11d96b51e7f1e0a9d8cfa88f12dfe7cdb46d07634Jesse Wilson/* 2f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Licensed to the Apache Software Foundation (ASF) under one or more 3f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * contributor license agreements. See the NOTICE file distributed with 4f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * this work for additional information regarding copyright ownership. 5f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * The ASF licenses this file to You under the Apache License, Version 2.0 6f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * (the "License"); you may not use this file except in compliance with 7f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * the License. You may obtain a copy of the License at 81d96b51e7f1e0a9d8cfa88f12dfe7cdb46d07634Jesse Wilson * 9f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * http://www.apache.org/licenses/LICENSE-2.0 101d96b51e7f1e0a9d8cfa88f12dfe7cdb46d07634Jesse Wilson * 11f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Unless required by applicable law or agreed to in writing, software 12f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * distributed under the License is distributed on an "AS IS" BASIS, 13f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * See the License for the specific language governing permissions and 15f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * limitations under the License. 16f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 17f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 18f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Projectpackage java.util.zip; 19f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 20f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project/** 21f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * The Adler-32 class is used to compute the {@code Adler32} checksum from a set 22f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * of data. Compared to the CRC-32 algorithm it trades reliabilty for speed. 23f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Refer to RFC 1950 for the specification. 24407a2013b289b6b0e860b4275671b7b0194c42fcJesse Wilson * 25f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @see CRC32 26f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 27f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Projectpublic class Adler32 implements java.util.zip.Checksum { 28f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 29f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project private long adler = 1; 30f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 31f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 32f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Returns the {@code Adler32} checksum for all input received. 331d96b51e7f1e0a9d8cfa88f12dfe7cdb46d07634Jesse Wilson * 34f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @return The checksum for this instance. 35f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 36f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public long getValue() { 37f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project return adler; 38f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 39f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 40f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 41f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Reset this instance to its initial checksum. 42f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 43f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public void reset() { 44f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project adler = 1; 45f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 46f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 47f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 48f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Update this {@code Adler32} checksum with the single byte provided as 49f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * argument. 501d96b51e7f1e0a9d8cfa88f12dfe7cdb46d07634Jesse Wilson * 51f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param i 52f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * the byte to update checksum with. 53f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 54f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public void update(int i) { 55f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project adler = updateByteImpl(i, adler); 56f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 57f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 58f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 59f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Update this {@code Adler32} checksum using the contents of {@code buf}. 601d96b51e7f1e0a9d8cfa88f12dfe7cdb46d07634Jesse Wilson * 61f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param buf 62f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * bytes to update checksum with. 63f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 64f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public void update(byte[] buf) { 65f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project update(buf, 0, buf.length); 66f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 67f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 68f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project /** 69f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * Update this {@code Adler32} checksum with the contents of {@code buf}, 70f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * starting from the offset provided and reading n bytes of data. 711d96b51e7f1e0a9d8cfa88f12dfe7cdb46d07634Jesse Wilson * 72f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param buf 73f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * buffer to obtain data from. 74f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param off 75f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * offset in {@code buf} to start reading from. 76f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @param nbytes 77f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * number of bytes from {@code buf} to use. 78f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * @throws ArrayIndexOutOfBoundsException 79f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * if {@code offset > buf.length} or {@code nbytes} is negative 80f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project * or {@code offset + nbytes > buf.length}. 81f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project */ 82f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project public void update(byte[] buf, int off, int nbytes) { 83f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project // avoid int overflow, check null buf 84f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project if (off <= buf.length && nbytes >= 0 && off >= 0 85f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project && buf.length - off >= nbytes) { 86f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project adler = updateImpl(buf, off, nbytes, adler); 87f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } else { 88f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project throw new ArrayIndexOutOfBoundsException(); 89f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 90f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project } 91f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 92f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project private native long updateImpl(byte[] buf, int off, int nbytes, long adler1); 93f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project 94f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project private native long updateByteImpl(int val, long adler1); 95f6c387128427e121477c1b32ad35cdcaa5101ba3The Android Open Source Project} 96