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}. * *
This is a value-based * class; programmers should treat instances that are * {@linkplain #equals(Object) equal} as interchangeable and should not * use instances for synchronization, or unpredictable behavior may * occur. For example, in a future release, synchronization may fail. * *
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 Hacker's
* Delight, (Addison Wesley, 2002) and Hacker's
* Delight, Second Edition, (Pearson Education, 2013).
*
* @author Lee Boynton
* @author Arthur van Hoff
* @author Josh Bloch
* @author Joseph D. Darcy
* @since 1.0
*/
@jdk.internal.ValueBased
public final class Long extends Number
implements Comparable 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.
*
* 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.
*
* 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:
*
* 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.
*
* Note that since the first argument is treated as an unsigned
* value, no leading sign character is printed.
*
* 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 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 {
return switch (radix) {
case 2 -> toBinaryString(i);
case 4 -> toUnsignedString0(i, 2);
case 8 -> 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;
yield toString(quot) + rem;
}
case 16 -> toHexString(i);
case 32 -> toUnsignedString0(i, 5);
default -> 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.
*
* The unsigned {@code long} value is the argument plus
* 264 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.
*
* 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)}.
*
* 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:
*
* The unsigned {@code long} value is the argument plus
* 264 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.
*
* 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)}.
*
* 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:
*
* The unsigned {@code long} value is the argument plus
* 264 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.
*
* 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)}.
*
* 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 byte buffer (LATIN1 version). 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 byte buffer to write to
* @param offset the offset in the destination buffer to start at
* @param len the number of characters to write
*/
private 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] = Integer.digits[((int) val) & mask];
val >>>= shift;
} while (charPos > offset);
}
/**
* Format a long (treated as unsigned) into a byte buffer (UTF16 version). 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 byte buffer to write to
* @param offset the offset in the destination buffer to start at
* @param len the number of characters to write
*/
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);
}
/**
* 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 = DecimalDigits.stringSize(i);
if (COMPACT_STRINGS) {
byte[] buf = new byte[size];
DecimalDigits.uncheckedGetCharsLatin1(i, size, buf);
return new String(buf, LATIN1);
} else {
byte[] buf = new byte[size * 2];
DecimalDigits.uncheckedGetCharsUTF16(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);
}
/**
* 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.
*
* 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.
*
* An exception of type {@code NumberFormatException} is
* thrown if any of the following situations occurs:
* Examples:
* 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);
Objects.checkFromToIndex(beginIndex, endIndex, s.length());
if (radix < Character.MIN_RADIX) {
throw new NumberFormatException(String.format(
"radix %s less than Character.MIN_RADIX", radix));
}
if (radix > Character.MAX_RADIX) {
throw new NumberFormatException(String.format(
"radix %s greater than Character.MAX_RADIX", radix));
}
/*
* While s can be concurrently modified, it is ensured that each
* of its characters is read at most once, from lower to higher indices.
* This is obtained by reading them using the pattern s.charAt(i++),
* and by not updating i anywhere else.
*/
if (beginIndex == endIndex) {
throw NumberFormatException.forInputString("", radix);
}
int digit = ~0xFF; // ~0xFF means firstChar char is sign
int i = beginIndex;
char firstChar = s.charAt(i++);
if (firstChar != '-' && firstChar != '+') {
digit = digit(firstChar, radix);
}
if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
long multmin = limit / radix;
long result = -(digit & 0xFF);
boolean inRange = true;
/* Accumulating negatively avoids surprises near MAX_VALUE */
while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
&& (inRange = result > multmin
|| result == multmin && digit <= (int) (radix * multmin - limit))) {
result = radix * result - digit;
}
if (inRange && i == endIndex && digit >= 0) {
return firstChar != '-' ? -result : result;
}
}
throw NumberFormatException.forCharSequence(s, beginIndex,
endIndex, i - (digit < -1 ? 0 : 1));
}
/**
* 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.
*
* 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.
