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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.

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/*
 *  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.sevenz;

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.Closeable;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.LinkedList;
import java.util.zip.CRC32;

import org.apache.commons.compress.utils.BoundedInputStream;
import org.apache.commons.compress.utils.CRC32VerifyingInputStream;
import org.apache.commons.compress.utils.CharsetNames;
import org.apache.commons.compress.utils.IOUtils;

/**
 * Reads a 7z file, using RandomAccessFile under
 * the covers.
 * 

* The 7z file format is a flexible container * that can contain many compression and * encryption types, but at the moment only * only Copy, LZMA, LZMA2, BZIP2, Deflate and AES-256 + SHA-256 * are supported. *

* The format is very Windows/Intel specific, * so it uses little-endian byte order, * doesn't store user/group or permission bits, * and represents times using NTFS timestamps * (100 nanosecond units since 1 January 1601). * Hence the official tools recommend against * using it for backup purposes on *nix, and * recommend .tar.7z or .tar.lzma or .tar.xz * instead. *

* Both the header and file contents may be * compressed and/or encrypted. With both * encrypted, neither file names nor file * contents can be read, but the use of * encryption isn't plausibly deniable. * * @NotThreadSafe * @since 1.6 */ public class SevenZFile implements Closeable { static final int SIGNATURE_HEADER_SIZE = 32; private final String fileName; private RandomAccessFile file; private final Archive archive; private int currentEntryIndex = -1; private int currentFolderIndex = -1; private InputStream currentFolderInputStream = null; private byte[] password; private final ArrayList deferredBlockStreams = new ArrayList(); static final byte[] sevenZSignature = { (byte)'7', (byte)'z', (byte)0xBC, (byte)0xAF, (byte)0x27, (byte)0x1C }; /** * Reads a file as 7z archive * * @param filename the file to read * @param password optional password if the archive is encrypted - * the byte array is supposed to be the UTF16-LE encoded * representation of the password. * @throws IOException if reading the archive fails */ public SevenZFile(final File filename, final byte[] password) throws IOException { boolean succeeded = false; this.file = new RandomAccessFile(filename, "r"); this.fileName = filename.getAbsolutePath(); try { archive = readHeaders(password); if (password != null) { this.password = new byte[password.length]; System.arraycopy(password, 0, this.password, 0, password.length); } else { this.password = null; } succeeded = true; } finally { if (!succeeded) { this.file.close(); } } } /** * Reads a file as unencrypted 7z archive * * @param filename the file to read * @throws IOException if reading the archive fails */ public SevenZFile(final File filename) throws IOException { this(filename, null); } /** * Closes the archive. * @throws IOException if closing the file fails */ @Override public void close() throws IOException { if (file != null) { try { file.close(); } finally { file = null; if (password != null) { Arrays.fill(password, (byte) 0); } password = null; } } } /** * Returns the next Archive Entry in this archive. * * @return the next entry, * or {@code null} if there are no more entries * @throws IOException if the next entry could not be read */ public SevenZArchiveEntry getNextEntry() throws IOException { if (currentEntryIndex >= archive.files.length - 1) { return null; } ++currentEntryIndex; final SevenZArchiveEntry entry = archive.files[currentEntryIndex]; buildDecodingStream(); return entry; } /** * Returns meta-data of all archive entries. * *

This method only provides meta-data, the entries can not be * used to read the contents, you still need to process all * entries in order using {@link #getNextEntry} for that.

* *

The content methods are only available for entries that have * already been reached via {@link #getNextEntry}.

