Java tutorial
/* * Copyright (c) 1994, 2019, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.lang; import java.lang.annotation.Native; import java.lang.invoke.MethodHandles; import java.lang.constant.Constable; import java.lang.constant.ConstantDesc; import java.math.*; import java.util.Objects; import java.util.Optional; import jdk.internal.HotSpotIntrinsicCandidate; import jdk.internal.misc.VM; import static java.lang.String.COMPACT_STRINGS; import static java.lang.String.LATIN1; import static java.lang.String.UTF16; /** * The {@code Long} class wraps a value of the primitive type {@code * long} in an object. An object of type {@code Long} contains a * single field whose type is {@code long}. * * <p> In addition, this class provides several methods for converting * a {@code long} to a {@code String} and a {@code String} to a {@code * long}, as well as other constants and methods useful when dealing * with a {@code long}. * * <p>Implementation note: The implementations of the "bit twiddling" * methods (such as {@link #highestOneBit(long) highestOneBit} and * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are * based on material from Henry S. Warren, Jr.'s <i>Hacker's * Delight</i>, (Addison Wesley, 2002). * * @author Lee Boynton * @author Arthur van Hoff * @author Josh Bloch * @author Joseph D. Darcy * @since 1.0 */ public final class Long extends Number implements Comparable<Long>, Constable, ConstantDesc { /** * A constant holding the minimum value a {@code long} can * have, -2<sup>63</sup>. */ @Native public static final long MIN_VALUE = 0x8000000000000000L; /** * A constant holding the maximum value a {@code long} can * have, 2<sup>63</sup>-1. */ @Native public static final long MAX_VALUE = 0x7fffffffffffffffL; /** * The {@code Class} instance representing the primitive type * {@code long}. * * @since 1.1 */ @SuppressWarnings("unchecked") public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long"); /** * Returns a string representation of the first argument in the * radix specified by the second argument. * * <p>If the radix is smaller than {@code Character.MIN_RADIX} * or larger than {@code Character.MAX_RADIX}, then the radix * {@code 10} is used instead. * * <p>If the first argument is negative, the first element of the * result is the ASCII minus sign {@code '-'} * ({@code '\u005Cu002d'}). If the first argument is not * negative, no sign character appears in the result. * * <p>The remaining characters of the result represent the magnitude * of the first argument. If the magnitude is zero, it is * represented by a single zero character {@code '0'} * ({@code '\u005Cu0030'}); otherwise, the first character of * the representation of the magnitude will not be the zero * character. The following ASCII characters are used as digits: * * <blockquote> * {@code 0123456789abcdefghijklmnopqrstuvwxyz} * </blockquote> * * These are {@code '\u005Cu0030'} through * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through * {@code '\u005Cu007a'}. If {@code radix} is * <var>N</var>, then the first <var>N</var> of these characters * are used as radix-<var>N</var> digits in the order shown. Thus, * the digits for hexadecimal (radix 16) are * {@code 0123456789abcdef}. If uppercase letters are * desired, the {@link java.lang.String#toUpperCase()} method may * be called on the result: * * <blockquote> * {@code Long.toString(n, 16).toUpperCase()} * </blockquote> * * @param i a {@code long} to be converted to a string. * @param radix the radix to use in the string representation. * @return a string representation of the argument in the specified radix. * @see java.lang.Character#MAX_RADIX * @see java.lang.Character#MIN_RADIX */ public static String toString(long i, int radix) { if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX) radix = 10; if (radix == 10) return toString(i); if (COMPACT_STRINGS) { byte[] buf = new byte[65]; int charPos = 64; boolean negative = (i < 0); if (!negative) { i = -i; } while (i <= -radix) { buf[charPos--] = (byte) Integer.digits[(int) (-(i % radix))]; i = i / radix; } buf[charPos] = (byte) Integer.digits[(int) (-i)]; if (negative) { buf[--charPos] = '-'; } return StringLatin1.newString(buf, charPos, (65 - charPos)); } return toStringUTF16(i, radix); } private static String toStringUTF16(long i, int radix) { byte[] buf = new byte[65 * 2]; int charPos = 64; boolean negative = (i < 0); if (!negative) { i = -i; } while (i <= -radix) { StringUTF16.putChar(buf, charPos--, Integer.digits[(int) (-(i % radix))]); i = i / radix; } StringUTF16.putChar(buf, charPos, Integer.digits[(int) (-i)]); if (negative) { StringUTF16.putChar(buf, --charPos, '-'); } return StringUTF16.newString(buf, charPos, (65 - charPos)); } /** * Returns a string representation of the first argument as an * unsigned integer value in the radix specified by the second * argument. * * <p>If the radix is smaller than {@code Character.MIN_RADIX} * or larger than {@code Character.MAX_RADIX}, then the radix * {@code 10} is used instead. * * <p>Note that since the first argument is treated as an unsigned * value, no leading sign character is printed. * * <p>If the magnitude is zero, it is represented by a single zero * character {@code '0'} ({@code '\u005Cu0030'}); otherwise, * the first character of the representation of the magnitude will * not be the