org.eclipse.jgit/src/org/eclipse/jgit/util/NB.java - sop/jgit - Git at Google

 /*
  * Copyright (C) 2008, 2015 Shawn O. Pearce <spearce@spearce.org>
  * and other copyright owners as documented in the project's IP log.
  *
  * This program and the accompanying materials are made available
  * under the terms of the Eclipse Distribution License v1.0 which
  * accompanies this distribution, is reproduced below, and is
  * available at http://www.eclipse.org/org/documents/edl-v10.php
  *
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or
  * without modification, are permitted provided that the following
  * conditions are met:
  *
  * - Redistributions of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
  *
  * - Redistributions in binary form must reproduce the above
  *   copyright notice, this list of conditions and the following
  *   disclaimer in the documentation and/or other materials provided
  *   with the distribution.
  *
  * - Neither the name of the Eclipse Foundation, Inc. nor the
  *   names of its contributors may be used to endorse or promote
  *   products derived from this software without specific prior
  *   written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 package org.eclipse.jgit.util;

 /** Conversion utilities for network byte order handling. */
 public final class NB {
 	/**
 	 * Compare a 32 bit unsigned integer stored in a 32 bit signed integer.
 	 * <p>
 	 * This function performs an unsigned compare operation, even though Java
 	 * does not natively support unsigned integer values. Negative numbers are
 	 * treated as larger than positive ones.
 	 *
 	 * @param a
 	 *            the first value to compare.
 	 * @param b
 	 *            the second value to compare.
 	 * @return &lt; 0 if a &lt; b; 0 if a == b; &gt; 0 if a &gt; b.
 	 */
 	public static int compareUInt32(final int a, final int b) {
 		final int cmp = (a >>> 1) - (b >>> 1);
 		if (cmp != 0)
 			return cmp;
 		return (a & 1) - (b & 1);
 	}

 	/**
 	 * Compare a 64 bit unsigned integer stored in a 64 bit signed integer.
 	 * <p>
 	 * This function performs an unsigned compare operation, even though Java
 	 * does not natively support unsigned integer values. Negative numbers are
 	 * treated as larger than positive ones.
 	 *
 	 * @param a
 	 *            the first value to compare.
 	 * @param b
 	 *            the second value to compare.
 	 * @return &lt; 0 if a &lt; b; 0 if a == b; &gt; 0 if a &gt; b.
 	 * @since 4.3
 	 */
 	public static int compareUInt64(final long a, final long b) {
 		long cmp = (a >>> 1) - (b >>> 1);
 		if (cmp > 0) {
 			return 1;
 		} else if (cmp < 0) {
 			return -1;
 		}
 		cmp = ((a & 1) - (b & 1));
 		if (cmp > 0) {
 			return 1;
 		} else if (cmp < 0) {
 			return -1;
 		} else {
 			return 0;
 		}
 	}

 	/**
 	 * Convert sequence of 2 bytes (network byte order) into unsigned value.
 	 *
 	 * @param intbuf
 	 *            buffer to acquire the 2 bytes of data from.
 	 * @param offset
 	 *            position within the buffer to begin reading from. This
 	 *            position and the next byte after it (for a total of 2 bytes)
 	 *            will be read.
 	 * @return unsigned integer value that matches the 16 bits read.
 	 */
 	public static int decodeUInt16(final byte[] intbuf, final int offset) {
 		int r = (intbuf[offset] & 0xff) << 8;
 		return r | (intbuf[offset + 1] & 0xff);
 	}

 	/**
 	 * Convert sequence of 3 bytes (network byte order) into unsigned value.
 	 *
 	 * @param intbuf
 	 *            buffer to acquire the 3 bytes of data from.
 	 * @param offset
 	 *            position within the buffer to begin reading from. This
 	 *            position and the next 2 bytes after it (for a total of 3
 	 *            bytes) will be read.
 	 * @return signed integer value that matches the 24 bits read.
 	 * @since 4.9
 	 */
 	public static int decodeUInt24(byte[] intbuf, int offset) {
 		int r = (intbuf[offset] & 0xff) << 8;
 		r |= intbuf[offset + 1] & 0xff;
 		return (r << 8) | (intbuf[offset + 2] & 0xff);
 	}