*
* An exception of type {@code NumberFormatException} is
* thrown if any of the following situations occurs:
* 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);
Objects.checkFromToIndex(beginIndex, endIndex, s.length());
if (radix < Character.MIN_RADIX) {
throw new NumberFormatException(String.format(
"radix %s less than Character.MIN_RADIX", radix));
}
if (radix > Character.MAX_RADIX) {
throw new NumberFormatException(String.format(
"radix %s greater than Character.MAX_RADIX", radix));
}
/*
* While s can be concurrently modified, it is ensured that each
* of its characters is read at most once, from lower to higher indices.
* This is obtained by reading them using the pattern s.charAt(i++),
* and by not updating i anywhere else.
*/
if (beginIndex == endIndex) {
throw NumberFormatException.forInputString("", radix);
}
int i = beginIndex;
char firstChar = s.charAt(i++);
if (firstChar == '-') {
throw new NumberFormatException(
"Illegal leading minus sign on unsigned string " + s + ".");
}
int digit = ~0xFF;
if (firstChar != '+') {
digit = digit(firstChar, radix);
}
if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
long result = digit & 0xFF;
boolean inRange = true;
while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
&& (inRange = compareUnsigned(result, multmax) < 0
|| result == multmax && digit < (int) (-radix * multmax))) {
result = radix * result + digit;
}
if (inRange && i == endIndex && digit >= 0) {
return result;
}
}
if (digit < 0) {
throw NumberFormatException.forCharSequence(s, beginIndex,
endIndex, i - (digit < -1 ? 0 : 1));
}
throw new NumberFormatException(String.format(
"String value %s exceeds range of unsigned long.", s));
}
/**
* 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.
*
* In other words, this method returns a {@code Long} object equal
* to the value of:
*
* In other words, this method returns a {@code Long} object
* equal to the value of:
*
* 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 = parseLong(nm, index, nm.length(), radix);
result = negative ? -result : 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 = parseLong(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.
*/
@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:
*
* 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.
*
* 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.
*
* In other words, this method returns a {@code Long} object
* equal to the value of:
*
* 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.
*
* 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.
*
* In other words, this method returns a {@code Long} object equal
* to the value of:
*
* 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.
*
* 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.
* @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 = nm != null && !nm.isEmpty() ? System.getProperty(nm) : null;
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:
* 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
*/
@IntrinsicCandidate
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
*/
@IntrinsicCandidate
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.
*
* Note that this method is closely related to the logarithm base 2.
* For all positive {@code long} values x:
* 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.)
*
* 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
*/
@IntrinsicCandidate
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 value obtained by compressing the bits of the
* specified {@code long} value, {@code i}, in accordance with
* the specified bit mask.
*
* For each one-bit value {@code mb} of the mask, from least
* significant to most significant, the bit value of {@code i} at
* the same bit location as {@code mb} is assigned to the compressed
* value contiguously starting from the least significant bit location.
* All the upper remaining bits of the compressed value are set
* to zero.
*
* @apiNote
* Consider the simple case of compressing the digits of a hexadecimal
* value:
* {@snippet lang="java" :
* // Compressing drink to food
* compress(0xCAFEBABEL, 0xFF00FFF0L) == 0xCABABL
* }
* Starting from the least significant hexadecimal digit at position 0
* from the right, the mask {@code 0xFF00FFF0} selects hexadecimal digits
* at positions 1, 2, 3, 6 and 7 of {@code 0xCAFEBABE}. The selected digits
* occur in the resulting compressed value contiguously from digit position
* 0 in the same order.
