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 CRC32 class is used to compute a CRC32 checksum from data provided as 24a5d31fa2ea5c9d3de6ac05ae4250f931bed2d445Elliott Hughes * input value. See also {@link Adler32} which is almost as good, but cheaper. 25adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 26a5d31fa2ea5c9d3de6ac05ae4250f931bed2d445Elliott Hughespublic class CRC32 implements Checksum { 27adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 28adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project private long crc = 0L; 29adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 30adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project long tbytes = 0L; 31adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 32adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 33adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Returns the CRC32 checksum for all input received. 34f7c6911047d63bc76292f55ce538da32818dd931Jesse Wilson * 35adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @return The checksum for this instance. 36adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 37adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public long getValue() { 38adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project return crc; 39adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 40adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 41adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 42adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Resets the CRC32 checksum to it initial state. 43adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 44adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public void reset() { 45adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project tbytes = crc = 0; 46adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 47adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 48adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 49adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 50adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Updates this checksum with the byte value provided as integer. 5157995e8186b54515d5a03bf2ab104c3dc247f1b6Jesse Wilson * 52adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @param val 53adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * represents the byte to update the checksum. 54adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 55adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public void update(int val) { 56adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project crc = updateByteImpl((byte) val, crc); 57adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 58adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 59adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 60adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Updates this checksum with the bytes contained in buffer {@code buf}. 61f7c6911047d63bc76292f55ce538da32818dd931Jesse Wilson * 62adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * @param buf 63adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * the buffer holding the data to update the checksum with. 64adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 65adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public void update(byte[] buf) { 66adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project update(buf, 0, buf.length); 67adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 68adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 69adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project /** 70b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes * Update this {@code CRC32} checksum with the contents of {@code buf}, 71b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes * starting from {@code offset} and reading {@code byteCount} bytes of data. 72adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 73b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes public void update(byte[] buf, int offset, int byteCount) { 74b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes Arrays.checkOffsetAndCount(buf.length, offset, byteCount); 75b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes tbytes += byteCount; 76b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes crc = updateImpl(buf, offset, byteCount, crc); 77adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 78adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 79b9cc455ed89df1a0cf4186c92b352c9649995d96Elliott Hughes private native long updateImpl(byte[] buf, int offset, int byteCount, long crc1); 80adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 81adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project private native long updateByteImpl(byte val, long crc1); 82adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project} 83