/*
* Copyright 2010 Srikanth Reddy Lingala
*
* Licensed 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 net.lingala.zip4j.io;
import java.io.EOFException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.zip.DataFormatException;
import java.util.zip.Inflater;
import net.lingala.zip4j.unzip.UnzipEngine;
import net.lingala.zip4j.util.InternalZipConstants;
import net.lingala.zip4j.util.Zip4jConstants;
public class InflaterInputStream extends PartInputStream {
private Inflater inflater;
private byte[] buff;
private byte[] oneByteBuff = new byte[1];
private UnzipEngine unzipEngine;
private long bytesWritten;
private long uncompressedSize;
public InflaterInputStream(RandomAccessFile raf, long start, long len,
UnzipEngine unzipEngine) {
super(raf, start, len, unzipEngine);
this.inflater = new Inflater(true);
this.buff = new byte[InternalZipConstants.BUFF_SIZE];
this.unzipEngine = unzipEngine;
bytesWritten = 0;
uncompressedSize = unzipEngine.getFileHeader().getUncompressedSize();
}
public int read() throws IOException {
return read(oneByteBuff, 0, 1) == -1 ? -1 : oneByteBuff[0] & 0xff;
}
public int read(byte[] b) throws IOException {
if (b == null) {
throw new NullPointerException("input buffer is null");
}
return read(b, 0, b.length);
}
public int read(byte[] b, int off, int len) throws IOException {
if (b == null) {
throw new NullPointerException("input buffer is null");
} else if (off < 0 || len < 0 || len > b.length - off) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return 0;
}
try {
int n;
if (bytesWritten >= uncompressedSize) {
finishInflating();
return -1;
}
while ((n = inflater.inflate(b, off, len)) == 0) {
if (inflater.finished() || inflater.needsDictionary()) {
finishInflating();
return -1;
}
if (inflater.needsInput()) {
fill();
}
}
bytesWritten += n;
return n;
} catch (DataFormatException e) {
String s = "Invalid ZLIB data format";
if (e.getMessage() != null) {
s = e.getMessage();
}
if (unzipEngine != null) {
if (unzipEngine.getLocalFileHeader().isEncrypted()
&& unzipEngine.getLocalFileHeader()
.getEncryptionMethod() == Zip4jConstants.ENC_METHOD_STANDARD) {
s += " - Wrong Password?";
}
}
throw new IOException(s);
}
}
private void finishInflating() throws IOException {
// In some cases, compelte data is not read even though inflater is
// complete
// make sure to read complete data before returning -1
byte[] b = new byte[1024];
while (super.read(b, 0, 1024) != -1) {
// read all data
}
checkAndReadAESMacBytes();
}
private void fill() throws IOException {
int len = super.read(buff, 0, buff.length);
if (len == -1) {
throw new EOFException("Unexpected end of ZLIB input stream");
}
inflater.setInput(buff, 0, len);
}
/**
* Skips specified number of bytes of uncompressed data.
*
* @param n the number of bytes to skip
* @return the actual number of bytes skipped.
* @exception IOException if an I/O error has occurred
* @exception IllegalArgumentException if n < 0
*/
public long skip(long n) throws IOException {
if (n < 0) {
throw new IllegalArgumentException("negative skip length");
}
int max = (int) Math.min(n, Integer.MAX_VALUE);
int total = 0;
byte[] b = new byte[512];
while (total < max) {
int len = max - total;
if (len > b.length) {
len = b.length;
}
len = read(b, 0, len);
if (len == -1) {
break;
}
total += len;
}
return total;
}
public void seek(long pos) throws IOException {
super.seek(pos);
}
/**
* Returns 0 after EOF has been reached, otherwise always return 1.
* <p>
* Programs should not count on this method to return the actual number of
* bytes that could be read without blocking.
*
* @return 1 before EOF and 0 after EOF.
* @exception IOException if an I/O error occurs.
*
*/
public int available() {
return inflater.finished() ? 0 : 1;
}
public void close() throws IOException {
inflater.end();
super.close();
}
public UnzipEngine getUnzipEngine() {
return super.getUnzipEngine();
}
}