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 CRC-32 of a data stream. 33 * 34 * <p> Passing a {@code null} argument to a method in this class will cause 35 * a {@link NullPointerException} to be thrown. 36 * 37 * @see Checksum 38 * @author David Connelly 39 */ 40 public 41 class CRC32 implements Checksum { 42 private int crc; 43 44 /** 45 * Creates a new CRC32 object. 46 */ 47 public CRC32() { 48 } 49 50 51 /** 52 * Updates the CRC-32 checksum with the specified byte (the low 53 * eight bits of the argument b). 54 * 55 * @param b the byte to update the checksum with 56 */ 57 public void update(int b) { 58 crc = update(crc, b); 59 } 60 61 /** 62 * Updates the CRC-32 checksum with the specified array of bytes. 63 * 64 * @throws ArrayIndexOutOfBoundsException 65 * if {@code off} is negative, or {@code len} is negative, 66 * or {@code off+len} is greater than the length of the 67 * array {@code b} 68 */ 69 public void update(byte[] b, int off, int len) { 70 if (b == null) { 71 throw new NullPointerException(); 72 } 73 if (off < 0 || len < 0 || off > b.length - len) { 74 throw new ArrayIndexOutOfBoundsException(); 75 } 76 crc = updateBytes(crc, b, off, len); 77 } 78 79 /** 80 * Updates the CRC-32 checksum with the specified array of bytes. 81 * 82 * @param b the array of bytes to update the checksum with 83 */ 84 public void update(byte[] b) { 85 crc = updateBytes(crc, b, 0, b.length); 86 } 87 88 /** 89 * Updates the checksum with the bytes from the specified buffer. 90 * 91 * The checksum is updated using 92 * buffer.{@link java.nio.Buffer#remaining() remaining()} 93 * bytes starting at 94 * buffer.{@link java.nio.Buffer#position() position()} 95 * Upon return, the buffer's position will 96 * be updated to its limit; its limit will not have been changed. 97 * 98 * @param buffer the ByteBuffer to update the checksum with 99 * @since 1.8 100 */ 101 public void update(ByteBuffer buffer) { 102 int pos = buffer.position(); 103 int limit = buffer.limit(); 104 assert (pos <= limit); 105 int rem = limit - pos; 106 if (rem <= 0) 107 return; 108 if (buffer instanceof DirectBuffer) { 109 crc = updateByteBuffer(crc, ((DirectBuffer)buffer).address(), pos, rem); 110 } else if (buffer.hasArray()) { 111 crc = updateBytes(crc, buffer.array(), pos + buffer.arrayOffset(), rem); 112 } else { 113 byte[] b = new byte[rem]; 114 buffer.get(b); 115 crc = updateBytes(crc, b, 0, b.length); 116 } 117 buffer.position(limit); 118 } 119 120 /** 121 * Resets CRC-32 to initial value. 122 */ 123 public void reset() { 124 crc = 0; 125 } 126 127 /** 128 * Returns CRC-32 value. 129 */ 130 public long getValue() { 131 return (long)crc & 0xffffffffL; 132 } 133 134 private native static int update(int crc, int b); 135 private native static int updateBytes(int crc, byte[] b, int off, int len); 136 137 private native static int updateByteBuffer(int adler, long addr, 138 int off, int len); 139 } | 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 CRC-32 of a data stream. 33 * 34 * <p> Passing a {@code null} argument to a method in this class will cause 35 * a {@link NullPointerException} to be thrown.</p> 36 * 37 * @author David Connelly 38 */ 39 public 40 class CRC32 implements Checksum { 41 private int crc; 42 43 /** 44 * Creates a new CRC32 object. 45 */ 46 public CRC32() { 47 } 48 49 50 /** 51 * Updates the CRC-32 checksum with the specified byte (the low 52 * eight bits of the argument b). 53 */ 54 @Override 55 public void update(int b) { 56 crc = update(crc, b); 57 } 58 59 /** 60 * Updates the CRC-32 checksum with the specified array of bytes. 61 * 62 * @throws ArrayIndexOutOfBoundsException 63 * if {@code off} is negative, or {@code len} is negative, or 64 * {@code off+len} is negative or greater than the length of 65 * the array {@code b}. 66 */ 67 @Override 68 public void update(byte[] b, int off, int len) { 69 if (b == null) { 70 throw new NullPointerException(); 71 } 72 if (off < 0 || len < 0 || off > b.length - len) { 73 throw new ArrayIndexOutOfBoundsException(); 74 } 75 crc = updateBytes(crc, b, off, len); 76 } 77 78 /** 79 * Updates the CRC-32 checksum with the bytes from the specified buffer. 80 * 81 * The checksum is updated with the remaining bytes in the buffer, starting 82 * at the buffer's position. Upon return, the buffer's position will be 83 * updated to its limit; its limit will not have been changed. 84 * 85 * @since 1.8 86 */ 87 @Override 88 public void update(ByteBuffer buffer) { 89 int pos = buffer.position(); 90 int limit = buffer.limit(); 91 assert (pos <= limit); 92 int rem = limit - pos; 93 if (rem <= 0) 94 return; 95 if (buffer instanceof DirectBuffer) { 96 crc = updateByteBuffer(crc, ((DirectBuffer)buffer).address(), pos, rem); 97 } else if (buffer.hasArray()) { 98 crc = updateBytes(crc, buffer.array(), pos + buffer.arrayOffset(), rem); 99 } else { 100 byte[] b = new byte[rem]; 101 buffer.get(b); 102 crc = updateBytes(crc, b, 0, b.length); 103 } 104 buffer.position(limit); 105 } 106 107 /** 108 * Resets CRC-32 to initial value. 109 */ 110 @Override 111 public void reset() { 112 crc = 0; 113 } 114 115 /** 116 * Returns CRC-32 value. 117 */ 118 @Override 119 public long getValue() { 120 return (long)crc & 0xffffffffL; 121 } 122 123 private native static int update(int crc, int b); 124 private native static int updateBytes(int crc, byte[] b, int off, int len); 125 126 private native static int updateByteBuffer(int adler, long addr, 127 int off, int len); 128 } |