| /* |
| * 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 org.apache.lucene.store; |
| |
| |
| import java.util.zip.Checksum; |
| |
| /** |
| * Wraps another {@link Checksum} with an internal buffer |
| * to speed up checksum calculations. |
| */ |
| public class BufferedChecksum implements Checksum { |
| private final Checksum in; |
| private final byte buffer[]; |
| private int upto; |
| /** Default buffer size: 256 */ |
| public static final int DEFAULT_BUFFERSIZE = 256; |
| |
| /** Create a new BufferedChecksum with {@link #DEFAULT_BUFFERSIZE} */ |
| public BufferedChecksum(Checksum in) { |
| this(in, DEFAULT_BUFFERSIZE); |
| } |
| |
| /** Create a new BufferedChecksum with the specified bufferSize */ |
| public BufferedChecksum(Checksum in, int bufferSize) { |
| this.in = in; |
| this.buffer = new byte[bufferSize]; |
| } |
| |
| @Override |
| public void update(int b) { |
| if (upto == buffer.length) { |
| flush(); |
| } |
| buffer[upto++] = (byte) b; |
| } |
| |
| @Override |
| public void update(byte[] b, int off, int len) { |
| if (len >= buffer.length) { |
| flush(); |
| in.update(b, off, len); |
| } else { |
| if (upto + len > buffer.length) { |
| flush(); |
| } |
| System.arraycopy(b, off, buffer, upto, len); |
| upto += len; |
| } |
| } |
| |
| @Override |
| public long getValue() { |
| flush(); |
| return in.getValue(); |
| } |
| |
| @Override |
| public void reset() { |
| upto = 0; |
| in.reset(); |
| } |
| |
| private void flush() { |
| if (upto > 0) { |
| in.update(buffer, 0, upto); |
| } |
| upto = 0; |
| } |
| } |