*
* The following identities all return {@code true} and are helpful to
* understand the behaviour of {@code compress}:
* {@snippet lang="java" :
* // Returns 1 if the bit at position n is one
* compress(x, 1L << n) == (x >> n & 1)
*
* // Logical shift right
* compress(x, -1L << n) == x >>> n
*
* // Any bits not covered by the mask are ignored
* compress(x, m) == compress(x & m, m)
*
* // Compressing a value by itself
* compress(m, m) == (m == -1 || m == 0) ? m : (1L << bitCount(m)) - 1
*
* // Expanding then compressing with the same mask
* compress(expand(x, m), m) == x & compress(m, m)
* }
*
* The Sheep And Goats (SAG) operation (see Hacker's Delight, Second Edition, section 7.7)
* can be implemented as follows:
* {@snippet lang="java" :
* long compressLeft(long i, long mask) {
* // This implementation follows the description in Hacker's Delight which
* // is informative. A more optimal implementation is:
* // Long.compress(i, mask) << -Long.bitCount(mask)
* return Long.reverse(
* Long.compress(Long.reverse(i), Long.reverse(mask)));
* }
*
* long sag(long i, long mask) {
* return compressLeft(i, mask) | Long.compress(i, ~mask);
* }
*
* // Separate the sheep from the goats
* sag(0x00000000_CAFEBABEL, 0xFFFFFFFF_FF00FFF0L) == 0x00000000_CABABFEEL
* }
*
* @param i the value whose bits are to be compressed
* @param mask the bit mask
* @return the compressed value
* @see #expand
* @since 19
*/
@IntrinsicCandidate
public static long compress(long i, long mask) {
// See Hacker's Delight (2nd ed) section 7.4 Compress, or Generalized Extract
i = i & mask; // Clear irrelevant bits
long maskCount = ~mask << 1; // Count 0's to right
for (int j = 0; j < 6; j++) {
// Parallel prefix
// Mask prefix identifies bits of the mask that have an odd number of 0's to the right
long maskPrefix = parallelSuffix(maskCount);
// Bits to move
long maskMove = maskPrefix & mask;
// Compress mask
mask = (mask ^ maskMove) | (maskMove >>> (1 << j));
// Bits of i to be moved
long t = i & maskMove;
// Compress i
i = (i ^ t) | (t >>> (1 << j));
// Adjust the mask count by identifying bits that have 0 to the right
maskCount = maskCount & ~maskPrefix;
}
return i;
}
/**
* Returns the value obtained by expanding the bits of the
* specified {@code long} value, {@code i}, in accordance with
* the specified bit mask.
*
* For each one-bit value {@code mb} of the mask, from least
* significant to most significant, the next contiguous bit value
* of {@code i} starting at the least significant bit is assigned
* to the expanded value at the same bit location as {@code mb}.
* All other remaining bits of the expanded value are set to zero.
*
* @apiNote
* Consider the simple case of expanding the digits of a hexadecimal
* value:
* {@snippet lang="java" :
* expand(0x0000CABABL, 0xFF00FFF0L) == 0xCA00BAB0L
* }
* Starting from the least significant hexadecimal digit at position 0
* from the right, the mask {@code 0xFF00FFF0} selects the first five
* hexadecimal digits of {@code 0x0000CABAB}. The selected digits occur
* in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.
