| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package java.util.zip; |
| |
| import java.util.Arrays; |
| |
| /** |
| * The CRC32 class is used to compute a CRC32 checksum from data provided as |
| * input value. See also {@link Adler32} which is almost as good, but cheaper. |
| */ |
| public class CRC32 implements Checksum { |
| |
| private long crc = 0L; |
| |
| long tbytes = 0L; |
| |
| /** |
| * Returns the CRC32 checksum for all input received. |
| * |
| * @return The checksum for this instance. |
| */ |
| public long getValue() { |
| return crc; |
| } |
| |
| /** |
| * Resets the CRC32 checksum to it initial state. |
| */ |
| public void reset() { |
| tbytes = crc = 0; |
| |
| } |
| |
| /** |
| * Updates this checksum with the byte value provided as integer. |
| * |
| * @param val |
| * represents the byte to update the checksum. |
| */ |
| public void update(int val) { |
| crc = updateByteImpl((byte) val, crc); |
| } |
| |
| /** |
| * Updates this checksum with the bytes contained in buffer {@code buf}. |
| * |
| * @param buf |
| * the buffer holding the data to update the checksum with. |
| */ |
| public void update(byte[] buf) { |
| update(buf, 0, buf.length); |
| } |
| |
| /** |
| * Update this {@code CRC32} checksum with the contents of {@code buf}, |
| * starting from {@code offset} and reading {@code byteCount} bytes of data. |
| */ |
| public void update(byte[] buf, int offset, int byteCount) { |
| Arrays.checkOffsetAndCount(buf.length, offset, byteCount); |
| tbytes += byteCount; |
| crc = updateImpl(buf, offset, byteCount, crc); |
| } |
| |
| private native long updateImpl(byte[] buf, int offset, int byteCount, long crc1); |
| |
| private native long updateByteImpl(byte val, long crc1); |
| } |