* * @return meta-data of all archive entries. * @since 1.11 */ public Iterable getEntries() { return Arrays.asList(archive.files); } private Archive readHeaders(final byte[] password) throws IOException { final byte[] signature = new byte[6]; file.readFully(signature); if (!Arrays.equals(signature, sevenZSignature)) { throw new IOException("Bad 7z signature"); } // 7zFormat.txt has it wrong - it's first major then minor final byte archiveVersionMajor = file.readByte(); final byte archiveVersionMinor = file.readByte(); if (archiveVersionMajor != 0) { throw new IOException(String.format("Unsupported 7z version (%d,%d)", archiveVersionMajor, archiveVersionMinor)); } final long startHeaderCrc = 0xffffFFFFL & Integer.reverseBytes(file.readInt()); final StartHeader startHeader = readStartHeader(startHeaderCrc); final int nextHeaderSizeInt = (int) startHeader.nextHeaderSize; if (nextHeaderSizeInt != startHeader.nextHeaderSize) { throw new IOException("cannot handle nextHeaderSize " + startHeader.nextHeaderSize); } file.seek(SIGNATURE_HEADER_SIZE + startHeader.nextHeaderOffset); final byte[] nextHeader = new byte[nextHeaderSizeInt]; file.readFully(nextHeader); final CRC32 crc = new CRC32(); crc.update(nextHeader); if (startHeader.nextHeaderCrc != crc.getValue()) { throw new IOException("NextHeader CRC mismatch"); } final ByteArrayInputStream byteStream = new ByteArrayInputStream(nextHeader); DataInputStream nextHeaderInputStream = new DataInputStream( byteStream); Archive archive = new Archive(); int nid = nextHeaderInputStream.readUnsignedByte(); if (nid == NID.kEncodedHeader) { nextHeaderInputStream = readEncodedHeader(nextHeaderInputStream, archive, password); // Archive gets rebuilt with the new header archive = new Archive(); nid = nextHeaderInputStream.readUnsignedByte(); } if (nid == NID.kHeader) { readHeader(nextHeaderInputStream, archive); nextHeaderInputStream.close(); } else { throw new IOException("Broken or unsupported archive: no Header"); } return archive; } private StartHeader readStartHeader(final long startHeaderCrc) throws IOException { final StartHeader startHeader = new StartHeader(); DataInputStream dataInputStream = null; try { dataInputStream = new DataInputStream(new CRC32VerifyingInputStream( new BoundedRandomAccessFileInputStream(file, 20), 20, startHeaderCrc)); startHeader.nextHeaderOffset = Long.reverseBytes(dataInputStream.readLong()); startHeader.nextHeaderSize = Long.reverseBytes(dataInputStream.readLong()); startHeader.nextHeaderCrc = 0xffffFFFFL & Integer.reverseBytes(dataInputStream.readInt()); return startHeader; } finally { if (dataInputStream != null) { dataInputStream.close(); } } } private void readHeader(final DataInput header, final Archive archive) throws IOException { int nid = header.readUnsignedByte(); if (nid == NID.kArchiveProperties) { readArchiveProperties(header); nid = header.readUnsignedByte(); } if (nid == NID.kAdditionalStreamsInfo) { throw new IOException("Additional streams unsupported"); //nid = header.readUnsignedByte(); } if (nid == NID.kMainStreamsInfo) { readStreamsInfo(header, archive); nid = header.readUnsignedByte(); } if (nid == NID.kFilesInfo) { readFilesInfo(header, archive); nid = header.readUnsignedByte(); } if (nid != NID.kEnd) { throw new IOException("Badly terminated header, found " + nid); } } private void readArchiveProperties(final DataInput input) throws IOException { // FIXME: the reference implementation just throws them away? int nid = input.readUnsignedByte(); while (nid != NID.kEnd) { final long propertySize = readUint64(input); final byte[] property = new byte[(int)propertySize]; input.readFully(property); nid = input.readUnsignedByte(); } } private DataInputStream readEncodedHeader(final DataInputStream header, final Archive archive, final byte[] password) throws IOException { readStreamsInfo(header, archive); // FIXME: merge with buildDecodingStream()/buildDecoderStack() at some stage? final Folder folder = archive.folders[0]; final int firstPackStreamIndex = 0; final long folderOffset = SIGNATURE_HEADER_SIZE + archive.packPos + 0; file.seek(folderOffset); InputStream inputStreamStack = new BoundedRandomAccessFileInputStream(file, archive.packSizes[firstPackStreamIndex]); for (final Coder coder : folder.getOrderedCoders()) { if (coder.numInStreams != 1 || coder.numOutStreams != 1) { throw new IOException("Multi input/output stream coders are not yet supported"); } inputStreamStack = Coders.addDecoder(fileName, inputStreamStack, folder.getUnpackSizeForCoder(coder), coder, password); } if (folder.hasCrc) { inputStreamStack = new CRC32VerifyingInputStream(inputStreamStack, folder.getUnpackSize(), folder.crc); } final byte[] nextHeader = new byte[(int)folder.getUnpackSize()]; final DataInputStream nextHeaderInputStream = new DataInputStream(inputStreamStack); try { nextHeaderInputStream.readFully(nextHeader); } finally { nextHeaderInputStream.close(); } return new DataInputStream(new ByteArrayInputStream(nextHeader)); } private void readStreamsInfo(final DataInput header, final Archive archive) throws IOException { int nid = header.readUnsignedByte(); if (nid == NID.kPackInfo) { readPackInfo(header, archive); nid = header.readUnsignedByte(); } if (nid == NID.kUnpackInfo) { readUnpackInfo(header, archive); nid = header.readUnsignedByte(); } else { // archive without unpack/coders info archive.folders = new Folder[0]; } if (nid == NID.kSubStreamsInfo) { readSubStreamsInfo(header, archive); nid = header.readUnsignedByte(); } if (nid != NID.kEnd) { throw new IOException("Badly terminated StreamsInfo"); } } private void readPackInfo(final DataInput header, final Archive archive) throws IOException { archive.packPos = readUint64(header); final long numPackStreams = readUint64(header); int nid = header.readUnsignedByte(); if (nid == NID.kSize) { archive.packSizes = new long[(int)numPackStreams]; for (int i = 0; i < archive.packSizes.length; i++) { archive.packSizes[i] = readUint64(header); } nid = header.readUnsignedByte(); } if (nid == NID.kCRC) { archive.packCrcsDefined = readAllOrBits(header, (int)numPackStreams); archive.packCrcs = new long[(int)numPackStreams]; for (int i = 0; i < (int)numPackStreams; i++) { if (archive.packCrcsDefined.get(i)) { archive.packCrcs[i] = 0xffffFFFFL & Integer.reverseBytes(header.readInt()); } } nid = header.readUnsignedByte(); } if (nid != NID.kEnd) { throw new IOException("Badly terminated PackInfo (" + nid + ")"); } } private void readUnpackInfo(final DataInput header, final Archive archive) throws IOException { int nid = header.readUnsignedByte(); if (nid != NID.kFolder) { throw new IOException("Expected kFolder, got " + nid); } final long numFolders = readUint64(header); final Folder[] folders = new Folder[(int)numFolders]; archive.folders = folders; final int external = header.readUnsignedByte(); if (external != 0) { throw new IOException("External unsupported"); } for (int i = 0; i < (int)numFolders; i++) { folders[i] = readFolder(header); } nid = header.readUnsignedByte(); if (nid != NID.kCodersUnpackSize) { throw new IOException("Expected kCodersUnpackSize, got " + nid); } for (final Folder folder : folders) { folder.unpackSizes = new long[(int)folder.totalOutputStreams]; for (int i = 0; i < folder.totalOutputStreams; i++) { folder.unpackSizes[i] = readUint64(header); } } nid = header.readUnsignedByte(); if (nid == NID.kCRC) { final BitSet crcsDefined = readAllOrBits(header, (int)numFolders); for (int i = 0; i < (int)numFolders; i++) { if (crcsDefined.get(i)) { folders[i].hasCrc = true; folders[i].crc = 0xffffFFFFL & Integer.reverseBytes(header.readInt()); } else { folders[i].hasCrc = false; } } nid = header.readUnsignedByte(); } if (nid != NID.kEnd) { throw new IOException("Badly terminated UnpackInfo"); } } private void readSubStreamsInfo(final DataInput header, final Archive archive) throws IOException { for (final Folder folder : archive.folders) { folder.numUnpackSubStreams = 1; } int totalUnpackStreams = archive.folders.length; int nid = header.readUnsignedByte(); if (nid == NID.kNumUnpackStream) { totalUnpackStreams = 0; for (final Folder folder : archive.folders) { final long numStreams = readUint64(header); folder.numUnpackSubStreams = (int)numStreams; totalUnpackStreams += numStreams; } nid = header.readUnsignedByte(); } final SubStreamsInfo subStreamsInfo = new SubStreamsInfo(); subStreamsInfo.unpackSizes = new long[totalUnpackStreams]; subStreamsInfo.hasCrc = new BitSet(totalUnpackStreams); subStreamsInfo.crcs = new long[totalUnpackStreams]; int nextUnpackStream = 0; for (final Folder folder : archive.folders) { if (folder.numUnpackSubStreams == 0) { continue; } long sum = 0; if (nid == NID.kSize) { for (int i = 0; i < folder.numUnpackSubStreams - 1; i++) { final long size = readUint64(header); subStreamsInfo.unpackSizes[nextUnpackStream++] = size; sum += size; } } subStreamsInfo.unpackSizes[nextUnpackStream++] = folder.getUnpackSize() - sum; } if (nid == NID.kSize) { nid = header.readUnsignedByte(); } int numDigests = 0; for (final Folder folder : archive.folders) { if (folder.numUnpackSubStreams != 1 || !folder.hasCrc) { numDigests += folder.numUnpackSubStreams; } } if (nid == NID.kCRC) { final BitSet hasMissingCrc = readAllOrBits(header, numDigests); final long[] missingCrcs = new long[numDigests]; for (int i = 0; i < numDigests; i++) { if (hasMissingCrc.get(i)) { missingCrcs[i] = 0xffffFFFFL & Integer.reverseBytes(header.readInt()); } } int nextCrc = 0; int nextMissingCrc = 0; for (final Folder folder: archive.folders) { if (folder.numUnpackSubStreams == 1 && folder.hasCrc) { subStreamsInfo.hasCrc.set(nextCrc, true); subStreamsInfo.crcs[nextCrc] = folder.crc; ++nextCrc; } else { for (int i = 0; i < folder.numUnpackSubStreams; i++) { subStreamsInfo.hasCrc.set(nextCrc, hasMissingCrc.get(nextMissingCrc)); subStreamsInfo.crcs[nextCrc] = missingCrcs[nextMissingCrc]; ++nextCrc; ++nextMissingCrc; } } } nid = header.readUnsignedByte(); } if (nid != NID.kEnd) { throw new IOException("Badly terminated SubStreamsInfo"); } archive.subStreamsInfo = subStreamsInfo; } private Folder readFolder(final DataInput header) throws IOException { final Folder folder = new Folder(); final long numCoders = readUint64(header); final Coder[] coders = new Coder[(int)numCoders]; long totalInStreams = 0; long totalOutStreams = 0; for (int i = 0; i < coders.length; i++) { coders[i] = new Coder(); final int bits = header.readUnsignedByte(); final int idSize = bits & 0xf; final boolean isSimple = (bits & 0x10) == 0; final boolean hasAttributes = (bits & 0x20) != 0; final boolean moreAlternativeMethods = (bits & 0x80) != 0; coders[i].decompressionMethodId = new byte[idSize]; header.readFully(coders[i].decompressionMethodId); if (isSimple) { coders[i].numInStreams = 1; coders[i].numOutStreams = 1; } else { coders[i].numInStreams = readUint64(header); coders[i].numOutStreams = readUint64(header); } totalInStreams += coders[i].numInStreams; totalOutStreams += coders[i].numOutStreams; if (hasAttributes) { final long