*
* The following identities all return {@code true} and are helpful to
* understand the behaviour of {@code expand}:
* {@snippet lang="java" :
* // Logically shift right the bit at position 0
* expand(x, 1L << n) == (x & 1) << n
*
* // Logically shift right
* expand(x, -1L << n) == x << n
*
* // Expanding all bits returns the mask
* expand(-1L, m) == m
*
* // Any bits not covered by the mask are ignored
* expand(x, m) == expand(x, m) & m
*
* // Compressing then expanding with the same mask
* expand(compress(x, m), m) == x & m
* }
*
* The select operation for determining the position of the one-bit with
* index {@code n} in a {@code long} value can be implemented as follows:
* {@snippet lang="java" :
* long select(long i, long n) {
* // the one-bit in i (the mask) with index n
* long nthBit = Long.expand(1L << n, i);
* // the bit position of the one-bit with index n
* return Long.numberOfTrailingZeros(nthBit);
* }
*
* // The one-bit with index 0 is at bit position 1
* select(0b10101010_10101010, 0) == 1
* // The one-bit with index 3 is at bit position 7
* select(0b10101010_10101010, 3) == 7
* }
*
* @param i the value whose bits are to be expanded
* @param mask the bit mask
* @return the expanded value
* @see #compress
* @since 19
*/
@IntrinsicCandidate
public static long expand(long i, long mask) {
// Save original mask
long originalMask = mask;
// Count 0's to right
long maskCount = ~mask << 1;
long maskPrefix = parallelSuffix(maskCount);
// Bits to move
long maskMove1 = maskPrefix & mask;
// Compress mask
mask = (mask ^ maskMove1) | (maskMove1 >>> (1 << 0));
maskCount = maskCount & ~maskPrefix;
maskPrefix = parallelSuffix(maskCount);
// Bits to move
long maskMove2 = maskPrefix & mask;
// Compress mask
mask = (mask ^ maskMove2) | (maskMove2 >>> (1 << 1));
maskCount = maskCount & ~maskPrefix;
maskPrefix = parallelSuffix(maskCount);
// Bits to move
long maskMove3 = maskPrefix & mask;
// Compress mask
mask = (mask ^ maskMove3) | (maskMove3 >>> (1 << 2));
maskCount = maskCount & ~maskPrefix;
maskPrefix = parallelSuffix(maskCount);
// Bits to move
long maskMove4 = maskPrefix & mask;
// Compress mask
mask = (mask ^ maskMove4) | (maskMove4 >>> (1 << 3));
maskCount = maskCount & ~maskPrefix;
maskPrefix = parallelSuffix(maskCount);
// Bits to move
long maskMove5 = maskPrefix & mask;
// Compress mask
mask = (mask ^ maskMove5) | (maskMove5 >>> (1 << 4));
maskCount = maskCount & ~maskPrefix;
maskPrefix = parallelSuffix(maskCount);
// Bits to move
long maskMove6 = maskPrefix & mask;
long t = i << (1 << 5);
i = (i & ~maskMove6) | (t & maskMove6);
t = i << (1 << 4);
i = (i & ~maskMove5) | (t & maskMove5);
t = i << (1 << 3);
i = (i & ~maskMove4) | (t & maskMove4);
t = i << (1 << 2);
i = (i & ~maskMove3) | (t & maskMove3);
t = i << (1 << 1);
i = (i & ~maskMove2) | (t & maskMove2);
t = i << (1 << 0);
i = (i & ~maskMove1) | (t & maskMove1);
// Clear irrelevant bits
return i & originalMask;
}
@ForceInline
private static long parallelSuffix(long maskCount) {
long maskPrefix = maskCount ^ (maskCount << 1);
maskPrefix = maskPrefix ^ (maskPrefix << 2);
maskPrefix = maskPrefix ^ (maskPrefix << 4);
maskPrefix = maskPrefix ^ (maskPrefix << 8);
maskPrefix = maskPrefix ^ (maskPrefix << 16);
maskPrefix = maskPrefix ^ (maskPrefix << 32);
return maskPrefix;
}
/**
* 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
* {@code 0123456789abcdefghijklmnopqrstuvwxyz}
*
*
* These are {@code '\u005Cu0030'} through
* {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
* {@code '\u005Cu007a'}. If {@code radix} is
* N, then the first N of these characters
* are used as radix-N 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:
*
*
* {@code Long.toString(n, 16).toUpperCase()}
*
*
* @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--] = Integer.digits[(int)(-(i % radix))];
i = i / radix;
}
buf[charPos] = 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.
*
*
* {@code 0123456789abcdef}
*
*
* 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:
*
*
* {@code Long.toHexString(n).toUpperCase()}
*
*
* @apiNote
* The {@link java.util.HexFormat} class provides formatting and parsing
* of byte arrays and primitives to return a string or adding to an {@link Appendable}.
* {@code HexFormat} formats and parses uppercase or lowercase hexadecimal characters,
* with leading zeros and for byte arrays includes for each byte
* a delimiter, prefix, and suffix.
*
* @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 java.util.HexFormat
* @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.
*
*
* {@code 01234567}
*
*
* 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.
