/*

 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.lang;

/**

 *

 * The {@code Byte} class wraps a value of primitive type {@code byte}

 * in an object.  An object of type {@code Byte} contains a single

 * field whose type is {@code byte}.

 *

 * <p>In addition, this class provides several methods for converting

 * a {@code byte} to a {@code String} and a {@code String} to a {@code

 * byte}, as well as other constants and methods useful when dealing

 * with a {@code byte}.

 *

 * @author  Nakul Saraiya

 * @author  Joseph D. Darcy

 * @see     java.lang.Number

 * @since   JDK1.1

 */

public final class Byte extends Number implements Comparable<Byte> {

    /**

     * A constant holding the minimum value a {@code byte} can

     * have, -2<sup>7</sup>.

     */

    public static final byte   MIN_VALUE = -128;

    /**

     * A constant holding the maximum value a {@code byte} can

     * have, 2<sup>7</sup>-1.

     */

    public static final byte   MAX_VALUE = 127;

    /**

     * The {@code Class} instance representing the primitive type

     * {@code byte}.

     */

    @SuppressWarnings("unchecked")

    public static final Class<Byte>     TYPE = (Class<Byte>) Class.getPrimitiveClass("byte");

    /**

     * Returns a new {@code String} object representing the

     * specified {@code byte}. The radix is assumed to be 10.

     *

     * @param b the {@code byte} to be converted

     * @return the string representation of the specified {@code byte}

     * @see java.lang.Integer#toString(int)

     */

    public static String toString(byte b) {

        return Integer.toString((int)b, 10);

    }

    private static class ByteCache {

        private ByteCache(){}

        static final Byte cache[] = new Byte[-(-128) + 127 + 1];

        static {

            for(int i = 0; i < cache.length; i++)

                cache[i] = new Byte((byte)(i - 128));

        }

    }

    /**

     * Returns a {@code Byte} instance representing the specified

     * {@code byte} value.

     * If a new {@code Byte} instance is not required, this method

     * should generally be used in preference to the constructor

     * {@link #Byte(byte)}, as this method is likely to yield

     * significantly better space and time performance since

     * all byte values are cached.

     *

     * @param  b a byte value.

     * @return a {@code Byte} instance representing {@code b}.

     * @since  1.5

     */

    public static Byte valueOf(byte b) {

        final int offset = 128;

        return ByteCache.cache[(int)b + offset];

    }

    /**

     * Parses the string argument as a signed {@code byte} 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 byte} value is

     * returned.

     *

     * <p>An exception of type {@code NumberFormatException} is

     * thrown if any of the following situations occurs:

     * <ul>

     * <li> The first argument is {@code null} or is a string of

     * length zero.

     *

     * <li> The radix is either smaller than {@link

     * java.lang.Character#MIN_RADIX} or larger than {@link

     * java.lang.Character#MAX_RADIX}.

     *

     * <li> Any character of the string is not a digit of the

     * specified radix, except that the first character may be a minus

     * sign {@code '-'} ({@code '\u005Cu002D'}) or plus sign

     * {@code '+'} ({@code '\u005Cu002B'}) provided that the

     * string is longer than length 1.

     *

     * <li> The value represented by the string is not a value of type

     * {@code byte}.

     * </ul>

     *

     * @param s         the {@code String} containing the

     *                  {@code byte}

     *                  representation to be parsed

     * @param radix     the radix to be used while parsing {@code s}

     * @return          the {@code byte} value represented by the string

     *                   argument in the specified radix

     * @throws          NumberFormatException If the string does

     *                  not contain a parsable {@code byte}.

     */

    public static byte parseByte(String s, int radix)

        throws NumberFormatException {

        int i = Integer.parseInt(s, radix);

        if (i < MIN_VALUE || i > MAX_VALUE)

            throw new NumberFormatException(

                "Value out of range. Value:\"" + s + "\" Radix:" + radix);

        return (byte)i;

    }

    /**

     * Parses the string argument as a signed decimal {@code

     * byte}. 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 byte} value is returned, exactly as if the

     * argument and the radix 10 were given as arguments to the {@link

     * #parseByte(java.lang.String, int)} method.

     *

     * @param s         a {@code String} containing the

     *                  {@code byte} representation to be parsed

     * @return          the {@code byte} value represented by the

     *                  argument in decimal

     * @throws          NumberFormatException if the string does not

     *                  contain a parsable {@code byte}.

