long result = Long.getLong(nm, null); |
|
return (result == null) ? Long.valueOf(val) : result; |
|
} |
|
|
|
/** |
|
* Returns the {@code long} 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 a {@code long} value, as per the |
|
* {@link Long#decode decode} method, and a {@code Long} 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 for 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>Note that, in every case, neither {@code L} |
|
* ({@code '\u005Cu004C'}) nor {@code l} |
|
* ({@code '\u005Cu006C'}) is permitted to appear at the end |
|
* of the property value as a type indicator, as would be |
|
* permitted in Java programming language source code. |
|
* |
|
* <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 Long} 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 Long getLong(String nm, Long val) { |
|
String v = null; |
|
try { |
|
v = System.getProperty(nm); |
|
} catch (IllegalArgumentException | NullPointerException e) { |
|
} |
|
if (v != null) { |
|
try { |
|
return Long.decode(v); |
|
} catch (NumberFormatException e) { |
|
} |
|
} |
|
return val; |
|
} |
|
|
|
/** |
|
* Compares two {@code Long} objects numerically. |
|
* |
|
* @param anotherLong the {@code Long} to be compared. |
|
* @return the value {@code 0} if this {@code Long} is |
|
* equal to the argument {@code Long}; a value less than |
|
* {@code 0} if this {@code Long} is numerically less |
|
* than the argument {@code Long}; and a value greater |
|
* than {@code 0} if this {@code Long} is numerically |
|
* greater than the argument {@code Long} (signed |
|
* comparison). |
|
* @since 1.2 |
|
*/ |
|
public int compareTo(Long anotherLong) { |
|
return compare(this.value, anotherLong.value); |
|
} |
|
|
|
/** |
|
* Compares two {@code long} values numerically. |
|
* The value returned is identical to what would be returned by: |
|
* <pre> |
|
* Long.valueOf(x).compareTo(Long.valueOf(y)) |
|
* </pre> |
|
* |
|
* @param x the first {@code long} to compare |
|
* @param y the second {@code long} 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(long x, long y) { |
|
return (x < y) ? -1 : ((x == y) ? 0 : 1); |
|
} |
|
|
|
/** |
|
* Compares two {@code long} values numerically treating the values |
|
* as unsigned. |
|
* |
|
* @param x the first {@code long} to compare |
|
* @param y the second {@code long} 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(long x, long y) { |
|
return compare(x + MIN_VALUE, y + MIN_VALUE); |
|
} |
|
|
|
|
|
/** |
|
* 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 long divideUnsigned(long dividend, long divisor) { |
|
/* See Hacker's Delight (2nd ed), section 9.3 */ |
|
if (divisor >= 0) { |
|
final long q = (dividend >>> 1) / divisor << 1; |
|
final long r = dividend - q * divisor; |
|
return q + ((r | ~(r - divisor)) >>> (Long.SIZE - 1)); |
|
} |
|
return (dividend & ~(dividend - divisor)) >>> (Long.SIZE - 1); |
|
} |
|
|
|
/** |
|
* 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 long remainderUnsigned(long dividend, long divisor) { |
|
/* See Hacker's Delight (2nd ed), section 9.3 */ |
|
if (divisor >= 0) { |
|
final long q = (dividend >>> 1) / divisor << 1; |
|
final long r = dividend - q * divisor; |
|
/* |
|
* Here, 0 <= r < 2 * divisor |
|
* (1) When 0 <= r < divisor, the remainder is simply r. |
|
* (2) Otherwise the remainder is r - divisor. |
|
* |
|
* In case (1), r - divisor < 0. Applying ~ produces a long with |
|
* sign bit 0, so >> produces 0. The returned value is thus r. |
|
* |
|
* In case (2), a similar reasoning shows that >> produces -1, |
|
* so the returned value is r - divisor. |
|
*/ |
|
return r - ((~(r - divisor) >> (Long.SIZE - 1)) & divisor); |
|
} |
|
/* |
|
* (1) When dividend >= 0, the remainder is dividend. |
|
* (2) Otherwise |
|
* (2.1) When dividend < divisor, the remainder is dividend. |
|
* (2.2) Otherwise the remainder is dividend - divisor |
|
* |
|
* A reasoning similar to the above shows that the returned value |
|
* is as expected. |
|
*/ |
|
return dividend - (((dividend & ~(dividend - divisor)) >> (Long.SIZE - 1)) & divisor); |
|
} |
|
|
|
// Bit Twiddling |
|
|
|
/** |
|
* The number of bits used to represent a {@code long} value in two's |
|
* complement binary form. |
|
* |
|
* @since 1.5 |
|
*/ |
|
@Native public static final int SIZE = 64; |
|
|
|
/** |
|
