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}. + * + *
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).
+ *
+ * @author Lee Boynton
+ * @author Arthur van Hoff
+ * @author Josh Bloch
+ * @author Joseph D. Darcy
+ * @since JDK1.0
+ */
+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 '-'}
+ * ( 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'}
+ * ( 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. If the unsigned magnitude is zero, it
+ * is represented by a single zero character {@code '0'}
+ * ( 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.
+ *
+ * If the unsigned magnitude is zero, it is represented by a
+ * single zero character {@code '0'}
+ * ( 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. If the unsigned magnitude is zero, it is
+ * represented by a single zero character {@code '0'}
+ * ( Note that neither the character {@code L}
+ * ( An exception of type {@code NumberFormatException} is
+ * thrown if any of the following situations occurs:
+ * Examples:
+ * Note that neither the character {@code L}
+ * ( 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.length() == 0)
+ throw new NumberFormatException("Zero length string");
+ char firstChar = nm.charAt(0);
+ // Handle sign, if present
+ if (firstChar == '-') {
+ negative = true;
+ index++;
+ } else if (firstChar == '+')
+ index++;
+
+ // Handle radix specifier, if present
+ if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
+ index += 2;
+ radix = 16;
+ }
+ else if (nm.startsWith("#", index)) {
+ index ++;
+ radix = 16;
+ }
+ else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
+ index ++;
+ radix = 8;
+ }
+
+ if (nm.startsWith("-", index) || nm.startsWith("+", index))
+ throw new NumberFormatException("Sign character in wrong position");
+
+ try {
+ result = 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.
+ */
+ 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}.
+ * @see java.lang.Long#parseLong(java.lang.String, int)
+ */
+ public Long(String s) throws NumberFormatException {
+ this.value = parseLong(s, 10);
+ }
+
+ /**
+ * Returns the value of this {@code Long} as a
+ * {@code byte}.
+ */
+ public byte byteValue() {
+ return (byte)value;
+ }
+
+ /**
+ * Returns the value of this {@code Long} as a
+ * {@code short}.
+ */
+ public short shortValue() {
+ return (short)value;
+ }
+
+ /**
+ * Returns the value of this {@code Long} as an
+ * {@code int}.
+ */
+ public int intValue() {
+ return (int)value;
+ }
+
+ /**
+ * Returns the value of this {@code Long} as a
+ * {@code long} value.
+ */
+ public long longValue() {
+ return (long)value;
+ }
+
+ /**
+ * Returns the value of this {@code Long} as a
+ * {@code float}.
+ */
+ public float floatValue() {
+ return (float)value;
+ }
+
+ /**
+ * Returns the value of this {@code Long} as a
+ * {@code double}.
+ */
+ 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 and a {@code Long} object
+ * representing this value is returned. Details of possible
+ * numeric formats can be found with the definition of
+ * {@code getProperty}.
+ *
+ * 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 and a {@code Long} object
+ * representing this value is returned. Details of possible
+ * numeric formats can be found with the definition of
+ * {@code getProperty}.
+ *
+ * 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}
+ * ( 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 java.lang.System#getProperty(java.lang.String)
+ * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
+ * @see java.lang.Long#decode
+ */
+ public static Long getLong(String nm, Long val) {
+ String v = null;
+ try {
+ v = AbstractStringBuilder.getProperty(nm);
+ } catch (IllegalArgumentException e) {
+ } catch (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:
+ * 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)}.
+ *
+ * @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)}.
+ *
+ * @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.
+ *
+ * @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;
+ i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
+ i = (i << 48) | ((i & 0xffff0000L) << 16) |
+ ((i >>> 16) & 0xffff0000L) | (i >>> 48);
+ return 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.)
+ *
+ * @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.
+ *
+ * @return the value obtained by reversing the bytes in the specified
+ * {@code long} value.
+ * @since 1.5
+ */
+ public static long reverseBytes(long i) {
+ i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
+ return (i << 48) | ((i & 0xffff0000L) << 16) |
+ ((i >>> 16) & 0xffff0000L) | (i >>> 48);
+ }
+
+ /** use serialVersionUID from JDK 1.0.2 for interoperability */
+ private static final long serialVersionUID = 4290774380558885855L;
+}
'\u002d'). If the first argument is not
+ * negative, no sign character appears in the result.
+ *
+ * '\u0030'); otherwise, the first character of
+ * the representation of the magnitude will not be the zero
+ * character. The following ASCII characters are used as digits:
+ *
+ *
+ * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
+ *
+ *
+ * These are '\u0030' through
+ * '\u0039' and '\u0061' through
+ * '\u007a'. 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);
+ char[] buf = new char[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 new String(buf, charPos, (65 - charPos));
+ }
+
+ /**
+ * Returns a string representation of the {@code long}
+ * argument as an unsigned integer in base 16.
