1f7c6911047d63bc76292f55ce538da32818dd931Jesse Wilson/* 2adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Licensed to the Apache Software Foundation (ASF) under one or more 3adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * contributor license agreements. See the NOTICE file distributed with 4adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * this work for additional information regarding copyright ownership. 5adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * The ASF licenses this file to You under the Apache License, Version 2.0 6adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * (the "License"); you may not use this file except in compliance with 7adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * the License. You may obtain a copy of the License at 8f7c6911047d63bc76292f55ce538da32818dd931Jesse Wilson * 9adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * http://www.apache.org/licenses/LICENSE-2.0 10f7c6911047d63bc76292f55ce538da32818dd931Jesse Wilson * 11adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Unless required by applicable law or agreed to in writing, software 12adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * distributed under the License is distributed on an "AS IS" BASIS, 13adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * See the License for the specific language governing permissions and 15adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * limitations under the License. 16adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 17adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 18adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Projectpackage java.util.zip; 19adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 20b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughesimport java.util.Arrays; 21b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes 22adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project/** 23adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * The Adler-32 class is used to compute the {@code Adler32} checksum from a set 2499c59bfa432e36933a7a5033fba8b89209f737bcElliott Hughes * of data. Compared to {@link CRC32} it trades reliability for speed. 25adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Refer to RFC 1950 for the specification. 26adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 27a5d31fa2ea5c9d3de6ac05ae4250f931bed2d445Elliott Hughespublic class Adler32 implements Checksum { 28adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 29adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project private long adler = 1; 30adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 31adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 32adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Returns the {@code Adler32} checksum for all input received. 33f7c6911047d63bc76292f55ce538da32818dd931Jesse Wilson * 34adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @return The checksum for this instance. 35adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 36adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public long getValue() { 37adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project return adler; 38adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 39adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 40adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 41adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Reset this instance to its initial checksum. 42adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 43adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public void reset() { 44adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project adler = 1; 45adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 46adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 47adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 48adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Update this {@code Adler32} checksum with the single byte provided as 49adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * argument. 50f7c6911047d63bc76292f55ce538da32818dd931Jesse Wilson * 51adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @param i 52adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * the byte to update checksum with. 53adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 54adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public void update(int i) { 55adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project adler = updateByteImpl(i, adler); 56adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 57adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 58adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 59adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Update this {@code Adler32} checksum using the contents of {@code buf}. 60f7c6911047d63bc76292f55ce538da32818dd931Jesse Wilson * 61adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @param buf 62adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * bytes to update checksum with. 63adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 64adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public void update(byte[] buf) { 65adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project update(buf, 0, buf.length); 66adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 67adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 68adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 69adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Update this {@code Adler32} checksum with the contents of {@code buf}, 70b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes * starting from {@code offset} and reading {@code byteCount} bytes of data. 71adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 72b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes public void update(byte[] buf, int offset, int byteCount) { 73b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes Arrays.checkOffsetAndCount(buf.length, offset, byteCount); 74b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes adler = updateImpl(buf, offset, byteCount, adler); 75adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 76adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 77b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes private native long updateImpl(byte[] buf, int offset, int byteCount, long adler1); 78adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 79adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project private native long updateByteImpl(int val, long adler1); 80adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project} 81