/*
* 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.
*
*/
/*
* This package is based on the work done by Timothy Gerard Endres
* (time@ice.com) to whom the Ant project is very grateful for his great code.
*/
package org.apache.tools.tar;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* The TarInputStream reads a UNIX tar archive as an InputStream.
* methods are provided to position at each successive entry in
* the archive, and the read each entry as a normal input stream
* using read().
*
*/
public class TarInputStream extends FilterInputStream {
private static final int SMALL_BUFFER_SIZE = 256;
private static final int BUFFER_SIZE = 8 * 1024;
private static final int LARGE_BUFFER_SIZE = 32 * 1024;
private static final int BYTE_MASK = 0xFF;
// CheckStyle:VisibilityModifier OFF - bc
protected boolean debug;
protected boolean hasHitEOF;
protected long entrySize;
protected long entryOffset;
protected byte[] readBuf;
protected TarBuffer buffer;
protected TarEntry currEntry;
/**
* This contents of this array is not used at all in this class,
* it is only here to avoid repreated object creation during calls
* to the no-arg read method.
*/
protected byte[] oneBuf;
// CheckStyle:VisibilityModifier ON
/**
* Constructor for TarInputStream.
* @param is the input stream to use
*/
public TarInputStream(InputStream is) {
this(is, TarBuffer.DEFAULT_BLKSIZE, TarBuffer.DEFAULT_RCDSIZE);
}
/**
* Constructor for TarInputStream.
* @param is the input stream to use
* @param blockSize the block size to use
*/
public TarInputStream(InputStream is, int blockSize) {
this(is, blockSize, TarBuffer.DEFAULT_RCDSIZE);
}
/**
* Constructor for TarInputStream.
* @param is the input stream to use
* @param blockSize the block size to use
* @param recordSize the record size to use
*/
public TarInputStream(InputStream is, int blockSize, int recordSize) {
super(is);
this.buffer = new TarBuffer(is, blockSize, recordSize);
this.readBuf = null;
this.oneBuf = new byte[1];
this.debug = false;
this.hasHitEOF = false;
}
/**
* Sets the debugging flag.
*
* @param debug True to turn on debugging.
*/
public void setDebug(boolean debug) {
this.debug = debug;
buffer.setDebug(debug);
}
/**
* Closes this stream. Calls the TarBuffer's close() method.
* @throws IOException on error
*/
public void close() throws IOException {
buffer.close();
}
/**
* Get the record size being used by this stream's TarBuffer.
*
* @return The TarBuffer record size.
*/
public int getRecordSize() {
return buffer.getRecordSize();
}
/**
* Get the available data that can be read from the current
* entry in the archive. This does not indicate how much data
* is left in the entire archive, only in the current entry.
* This value is determined from the entry's size header field
* and the amount of data already read from the current entry.
* Integer.MAX_VALUE is returen in case more than Integer.MAX_VALUE
* bytes are left in the current entry in the archive.
*
* @return The number of available bytes for the current entry.
* @throws IOException for signature
*/
public int available() throws IOException {
if (entrySize - entryOffset > Integer.MAX_VALUE) {
return Integer.MAX_VALUE;
}
return (int) (entrySize - entryOffset);
}
/**
* Skip bytes in the input buffer. This skips bytes in the
* current entry's data, not the entire archive, and will
* stop at the end of the current entry's data if the number
* to skip extends beyond that point.
*
* @param numToSkip The number of bytes to skip.
* @return the number actually skipped
* @throws IOException on error
*/
public long skip(long numToSkip) throws IOException {
// REVIEW
// This is horribly inefficient, but it ensures that we
// properly skip over bytes via the TarBuffer...
//
byte[] skipBuf = new byte[BUFFER_SIZE];
long skip = numToSkip;
while (skip > 0) {
int realSkip = (int) (skip > skipBuf.length ? skipBuf.length : skip);
int numRead = read(skipBuf, 0, realSkip);
if (numRead == -1) {
break;
}
skip -= numRead;
}
return (numToSkip - skip);
}
/**
* Since we do not support marking just yet, we return false.
*
* @return False.
*/
public boolean markSupported() {
return false;
}
/**
* Since we do not support marking just yet, we do nothing.
*
* @param markLimit The limit to mark.
*/
public void mark(int markLimit) {
}
/**
* Since we do not support marking just yet, we do nothing.
*/
public void reset() {
}
/**
* Get the next entry in this tar archive. This will skip
* over any remaining data in the current entry, if there
* is one, and place the input stream at the header of the
* next entry, and read the header and instantiate a new
* TarEntry from the header bytes and return that entry.
* If there are no more entries in the archive, null will
* be returned to indicate that the end of the archive has
* been reached.
*
* @return The next TarEntry in the archive, or null.