+ *
+ * '\u0030'); 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:
+ *
+ *
+ * {@code 0123456789abcdef}
+ *
+ *
+ * These are the characters '\u0030' through
+ * '\u0039' and '\u0061' through
+ * '\u0066'. If uppercase letters are desired,
+ * the {@link java.lang.String#toUpperCase()} method may be called
+ * on the result:
+ *
+ *
+ * {@code Long.toHexString(n).toUpperCase()}
+ *
+ *
+ * @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).
+ * @since JDK 1.0.2
+ */
+ public static String toHexString(long i) {
+ return toUnsignedString(i, 4);
+ }
+
+ /**
+ * Returns a string representation of the {@code long}
+ * argument as an unsigned integer in base 8.
+ *
+ * '\u0030'); 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:
+ *
+ *
+ * {@code 01234567}
+ *
+ *
+ * These are the characters '\u0030' through
+ * '\u0037'.
+ *
+ * @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).
+ * @since JDK 1.0.2
+ */
+ public static String toOctalString(long i) {
+ return toUnsignedString(i, 3);
+ }
+
+ /**
+ * Returns a string representation of the {@code long}
+ * argument as an unsigned integer in base 2.
+ *
+ * '\u0030'); otherwise, the first character of
+ * the representation of the unsigned magnitude will not be the
+ * zero character. The characters {@code '0'}
+ * ('\u0030') and {@code '1'}
+ * ('\u0031') 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).
+ * @since JDK 1.0.2
+ */
+ public static String toBinaryString(long i) {
+ return toUnsignedString(i, 1);
+ }
+
+ /**
+ * Convert the integer to an unsigned number.
+ */
+ private static String toUnsignedString(long i, int shift) {
+ char[] buf = new char[64];
+ int charPos = 64;
+ int radix = 1 << shift;
+ long mask = radix - 1;
+ do {
+ buf[--charPos] = Integer.digits[(int)(i & mask)];
+ i >>>= shift;
+ } while (i != 0);
+ return new String(buf, charPos, (64 - charPos));
+ }
+
+ /**
+ * 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.
+ */
+ @JavaScriptBody(args = "i", body = "return i.toExactString();")
+ public static String toString(long i) {
+ if (i == Long.MIN_VALUE)
+ return "-9223372036854775808";
+ int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
+ char[] buf = new char[size];
+ getChars(i, size, buf);
+ return new String(buf, 0, size);
+ }
+
+ /**
+ * Places characters representing the integer i into the
+ * character array buf. The characters are placed into
+ * the buffer backwards starting with the least significant
+ * digit at the specified index (exclusive), and working
+ * backwards from there.
+ *
+ * Will fail if i == Long.MIN_VALUE
+ */
+ static void getChars(long i, int index, char[] buf) {
+ long q;
+ int r;
+ int charPos = index;
+ char sign = 0;
+
+ if (i < 0) {
+ sign = '-';
+ i = -i;
+ }
+
+ // Get 2 digits/iteration using longs until quotient fits into an int
+ while (i > Integer.MAX_VALUE) {
+ q = i / 100;
+ // really: r = i - (q * 100);
+ r = (int)(i - ((q << 6) + (q << 5) + (q << 2)));
+ 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 >= 65536) {
+ q2 = i2 / 100;
+ // really: r = i2 - (q * 100);
+ r = i2 - ((q2 << 6) + (q2 << 5) + (q2 << 2));
+ i2 = q2;
+ buf[--charPos] = Integer.DigitOnes[r];
+ buf[--charPos] = Integer.DigitTens[r];
+ }
+
+ // Fall thru to fast mode for smaller numbers
+ // assert(i2 <= 65536, i2);
+ for (;;) {
+ q2 = (i2 * 52429) >>> (16+3);
+ r = i2 - ((q2 << 3) + (q2 << 1)); // r = i2-(q2*10) ...
+ buf[--charPos] = Integer.digits[r];
+ i2 = q2;
+ if (i2 == 0) break;
+ }
+ if (sign != 0) {
+ buf[--charPos] = sign;
+ }
+ }
+
+ // Requires positive x
+ static int stringSize(long x) {
+ long p = 10;
+ for (int i=1; i<19; i++) {
+ if (x < p)
+ return i;
+ p = 10*p;
+ }
+ return 19;
+ }
+
+ /**
+ * 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 '-'} ('\u002D') to
+ * indicate a negative value or an ASCII plus sign {@code '+'}
+ * ('\u002B') to indicate a positive value. The
+ * resulting {@code long} value is returned.
+ *
+ * '\u004C') nor {@code l}
+ * ('\u006C') 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 22.
+ *
+ *
+ *
+ *
+ *
+ * '\u002d') or plus sign {@code
+ * '+'} ('\u002B') provided that the string is
+ * longer than length 1.
