DecompressorStream.java
上传用户:quxuerui
上传日期:2018-01-08
资源大小:41811k
文件大小:4k
- /*
- * 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.hadoop.io.compress;
- import java.io.EOFException;
- import java.io.IOException;
- import java.io.InputStream;
- import org.apache.hadoop.io.compress.Decompressor;
- public class DecompressorStream extends CompressionInputStream {
- protected Decompressor decompressor = null;
- protected byte[] buffer;
- protected boolean eof = false;
- protected boolean closed = false;
-
- public DecompressorStream(InputStream in, Decompressor decompressor, int bufferSize) {
- super(in);
- if (in == null || decompressor == null) {
- throw new NullPointerException();
- } else if (bufferSize <= 0) {
- throw new IllegalArgumentException("Illegal bufferSize");
- }
- this.decompressor = decompressor;
- buffer = new byte[bufferSize];
- }
- public DecompressorStream(InputStream in, Decompressor decompressor) {
- this(in, decompressor, 512);
- }
- /**
- * Allow derived classes to directly set the underlying stream.
- *
- * @param in Underlying input stream.
- */
- protected DecompressorStream(InputStream in) {
- super(in);
- }
-
- private byte[] oneByte = new byte[1];
- public int read() throws IOException {
- checkStream();
- return (read(oneByte, 0, oneByte.length) == -1) ? -1 : (oneByte[0] & 0xff);
- }
- public int read(byte[] b, int off, int len) throws IOException {
- checkStream();
-
- if ((off | len | (off + len) | (b.length - (off + len))) < 0) {
- throw new IndexOutOfBoundsException();
- } else if (len == 0) {
- return 0;
- }
- return decompress(b, off, len);
- }
- protected int decompress(byte[] b, int off, int len) throws IOException {
- int n = 0;
-
- while ((n = decompressor.decompress(b, off, len)) == 0) {
- if (decompressor.finished() || decompressor.needsDictionary()) {
- eof = true;
- return -1;
- }
- if (decompressor.needsInput()) {
- getCompressedData();
- }
- }
-
- return n;
- }
-
- protected void getCompressedData() throws IOException {
- checkStream();
-
- int n = in.read(buffer, 0, buffer.length);
- if (n == -1) {
- throw new EOFException("Unexpected end of input stream");
- }
- decompressor.setInput(buffer, 0, n);
- }
-
- protected void checkStream() throws IOException {
- if (closed) {
- throw new IOException("Stream closed");
- }
- }
-
- public void resetState() throws IOException {
- decompressor.reset();
- }
- private byte[] skipBytes = new byte[512];
- public long skip(long n) throws IOException {
- // Sanity checks
- if (n < 0) {
- throw new IllegalArgumentException("negative skip length");
- }
- checkStream();
-
- // Read 'n' bytes
- int skipped = 0;
- while (skipped < n) {
- int len = Math.min(((int)n - skipped), skipBytes.length);
- len = read(skipBytes, 0, len);
- if (len == -1) {
- eof = true;
- break;
- }
- skipped += len;
- }
- return skipped;
- }
- public int available() throws IOException {
- checkStream();
- return (eof) ? 0 : 1;
- }
- public void close() throws IOException {
- if (!closed) {
- in.close();
- closed = true;
- }
- }
- public boolean markSupported() {
- return false;
- }
- public synchronized void mark(int readlimit) {
- }
- public synchronized void reset() throws IOException {
- throw new IOException("mark/reset not supported");
- }
- }