     */

    public static byte parseByte(String s) throws NumberFormatException {

        return parseByte(s, 10);

    }

    /**

     * Returns a {@code Byte} 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 byte} in

     * the radix specified by the second argument, exactly as if the

     * argument were given to the {@link #parseByte(java.lang.String,

     * int)} method. The result is a {@code Byte} object that

     * represents the {@code byte} value specified by the string.

     *

     * <p> In other words, this method returns a {@code Byte} object

     * equal to the value of:

     *

     * <blockquote>

     * {@code new Byte(Byte.parseByte(s, radix))}

     * </blockquote>

     *

     * @param s         the string to be parsed

     * @param radix     the radix to be used in interpreting {@code s}

     * @return          a {@code Byte} 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 byte}.

     */

    public static Byte valueOf(String s, int radix)

        throws NumberFormatException {

        return valueOf(parseByte(s, radix));

    }

    /**

     * Returns a {@code Byte} object holding the value

     * given by the specified {@code String}. The argument is

     * interpreted as representing a signed decimal {@code byte},

     * exactly as if the argument were given to the {@link

     * #parseByte(java.lang.String)} method. The result is a

     * {@code Byte} object that represents the {@code byte}

     * value specified by the string.

     *

     * <p> In other words, this method returns a {@code Byte} object

     * equal to the value of:

     *

     * <blockquote>

     * {@code new Byte(Byte.parseByte(s))}

     * </blockquote>

     *

     * @param s         the string to be parsed

     * @return          a {@code Byte} object holding the value

     *                  represented by the string argument

     * @throws          NumberFormatException If the {@code String} does

     *                  not contain a parsable {@code byte}.

     */

    public static Byte valueOf(String s) throws NumberFormatException {

        return valueOf(s, 10);

    }

    /**

     * Decodes a {@code String} into a {@code Byte}.

     * Accepts decimal, hexadecimal, and octal numbers given by

     * the following grammar:

     *

     * <blockquote>

     * <dl>

     * <dt><i>DecodableString:</i>

     * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>

     * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>

     * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>

     * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>

     * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>

     * <p>

     * <dt><i>Sign:</i>

     * <dd>{@code -}

     * <dd>{@code +}

     * </dl>

     * </blockquote>

     *

     * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>

     * are as defined in section 3.10.1 of

     * <cite>The Java&trade; Language Specification</cite>,

     * except that underscores are not accepted between digits.

     *

     * <p>The sequence of characters following an optional

     * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",

     * "{@code #}", or leading zero) is parsed as by the {@code

     * Byte.parseByte} 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 Byte} object holding the {@code byte}

     *          value represented by {@code nm}

     * @throws  NumberFormatException  if the {@code String} does not

     *            contain a parsable {@code byte}.

     * @see java.lang.Byte#parseByte(java.lang.String, int)

     */

    public static Byte decode(String nm) throws NumberFormatException {

        int i = Integer.decode(nm);

        if (i < MIN_VALUE || i > MAX_VALUE)

            throw new NumberFormatException(

                    "Value " + i + " out of range from input " + nm);

        return valueOf((byte)i);

    }

    /**

     * The value of the {@code Byte}.

     *

     * @serial

     */

    private final byte value;

    /**

     * Constructs a newly allocated {@code Byte} object that

     * represents the specified {@code byte} value.

     *

     * @param value     the value to be represented by the

     *                  {@code Byte}.

     */

    public Byte(byte value) {

        this.value = value;

    }

    /**

     * Constructs a newly allocated {@code Byte} object that

     * represents the {@code byte} value indicated by the

     * {@code String} parameter. The string is converted to a

     * {@code byte} value in exactly the manner used by the

     * {@code parseByte} method for radix 10.

     *

     * @param s         the {@code String} to be converted to a

     *                  {@code Byte}

     * @throws           NumberFormatException If the {@code String}

     *                  does not contain a parsable {@code byte}.

     * @see        java.lang.Byte#parseByte(java.lang.String, int)

     */

    public Byte(String s) throws NumberFormatException {

        this.value = parseByte(s, 10);

    }

    /**

     * Returns the value of this {@code Byte} as a

     * {@code byte}.

     */

    public byte byteValue() {

        return value;

    }

    /**

     * Returns the value of this {@code Byte} as a {@code short} after

     * a widening primitive conversion.

     * @jls 5.1.2 Widening Primitive Conversions

     */

    public short shortValue() {

        return (short)value;

    }

    /**

     * Returns the value of this {@code Byte} as an {@code int} after

     * a widening primitive conversion.

     * @jls 5.1.2 Widening Primitive Conversions

     */

    public int intValue() {

        return (int)value;

    }

    /**

     * Returns the value of this {@code Byte} as a {@code long} after

     * a widening primitive conversion.