+ *
+ *
+ *
+ * @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");
+ }
+
+ long result = 0;
+ boolean negative = false;
+ int i = 0, len = s.length();
+ long limit = -Long.MAX_VALUE;
+ long multmin;
+ int digit;
+
+ 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);
+
+ if (len == 1) // Cannot have lone "+" or "-"
+ throw NumberFormatException.forInputString(s);
+ i++;
+ }
+ multmin = limit / radix;
+ while (i < len) {
+ // Accumulating negatively avoids surprises near MAX_VALUE
+ digit = Character.digit(s.charAt(i++),radix);
+ if (digit < 0) {
+ throw NumberFormatException.forInputString(s);
+ }
+ if (result < multmin) {
+ throw NumberFormatException.forInputString(s);
+ }
+ result *= radix;
+ if (result < limit + digit) {
+ throw NumberFormatException.forInputString(s);
+ }
+ result -= digit;
+ }
+ } else {
+ throw NumberFormatException.forInputString(s);
+ }
+ return negative ? result : -result;
+ }
+
+ /**
+ * Parses the string argument as a signed decimal {@code long}.
+ * The characters in the string must all be decimal digits, except
+ * that the first character may be an ASCII minus sign {@code '-'}
+ * (
+ * 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
+ * \u002D') to indicate a negative value or an
+ * ASCII plus sign {@code '+'} ('\u002B') 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.
+ *
+ * '\u004C') nor {@code l}
+ * ('\u006C') 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);
+ }
+
+ /**
+ * 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.
+ *
+ *
+ * {@code new Long(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 new Long(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 class LongCache {
+ private LongCache(){}
+
+ static final Long cache[] = new Long[-(-128) + 127 + 1];
+
+ static {
+ for(int i = 0; i < cache.length; i++)
+ cache[i] = new Long(i - 128);
+ }
+ }
+
+ /**
+ * 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.
+ *
+ * Note that unlike the {@linkplain Integer#valueOf(int)
+ * corresponding method} in the {@code Integer} class, this method
+ * is not required to cache values within a particular
+ * range.
+ *
+ * @param l a long value.
+ * @return a {@code Long} instance representing {@code l}.
+ * @since 1.5
+ */
+ 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 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.
+ */
+ public int hashCode() {
+ 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.
+ *
+ *
+ * {@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, new Long(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
+ * {@code Long.decode} method, and a {@code Long} object
+ * representing this value is returned.
+ *
+ *
+ * Long result = getLong(nm, null);
+ * return (result == null) ? new Long(val) : result;
+ *
+ *
+ *
+ * '\u004C') nor {@code l}
+ * ('\u006C') 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.
+ *
+ *
+ * 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);
+ }
+
+
+ // Bit Twiddling
+
+ /**
+ * The number of bits used to represent a {@code long} value in two's
+ * complement binary form.
+ *
+ * @since 1.5
+ */
+ public static final int SIZE = 64;
+
+ /**
+ * 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.
+ *
+ * @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) {
+ // HD, Figure 3-1
+ i |= (i >> 1);
+ i |= (i >> 2);
+ i |= (i >> 4);
+ i |= (i >> 8);
+ i |= (i >> 16);
+ i |= (i >> 32);
+ return i - (i >>> 1);
+ }
+
+ /**
+ * 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.
+ *
+ * @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.
+ *
+ *
+ *
+ *
+ * @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
+ */
+ public static int numberOfLeadingZeros(long i) {
+ // HD, Figure 5-6
+ if (i == 0)
+ return 64;
+ int n = 1;
+ int x = (int)(i >>> 32);
+ if (x == 0) { n += 32; x = (int)i; }
+ if (x >>> 16 == 0) { n += 16; x <<= 16; }
+ if (x >>> 24 == 0) { n += 8; x <<= 8; }
+ if (x >>> 28 == 0) { n += 4; x <<= 4; }
+ if (x >>> 30 == 0) { n += 2; x <<= 2; }
+ n -= x >>> 31;
+ return n;
+ }
+
+ /**
+ * Returns the number of zero bits following the lowest-order ("rightmost")
+ * one-bit in the two's complement binary representation of the specified
+ * {@code 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.
+ *
+ * @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
+ */
+ public static int numberOfTrailingZeros(long i) {
+ // HD, Figure 5-14
+ int x, y;
+ if (i == 0) return 64;
+ int n = 63;
+ y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32);
+ y = x <<16; if (y != 0) { n = n -16; x = y; }
+ y = x << 8; if (y != 0) { n = n - 8; x = y; }
+ y = x << 4; if (y != 0) { n = n - 4; x = y; }
+ y = x << 2; if (y != 0) { n = n - 2; x = y; }
+ return n - ((x << 1) >>> 31);
+ }
+
+ /**
+ * 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.
+ *
+ * @return the number of one-bits in the two's complement binary
+ * representation of the specified {@code long} value.
+ * @since 1.5
+ */
+ public static int bitCount(long i) {
+ // HD, Figure 5-14
+ 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.)
+ *
+ *