propertiesSize = readUint64(header); coders[i].properties = new byte[(int)propertiesSize]; header.readFully(coders[i].properties); } // would need to keep looping as above: while (moreAlternativeMethods) { throw new IOException("Alternative methods are unsupported, please report. " + "The reference implementation doesn't support them either."); } } folder.coders = coders; folder.totalInputStreams = totalInStreams; folder.totalOutputStreams = totalOutStreams; if (totalOutStreams == 0) { throw new IOException("Total output streams can't be 0"); } final long numBindPairs = totalOutStreams - 1; final BindPair[] bindPairs = new BindPair[(int)numBindPairs]; for (int i = 0; i < bindPairs.length; i++) { bindPairs[i] = new BindPair(); bindPairs[i].inIndex = readUint64(header); bindPairs[i].outIndex = readUint64(header); } folder.bindPairs = bindPairs; if (totalInStreams < numBindPairs) { throw new IOException("Total input streams can't be less than the number of bind pairs"); } final long numPackedStreams = totalInStreams - numBindPairs; final long packedStreams[] = new long[(int)numPackedStreams]; if (numPackedStreams == 1) { int i; for (i = 0; i < (int)totalInStreams; i++) { if (folder.findBindPairForInStream(i) < 0) { break; } } if (i == (int)totalInStreams) { throw new IOException("Couldn't find stream's bind pair index"); } packedStreams[0] = i; } else { for (int i = 0; i < (int)numPackedStreams; i++) { packedStreams[i] = readUint64(header); } } folder.packedStreams = packedStreams; return folder; } private BitSet readAllOrBits(final DataInput header, final int size) throws IOException { final int areAllDefined = header.readUnsignedByte(); final BitSet bits; if (areAllDefined != 0) { bits = new BitSet(size); for (int i = 0; i < size; i++) { bits.set(i, true); } } else { bits = readBits(header, size); } return bits; } private BitSet readBits(final DataInput header, final int size) throws IOException { final BitSet bits = new BitSet(size); int mask = 0; int cache = 0; for (int i = 0; i < size; i++) { if (mask == 0) { mask = 0x80; cache = header.readUnsignedByte(); } bits.set(i, (cache & mask) != 0); mask >>>= 1; } return bits; } private void readFilesInfo(final DataInput header, final Archive archive) throws IOException { final long numFiles = readUint64(header); final SevenZArchiveEntry[] files = new SevenZArchiveEntry[(int)numFiles]; for (int i = 0; i < files.length; i++) { files[i] = new SevenZArchiveEntry(); } BitSet isEmptyStream = null; BitSet isEmptyFile = null; BitSet isAnti = null; while (true) { final int propertyType = header.readUnsignedByte(); if (propertyType == 0) { break; } final long size = readUint64(header); switch (propertyType) { case NID.kEmptyStream: { isEmptyStream = readBits(header, files.length); break; } case NID.kEmptyFile: { if (isEmptyStream == null) { // protect against NPE throw new IOException("Header format error: kEmptyStream must appear before kEmptyFile"); } isEmptyFile = readBits(header, isEmptyStream.cardinality()); break; } case NID.kAnti: { if (isEmptyStream == null) { // protect against NPE throw new IOException("Header format error: kEmptyStream must appear before kAnti"); } isAnti = readBits(header, isEmptyStream.cardinality()); break; } case NID.kName: { final int external = header.readUnsignedByte(); if (external != 0) { throw new IOException("Not implemented"); } if (((size - 1) & 1) != 0) { throw new IOException("File names length invalid"); } final byte[] names = new byte[(int)(size - 1)]; header.readFully(names); int nextFile = 0; int nextName = 0; for (int i = 0; i < names.length; i += 2) { if (names[i] == 0 && names[i+1] == 0) { files[nextFile++].setName(new