Here you can find the source of shiftLeft(byte[] data, int shiftBy)
| Parameter | Description |
|---|---|
| data | the array to be shifted |
| shiftBy | the amount to shift. Currently only supports maximum value of 8 |
public static byte[] shiftLeft(byte[] data, int shiftBy)
//package com.java2s; /*//from w ww .j a v a 2 s.com * The MIT License (MIT) * * Copyright (c) 2015 Ziver Koc * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ public class Main { /** Bitmask array used by utility functions **/ private static final int[][] BYTE_MASK = new int[][] { { 0b0000_0001 }, { 0b0000_0010, 0b0000_0011 }, { 0b0000_0100, 0b0000_0110, 0b0000_0111 }, { 0b0000_1000, 0b0000_1100, 0b0000_1110, 0b0000_1111 }, { 0b0001_0000, 0b0001_1000, 0b0001_1100, 0b0001_1110, 0b0001_1111 }, { 0b0010_0000, 0b0011_0000, 0b0011_1000, 0b0011_1100, 0b0011_1110, 0b0011_1111 }, { 0b0100_0000, 0b0110_0000, 0b0111_0000, 0b0111_1000, 0b0111_1100, 0b0111_1110, 0b0111_1111 }, { 0b1000_0000, 0b1100_0000, 0b1110_0000, 0b1111_0000, 0b1111_1000, 0b1111_1100, 0b1111_1110, 0b1111_1111 } }; /** * Shifts a whole byte array to the left by the specified amount. * * @param data the array to be shifted * @param shiftBy the amount to shift. Currently only supports maximum value of 8 * @return same data reference as the data input */ public static byte[] shiftLeft(byte[] data, int shiftBy) { if (0 > shiftBy || shiftBy > 8) throw new IllegalArgumentException("Invalid shiftBy(" + shiftBy + ") argument, allowed values: 0-8"); if (shiftBy == 0) return data; byte rest = 0; for (int i = 0; i < data.length; ++i) { rest = (byte) (getBits(data[i], shiftBy - 1, shiftBy) << 8 - shiftBy); data[i] = (byte) ((data[i] & 0xFF) >>> shiftBy); if (i != 0) data[i - 1] |= rest; } return data; } /** * Creates a new sub byte from index and with the given length length * * @param data is the byte data * @param index is the bit index, valid values 0-7 * @param length is the length of bits to return, valid values 1-8 * @return a new byte containing a sub byte defined by the index and length */ public static byte getBits(byte data, int index, int length) { byte ret = (byte) (data & getBitMask(index, length)); return ret; } /** * Creates a new sub byte from LSB to the given length * * @param data is the byte data * @param length is the length of bits to return, valid values 1-8 * @return a new byte containing a sub byte defined by the index and length */ public static byte getBits(byte data, int length) { return getBits(data, length - 1, length); } /** * Creates a new sub byte array with only the given length of bits from the LSB. * * @param data is the byte data array * @param length is the length of bits to return * @return a new byte array of te given length containing the given data. */ public static byte[] getBits(byte[] data, int length) { byte[] dest = new byte[(int) Math.ceil(length / 8.0)]; System.arraycopy(data, 0, dest, 0, Math.min(data.length, dest.length)); if (length % 8 != 0) dest[dest.length - 1] = getBits(dest[dest.length - 1], length % 8); return dest; } /** * Returns a byte bitmask * * @param index start index of the mask, valid values 0-7 * @param length length of mask from index, valid values 1-8 depending on index */ public static byte getBitMask(int index, int length) { --length; if (0 > index || index > 7) throw new IllegalArgumentException("Invalid index argument, allowed values: 0-7"); if (length < 0 || index - length < 0) throw new IllegalArgumentException("Invalid length argument: " + length + ", allowed values: 1 to " + (index + 1) + " for index " + index); return (byte) BYTE_MASK[index][length]; } }