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Apache Commons Compress software defines an API for working with
compression and archive formats. These include: bzip2, gzip, pack200,
lzma, xz, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4,
Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj.
/*
* 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.commons.compress.archivers.zip;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.zip.ZipException;
/**
* ZipExtraField related methods
* @NotThreadSafe because the HashMap is not synch.
*/
// CheckStyle:HideUtilityClassConstructorCheck OFF (bc)
public class ExtraFieldUtils {
private static final int WORD = 4;
/**
* Static registry of known extra fields.
*/
private static final Map> implementations;
static {
implementations = new ConcurrentHashMap>();
register(AsiExtraField.class);
register(X5455_ExtendedTimestamp.class);
register(X7875_NewUnix.class);
register(JarMarker.class);
register(UnicodePathExtraField.class);
register(UnicodeCommentExtraField.class);
register(Zip64ExtendedInformationExtraField.class);
}
/**
* Register a ZipExtraField implementation.
*
* The given class must have a no-arg constructor and implement
* the {@link ZipExtraField ZipExtraField interface}.
* @param c the class to register
*/
public static void register(Class c) {
try {
ZipExtraField ze = (ZipExtraField) c.newInstance();
implementations.put(ze.getHeaderId(), c);
} catch (ClassCastException cc) {
throw new RuntimeException(c + " doesn\'t implement ZipExtraField");
} catch (InstantiationException ie) {
throw new RuntimeException(c + " is not a concrete class");
} catch (IllegalAccessException ie) {
throw new RuntimeException(c + "\'s no-arg constructor is not public");
}
}
/**
* Create an instance of the appropriate ExtraField, falls back to
* {@link UnrecognizedExtraField UnrecognizedExtraField}.
* @param headerId the header identifier
* @return an instance of the appropriate ExtraField
* @exception InstantiationException if unable to instantiate the class
* @exception IllegalAccessException if not allowed to instantiate the class
*/
public static ZipExtraField createExtraField(ZipShort headerId)
throws InstantiationException, IllegalAccessException {
Class c = implementations.get(headerId);
if (c != null) {
return (ZipExtraField) c.newInstance();
}
UnrecognizedExtraField u = new UnrecognizedExtraField();
u.setHeaderId(headerId);
return u;
}
/**
* Split the array into ExtraFields and populate them with the
* given data as local file data, throwing an exception if the
* data cannot be parsed.
* @param data an array of bytes as it appears in local file data
* @return an array of ExtraFields
* @throws ZipException on error
*/
public static ZipExtraField[] parse(byte[] data) throws ZipException {
return parse(data, true, UnparseableExtraField.THROW);
}
/**
* Split the array into ExtraFields and populate them with the
* given data, throwing an exception if the data cannot be parsed.
* @param data an array of bytes
* @param local whether data originates from the local file data
* or the central directory
* @return an array of ExtraFields
* @throws ZipException on error
*/
public static ZipExtraField[] parse(byte[] data, boolean local)
throws ZipException {
return parse(data, local, UnparseableExtraField.THROW);
}
/**
* Split the array into ExtraFields and populate them with the
* given data.
* @param data an array of bytes
* @param local whether data originates from the local file data
* or the central directory
* @param onUnparseableData what to do if the extra field data
* cannot be parsed.
* @return an array of ExtraFields
* @throws ZipException on error
*
* @since 1.1
*/
public static ZipExtraField[] parse(byte[] data, boolean local,
UnparseableExtraField onUnparseableData)
throws ZipException {
List v = new ArrayList();
int start = 0;
LOOP:
while (start <= data.length - WORD) {
ZipShort headerId = new ZipShort(data, start);
int length = new ZipShort(data, start + 2).getValue();
if (start + WORD + length > data.length) {
switch(onUnparseableData.getKey()) {
case UnparseableExtraField.THROW_KEY:
throw new ZipException("bad extra field starting at "
+ start + ". Block length of "
+ length + " bytes exceeds remaining"
+ " data of "
+ (data.length - start - WORD)
+ " bytes.");
case UnparseableExtraField.READ_KEY:
UnparseableExtraFieldData field =
new UnparseableExtraFieldData();
if (local) {
field.parseFromLocalFileData(data, start,
data.length - start);
} else {
field.parseFromCentralDirectoryData(data, start,
data.length - start);
}
v.add(field);
//$FALL-THROUGH$
case UnparseableExtraField.SKIP_KEY:
// since we cannot parse the data we must assume
// the extra field consumes the whole rest of the
// available data
break LOOP;
default:
throw new ZipException("unknown UnparseableExtraField key: "
+ onUnparseableData.getKey());
}
}
try {
ZipExtraField ze = createExtraField(headerId);
if (local) {
ze.parseFromLocalFileData(data, start + WORD, length);
} else {
ze.parseFromCentralDirectoryData(data, start + WORD,
length);
}
v.add(ze);
} catch (InstantiationException ie) {
throw (ZipException) new ZipException(ie.getMessage()).initCause(ie);
} catch (IllegalAccessException iae) {
throw (ZipException) new ZipException(iae.getMessage()).initCause(iae);
}
start += length + WORD;
}
ZipExtraField[] result = new ZipExtraField[v.size()];
return v.toArray(result);
}
/**
* Merges the local file data fields of the given ZipExtraFields.