*
*
*
*
*
*
*
* @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(String.format(
"radix %s less than Character.MIN_RADIX", radix));
}
if (radix > Character.MAX_RADIX) {
throw new NumberFormatException(String.format(
"radix %s greater than Character.MAX_RADIX", radix));
}
int len = s.length();
if (len == 0) {
throw NumberFormatException.forInputString("", radix);
}
int digit = ~0xFF;
int i = 0;
char firstChar = s.charAt(i++);
if (firstChar != '-' && firstChar != '+') {
digit = digit(firstChar, radix);
}
if (digit >= 0 || digit == ~0xFF && len > 1) {
long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
long multmin = limit / radix;
long result = -(digit & 0xFF);
boolean inRange = true;
/* Accumulating negatively avoids surprises near MAX_VALUE */
while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
&& (inRange = result > multmin
|| result == multmin && digit <= (int) (radix * multmin - limit))) {
result = radix * result - digit;
}
if (inRange && i == len && digit >= 0) {
return firstChar != '-' ? -result : result;
}
}
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}.
*
*
* 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
*
*
*
*
* @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");
}
if (radix < Character.MIN_RADIX) {
throw new NumberFormatException(String.format(
"radix %s less than Character.MIN_RADIX", radix));
}
if (radix > Character.MAX_RADIX) {
throw new NumberFormatException(String.format(
"radix %s greater than Character.MAX_RADIX", radix));
}
int len = s.length();
if (len == 0) {
throw NumberFormatException.forInputString(s, radix);
}
int i = 0;
char firstChar = s.charAt(i++);
if (firstChar == '-') {
throw new NumberFormatException(String.format(
"Illegal leading minus sign on unsigned string %s.", s));
}
int digit = ~0xFF;
if (firstChar != '+') {
digit = digit(firstChar, radix);
}
if (digit >= 0 || digit == ~0xFF && len > 1) {
long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
long result = digit & 0xFF;
boolean inRange = true;
while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
&& (inRange = compareUnsigned(result, multmax) < 0
|| result == multmax && digit < (int) (-radix * multmax))) {
result = radix * result + digit;
}
if (inRange && i == len && digit >= 0) {
return result;
}
}
if (digit < 0) {
throw NumberFormatException.forInputString(s, radix);
}
throw new NumberFormatException(String.format(
"String value %s exceeds range of unsigned long.", s));
}
/**
* 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}.
*
*
* {@code Long.valueOf(Long.parseLong(s, radix))}
*
*
* @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.
*
*
* {@code Long.valueOf(Long.parseLong(s))}
*
*
* @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 final class LongCache {
private LongCache() {}
@Stable
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) {
Long[] c = new Long[size];
long value = -128;
for(int i = 0; i < size; i++) {
c[i] = new Long(value++);
}
archivedCache = c;
}
cache = archivedCache;
assert cache.length == size;
}
}
/**
* 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:
*
*
*
*
* DecimalNumeral, HexDigits, and OctalDigits
* are as defined in section {@jls 3.10.1} of
* The Java Language Specification,
* except that underscores are not accepted between digits.
*
*
*
*
* {@code (int)(this.longValue()^(this.longValue()>>>32))}
*
*
* @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 ell) {
return value == ell.longValue();
}
return false;
}
/**
* Determines the {@code long} value of the system property
* with the specified name.
*
*
* {@code getLong(nm, null)}
*
*
* @param nm property name.
* @return the {@code Long} value of the property.
* @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.
*
*
* {@code getLong(nm, Long.valueOf(val))}
*
*
* but in practice it may be implemented in a manner such as:
*
*
*
* 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.
* @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:
*
*
* Long result = getLong(nm, null);
* return (result == null) ? Long.valueOf(val) : result;
*
*
*
*
* Long.valueOf(x).compareTo(Long.valueOf(y))
*
*
* @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
*/
@IntrinsicCandidate
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.
*
*
*
*
* @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 population count.
*
* @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.)
*
*