* The number of bytes used to represent a {@code long} value in two's |
|
* complement binary form. |
|
* |
|
* @since 1.8 |
|
*/ |
|
public static final int BYTES = SIZE / Byte.SIZE; |
|
|
|
/** |
|
* Returns a {@code long} value with at most a single one-bit, in the |
|
* position of the highest-order ("leftmost") one-bit in the specified |
|
* {@code long} 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. |
|
* |
|
* @param i the value whose highest one bit is to be computed |
|
* @return a {@code long} 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 long highestOneBit(long i) { |
|
return i & (MIN_VALUE >>> numberOfLeadingZeros(i)); |
|
} |
|
|
|
/** |
|
* Returns a {@code long} value with at most a single one-bit, in the |
|
* position of the lowest-order ("rightmost") one-bit in the specified |
|
* {@code long} 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. |
|
* |
|
* @param i the value whose lowest one bit is to be computed |
|
* @return a {@code long} 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 long lowestOneBit(long 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 long} value. Returns 64 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 long} values x: |
|
* <ul> |
|
* <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)} |
|
* <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)} |
|
* </ul> |
|
* |
|
* @param i the value whose number of leading zeros is to be computed |
|
* @return the number of zero bits preceding the highest-order |
|
* ("leftmost") one-bit in the two's complement binary representation |
|
* of the specified {@code long} value, or 64 if the value |
|
* is equal to zero. |
|
* @since 1.5 |
|
*/ |
|
@IntrinsicCandidate |
|
public static int numberOfLeadingZeros(long i) { |
|
int x = (int)(i >>> 32); |
|
return x == 0 ? 32 + Integer.numberOfLeadingZeros((int)i) |
|
: Integer.numberOfLeadingZeros(x); |
|
} |
|
|
|
/** |
|
* Returns the number of zero bits following the lowest-order ("rightmost") |
|
* one-bit in the two's complement binary representation of the specified |
|
* {@code long} value. Returns 64 if the specified value has no |
|
* one-bits in its two's complement representation, in other words if it is |
|
* equal to zero. |
|
* |
|
* @param i the value whose number of trailing zeros is to be computed |
|
* @return the number of zero bits following the lowest-order ("rightmost") |
|
* one-bit in the two's complement binary representation of the |
|
* specified {@code long} value, or 64 if the value is equal |
|
* to zero. |
|
* @since 1.5 |
|
*/ |
|
@IntrinsicCandidate |
|
public static int numberOfTrailingZeros(long i) { |
|
int x = (int)i; |
|
return x == 0 ? 32 + Integer.numberOfTrailingZeros((int)(i >>> 32)) |
|
: Integer.numberOfTrailingZeros(x); |
|
} |
|
|
|
/** |
|
* Returns the number of one-bits in the two's complement binary |
|
* representation of the specified {@code long} value. This function is |
|
* sometimes referred to as the <i>population count</i>. |
|
* |
|
* @param i the value whose bits are to be counted |
|
* @return the number of one-bits in the two's complement binary |
|
* representation of the specified {@code long} value. |
|
* @since 1.5 |
|
*/ |
|
@IntrinsicCandidate |
|
public static int bitCount(long i) { |
|
// HD, Figure 5-2 |
|
i = i - ((i >>> 1) & 0x5555555555555555L); |
|
i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L); |
|
i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL; |
|
i = i + (i >>> 8); |
|
i = i + (i >>> 16); |
|
i = i + (i >>> 32); |
|
return (int)i & 0x7f; |
|
} |
|
|
|
/** |
|
* Returns the value obtained by rotating the two's complement binary |
|
* representation of the specified {@code long} 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 64 is a |
|
* no-op, so all but the last six bits of the rotation distance can be |
|
* ignored, even if the distance is negative: {@code rotateLeft(val, |
|
* distance) == rotateLeft(val, distance & 0x3F)}. |
|
* |
|
* @param i the value whose bits are to be rotated left |
|
* @param distance the number of bit positions to rotate left |
|
* @return the value obtained by rotating the two's complement binary |
|
* representation of the specified {@code long} value left by the |
|
* specified number of bits. |
|
* @since 1.5 |
|
*/ |
|
public static long rotateLeft(long i, int distance) { |