     * @jls 5.1.2 Widening Primitive Conversions

     */

    public long longValue() {

        return (long)value;

    }

    /**

     * Returns the value of this {@code Byte} as a {@code float} after

     * a widening primitive conversion.

     * @jls 5.1.2 Widening Primitive Conversions

     */

    public float floatValue() {

        return (float)value;

    }

    /**

     * Returns the value of this {@code Byte} as a {@code double}

     * after a widening primitive conversion.

     * @jls 5.1.2 Widening Primitive Conversions

     */

    public double doubleValue() {

        return (double)value;

    }

    /**

     * Returns a {@code String} object representing this

     * {@code Byte}'s value.  The value is converted to signed

     * decimal representation and returned as a string, exactly as if

     * the {@code byte} value were given as an argument to the

     * {@link java.lang.Byte#toString(byte)} method.

     *

     * @return  a string representation of the value of this object in

     *          base 10.

     */

    public String toString() {

        return Integer.toString((int)value);

    }

    /**

     * Returns a hash code for this {@code Byte}; equal to the result

     * of invoking {@code intValue()}.

     *

     * @return a hash code value for this {@code Byte}

     */

    @Override

    public int hashCode() {

        return Byte.hashCode(value);

    }

    /**

     * Returns a hash code for a {@code byte} value; compatible with

     * {@code Byte.hashCode()}.

     *

     * @param value the value to hash

     * @return a hash code value for a {@code byte} value.

     * @since 1.8

     */

    public static int hashCode(byte value) {

        return (int)value;

    }

    /**

     * 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 Byte} object that

     * contains the same {@code byte} 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 Byte) {

            return value == ((Byte)obj).byteValue();

        }

        return false;

    }

    /**

     * Compares two {@code Byte} objects numerically.

     *

     * @param   anotherByte   the {@code Byte} to be compared.

     * @return  the value {@code 0} if this {@code Byte} is

     *          equal to the argument {@code Byte}; a value less than

     *          {@code 0} if this {@code Byte} is numerically less

     *          than the argument {@code Byte}; and a value greater than

     *           {@code 0} if this {@code Byte} is numerically

     *           greater than the argument {@code Byte} (signed

     *           comparison).

     * @since   1.2

     */

    public int compareTo(Byte anotherByte) {

        return compare(this.value, anotherByte.value);

    }

    /**

     * Compares two {@code byte} values numerically.

     * The value returned is identical to what would be returned by:

     * <pre>

     *    Byte.valueOf(x).compareTo(Byte.valueOf(y))

     * </pre>

     *

     * @param  x the first {@code byte} to compare

     * @param  y the second {@code byte} 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(byte x, byte y) {

        return x - y;

    }

    /**

     * Converts the argument to an {@code int} by an unsigned

     * conversion.  In an unsigned conversion to an {@code int}, the

     * high-order 24 bits of the {@code int} are zero and the

     * low-order 8 bits are equal to the bits of the {@code byte} argument.

     *

     * Consequently, zero and positive {@code byte} values are mapped

     * to a numerically equal {@code int} value and negative {@code

     * byte} values are mapped to an {@code int} value equal to the

     * input plus 2<sup>8</sup>.

     *

     * @param  x the value to convert to an unsigned {@code int}

     * @return the argument converted to {@code int} by an unsigned

     *         conversion

     * @since 1.8

     */

    public static int toUnsignedInt(byte x) {

        return ((int) x) & 0xff;

    }

    /**

     * Converts the argument to a {@code long} by an unsigned

     * conversion.  In an unsigned conversion to a {@code long}, the

     * high-order 56 bits of the {@code long} are zero and the

     * low-order 8 bits are equal to the bits of the {@code byte} argument.

     *

     * Consequently, zero and positive {@code byte} values are mapped

     * to a numerically equal {@code long} value and negative {@code

     * byte} values are mapped to a {@code long} value equal to the

     * input plus 2<sup>8</sup>.

     *

     * @param  x the value to convert to an unsigned {@code long}

     * @return the argument converted to {@code long} by an unsigned

     *         conversion

     * @since 1.8

     */

    public static long toUnsignedLong(byte x) {

        return ((long) x) & 0xffL;

    }

    /**

     * The number of bits used to represent a {@code byte} value in two's

     * complement binary form.

     *

     * @since 1.5

     */

    public static final int SIZE = 8;

    /**

     * The number of bytes used to represent a {@code byte} value in two's

     * complement binary form.

     *

     * @since 1.8

     */

    public static final int BYTES = SIZE / Byte.SIZE;