String(names, nextName, i-nextName, CharsetNames.UTF_16LE)); nextName = i + 2; } } if (nextName != names.length || nextFile != files.length) { throw new IOException("Error parsing file names"); } break; } case NID.kCTime: { final BitSet timesDefined = readAllOrBits(header, files.length); final int external = header.readUnsignedByte(); if (external != 0) { throw new IOException("Unimplemented"); } for (int i = 0; i < files.length; i++) { files[i].setHasCreationDate(timesDefined.get(i)); if (files[i].getHasCreationDate()) { files[i].setCreationDate(Long.reverseBytes(header.readLong())); } } break; } case NID.kATime: { final BitSet timesDefined = readAllOrBits(header, files.length); final int external = header.readUnsignedByte(); if (external != 0) { throw new IOException("Unimplemented"); } for (int i = 0; i < files.length; i++) { files[i].setHasAccessDate(timesDefined.get(i)); if (files[i].getHasAccessDate()) { files[i].setAccessDate(Long.reverseBytes(header.readLong())); } } break; } case NID.kMTime: { final BitSet timesDefined = readAllOrBits(header, files.length); final int external = header.readUnsignedByte(); if (external != 0) { throw new IOException("Unimplemented"); } for (int i = 0; i < files.length; i++) { files[i].setHasLastModifiedDate(timesDefined.get(i)); if (files[i].getHasLastModifiedDate()) { files[i].setLastModifiedDate(Long.reverseBytes(header.readLong())); } } break; } case NID.kWinAttributes: { final BitSet attributesDefined = readAllOrBits(header, files.length); final int external = header.readUnsignedByte(); if (external != 0) { throw new IOException("Unimplemented"); } for (int i = 0; i < files.length; i++) { files[i].setHasWindowsAttributes(attributesDefined.get(i)); if (files[i].getHasWindowsAttributes()) { files[i].setWindowsAttributes(Integer.reverseBytes(header.readInt())); } } break; } case NID.kStartPos: { throw new IOException("kStartPos is unsupported, please report"); } case NID.kDummy: { // 7z 9.20 asserts the content is all zeros and ignores the property // Compress up to 1.8.1 would throw an exception, now we ignore it (see COMPRESS-287 if (skipBytesFully(header, size) < size) { throw new IOException("Incomplete kDummy property"); } break; } default: { // Compress up to 1.8.1 would throw an exception, now we ignore it (see COMPRESS-287 if (skipBytesFully(header, size) < size) { throw new IOException("Incomplete property of type " + propertyType); } break; } } } int nonEmptyFileCounter = 0; int emptyFileCounter = 0; for (int i = 0; i < files.length; i++) { files[i].setHasStream(isEmptyStream == null ? true : !isEmptyStream.get(i)); if (files[i].hasStream()) { files[i].setDirectory(false); files[i].setAntiItem(false); files[i].setHasCrc(archive.subStreamsInfo.hasCrc.get(nonEmptyFileCounter)); files[i].setCrcValue(archive.subStreamsInfo.crcs[nonEmptyFileCounter]); files[i].setSize(archive.subStreamsInfo.unpackSizes[nonEmptyFileCounter]); ++nonEmptyFileCounter; } else { files[i].setDirectory(isEmptyFile == null ? true : !isEmptyFile.get(emptyFileCounter)); files[i].setAntiItem(isAnti == null ? false : isAnti.get(emptyFileCounter)); files[i].setHasCrc(false); files[i].setSize(0); ++emptyFileCounter; } } archive.files = files; calculateStreamMap(archive); } private void calculateStreamMap(final Archive archive) throws IOException { final StreamMap streamMap = new StreamMap(); int nextFolderPackStreamIndex = 0; final int numFolders = archive.folders != null ? archive.folders.length : 0; streamMap.folderFirstPackStreamIndex = new int[numFolders]; for (int i = 0; i < numFolders; i++) { streamMap.folderFirstPackStreamIndex[i] = nextFolderPackStreamIndex; nextFolderPackStreamIndex += archive.folders[i].packedStreams.length; } long nextPackStreamOffset = 0; final int numPackSizes = archive.packSizes != null ? archive.packSizes.length : 0; streamMap.packStreamOffsets = new long[numPackSizes]; for (int i = 0; i < numPackSizes; i++) { streamMap.packStreamOffsets[i] = nextPackStreamOffset; nextPackStreamOffset += archive.packSizes[i]; } streamMap.folderFirstFileIndex = new int[numFolders]; streamMap.fileFolderIndex = new int[archive.files.length]; int nextFolderIndex = 0; int nextFolderUnpackStreamIndex = 0; for (int i = 0; i < archive.files.length; i++) { if (!archive.files[i].hasStream() && nextFolderUnpackStreamIndex == 0) { streamMap.fileFolderIndex[i] = -1; continue; } if (nextFolderUnpackStreamIndex == 0) { for (; nextFolderIndex < archive.folders.length; ++nextFolderIndex) { streamMap.folderFirstFileIndex[nextFolderIndex] = i; if (archive.folders[nextFolderIndex].numUnpackSubStreams > 0) { break; } } if (nextFolderIndex >= archive.folders.length) { throw new IOException("Too few folders in archive"); } } streamMap.fileFolderIndex[i] = nextFolderIndex; if (!archive.files[i].hasStream()) { continue; } ++nextFolderUnpackStreamIndex; if (nextFolderUnpackStreamIndex >= archive.folders[nextFolderIndex].numUnpackSubStreams) { ++nextFolderIndex; nextFolderUnpackStreamIndex = 0; } } archive.streamMap = streamMap; } private void buildDecodingStream() throws IOException { final int folderIndex = archive.streamMap.fileFolderIndex[currentEntryIndex]; if (folderIndex < 0) { deferredBlockStreams.clear(); // TODO: previously it'd return an empty stream? // new BoundedInputStream(new ByteArrayInputStream(new byte[0]), 0); return; } final SevenZArchiveEntry file = archive.files[currentEntryIndex]; if (currentFolderIndex == folderIndex) { // (COMPRESS-320). // The current entry is within the same (potentially opened) folder. The // previous stream has to be fully decoded before we can start reading // but don't do it eagerly -- if the user skips over the entire folder nothing // is effectively decompressed. file.setContentMethods(archive.files[currentEntryIndex - 1].getContentMethods()); } else { // We're opening a new folder. Discard any queued streams/ folder stream. currentFolderIndex = folderIndex; deferredBlockStreams.clear(); if (currentFolderInputStream != null) { currentFolderInputStream.close(); currentFolderInputStream = null; } final Folder folder = archive.folders[folderIndex]; final int firstPackStreamIndex = archive.streamMap.folderFirstPackStreamIndex[folderIndex]; final long folderOffset = SIGNATURE_HEADER_SIZE + archive.packPos + archive.streamMap.packStreamOffsets[firstPackStreamIndex]; currentFolderInputStream = buildDecoderStack(folder, folderOffset, firstPackStreamIndex, file); } InputStream fileStream = new BoundedInputStream(currentFolderInputStream, file.getSize()); if (file.getHasCrc()) { fileStream = new CRC32VerifyingInputStream(fileStream, file.getSize(), file.getCrcValue()); } deferredBlockStreams.add(fileStream); } private InputStream buildDecoderStack(final Folder folder, final long folderOffset, final int firstPackStreamIndex, final SevenZArchiveEntry entry) throws IOException { file.seek(folderOffset); InputStream inputStreamStack = new BufferedInputStream( new BoundedRandomAccessFileInputStream(file, archive.packSizes[firstPackStreamIndex])); final LinkedList methods = new LinkedList(); for (final Coder coder : folder.getOrderedCoders()) { if (coder.numInStreams != 1 || coder.numOutStreams != 1) { throw new IOException("Multi input/output stream coders are not yet supported"); } final SevenZMethod method = SevenZMethod.byId(coder.decompressionMethodId); inputStreamStack = Coders.addDecoder(fileName, inputStreamStack, folder.getUnpackSizeForCoder(coder), coder, password); methods.addFirst(new SevenZMethodConfiguration(method, Coders.findByMethod(method).getOptionsFromCoder(coder, inputStreamStack))); } entry.setContentMethods(methods); if (folder.hasCrc) { return new CRC32VerifyingInputStream(inputStreamStack, folder.getUnpackSize(), folder.crc); } return inputStreamStack; } /** * Reads a byte of data. * * @return the byte read, or -1 if end of input is reached * @throws IOException * if an I/O error has occurred */ public int read() throws IOException { return getCurrentStream().read(); } private InputStream getCurrentStream() throws IOException { if (archive.files[currentEntryIndex].getSize() == 0) { return new ByteArrayInputStream(new byte[0]); } if (deferredBlockStreams.isEmpty()) { throw new IllegalStateException("No current 7z entry (call getNextEntry() first)."); } while (deferredBlockStreams.size() > 1) { // In solid compression mode we need to decompress all leading folder' // streams to get access to an entry. We defer this until really needed // so that entire blocks can be skipped without wasting time for decompression. final InputStream stream = deferredBlockStreams.remove(0); IOUtils.skip(stream, Long.MAX_VALUE); stream.close(); } return deferredBlockStreams.get(0); } /** * Reads data into an array of bytes. * * @param b the array to write data to * @return the number of bytes read, or -1 if end of input is reached * @throws IOException * if an I/O error has occurred */ public int read(final byte[] b) throws IOException { return read(b, 0, b.length); } /** * Reads data into an array of bytes. * * @param b the array to write data to * @param off offset into the buffer to start filling at * @param len of bytes to read * @return the number of bytes read, or -1 if end of input is reached * @throws IOException * if an I/O error has occurred */ public int read(final byte[] b, final int off, final int len) throws IOException { return getCurrentStream().read(b, off, len); } private static long readUint64(final DataInput in) throws IOException { // long rather than int as it might get shifted beyond the range of an int final long firstByte = in.readUnsignedByte(); int mask = 0x80; long value = 0; for (int i = 0; i < 8; i++) { if ((firstByte & mask) == 0) { return value | ((firstByte & (mask - 1)) << (8 * i)); } final long nextByte = in.readUnsignedByte(); value |= nextByte << (8 * i); mask >>>= 1; } return value; } /** * Checks if the signature matches what is expected for a 7z file. * * @param signature * the bytes to check * @param length * the number of bytes to check * @return true, if this is the signature of a 7z archive. * @since 1.8 */ public static boolean matches(final byte[] signature, final int length) { if (length < sevenZSignature.length) { return false; } for (int i = 0; i < sevenZSignature.length; i++) { if (signature[i] != sevenZSignature[i]) { return false; } } return true; } private static long skipBytesFully(final DataInput input, long bytesToSkip) throws IOException { if (bytesToSkip < 1) { return 0; } long skipped = 0; while (bytesToSkip > Integer.MAX_VALUE) { final long skippedNow = skipBytesFully(input, Integer.MAX_VALUE); if (skippedNow == 0) { return skipped; } skipped += skippedNow; bytesToSkip -= skippedNow; } while (bytesToSkip > 0) { final int skippedNow = input.skipBytes((int) bytesToSkip); if (skippedNow == 0) { return skipped; } skipped += skippedNow; bytesToSkip -= skippedNow; } return skipped; } @Override public String toString() { return archive.toString(); } }




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