|
return (i << distance) | (i >>> -distance); |
|
} |
|
|
|
/** |
|
* Returns the value obtained by rotating the two's complement binary |
|
* representation of the specified {@code long} 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 64 is a |
|
* no-op, so all but the last six bits of the rotation distance can be |
|
* ignored, even if the distance is negative: {@code rotateRight(val, |
|
* distance) == rotateRight(val, distance & 0x3F)}. |
|
* |
|
* @param i the value whose bits are to be rotated right |
|
* @param distance the number of bit positions to rotate right |
|
* @return the value obtained by rotating the two's complement binary |
|
* representation of the specified {@code long} value right by the |
|
* specified number of bits. |
|
* @since 1.5 |
|
*/ |
|
public static long rotateRight(long 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 long} |
|
* value. |
|
* |
|
* @param i the value to be reversed |
|
* @return the value obtained by reversing order of the bits in the |
|
* specified {@code long} value. |
|
* @since 1.5 |
|
*/ |
|
public static long reverse(long i) { |
|
// HD, Figure 7-1 |
|
i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L; |
|
i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L; |
|
i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL; |
|
|
|
return reverseBytes(i); |
|
} |
|
|
|
/** |
|
* Returns the signum function of the specified {@code long} 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.) |
|
* |
|
* @param i the value whose signum is to be computed |
|
* @return the signum function of the specified {@code long} value. |
|
* @since 1.5 |
|
*/ |
|
public static int signum(long i) { |
|
// HD, Section 2-7 |
|
return (int) ((i >> 63) | (-i >>> 63)); |
|
} |
|
|
|
/** |
|
* Returns the value obtained by reversing the order of the bytes in the |
|
* two's complement representation of the specified {@code long} value. |
|
* |
|
* @param i the value whose bytes are to be reversed |
|
* @return the value obtained by reversing the bytes in the specified |
|
* {@code long} value. |
|
* @since 1.5 |
|
*/ |
|
@IntrinsicCandidate |
|
public static long reverseBytes(long i) { |
|
i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL; |
|
return (i << 48) | ((i & 0xffff0000L) << 16) | |
|
((i >>> 16) & 0xffff0000L) | (i >>> 48); |
|
} |
|
|
|
/** |
|
* Adds two {@code long} values together as per the + operator. |
|
* |
|
* @param a the first operand |
|
* @param b the second operand |
|
* @return the sum of {@code a} and {@code b} |
|
* @see java.util.function.BinaryOperator |
|
* @since 1.8 |
|
*/ |
|
public static long sum(long a, long b) { |
|
return a + b; |
|
} |
|
|
|
/** |
|
* Returns the greater of two {@code long} values |
|
* as if by calling {@link Math#max(long, long) Math.max}. |
|
* |
|
* @param a the first operand |
|
* @param b the second operand |
|
* @return the greater of {@code a} and {@code b} |
|
* @see java.util.function.BinaryOperator |
|
* @since 1.8 |
|
*/ |
|
public static long max(long a, long b) { |
|
return Math.max(a, b); |
|
} |
|
|
|
/** |
|
* Returns the smaller of two {@code long} values |
|
* as if by calling {@link Math#min(long, long) Math.min}. |
|
* |
|
* @param a the first operand |
|
* @param b the second operand |
|
* @return the smaller of {@code a} and {@code b} |
|
* @see java.util.function.BinaryOperator |
|
* @since 1.8 |
|
*/ |
|
public static long min(long a, long b) { |
|
return Math.min(a, b); |
|
} |
|
|
|
/** |
|
* Returns an {@link Optional} containing the nominal descriptor for this |
|
* instance, which is the instance itself. |
|
* |
|
* @return an {@link Optional} describing the {@linkplain Long} instance |
|
* @since 12 |
|
*/ |
|
@Override |
|
public Optional<Long> describeConstable() { |
|
return Optional.of(this); |
|
} |
|
|
|
/** |
|
* Resolves this instance as a {@link ConstantDesc}, the result of which is |
|
* the instance itself. |
|
* |
|
* @param lookup ignored |
|
* @return the {@linkplain Long} instance |
|
* @since 12 |
|
*/ |
|
@Override |
|
public Long resolveConstantDesc(MethodHandles.Lookup lookup) { |
|
return this; |
|
} |
|
|
|
/** use serialVersionUID from JDK 1.0.2 for interoperability */ |
|
@java.io.Serial |
|
@Native private static final long serialVersionUID = 4290774380558885855L; |
|
} |