| // Copyright 2015 The Bazel Authors. All rights reserved. |
| // |
| // 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 com.google.devtools.build.zip; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.util.zip.ZipException; |
| |
| class EndOfCentralDirectoryRecord { |
| static final int SIGNATURE = 0x06054b50; |
| static final int FIXED_DATA_SIZE = 22; |
| static final int SIGNATURE_OFFSET = 0; |
| static final int DISK_NUMBER_OFFSET = 4; |
| static final int CD_DISK_OFFSET = 6; |
| static final int DISK_ENTRIES_OFFSET = 8; |
| static final int TOTAL_ENTRIES_OFFSET = 10; |
| static final int CD_SIZE_OFFSET = 12; |
| static final int CD_OFFSET_OFFSET = 16; |
| static final int COMMENT_LENGTH_OFFSET = 20; |
| |
| /** |
| * Read the end of central directory record from the input stream and parse {@link ZipFileData} |
| * from it. |
| */ |
| static ZipFileData read(InputStream in, ZipFileData file) throws IOException { |
| if (file == null) { |
| throw new NullPointerException(); |
| } |
| |
| byte[] fixedSizeData = new byte[FIXED_DATA_SIZE]; |
| if (ZipUtil.readFully(in, fixedSizeData) != FIXED_DATA_SIZE) { |
| throw new ZipException( |
| "Unexpected end of file while reading End of Central Directory Record."); |
| } |
| if (!ZipUtil.arrayStartsWith(fixedSizeData, ZipUtil.intToLittleEndian(SIGNATURE))) { |
| throw new ZipException(String.format( |
| "Malformed End of Central Directory Record; does not start with %08x", SIGNATURE)); |
| } |
| |
| byte[] comment = new byte[ZipUtil.getUnsignedShort(fixedSizeData, COMMENT_LENGTH_OFFSET)]; |
| if (comment.length > 0 && ZipUtil.readFully(in, comment) != comment.length) { |
| throw new ZipException( |
| "Unexpected end of file while reading End of Central Directory Record."); |
| } |
| short diskNumber = ZipUtil.get16(fixedSizeData, DISK_NUMBER_OFFSET); |
| short centralDirectoryDisk = ZipUtil.get16(fixedSizeData, CD_DISK_OFFSET); |
| short entriesOnDisk = ZipUtil.get16(fixedSizeData, DISK_ENTRIES_OFFSET); |
| short totalEntries = ZipUtil.get16(fixedSizeData, TOTAL_ENTRIES_OFFSET); |
| int centralDirectorySize = ZipUtil.get32(fixedSizeData, CD_SIZE_OFFSET); |
| int centralDirectoryOffset = ZipUtil.get32(fixedSizeData, CD_OFFSET_OFFSET); |
| if (diskNumber == -1 || centralDirectoryDisk == -1 || entriesOnDisk == -1 |
| || totalEntries == -1 || centralDirectorySize == -1 || centralDirectoryOffset == -1) { |
| file.setMaybeZip64(true); |
| } |
| file.setComment(comment); |
| file.setCentralDirectorySize(ZipUtil.getUnsignedInt(fixedSizeData, CD_SIZE_OFFSET)); |
| file.setCentralDirectoryOffset(ZipUtil.getUnsignedInt(fixedSizeData, CD_OFFSET_OFFSET)); |
| file.setExpectedEntries(ZipUtil.getUnsignedShort(fixedSizeData, TOTAL_ENTRIES_OFFSET)); |
| return file; |
| } |
| |
| /** |
| * Generates the raw byte data of the end of central directory record for the specified |
| * {@link ZipFileData}. |
| * @throws ZipException if the file comment is too long |
| */ |
| static byte[] create(ZipFileData file, boolean allowZip64) throws ZipException { |
| byte[] comment = file.getBytes(file.getComment()); |
| |
| byte[] buf = new byte[FIXED_DATA_SIZE + comment.length]; |
| |
| // Allow writing of Zip file without Zip64 extensions for large archives as a special case |
| // since many reading implementations can handle this. |
| short numEntries = (short) (file.getNumEntries() > 0xffff && allowZip64 |
| ? -1 : file.getNumEntries()); |
| int cdSize = (int) (file.getCentralDirectorySize() > 0xffffffffL && allowZip64 |
| ? -1 : file.getCentralDirectorySize()); |
| int cdOffset = (int) (file.getCentralDirectoryOffset() > 0xffffffffL && allowZip64 |
| ? -1 : file.getCentralDirectoryOffset()); |
| ZipUtil.intToLittleEndian(buf, SIGNATURE_OFFSET, SIGNATURE); |
| ZipUtil.shortToLittleEndian(buf, DISK_NUMBER_OFFSET, (short) 0); |
| ZipUtil.shortToLittleEndian(buf, CD_DISK_OFFSET, (short) 0); |
| ZipUtil.shortToLittleEndian(buf, DISK_ENTRIES_OFFSET, numEntries); |
| ZipUtil.shortToLittleEndian(buf, TOTAL_ENTRIES_OFFSET, numEntries); |
| ZipUtil.intToLittleEndian(buf, CD_SIZE_OFFSET, cdSize); |
| ZipUtil.intToLittleEndian(buf, CD_OFFSET_OFFSET, cdOffset); |
| ZipUtil.shortToLittleEndian(buf, COMMENT_LENGTH_OFFSET, (short) comment.length); |
| System.arraycopy(comment, 0, buf, FIXED_DATA_SIZE, comment.length); |
| |
| return buf; |
| } |
| } |