 	/**
 	 * Convert sequence of 4 bytes (network byte order) into signed value.
 	 *
 	 * @param intbuf
 	 *            buffer to acquire the 4 bytes of data from.
 	 * @param offset
 	 *            position within the buffer to begin reading from. This
 	 *            position and the next 3 bytes after it (for a total of 4
 	 *            bytes) will be read.
 	 * @return signed integer value that matches the 32 bits read.
 	 */
 	public static int decodeInt32(final byte[] intbuf, final int offset) {
 		int r = intbuf[offset] << 8;

 		r |= intbuf[offset + 1] & 0xff;
 		r <<= 8;

 		r |= intbuf[offset + 2] & 0xff;
 		return (r << 8) | (intbuf[offset + 3] & 0xff);
 	}

 	/**
 	 * Convert sequence of 8 bytes (network byte order) into signed value.
 	 *
 	 * @param intbuf
 	 *            buffer to acquire the 8 bytes of data from.
 	 * @param offset
 	 *            position within the buffer to begin reading from. This
 	 *            position and the next 7 bytes after it (for a total of 8
 	 *            bytes) will be read.
 	 * @return signed integer value that matches the 64 bits read.
 	 * @since 3.0
 	 */
 	public static long decodeInt64(final byte[] intbuf, final int offset) {
 		long r = intbuf[offset] << 8;

 		r |= intbuf[offset + 1] & 0xff;
 		r <<= 8;

 		r |= intbuf[offset + 2] & 0xff;
 		r <<= 8;

 		r |= intbuf[offset + 3] & 0xff;
 		r <<= 8;

 		r |= intbuf[offset + 4] & 0xff;
 		r <<= 8;

 		r |= intbuf[offset + 5] & 0xff;
 		r <<= 8;

 		r |= intbuf[offset + 6] & 0xff;
 		return (r << 8) | (intbuf[offset + 7] & 0xff);
 	}

 	/**
 	 * Convert sequence of 4 bytes (network byte order) into unsigned value.
 	 *
 	 * @param intbuf
 	 *            buffer to acquire the 4 bytes of data from.
 	 * @param offset
 	 *            position within the buffer to begin reading from. This
 	 *            position and the next 3 bytes after it (for a total of 4
 	 *            bytes) will be read.
 	 * @return unsigned integer value that matches the 32 bits read.
 	 */
 	public static long decodeUInt32(final byte[] intbuf, final int offset) {
 		int low = (intbuf[offset + 1] & 0xff) << 8;
 		low |= (intbuf[offset + 2] & 0xff);
 		low <<= 8;

 		low |= (intbuf[offset + 3] & 0xff);
 		return ((long) (intbuf[offset] & 0xff)) << 24 | low;
 	}

 	/**
 	 * Convert sequence of 8 bytes (network byte order) into unsigned value.
 	 *
 	 * @param intbuf
 	 *            buffer to acquire the 8 bytes of data from.
 	 * @param offset
 	 *            position within the buffer to begin reading from. This
 	 *            position and the next 7 bytes after it (for a total of 8
 	 *            bytes) will be read.
 	 * @return unsigned integer value that matches the 64 bits read.
 	 */
 	public static long decodeUInt64(final byte[] intbuf, final int offset) {
 		return (decodeUInt32(intbuf, offset) << 32)
 				| decodeUInt32(intbuf, offset + 4);
 	}

 	/**
 	 * Write a 16 bit integer as a sequence of 2 bytes (network byte order).
 	 *
 	 * @param intbuf
 	 *            buffer to write the 2 bytes of data into.
 	 * @param offset
 	 *            position within the buffer to begin writing to. This position
 	 *            and the next byte after it (for a total of 2 bytes) will be
 	 *            replaced.
 	 * @param v
 	 *            the value to write.
 	 */
 	public static void encodeInt16(final byte[] intbuf, final int offset, int v) {
 		intbuf[offset + 1] = (byte) v;
 		v >>>= 8;

