| /* |
| * 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; |
| |
| /** |
| * The CRC32 class is used to compute a CRC32 checksum from data provided as |
| * input value. |
| */ |
| public class CRC32 implements java.util.zip.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); |
| } |
| |
| /** |
| * Updates this checksum with n bytes of data obtained from buffer {@code |
| * buf}, starting at offset {@code off}. |
| * |
| * @param buf |
| * the buffer to update the checksum. |
| * @param off |
| * the offset in {@code buf} to obtain data from. |
| * @param nbytes |
| * the number of bytes to read from {@code buf}. |
| */ |
| public void update(byte[] buf, int off, int nbytes) { |
| // avoid int overflow, check null buf |
| if (off <= buf.length && nbytes >= 0 && off >= 0 |
| && buf.length - off >= nbytes) { |
| tbytes += nbytes; |
| crc = updateImpl(buf, off, nbytes, crc); |
| } else { |
| throw new ArrayIndexOutOfBoundsException(); |
| } |
| } |
| |
| private native long updateImpl(byte[] buf, int off, int nbytes, long crc1); |
| |
| private native long updateByteImpl(byte val, long crc1); |
| } |