1 /* 2 * Javassist, a Java-bytecode translator toolkit. 3 * Copyright (C) 1999- 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 * or the Apache License Version 2.0. 10 * 11 * Software distributed under the License is distributed on an "AS IS" basis, 12 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License 13 * for the specific language governing rights and limitations under the 14 * License. 15 */ 16 17 package javassist.bytecode; 18 19 /** 20 * A collection of static methods for reading and writing a byte array. 21 */ 22 public class ByteArray { 23 /** 24 * Reads an unsigned 16bit integer at the index. 25 */ readU16bit(byte[] code, int index)26 public static int readU16bit(byte[] code, int index) { 27 return ((code[index] & 0xff) << 8) | (code[index + 1] & 0xff); 28 } 29 30 /** 31 * Reads a signed 16bit integer at the index. 32 */ readS16bit(byte[] code, int index)33 public static int readS16bit(byte[] code, int index) { 34 return (code[index] << 8) | (code[index + 1] & 0xff); 35 } 36 37 /** 38 * Writes a 16bit integer at the index. 39 */ write16bit(int value, byte[] code, int index)40 public static void write16bit(int value, byte[] code, int index) { 41 code[index] = (byte)(value >>> 8); 42 code[index + 1] = (byte)value; 43 } 44 45 /** 46 * Reads a 32bit integer at the index. 47 */ read32bit(byte[] code, int index)48 public static int read32bit(byte[] code, int index) { 49 return (code[index] << 24) | ((code[index + 1] & 0xff) << 16) 50 | ((code[index + 2] & 0xff) << 8) | (code[index + 3] & 0xff); 51 } 52 53 /** 54 * Writes a 32bit integer at the index. 55 */ write32bit(int value, byte[] code, int index)56 public static void write32bit(int value, byte[] code, int index) { 57 code[index] = (byte)(value >>> 24); 58 code[index + 1] = (byte)(value >>> 16); 59 code[index + 2] = (byte)(value >>> 8); 60 code[index + 3] = (byte)value; 61 } 62 63 /** 64 * Copies a 32bit integer. 65 * 66 * @param src the source byte array. 67 * @param isrc the index into the source byte array. 68 * @param dest the destination byte array. 69 * @param idest the index into the destination byte array. 70 */ copy32bit(byte[] src, int isrc, byte[] dest, int idest)71 static void copy32bit(byte[] src, int isrc, byte[] dest, int idest) { 72 dest[idest] = src[isrc]; 73 dest[idest + 1] = src[isrc + 1]; 74 dest[idest + 2] = src[isrc + 2]; 75 dest[idest + 3] = src[isrc + 3]; 76 } 77 } 78