 		intbuf[offset] = (byte) v;
 	}

 	/**
 	 * Write a 24 bit integer as a sequence of 3 bytes (network byte order).
 	 *
 	 * @param intbuf
 	 *            buffer to write the 3 bytes of data into.
 	 * @param offset
 	 *            position within the buffer to begin writing to. This position
 	 *            and the next 2 bytes after it (for a total of 3 bytes) will be
 	 *            replaced.
 	 * @param v
 	 *            the value to write.
 	 * @since 4.9
 	 */
 	public static void encodeInt24(byte[] intbuf, int offset, int v) {
 		intbuf[offset + 2] = (byte) v;
 		v >>>= 8;

 		intbuf[offset + 1] = (byte) v;
 		v >>>= 8;

 		intbuf[offset] = (byte) v;
 	}

 	/**
 	 * Write a 32 bit integer as a sequence of 4 bytes (network byte order).
 	 *
 	 * @param intbuf
 	 *            buffer to write the 4 bytes of data into.
 	 * @param offset
 	 *            position within the buffer to begin writing to. This position
 	 *            and the next 3 bytes after it (for a total of 4 bytes) will be
 	 *            replaced.
 	 * @param v
 	 *            the value to write.
 	 */
 	public static void encodeInt32(final byte[] intbuf, final int offset, int v) {
 		intbuf[offset + 3] = (byte) v;
 		v >>>= 8;

 		intbuf[offset + 2] = (byte) v;
 		v >>>= 8;

 		intbuf[offset + 1] = (byte) v;
 		v >>>= 8;

 		intbuf[offset] = (byte) v;
 	}

 	/**
 	 * Write a 64 bit integer as a sequence of 8 bytes (network byte order).
 	 *
 	 * @param intbuf
 	 *            buffer to write the 8 bytes of data into.
 	 * @param offset
 	 *            position within the buffer to begin writing to. This position
 	 *            and the next 7 bytes after it (for a total of 8 bytes) will be
 	 *            replaced.
 	 * @param v
 	 *            the value to write.
 	 */
 	public static void encodeInt64(final byte[] intbuf, final int offset, long v) {
 		intbuf[offset + 7] = (byte) v;
 		v >>>= 8;

 		intbuf[offset + 6] = (byte) v;
 		v >>>= 8;

 		intbuf[offset + 5] = (byte) v;
 		v >>>= 8;

 		intbuf[offset + 4] = (byte) v;
 		v >>>= 8;

 		intbuf[offset + 3] = (byte) v;
 		v >>>= 8;

 		intbuf[offset + 2] = (byte) v;
 		v >>>= 8;

 		intbuf[offset + 1] = (byte) v;
 		v >>>= 8;

 		intbuf[offset] = (byte) v;
 	}

 	private NB() {
 		// Don't create instances of a static only utility.
 	}
 }
	/*
	* Copyright (C) 2008, 2015 Shawn O. Pearce <spearce@spearce.org>
	* and other copyright owners as documented in the project's IP log.
	*
	* This program and the accompanying materials are made available
	* under the terms of the Eclipse Distribution License v1.0 which
	* accompanies this distribution, is reproduced below, and is
	* available at http://www.eclipse.org/org/documents/edl-v10.php
	*
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or
	* without modification, are permitted provided that the following
	* conditions are met:
	*
	* - Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* - Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following
	* disclaimer in the documentation and/or other materials provided
	* with the distribution.
	*
	* - Neither the name of the Eclipse Foundation, Inc. nor the
	* names of its contributors may be used to endorse or promote
	* products derived from this software without specific prior
	* written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
	* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
	* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
	* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
	* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	package org.eclipse.jgit.util;

	/** Conversion utilities for network byte order handling. */
	public final class NB {
	/**
	* Compare a 32 bit unsigned integer stored in a 32 bit signed integer.
	* <p>
	* This function performs an unsigned compare operation, even though Java
	* does not natively support unsigned integer values. Negative numbers are
	* treated as larger than positive ones.
	*
	* @param a
	* the first value to compare.
	* @param b
	* the second value to compare.
	* @return < 0 if a < b; 0 if a == b; > 0 if a > b.
	*/
	public static int compareUInt32(final int a, final int b) {
	final int cmp = (a >>> 1) - (b >>> 1);
	if (cmp != 0)
	return cmp;
	return (a & 1) - (b & 1);
	}

