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1 | /* |
2 | * Copyright (C) 2010 The Android Open Source Project | |
3 | * | |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); | |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at | |
7 | * | |
8 | * http://www.apache.org/licenses/LICENSE-2.0 | |
9 | * | |
10 | * Unless required by applicable law or agreed to in writing, software | |
11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | * See the License for the specific language governing permissions and | |
14 | * limitations under the License. | |
15 | */ | |
16 | ||
17 | package be.nikiroo.utils.streams; | |
18 | ||
19 | import java.io.FilterInputStream; | |
20 | import java.io.IOException; | |
21 | import java.io.InputStream; | |
22 | ||
23 | /** | |
24 | * An InputStream that does Base64 decoding on the data read through | |
25 | * it. | |
26 | */ | |
27 | public class Base64InputStream extends FilterInputStream { | |
28 | private final Base64.Coder coder; | |
29 | ||
30 | private static byte[] EMPTY = new byte[0]; | |
31 | ||
32 | private static final int BUFFER_SIZE = 2048; | |
33 | private boolean eof; | |
34 | private byte[] inputBuffer; | |
35 | private int outputStart; | |
36 | private int outputEnd; | |
37 | ||
38 | /** | |
39 | * An InputStream that performs Base64 decoding on the data read | |
40 | * from the wrapped stream. | |
41 | * | |
42 | * @param in the InputStream to read the source data from | |
43 | */ | |
44 | public Base64InputStream(InputStream in) { | |
45 | this(in, false); | |
46 | } | |
47 | ||
48 | /** | |
49 | * Performs Base64 encoding or decoding on the data read from the | |
50 | * wrapped InputStream. | |
51 | * | |
52 | * @param in the InputStream to read the source data from | |
53 | * @param flags bit flags for controlling the decoder; see the | |
54 | * constants in {@link Base64} | |
55 | * @param encode true to encode, false to decode | |
56 | * | |
57 | * @hide | |
58 | */ | |
59 | public Base64InputStream(InputStream in, boolean encode) { | |
60 | super(in); | |
61 | eof = false; | |
62 | inputBuffer = new byte[BUFFER_SIZE]; | |
63 | if (encode) { | |
64 | coder = new Base64.Encoder(Base64.NO_WRAP, null); | |
65 | } else { | |
66 | coder = new Base64.Decoder(Base64.NO_WRAP, null); | |
67 | } | |
68 | coder.output = new byte[coder.maxOutputSize(BUFFER_SIZE)]; | |
69 | outputStart = 0; | |
70 | outputEnd = 0; | |
71 | } | |
72 | ||
73 | public boolean markSupported() { | |
74 | return false; | |
75 | } | |
76 | ||
77 | public void mark(int readlimit) { | |
78 | throw new UnsupportedOperationException(); | |
79 | } | |
80 | ||
81 | public void reset() { | |
82 | throw new UnsupportedOperationException(); | |
83 | } | |
84 | ||
85 | public void close() throws IOException { | |
86 | in.close(); | |
87 | inputBuffer = null; | |
88 | } | |
89 | ||
90 | public int available() { | |
91 | return outputEnd - outputStart; | |
92 | } | |
93 | ||
94 | public long skip(long n) throws IOException { | |
95 | if (outputStart >= outputEnd) { | |
96 | refill(); | |
97 | } | |
98 | if (outputStart >= outputEnd) { | |
99 | return 0; | |
100 | } | |
101 | long bytes = Math.min(n, outputEnd-outputStart); | |
102 | outputStart += bytes; | |
103 | return bytes; | |
104 | } | |
105 | ||
106 | public int read() throws IOException { | |
107 | if (outputStart >= outputEnd) { | |
108 | refill(); | |
109 | } | |
110 | if (outputStart >= outputEnd) { | |
111 | return -1; | |
112 | } else { | |
113 | return coder.output[outputStart++] & 0xff; | |
114 | } | |
115 | } | |
116 | ||
117 | public int read(byte[] b, int off, int len) throws IOException { | |
118 | if (outputStart >= outputEnd) { | |
119 | refill(); | |
120 | } | |
121 | if (outputStart >= outputEnd) { | |
122 | return -1; | |
123 | } | |
124 | int bytes = Math.min(len, outputEnd-outputStart); | |
125 | System.arraycopy(coder.output, outputStart, b, off, bytes); | |
126 | outputStart += bytes; | |
127 | return bytes; | |
128 | } | |
129 | ||
130 | /** | |
131 | * Read data from the input stream into inputBuffer, then | |
132 | * decode/encode it into the empty coder.output, and reset the | |
133 | * outputStart and outputEnd pointers. | |
134 | */ | |
135 | private void refill() throws IOException { | |
136 | if (eof) return; | |
137 | int bytesRead = in.read(inputBuffer); | |
138 | boolean success; | |
139 | if (bytesRead == -1) { | |
140 | eof = true; | |
141 | success = coder.process(EMPTY, 0, 0, true); | |
142 | } else { | |
143 | success = coder.process(inputBuffer, 0, bytesRead, false); | |
144 | } | |
145 | if (!success) { | |
146 | throw new IOException("bad base-64"); | |
147 | } | |
148 | outputEnd = coder.op; | |
149 | outputStart = 0; | |
150 | } | |
151 | } |