| /* |
| * The Apache Software License, Version 1.1 |
| * |
| * Copyright (c) 1999 The Apache Software Foundation. All rights |
| * reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The end-user documentation included with the redistribution, if |
| * any, must include the following acknowlegement: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowlegement may appear in the software itself, |
| * if and wherever such third-party acknowlegements normally appear. |
| * |
| * 4. The names "The Jakarta Project", "Ant", and "Apache Software |
| * Foundation" must not be used to endorse or promote products derived |
| * from this software without prior written permission. For written |
| * permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache" |
| * nor may "Apache" appear in their names without prior written |
| * permission of the Apache Group. |
| * |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
| * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
| * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| |
| /* |
| * 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; |
| |
| /** |
| * This class provides static utility methods to work with byte streams. |
| * |
| * @author Timothy Gerard Endres <a href="mailto:time@ice.com">time@ice.com</a> |
| * @author Stefano Mazzocchi <a href="mailto:stefano@apache.org">stefano@apache.org</a> |
| */ |
| public class TarUtils { |
| |
| /** |
| * Parse an octal string from a header buffer. This is used for the |
| * file permission mode value. |
| * |
| * @param header The header buffer from which to parse. |
| * @param offset The offset into the buffer from which to parse. |
| * @param length The number of header bytes to parse. |
| * @return The long value of the octal string. |
| */ |
| public static long parseOctal(byte[] header, int offset, int length) { |
| long result = 0; |
| boolean stillPadding = true; |
| int end = offset + length; |
| |
| for (int i = offset; i < end; ++i) { |
| if (header[i] == 0) { |
| break; |
| } |
| |
| if (header[i] == (byte) ' ' || header[i] == '0') { |
| if (stillPadding) { |
| continue; |
| } |
| |
| if (header[i] == (byte) ' ') { |
| break; |
| } |
| } |
| |
| stillPadding = false; |
| result = (result << 3) + (header[i] - '0'); |
| } |
| |
| return result; |
| } |
| |
| /** |
| * Parse an entry name from a header buffer. |
| * |
| * @param header The header buffer from which to parse. |
| * @param offset The offset into the buffer from which to parse. |
| * @param length The number of header bytes to parse. |
| * @return The header's entry name. |
| */ |
| public static StringBuffer parseName(byte[] header, int offset, int length) { |
| StringBuffer result = new StringBuffer(length); |
| int end = offset + length; |
| |
| for (int i = offset; i < end; ++i) { |
| if (header[i] == 0) { |
| break; |
| } |
| |
| result.append((char) header[i]); |
| } |
| |
| return result; |
| } |
| |
| /** |
| * Determine the number of bytes in an entry name. |
| * |
| * @param header The header buffer from which to parse. |
| * @param offset The offset into the buffer from which to parse. |
| * @param length The number of header bytes to parse. |
| * @return The number of bytes in a header's entry name. |
| */ |
| public static int getNameBytes(StringBuffer name, byte[] buf, int offset, int length) { |
| int i; |
| |
| for (i = 0; i < length && i < name.length(); ++i) { |
| buf[offset + i] = (byte) name.charAt(i); |
| } |
| |
| for (; i < length; ++i) { |
| buf[offset + i] = 0; |
| } |
| |
| return offset + length; |
| } |
| |
| /** |
| * Parse an octal integer from a header buffer. |
| * |
| * @param header The header buffer from which to parse. |
| * @param offset The offset into the buffer from which to parse. |
| * @param length The number of header bytes to parse. |
| * @return The integer value of the octal bytes. |
| */ |
| public static int getOctalBytes(long value, byte[] buf, int offset, int length) { |
| byte[] result = new byte[length]; |
| int idx = length - 1; |
| |
| buf[offset + idx] = 0; |
| --idx; |
| buf[offset + idx] = (byte) ' '; |
| --idx; |
| |
| if (value == 0) { |
| buf[offset + idx] = (byte) '0'; |
| --idx; |
| } else { |
| for (long val = value; idx >= 0 && val > 0; --idx) { |
| buf[offset + idx] = (byte) ((byte) '0' + (byte) (val & 7)); |
| val = val >> 3; |
| } |
| } |
| |
| for (; idx >= 0; --idx) { |
| buf[offset + idx] = (byte) ' '; |
| } |
| |
| return offset + length; |
| } |
| |
| /** |
| * Parse an octal long integer from a header buffer. |
| * |
| * @param header The header buffer from which to parse. |
| * @param offset The offset into the buffer from which to parse. |
| * @param length The number of header bytes to parse. |
| * @return The long value of the octal bytes. |
| */ |
| public static int getLongOctalBytes(long value, byte[] buf, int offset, int length) { |
| byte[] temp = new byte[length + 1]; |
| |
| getOctalBytes(value, temp, 0, length + 1); |
| System.arraycopy(temp, 0, buf, offset, length); |
| |
| return offset + length; |
| } |
| |
| /** |
| * Parse the checksum octal integer from a header buffer. |
| * |
| * @param header The header buffer from which to parse. |
| * @param offset The offset into the buffer from which to parse. |
| * @param length The number of header bytes to parse. |
| * @return The integer value of the entry's checksum. |
| */ |
| public static int getCheckSumOctalBytes(long value, byte[] buf, int offset, int length) { |
| getOctalBytes(value, buf, offset, length); |
| |
| buf[offset + length - 1] = (byte) ' '; |
| buf[offset + length - 2] = 0; |
| |
| return offset + length; |
| } |
| |
| /** |
| * Compute the checksum of a tar entry header. |
| * |
| * @param buf The tar entry's header buffer. |
| * @return The computed checksum. |
| */ |
| public static long computeCheckSum(byte[] buf) { |
| long sum = 0; |
| |
| for (int i = 0; i < buf.length; ++i) { |
| sum += 255 & buf[i]; |
| } |
| |
| return sum; |
| } |
| } |