1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.commons.compress.archivers.cpio;
20
21 import java.nio.charset.StandardCharsets;
22 import java.util.Arrays;
23
24 /**
25 * Package private utility class for Cpio
26 *
27 * @Immutable
28 */
29 final class CpioUtil {
30
31 static final String DEFAULT_CHARSET_NAME = StandardCharsets.US_ASCII.name();
32
33 /**
34 * Converts a byte array to a long. Halfwords can be swapped by setting swapHalfWord=true.
35 *
36 * @param number An array of bytes containing a number
37 * @param swapHalfWord Swap halfwords ([0][1][2][3]->[1][0][3][2])
38 * @return The long value
39 * @throws UnsupportedOperationException if number length is not a multiple of 2
40 */
41 static long byteArray2long(final byte[] number, final boolean swapHalfWord) {
42 if (number.length % 2 != 0) {
43 throw new UnsupportedOperationException();
44 }
45
46 long ret;
47 int pos = 0;
48 final byte[] tmpNumber = Arrays.copyOf(number, number.length);
49
50 if (!swapHalfWord) {
51 byte tmp = 0;
52 for (pos = 0; pos < tmpNumber.length; pos++) {
53 tmp = tmpNumber[pos];
54 tmpNumber[pos++] = tmpNumber[pos];
55 tmpNumber[pos] = tmp;
56 }
57 }
58
59 ret = tmpNumber[0] & 0xFF;
60 for (pos = 1; pos < tmpNumber.length; pos++) {
61 ret <<= 8;
62 ret |= tmpNumber[pos] & 0xFF;
63 }
64 return ret;
65 }
66
67 /**
68 * Extracts the file type bits from a mode.
69 */
70 static long fileType(final long mode) {
71 return mode & CpioConstants.S_IFMT;
72 }
73
74 /**
75 * Converts a long number to a byte array Halfwords can be swapped by setting swapHalfWord=true.
76 *
77 * @param number the input long number to be converted
78 *
79 * @param length The length of the returned array
80 * @param swapHalfWord Swap halfwords ([0][1][2][3]->[1][0][3][2])
81 * @return The long value
82 * @throws UnsupportedOperationException if the length is not a positive multiple of two
83 */
84 static byte[] long2byteArray(final long number, final int length, final boolean swapHalfWord) {
85 final byte[] ret = new byte[length];
86 int pos = 0;
87 long tmp_number;
88
89 if (length % 2 != 0 || length < 2) {
90 throw new UnsupportedOperationException();
91 }
92
93 tmp_number = number;
94 for (pos = length - 1; pos >= 0; pos--) {
95 ret[pos] = (byte) (tmp_number & 0xFF);
96 tmp_number >>= 8;
97 }
98
99 if (!swapHalfWord) {
100 byte tmp = 0;
101 for (pos = 0; pos < length; pos++) {
102 tmp = ret[pos];
103 ret[pos++] = ret[pos];
104 ret[pos] = tmp;
105 }
106 }
107
108 return ret;
109 }
110 }