Here you can find the source of bitRangeValueLong(byte[] b, int offset, int length)
| Parameter | Description |
|---|---|
| b | the array of bytes. |
| offset | the location at which to begin |
| length | the number of bits to include in the value. |
public static long bitRangeValueLong(byte[] b, int offset, int length)
//package com.java2s; /*/*from www .j a v a 2s .c o m*/ * ============================================================================ * GNU General Public License * ============================================================================ * * Copyright (C) 2015 Infinite Automation Software. All rights reserved. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program 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 for more details. * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * * When signing a commercial license with Infinite Automation Software, * the following extension to GPL is made. A special exception to the GPL is * included to allow you to distribute a combined work that includes BAcnet4J * without being obliged to provide the source code for any proprietary components. * * See www.infiniteautomation.com for commercial license options. * * @author Matthew Lohbihler */ public class Main { private static int[] bitFromMask = { 0xff, 0x7f, 0x3f, 0x1f, 0xf, 0x7, 0x3, 0x1 }; /** * Returns the value of the bits in the given range. Ranges can extend multiple bytes. No range checking is done. * Invalid ranges will result in {@link ArrayIndexOutOfBoundsException}. * * @param b * the array of bytes. * @param offset * the location at which to begin * @param length * the number of bits to include in the value. * @return the value of the bits in the range. */ public static long bitRangeValueLong(byte[] b, int offset, int length) { if (length <= 0) return 0; int byteFrom = offset / 8; int byteTo = (offset + length - 1) / 8; long result = b[byteFrom] & bitFromMask[offset % 8]; for (int i = byteFrom + 1; i <= byteTo; i++) { result <<= 8; result |= b[i] & 0xff; } result >>= 8 - (((offset + length - 1) % 8) + 1); return result; } }