zero character. * * <p>The behavior of radixes and the characters used as digits * are the same as {@link #toString(long, int) toString}. * * @param i an integer to be converted to an unsigned string. * @param radix the radix to use in the string representation. * @return an unsigned string representation of the argument in the specified radix. * @see #toString(long, int) * @since 1.8 */ public static String toUnsignedString(long i, int radix) { if (i >= 0) return toString(i, radix); else { switch (radix) { case 2: return toBinaryString(i); case 4: return toUnsignedString0(i, 2); case 8: return toOctalString(i); case 10: /* * We can get the effect of an unsigned division by 10 * on a long value by first shifting right, yielding a * positive value, and then dividing by 5. This * allows the last digit and preceding digits to be * isolated more quickly than by an initial conversion * to BigInteger. */ long quot = (i >>> 1) / 5; long rem = i - quot * 10; return toString(quot) + rem; case 16: return toHexString(i); case 32: return toUnsignedString0(i, 5); default: return toUnsignedBigInteger(i).toString(radix); } } } /** * Return a BigInteger equal to the unsigned value of the * argument. */ private static BigInteger toUnsignedBigInteger(long i) { if (i >= 0L) return BigInteger.valueOf(i); else { int upper = (int) (i >>> 32); int lower = (int) i; // return (upper << 32) + lower return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32) .add(BigInteger.valueOf(Integer.toUnsignedLong(lower))); } } /** * Returns a string representation of the {@code long} * argument as an unsigned integer in base 16. * * <p>The unsigned {@code long} value is the argument plus * 2<sup>64</sup> if the argument is negative; otherwise, it is * equal to the argument. This value is converted to a string of * ASCII digits in hexadecimal (base 16) with no extra * leading {@code 0}s. * * <p>The value of the argument can be recovered from the returned * string {@code s} by calling {@link * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, * 16)}. * * <p>If the unsigned magnitude is zero, it is represented by a * single zero character {@code '0'} ({@code '\u005Cu0030'}); * otherwise, the first character of the representation of the * unsigned magnitude will not be the zero character. The * following characters are used as hexadecimal digits: * * <blockquote> * {@code 0123456789abcdef} * </blockquote> * * These are the characters {@code '\u005Cu0030'} through * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through * {@code '\u005Cu0066'}. If uppercase letters are desired, * the {@link java.lang.String#toUpperCase()} method may be called * on the result: * * <blockquote> * {@code Long.toHexString(n).toUpperCase()} * </blockquote> * * @param i a {@code long} to be converted to a string. * @return the string representation of the unsigned {@code long} * value represented by the argument in hexadecimal * (base 16). * @see #parseUnsignedLong(String, int) * @see #toUnsignedString(long, int) * @since 1.0.2 */ public static String toHexString(long i) { return toUnsignedString0(i, 4); } /** * Returns a string representation of the {@code long} * argument as an unsigned integer in base 8. * * <p>The unsigned {@code long} value is the argument plus * 2<sup>64</sup> if the argument is negative; otherwise, it is * equal to the argument. This value is converted to a string of * ASCII digits in octal (base 8) with no extra leading * {@code 0}s. * * <p>The value of the argument can be recovered from the returned * string {@code s} by calling {@link * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, * 8)}. * * <p>If the unsigned magnitude is zero, it is represented by a * single zero character {@code '0'} ({@code '\u005Cu0030'}); * otherwise, the first character of the representation of the * unsigned magnitude will not be the zero character. The * following characters are used as octal digits: * * <blockquote> * {@code 01234567} * </blockquote> * * These are the characters {@code '\u005Cu0030'} through * {@code '\u005Cu0037'}. * * @param i a {@code long} to be converted to a string. * @return the string representation of the unsigned {@code long} * value represented by the argument in octal (base 8). * @see #parseUnsignedLong(String, int) * @see #toUnsignedString(long, int) * @since 1.0.2 */ public static String toOctalString(long i) { return toUnsignedString0(i, 3); } /** * Returns a string representation of the {@code long} * argument as an unsigned integer in base 2. * * <p>The unsigned {@code long} value is the argument plus * 2<sup>64</sup> if the argument is negative; otherwise, it is * equal to the argument. This value is converted to a string of * ASCII digits in binary (base 2) with no extra leading * {@code 0}s. * * <p>The value of the argument can be recovered from the returned * string {@code s} by calling {@link * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, * 2)}. * * <p>If the unsigned magnitude is zero, it is represented by a * single zero character {@code '0'} ({@code '\u005Cu0030'}); * otherwise, the first character of the representation of the * unsigned magnitude will not be the zero character. The * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code * '1'} ({@code '\u005Cu0031'}) are used as binary digits. * * @param i a {@code long} to be