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 * https://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.sevenz;
20
21 import java.io.IOException;
22 import java.io.InputStream;
23 import java.io.OutputStream;
24 import java.util.Objects;
25 import java.util.stream.Stream;
26
27 import org.apache.commons.compress.utils.ByteUtils;
28
29 /**
30 * Abstracts a base Codec class.
31 */
32 abstract class AbstractCoder {
33
34 /**
35 * If the option represents a number, return its integer value, otherwise return the given default value.
36 *
37 * @param options A Number.
38 * @param defaultValue A default value if options is not a number.
39 * @return The given number or default value.
40 */
41 protected static int toInt(final Object options, final int defaultValue) {
42 return options instanceof Number ? ((Number) options).intValue() : defaultValue;
43 }
44
45 private final Class<?>[] optionClasses;
46
47 /**
48 * Constructs a new instance.
49 *
50 * @param optionClasses types that can be used as options for this codec.
51 */
52 protected AbstractCoder(final Class<?>... optionClasses) {
53 this.optionClasses = Objects.requireNonNull(optionClasses, "optionClasses");
54 }
55
56 /**
57 * Decodes using stream that reads from in using the configured coder and password.
58 *
59 * @return a stream that reads from in using the configured coder and password.
60 */
61 abstract InputStream decode(String archiveName, InputStream in, long uncompressedLength, Coder coder, byte[] password, int maxMemoryLimitKiB)
62 throws IOException;
63
64 /**
65 * Encodes using a stream that writes to out using the given configuration.
66 *
67 * @return a stream that writes to out using the given configuration.
68 * @throws IOException Optionally thrown by subclassses.
69 */
70 OutputStream encode(final OutputStream out, final Object options) throws IOException {
71 throw new UnsupportedOperationException("Method doesn't support writing");
72 }
73
74 /**
75 * Gets property bytes to write in a Folder block.
76 *
77 * @return property bytes to write in a Folder block.
78 * @throws IOException Optionally thrown by subclassses.
79 */
80 byte[] getOptionsAsProperties(final Object options) throws IOException {
81 return ByteUtils.EMPTY_BYTE_ARRAY;
82 }
83
84 /**
85 * Gets configuration options that have been used to create the given InputStream from the given Coder.
86 *
87 * @return configuration options that have been used to create the given InputStream from the given Coder
88 * @throws IOException Optionally thrown by subclassses.
89 */
90 Object getOptionsFromCoder(final Coder coder, final InputStream in) throws IOException {
91 return null;
92 }
93
94 /**
95 * Tests whether this method can extract options from the given object.
96 *
97 * @return whether this method can extract options from the given object.
98 */
99 boolean isOptionInstance(final Object opts) {
100 return Stream.of(optionClasses).anyMatch(c -> c.isInstance(opts));
101 }
102 }