	/**
	* Compare a 64 bit unsigned integer stored in a 64 bit signed integer.
	* <p>
	* This function performs an unsigned compare operation, even though Java
	* does not natively support unsigned integer values. Negative numbers are
	* treated as larger than positive ones.
	*
	* @param a
	* the first value to compare.
	* @param b
	* the second value to compare.
	* @return < 0 if a < b; 0 if a == b; > 0 if a > b.
	* @since 4.3
	*/
	public static int compareUInt64(final long a, final long b) {
	long cmp = (a >>> 1) - (b >>> 1);
	if (cmp > 0) {
	return 1;
	} else if (cmp < 0) {
	return -1;
	}
	cmp = ((a & 1) - (b & 1));
	if (cmp > 0) {
	return 1;
	} else if (cmp < 0) {
	return -1;
	} else {
	return 0;
	}
	}

	/**
	* Convert sequence of 2 bytes (network byte order) into unsigned value.
	*
	* @param intbuf
	* buffer to acquire the 2 bytes of data from.
	* @param offset
	* position within the buffer to begin reading from. This
	* position and the next byte after it (for a total of 2 bytes)
	* will be read.
	* @return unsigned integer value that matches the 16 bits read.
	*/
	public static int decodeUInt16(final byte[] intbuf, final int offset) {
	int r = (intbuf[offset] & 0xff) << 8;
	return r \| (intbuf[offset + 1] & 0xff);
	}

	/**
	* Convert sequence of 3 bytes (network byte order) into unsigned value.
	*
	* @param intbuf
	* buffer to acquire the 3 bytes of data from.
	* @param offset
	* position within the buffer to begin reading from. This
	* position and the next 2 bytes after it (for a total of 3
	* bytes) will be read.
	* @return signed integer value that matches the 24 bits read.
	* @since 4.9
	*/
	public static int decodeUInt24(byte[] intbuf, int offset) {
	int r = (intbuf[offset] & 0xff) << 8;
	r \|= intbuf[offset + 1] & 0xff;
	return (r << 8) \| (intbuf[offset + 2] & 0xff);
	}

	/**
	* Convert sequence of 4 bytes (network byte order) into signed value.
	*
	* @param intbuf
	* buffer to acquire the 4 bytes of data from.
	* @param offset
	* position within the buffer to begin reading from. This
	* position and the next 3 bytes after it (for a total of 4
	* bytes) will be read.
	* @return signed integer value that matches the 32 bits read.
	*/
	public static int decodeInt32(final byte[] intbuf, final int offset) {
	int r = intbuf[offset] << 8;

	r \|= intbuf[offset + 1] & 0xff;
	r <<= 8;

	r \|= intbuf[offset + 2] & 0xff;
	return (r << 8) \| (intbuf[offset + 3] & 0xff);
	}

	/**
	* Convert sequence of 8 bytes (network byte order) into signed value.
	*
	* @param intbuf
	* buffer to acquire the 8 bytes of data from.
	* @param offset
	* position within the buffer to begin reading from. This
	* position and the next 7 bytes after it (for a total of 8
	* bytes) will be read.
	* @return signed integer value that matches the 64 bits read.
	* @since 3.0
	*/
	public static long decodeInt64(final byte[] intbuf, final int offset) {
	long r = intbuf[offset] << 8;

	r \|= intbuf[offset + 1] & 0xff;
	r <<= 8;

	r \|= intbuf[offset + 2] & 0xff;
	r <<= 8;

	r \|= intbuf[offset + 3] & 0xff;
	r <<= 8;

	r \|= intbuf[offset + 4] & 0xff;
	r <<= 8;

	r \|= intbuf[offset + 5] & 0xff;
	r <<= 8;

	r \|= intbuf[offset + 6] & 0xff;
	return (r << 8) \| (intbuf[offset + 7] & 0xff);
	}