converted to a string. * @return the string representation of the unsigned {@code long} * value represented by the argument in binary (base 2). * @see #parseUnsignedLong(String, int) * @see #toUnsignedString(long, int) * @since 1.0.2 */ public static String toBinaryString(long i) { return toUnsignedString0(i, 1); } /** * Format a long (treated as unsigned) into a String. * @param val the value to format * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) */ static String toUnsignedString0(long val, int shift) { // assert shift > 0 && shift <=5 : "Illegal shift value"; int mag = Long.SIZE - Long.numberOfLeadingZeros(val); int chars = Math.max(((mag + (shift - 1)) / shift), 1); if (COMPACT_STRINGS) { byte[] buf = new byte[chars]; formatUnsignedLong0(val, shift, buf, 0, chars); return new String(buf, LATIN1); } else { byte[] buf = new byte[chars * 2]; formatUnsignedLong0UTF16(val, shift, buf, 0, chars); return new String(buf, UTF16); } } /** * Format a long (treated as unsigned) into a character buffer. If * {@code len} exceeds the formatted ASCII representation of {@code val}, * {@code buf} will be padded with leading zeroes. * * @param val the unsigned long to format * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) * @param buf the character buffer to write to * @param offset the offset in the destination buffer to start at * @param len the number of characters to write */ /** byte[]/LATIN1 version */ static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) { int charPos = offset + len; int radix = 1 << shift; int mask = radix - 1; do { buf[--charPos] = (byte) Integer.digits[((int) val) & mask]; val >>>= shift; } while (charPos > offset); } /** byte[]/UTF16 version */ private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) { int charPos = offset + len; int radix = 1 << shift; int mask = radix - 1; do { StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]); val >>>= shift; } while (charPos > offset); } static String fastUUID(long lsb, long msb) { if (COMPACT_STRINGS) { byte[] buf = new byte[36]; formatUnsignedLong0(lsb, 4, buf, 24, 12); formatUnsignedLong0(lsb >>> 48, 4, buf, 19, 4); formatUnsignedLong0(msb, 4, buf, 14, 4); formatUnsignedLong0(msb >>> 16, 4, buf, 9, 4); formatUnsignedLong0(msb >>> 32, 4, buf, 0, 8); buf[23] = '-'; buf[18] = '-'; buf[13] = '-'; buf[8] = '-'; return new String(buf, LATIN1); } else { byte[] buf = new byte[72]; formatUnsignedLong0UTF16(lsb, 4, buf, 24, 12); formatUnsignedLong0UTF16(lsb >>> 48, 4, buf, 19, 4); formatUnsignedLong0UTF16(msb, 4, buf, 14, 4); formatUnsignedLong0UTF16(msb >>> 16, 4, buf, 9, 4); formatUnsignedLong0UTF16(msb >>> 32, 4, buf, 0, 8); StringUTF16.putChar(buf, 23, '-'); StringUTF16.putChar(buf, 18, '-'); StringUTF16.putChar(buf, 13, '-'); StringUTF16.putChar(buf, 8, '-'); 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("null"); } if (radix < Character.MIN_RADIX) { throw new NumberFormatException("radix " + radix + " less than Character.MIN_RADIX"); } if (radix > Character.MAX_RADIX) { throw new NumberFormatException("radix " + radix + " greater than Character.MAX_RADIX"); } 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 { s = 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("null"); } int len = s.length(); if (len > 0) { char firstChar = s.charAt(0); if (firstChar == '-') { throw new NumberFormatException( String.format("Illegal leading minus sign " + "on unsigned string %s.", s)); } else { if (len <= 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 { s = 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 VM.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 */ @HotSpotIntrinsicCandidate 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 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") 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") 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. */ @HotSpotIntrinsicCandidate 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) { if (divisor < 0L) { // signed comparison // Answer must be 0 or 1 depending on relative magnitude // of dividend and divisor. return (compareUnsigned(dividend, divisor)) < 0 ? 0L : 1L; } if (dividend > 0) // Both inputs non-negative return dividend / divisor; else { /* * For simple code, leveraging BigInteger. Longer and faster * code written directly in terms of operations on longs is * possible; see "Hacker's Delight" for divide and remainder * algorithms. */ return toUnsignedBigInteger(dividend).divide(toUnsignedBigInteger(divisor)).longValue(); } } /** * 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) { if (dividend > 0 && divisor > 0) { // signed comparisons return dividend % divisor; } else { if (compareUnsigned(dividend, divisor) < 0) // Avoid explicit check for 0 divisor return dividend; else return toUnsignedBigInteger(dividend).remainder(toUnsignedBigInteger(divisor)).longValue(); } } // 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 */ @HotSpotIntrinsicCandidate 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 */ @HotSpotIntrinsicCandidate 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 */ @HotSpotIntrinsicCandidate 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 */ @HotSpotIntrinsicCandidate 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 */ @Native private static final long serialVersionUID = 4290774380558885855L; }