1/*
2 * Copyright (C) 2015 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 */
16package com.android.voicemail.impl.mail;
17
18import java.io.IOException;
19import java.io.InputStream;
20
21/**
22 * A filtering InputStream that stops allowing reads after the given length has been read. This is
23 * used to allow a client to read directly from an underlying protocol stream without reading past
24 * where the protocol handler intended the client to read.
25 */
26public class FixedLengthInputStream extends InputStream {
27  private final InputStream mIn;
28  private final int mLength;
29  private int mCount;
30
31  public FixedLengthInputStream(InputStream in, int length) {
32    this.mIn = in;
33    this.mLength = length;
34  }
35
36  @Override
37  public int available() throws IOException {
38    return mLength - mCount;
39  }
40
41  @Override
42  public int read() throws IOException {
43    if (mCount < mLength) {
44      mCount++;
45      return mIn.read();
46    } else {
47      return -1;
48    }
49  }
50
51  @Override
52  public int read(byte[] b, int offset, int length) throws IOException {
53    if (mCount < mLength) {
54      int d = mIn.read(b, offset, Math.min(mLength - mCount, length));
55      if (d == -1) {
56        return -1;
57      } else {
58        mCount += d;
59        return d;
60      }
61    } else {
62      return -1;
63    }
64  }
65
66  @Override
67  public int read(byte[] b) throws IOException {
68    return read(b, 0, b.length);
69  }
70
71  public int getLength() {
72    return mLength;
73  }
74
75  @Override
76  public String toString() {
77    return String.format("FixedLengthInputStream(in=%s, length=%d)", mIn.toString(), mLength);
78  }
79}
80