* @throws IOException on error
*/
public TarEntry getNextEntry() throws IOException {
if (hasHitEOF) {
return null;
}
if (currEntry != null) {
long numToSkip = entrySize - entryOffset;
if (debug) {
System.err.println("TarInputStream: SKIP currENTRY '"
+ currEntry.getName() + "' SZ "
+ entrySize + " OFF "
+ entryOffset + " skipping "
+ numToSkip + " bytes");
}
while (numToSkip > 0) {
long skipped = skip(numToSkip);
if (skipped <= 0) {
throw new RuntimeException("failed to skip current tar"
+ " entry");
}
numToSkip -= skipped;
}
readBuf = null;
}
byte[] headerBuf = buffer.readRecord();
if (headerBuf == null) {
if (debug) {
System.err.println("READ NULL RECORD");
}
hasHitEOF = true;
} else if (buffer.isEOFRecord(headerBuf)) {
if (debug) {
System.err.println("READ EOF RECORD");
}
hasHitEOF = true;
}
if (hasHitEOF) {
currEntry = null;
} else {
currEntry = new TarEntry(headerBuf);
if (debug) {
System.err.println("TarInputStream: SET CURRENTRY '"
+ currEntry.getName()
+ "' size = "
+ currEntry.getSize());
}
entryOffset = 0;
entrySize = currEntry.getSize();
}
if (currEntry != null && currEntry.isGNULongNameEntry()) {
// read in the name
StringBuffer longName = new StringBuffer();
byte[] buf = new byte[SMALL_BUFFER_SIZE];
int length = 0;
while ((length = read(buf)) >= 0) {
longName.append(new String(buf, 0, length));
}
getNextEntry();
if (currEntry == null) {
// Bugzilla: 40334
// Malformed tar file - long entry name not followed by entry
return null;
}
// remove trailing null terminator
if (longName.length() > 0
&& longName.charAt(longName.length() - 1) == 0) {
longName.deleteCharAt(longName.length() - 1);
}
currEntry.setName(longName.toString());
}
return currEntry;
}
/**
* Reads a byte from the current tar archive entry.
*
* This method simply calls read( byte[], int, int ).
*
* @return The byte read, or -1 at EOF.
* @throws IOException on error
*/
public int read() throws IOException {
int num = read(oneBuf, 0, 1);
return num == -1 ? -1 : ((int) oneBuf[0]) & BYTE_MASK;
}
/**
* Reads bytes from the current tar archive entry.
*
* This method is aware of the boundaries of the current
* entry in the archive and will deal with them as if they
* were this stream's start and EOF.
*
* @param buf The buffer into which to place bytes read.
* @param offset The offset at which to place bytes read.
* @param numToRead The number of bytes to read.
* @return The number of bytes read, or -1 at EOF.
* @throws IOException on error
*/
public int read(byte[] buf, int offset, int numToRead) throws IOException {
int totalRead = 0;
if (entryOffset >= entrySize) {
return -1;
}
if ((numToRead + entryOffset) > entrySize) {
numToRead = (int) (entrySize - entryOffset);
}
if (readBuf != null) {
int sz = (numToRead > readBuf.length) ? readBuf.length
: numToRead;
System.arraycopy(readBuf, 0, buf, offset, sz);
if (sz >= readBuf.length) {
readBuf = null;
} else {
int newLen = readBuf.length - sz;
byte[] newBuf = new byte[newLen];
System.arraycopy(readBuf, sz, newBuf, 0, newLen);
readBuf = newBuf;
}
totalRead += sz;
numToRead -= sz;
offset += sz;
}
while (numToRead > 0) {
byte[] rec = buffer.readRecord();
if (rec == null) {
// Unexpected EOF!
throw new IOException("unexpected EOF with " + numToRead
+ " bytes unread");
}
int sz = numToRead;
int recLen = rec.length;
if (recLen > sz) {
System.arraycopy(rec, 0, buf, offset, sz);
readBuf = new byte[recLen - sz];
System.arraycopy(rec, sz, readBuf, 0, recLen - sz);
} else {
sz = recLen;
System.arraycopy(rec, 0, buf, offset, recLen);
}
totalRead += sz;
numToRead -= sz;
offset += sz;
}
entryOffset += totalRead;
return totalRead;
}
/**
* Copies the contents of the current tar archive entry directly into
* an output stream.
*
* @param out The OutputStream into which to write the entry's data.
* @throws IOException on error
*/
public void copyEntryContents(OutputStream out) throws IOException {
byte[] buf = new byte[LARGE_BUFFER_SIZE];
while (true) {
int numRead = read(buf, 0, buf.length);
if (numRead == -1) {
break;
}
out.write(buf, 0, numRead);
}
}
}