1 /* 2 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.util.zip; 27 28 import java.nio.ByteBuffer; 29 import sun.nio.ch.DirectBuffer; 30 31 /** 32 * A class that can be used to compute the Adler-32 checksum of a data 33 * stream. An Adler-32 checksum is almost as reliable as a CRC-32 but 34 * can be computed much faster. 35 * 36 * <p> Passing a {@code null} argument to a method in this class will cause 37 * a {@link NullPointerException} to be thrown. 38 * 39 * @see Checksum 40 * @author David Connelly 41 */ 42 public 43 class Adler32 implements Checksum { 44 45 private int adler = 1; 46 47 /** 48 * Creates a new Adler32 object. 49 */ 50 public Adler32() { 51 } 52 53 /** 54 * Updates the checksum with the specified byte (the low eight 55 * bits of the argument b). 56 * 57 * @param b the byte to update the checksum with 58 */ 59 public void update(int b) { 60 adler = update(adler, b); 61 } 62 63 /** 64 * Updates the checksum with the specified array of bytes. 65 * 66 * @throws ArrayIndexOutOfBoundsException 67 * if {@code off} is negative, or {@code len} is negative, 68 * or {@code off+len} is greater than the length of the 69 * array {@code b} 70 */ 71 public void update(byte[] b, int off, int len) { 72 if (b == null) { 73 throw new NullPointerException(); 74 } 75 if (off < 0 || len < 0 || off > b.length - len) { 76 throw new ArrayIndexOutOfBoundsException(); 77 } 78 adler = updateBytes(adler, b, off, len); 79 } 80 81 /** 82 * Updates the checksum with the specified array of bytes. 83 * 84 * @param b the byte array to update the checksum with 85 */ 86 public void update(byte[] b) { 87 adler = updateBytes(adler, b, 0, b.length); 88 } 89 90 91 /** 92 * Updates the checksum with the bytes from the specified buffer. 93 * 94 * The checksum is updated using 95 * buffer.{@link java.nio.Buffer#remaining() remaining()} 96 * bytes starting at 97 * buffer.{@link java.nio.Buffer#position() position()} 98 * Upon return, the buffer's position will be updated to its 99 * limit; its limit will not have been changed. 100 * 101 * @param buffer the ByteBuffer to update the checksum with 102 * @since 1.8 103 */ 104 public void update(ByteBuffer buffer) { 105 int pos = buffer.position(); 106 int limit = buffer.limit(); 107 assert (pos <= limit); 108 int rem = limit - pos; 109 if (rem <= 0) 110 return; 111 if (buffer instanceof DirectBuffer) { 112 adler = updateByteBuffer(adler, ((DirectBuffer)buffer).address(), pos, rem); 113 } else if (buffer.hasArray()) { 114 adler = updateBytes(adler, buffer.array(), pos + buffer.arrayOffset(), rem); 115 } else { 116 byte[] b = new byte[rem]; 117 buffer.get(b); 118 adler = updateBytes(adler, b, 0, b.length); 119 } 120 buffer.position(limit); 121 } 122 123 /** 124 * Resets the checksum to initial value. 125 */ 126 public void reset() { 127 adler = 1; 128 } 129 130 /** 131 * Returns the checksum value. 132 */ 133 public long getValue() { 134 return (long)adler & 0xffffffffL; 135 } 136 137 private native static int update(int adler, int b); 138 private native static int updateBytes(int adler, byte[] b, int off, 139 int len); 140 private native static int updateByteBuffer(int adler, long addr, 141 int off, int len); 142 } | 1 /* 2 * Copyright (c) 1996, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.util.zip; 27 28 import java.nio.ByteBuffer; 29 import sun.nio.ch.DirectBuffer; 30 31 /** 32 * A class that can be used to compute the Adler-32 checksum of a data 33 * stream. An Adler-32 checksum is almost as reliable as a CRC-32 but 34 * can be computed much faster. 35 * 36 * <p> Passing a {@code null} argument to a method in this class will cause 37 * a {@link NullPointerException} to be thrown.</p> 38 * 39 * @author David Connelly 40 */ 41 public 42 class Adler32 implements Checksum { 43 44 private int adler = 1; 45 46 /** 47 * Creates a new Adler32 object. 48 */ 49 public Adler32() { 50 } 51 52 /** 53 * Updates the checksum with the specified byte (the low eight 54 * bits of the argument b). 55 */ 56 @Override 57 public void update(int b) { 58 adler = update(adler, b); 59 } 60 61 /** 62 * Updates the checksum with the specified array of bytes. 63 * 64 * @throws ArrayIndexOutOfBoundsException 65 * if {@code off} is negative, or {@code len} is negative, or 66 * {@code off+len} is negative or greater than the length of 67 * the array {@code b}. 68 */ 69 @Override 70 public void update(byte[] b, int off, int len) { 71 if (b == null) { 72 throw new NullPointerException(); 73 } 74 if (off < 0 || len < 0 || off > b.length - len) { 75 throw new ArrayIndexOutOfBoundsException(); 76 } 77 adler = updateBytes(adler, b, off, len); 78 } 79 80 /** 81 * Updates the checksum with the bytes from the specified buffer. 82 * 83 * The checksum is updated with the remaining bytes in the buffer, starting 84 * at the buffer's position. Upon return, the buffer's position will be 85 * updated to its limit; its limit will not have been changed. 86 * 87 * @since 1.8 88 */ 89 @Override 90 public void update(ByteBuffer buffer) { 91 int pos = buffer.position(); 92 int limit = buffer.limit(); 93 assert (pos <= limit); 94 int rem = limit - pos; 95 if (rem <= 0) 96 return; 97 if (buffer instanceof DirectBuffer) { 98 adler = updateByteBuffer(adler, ((DirectBuffer)buffer).address(), pos, rem); 99 } else if (buffer.hasArray()) { 100 adler = updateBytes(adler, buffer.array(), pos + buffer.arrayOffset(), rem); 101 } else { 102 byte[] b = new byte[rem]; 103 buffer.get(b); 104 adler = updateBytes(adler, b, 0, b.length); 105 } 106 buffer.position(limit); 107 } 108 109 /** 110 * Resets the checksum to initial value. 111 */ 112 @Override 113 public void reset() { 114 adler = 1; 115 } 116 117 /** 118 * Returns the checksum value. 119 */ 120 @Override 121 public long getValue() { 122 return (long)adler & 0xffffffffL; 123 } 124 125 private native static int update(int adler, int b); 126 private native static int updateBytes(int adler, byte[] b, int off, 127 int len); 128 private native static int updateByteBuffer(int adler, long addr, 129 int off, int len); 130 } |