	/**
	* Convert sequence of 4 bytes (network byte order) into unsigned value.
	*
	* @param intbuf
	* buffer to acquire the 4 bytes of data from.
	* @param offset
	* position within the buffer to begin reading from. This
	* position and the next 3 bytes after it (for a total of 4
	* bytes) will be read.
	* @return unsigned integer value that matches the 32 bits read.
	*/
	public static long decodeUInt32(final byte[] intbuf, final int offset) {
	int low = (intbuf[offset + 1] & 0xff) << 8;
	low \|= (intbuf[offset + 2] & 0xff);
	low <<= 8;

	low \|= (intbuf[offset + 3] & 0xff);
	return ((long) (intbuf[offset] & 0xff)) << 24 \| low;
	}

	/**
	* Convert sequence of 8 bytes (network byte order) into unsigned value.
	*
	* @param intbuf
	* buffer to acquire the 8 bytes of data from.
	* @param offset
	* position within the buffer to begin reading from. This
	* position and the next 7 bytes after it (for a total of 8
	* bytes) will be read.
	* @return unsigned integer value that matches the 64 bits read.
	*/
	public static long decodeUInt64(final byte[] intbuf, final int offset) {
	return (decodeUInt32(intbuf, offset) << 32)
	\| decodeUInt32(intbuf, offset + 4);
	}

	/**
	* Write a 16 bit integer as a sequence of 2 bytes (network byte order).
	*
	* @param intbuf
	* buffer to write the 2 bytes of data into.
	* @param offset
	* position within the buffer to begin writing to. This position
	* and the next byte after it (for a total of 2 bytes) will be
	* replaced.
	* @param v
	* the value to write.
	*/
	public static void encodeInt16(final byte[] intbuf, final int offset, int v) {
	intbuf[offset + 1] = (byte) v;
	v >>>= 8;

	intbuf[offset] = (byte) v;
	}

	/**
	* Write a 24 bit integer as a sequence of 3 bytes (network byte order).
	*
	* @param intbuf
	* buffer to write the 3 bytes of data into.
	* @param offset
	* position within the buffer to begin writing to. This position
	* and the next 2 bytes after it (for a total of 3 bytes) will be
	* replaced.
	* @param v
	* the value to write.
	* @since 4.9
	*/
	public static void encodeInt24(byte[] intbuf, int offset, int v) {
	intbuf[offset + 2] = (byte) v;
	v >>>= 8;

	intbuf[offset + 1] = (byte) v;
	v >>>= 8;

	intbuf[offset] = (byte) v;
	}

	/**
	* Write a 32 bit integer as a sequence of 4 bytes (network byte order).
	*
	* @param intbuf
	* buffer to write the 4 bytes of data into.
	* @param offset
	* position within the buffer to begin writing to. This position
	* and the next 3 bytes after it (for a total of 4 bytes) will be
	* replaced.
	* @param v
	* the value to write.
	*/
	public static void encodeInt32(final byte[] intbuf, final int offset, int v) {
	intbuf[offset + 3] = (byte) v;
	v >>>= 8;

	intbuf[offset + 2] = (byte) v;
	v >>>= 8;

	intbuf[offset + 1] = (byte) v;
	v >>>= 8;

	intbuf[offset] = (byte) v;
	}

	/**
	* Write a 64 bit integer as a sequence of 8 bytes (network byte order).
	*
	* @param intbuf
	* buffer to write the 8 bytes of data into.
	* @param offset
	* position within the buffer to begin writing to. This position
	* and the next 7 bytes after it (for a total of 8 bytes) will be
	* replaced.
	* @param v
	* the value to write.
	*/
	public static void encodeInt64(final byte[] intbuf, final int offset, long v) {
	intbuf[offset + 7] = (byte) v;
	v >>>= 8;

	intbuf[offset + 6] = (byte) v;
	v >>>= 8;

	intbuf[offset + 5] = (byte) v;
	v >>>= 8;

	intbuf[offset + 4] = (byte) v;
	v >>>= 8;

	intbuf[offset + 3] = (byte) v;
	v >>>= 8;

	intbuf[offset + 2] = (byte) v;
	v >>>= 8;

	intbuf[offset + 1] = (byte) v;
	v >>>= 8;

	intbuf[offset] = (byte) v;
	}

	private NB() {
	// Don't create instances of a static only utility.
	}
	}