1/*
2 *  Licensed to the Apache Software Foundation (ASF) under one or more
3 *  contributor license agreements.  See the NOTICE file distributed with
4 *  this work for additional information regarding copyright ownership.
5 *  The ASF licenses this file to You under the Apache License, Version 2.0
6 *  (the "License"); you may not use this file except in compliance with
7 *  the License.  You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 *  Unless required by applicable law or agreed to in writing, software
12 *  distributed under the License is distributed on an "AS IS" BASIS,
13 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 *  See the License for the specific language governing permissions and
15 *  limitations under the License.
16 */
17
18package org.apache.harmony.xnet.provider.jsse;
19
20import java.io.IOException;
21import java.io.InputStream;
22
23/**
24 * This class is a base for all input stream classes used
25 * in protocol implementation. It extends an InputStream with
26 * some additional read methods allowing to read TLS specific
27 * data types such as uint8, uint32 etc (see TLS v 1 specification
28 * at http://www.ietf.org/rfc/rfc2246.txt).
29 */
30public abstract class SSLInputStream extends InputStream {
31
32    @Override
33    public abstract int available() throws IOException;
34
35    /**
36     * Reads the following byte value. Note that in the case of
37     * reaching of the end of the data this methods throws the
38     * exception, not return -1. The type of exception depends
39     * on implementation. It was done for simplifying and speeding
40     * up of processing of such cases.
41     * @see org.apache.harmony.xnet.provider.jsse.SSLStreamedInput#read()
42     * @see org.apache.harmony.xnet.provider.jsse.SSLBufferedInput#read()
43     * @see org.apache.harmony.xnet.provider.jsse.HandshakeIODataStream#read()
44     */
45    @Override
46    public abstract int read() throws IOException;
47
48    @Override
49    public long skip(long n) throws IOException {
50        long skept = n;
51        while (n > 0) {
52            read();
53            n--;
54        }
55        return skept;
56    }
57
58    /**
59     * Reads and returns uint8 value.
60     */
61    public int readUint8() throws IOException {
62        return read() & 0x00FF;
63    }
64
65    /**
66     * Reads and returns uint16 value.
67     */
68    public int readUint16() throws IOException {
69        return (read() << 8) | (read() & 0x00FF);
70    }
71
72    /**
73     * Reads and returns uint24 value.
74     */
75    public int readUint24() throws IOException {
76        return (read() << 16) | (read() << 8) | (read() & 0x00FF);
77    }
78
79    /**
80     * Reads and returns uint32 value.
81     */
82    public long readUint32() throws IOException {
83        return (read() << 24) | (read() << 16)
84              | (read() << 8) | (read() & 0x00FF);
85    }
86
87    /**
88     * Reads and returns uint64 value.
89     */
90    public long readUint64() throws IOException {
91        // BEGIN android-changed
92        long hi = readUint32();
93        long lo = readUint32();
94        return (hi << 32) | lo;
95        // END android-changed
96    }
97
98    /**
99     * Returns the vector of opaque values of specified length;
100     * @param length - the length of the vector to be read.
101     * @return the read data
102     * @throws IOException if read operation could not be finished.
103     */
104    public byte[] read(int length) throws IOException {
105        byte[] res = new byte[length];
106        for (int i=0; i<length; i++) {
107            res[i] = (byte) read();
108        }
109        return res;
110    }
111
112    @Override
113    public int read(byte[] b, int off, int len) throws IOException {
114        int read_b;
115        int i = 0;
116        do {
117            if ((read_b = read()) == -1) {
118                return (i == 0) ? -1 : i;
119            }
120            b[off+i] = (byte) read_b;
121            i++;
122        } while ((available() != 0) && (i<len));
123        return i;
124    }
125}
126