* @param data an array of ExtraFiles
* @return an array of bytes
*/
public static byte[] mergeLocalFileDataData(ZipExtraField[] data) {
final boolean lastIsUnparseableHolder = data.length > 0
&& data[data.length - 1] instanceof UnparseableExtraFieldData;
int regularExtraFieldCount =
lastIsUnparseableHolder ? data.length - 1 : data.length;
int sum = WORD * regularExtraFieldCount;
for (ZipExtraField element : data) {
sum += element.getLocalFileDataLength().getValue();
}
byte[] result = new byte[sum];
int start = 0;
for (int i = 0; i < regularExtraFieldCount; i++) {
System.arraycopy(data[i].getHeaderId().getBytes(),
0, result, start, 2);
System.arraycopy(data[i].getLocalFileDataLength().getBytes(),
0, result, start + 2, 2);
byte[] local = data[i].getLocalFileDataData();
System.arraycopy(local, 0, result, start + WORD, local.length);
start += local.length + WORD;
}
if (lastIsUnparseableHolder) {
byte[] local = data[data.length - 1].getLocalFileDataData();
System.arraycopy(local, 0, result, start, local.length);
}
return result;
}
/**
* Merges the central directory fields of the given ZipExtraFields.
* @param data an array of ExtraFields
* @return an array of bytes
*/
public static byte[] mergeCentralDirectoryData(ZipExtraField[] data) {
final boolean lastIsUnparseableHolder = data.length > 0
&& data[data.length - 1] instanceof UnparseableExtraFieldData;
int regularExtraFieldCount =
lastIsUnparseableHolder ? data.length - 1 : data.length;
int sum = WORD * regularExtraFieldCount;
for (ZipExtraField element : data) {
sum += element.getCentralDirectoryLength().getValue();
}
byte[] result = new byte[sum];
int start = 0;
for (int i = 0; i < regularExtraFieldCount; i++) {
System.arraycopy(data[i].getHeaderId().getBytes(),
0, result, start, 2);
System.arraycopy(data[i].getCentralDirectoryLength().getBytes(),
0, result, start + 2, 2);
byte[] local = data[i].getCentralDirectoryData();
System.arraycopy(local, 0, result, start + WORD, local.length);
start += local.length + WORD;
}
if (lastIsUnparseableHolder) {
byte[] local = data[data.length - 1].getCentralDirectoryData();
System.arraycopy(local, 0, result, start, local.length);
}
return result;
}
/**
* "enum" for the possible actions to take if the extra field
* cannot be parsed.
*
* @since 1.1
*/
public static final class UnparseableExtraField {
/**
* Key for "throw an exception" action.
*/
public static final int THROW_KEY = 0;
/**
* Key for "skip" action.
*/
public static final int SKIP_KEY = 1;
/**
* Key for "read" action.
*/
public static final int READ_KEY = 2;
/**
* Throw an exception if field cannot be parsed.
*/
public static final UnparseableExtraField THROW
= new UnparseableExtraField(THROW_KEY);
/**
* Skip the extra field entirely and don't make its data
* available - effectively removing the extra field data.
*/
public static final UnparseableExtraField SKIP
= new UnparseableExtraField(SKIP_KEY);
/**
* Read the extra field data into an instance of {@link
* UnparseableExtraFieldData UnparseableExtraFieldData}.
*/
public static final UnparseableExtraField READ
= new UnparseableExtraField(READ_KEY);
private final int key;
private UnparseableExtraField(int k) {
key = k;
}
/**
* Key of the action to take.
*/
public int getKey() { return key; }
}
}