1 /* 2 * Javassist, a Java-bytecode translator toolkit. 3 * Copyright (C) 1999-2007 Shigeru Chiba. All Rights Reserved. 4 * 5 * The contents of this file are subject to the Mozilla Public License Version 6 * 1.1 (the "License"); you may not use this file except in compliance with 7 * the License. Alternatively, the contents of this file may be used under 8 * the terms of the GNU Lesser General Public License Version 2.1 or later. 9 * 10 * Software distributed under the License is distributed on an "AS IS" basis, 11 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License 12 * for the specific language governing rights and limitations under the 13 * License. 14 */ 15 16 package javassist.bytecode; 17 18 /** 19 * A collection of static methods for reading and writing a byte array. 20 */ 21 public class ByteArray { 22 /** 23 * Reads an unsigned 16bit integer at the index. 24 */ 25 public static int readU16bit(byte[] code, int index) { 26 return ((code[index] & 0xff) << 8) | (code[index + 1] & 0xff); 27 } 28 29 /** 30 * Reads a signed 16bit integer at the index. 31 */ 32 public static int readS16bit(byte[] code, int index) { 33 return (code[index] << 8) | (code[index + 1] & 0xff); 34 } 35 36 /** 37 * Writes a 16bit integer at the index. 38 */ 39 public static void write16bit(int value, byte[] code, int index) { 40 code[index] = (byte)(value >>> 8); 41 code[index + 1] = (byte)value; 42 } 43 44 /** 45 * Reads a 32bit integer at the index. 46 */ 47 public static int read32bit(byte[] code, int index) { 48 return (code[index] << 24) | ((code[index + 1] & 0xff) << 16) 49 | ((code[index + 2] & 0xff) << 8) | (code[index + 3] & 0xff); 50 } 51 52 /** 53 * Writes a 32bit integer at the index. 54 */ 55 public static void write32bit(int value, byte[] code, int index) { 56 code[index] = (byte)(value >>> 24); 57 code[index + 1] = (byte)(value >>> 16); 58 code[index + 2] = (byte)(value >>> 8); 59 code[index + 3] = (byte)value; 60 } 61 62 /** 63 * Copies a 32bit integer. 64 * 65 * @param src the source byte array. 66 * @param isrc the index into the source byte array. 67 * @param dest the destination byte array. 68 * @param idest the index into the destination byte array. 69 */ 70 static void copy32bit(byte[] src, int isrc, byte[] dest, int idest) { 71 dest[idest] = src[isrc]; 72 dest[idest + 1] = src[isrc + 1]; 73 dest[idest + 2] = src[isrc + 2]; 74 dest[idest + 3] = src[isrc + 3]; 75 } 76 } 77
