| /* |
| * 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. |
| } |
| } |