1// Protocol Buffers - Google's data interchange format
2// Copyright 2008 Google Inc.  All rights reserved.
3// http://code.google.com/p/protobuf/
4//
5// Redistribution and use in source and binary forms, with or without
6// modification, are permitted provided that the following conditions are
7// met:
8//
9//     * Redistributions of source code must retain the above copyright
10// notice, this list of conditions and the following disclaimer.
11//     * Redistributions in binary form must reproduce the above
12// copyright notice, this list of conditions and the following disclaimer
13// in the documentation and/or other materials provided with the
14// distribution.
15//     * Neither the name of Google Inc. nor the names of its
16// contributors may be used to endorse or promote products derived from
17// this software without specific prior written permission.
18//
19// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31package com.google.protobuf.micro;
32
33import java.io.UnsupportedEncodingException;
34
35/**
36 * Immutable array of bytes.
37 *
38 * @author crazybob@google.com Bob Lee
39 * @author kenton@google.com Kenton Varda
40 */
41public final class ByteStringMicro {
42  private final byte[] bytes;
43
44  private ByteStringMicro(final byte[] bytes) {
45    this.bytes = bytes;
46  }
47
48  /**
49   * Gets the byte at the given index.
50   *
51   * @throws ArrayIndexOutOfBoundsException {@code index} is < 0 or >= size
52   */
53  public byte byteAt(final int index) {
54    return bytes[index];
55  }
56
57  /**
58   * Gets the number of bytes.
59   */
60  public int size() {
61    return bytes.length;
62  }
63
64  /**
65   * Returns {@code true} if the size is {@code 0}, {@code false} otherwise.
66   */
67  public boolean isEmpty() {
68    return bytes.length == 0;
69  }
70
71  // =================================================================
72  // byte[] -> ByteStringMicro
73
74  /**
75   * Empty ByteStringMicro.
76   */
77  public static final ByteStringMicro EMPTY = new ByteStringMicro(new byte[0]);
78
79  /**
80   * Copies the given bytes into a {@code ByteStringMicro}.
81   */
82  public static ByteStringMicro copyFrom(final byte[] bytes, final int offset,
83                                    final int size) {
84    final byte[] copy = new byte[size];
85    System.arraycopy(bytes, offset, copy, 0, size);
86    return new ByteStringMicro(copy);
87  }
88
89  /**
90   * Copies the given bytes into a {@code ByteStringMicro}.
91   */
92  public static ByteStringMicro copyFrom(final byte[] bytes) {
93    return copyFrom(bytes, 0, bytes.length);
94  }
95
96  /**
97   * Encodes {@code text} into a sequence of bytes using the named charset
98   * and returns the result as a {@code ByteStringMicro}.
99   */
100  public static ByteStringMicro copyFrom(final String text, final String charsetName)
101      throws UnsupportedEncodingException {
102    return new ByteStringMicro(text.getBytes(charsetName));
103  }
104
105  /**
106   * Encodes {@code text} into a sequence of UTF-8 bytes and returns the
107   * result as a {@code ByteStringMicro}.
108   */
109  public static ByteStringMicro copyFromUtf8(final String text) {
110    try {
111      return new ByteStringMicro(text.getBytes("UTF-8"));
112    } catch (UnsupportedEncodingException e) {
113      throw new RuntimeException("UTF-8 not supported?");
114    }
115  }
116
117  // =================================================================
118  // ByteStringMicro -> byte[]
119
120  /**
121   * Copies bytes into a buffer at the given offset.
122   *
123   * @param target buffer to copy into
124   * @param offset in the target buffer
125   */
126  public void copyTo(final byte[] target, final int offset) {
127    System.arraycopy(bytes, 0, target, offset, bytes.length);
128  }
129
130  /**
131   * Copies bytes into a buffer.
132   *
133   * @param target buffer to copy into
134   * @param sourceOffset offset within these bytes
135   * @param targetOffset offset within the target buffer
136   * @param size number of bytes to copy
137   */
138  public void copyTo(final byte[] target, final int sourceOffset,
139                     final int targetOffset,
140      final int size) {
141    System.arraycopy(bytes, sourceOffset, target, targetOffset, size);
142  }
143
144  /**
145   * Copies bytes to a {@code byte[]}.
146   */
147  public byte[] toByteArray() {
148    final int size = bytes.length;
149    final byte[] copy = new byte[size];
150    System.arraycopy(bytes, 0, copy, 0, size);
151    return copy;
152  }
153
154  /**
155   * Constructs a new {@code String} by decoding the bytes using the
156   * specified charset.
157   */
158  public String toString(final String charsetName)
159      throws UnsupportedEncodingException {
160    return new String(bytes, charsetName);
161  }
162
163  /**
164   * Constructs a new {@code String} by decoding the bytes as UTF-8.
165   */
166  public String toStringUtf8() {
167    try {
168      return new String(bytes, "UTF-8");
169    } catch (UnsupportedEncodingException e) {
170      throw new RuntimeException("UTF-8 not supported?");
171    }
172  }
173
174  // =================================================================
175  // equals() and hashCode()
176
177  //@Override for compatibility with Java 1.3 code we can't use annotations
178  public boolean equals(final Object o) {
179    if (o == this) {
180      return true;
181    }
182
183    if (!(o instanceof ByteStringMicro)) {
184      return false;
185    }
186
187    final ByteStringMicro other = (ByteStringMicro) o;
188    final int size = bytes.length;
189    if (size != other.bytes.length) {
190      return false;
191    }
192
193    final byte[] thisBytes = bytes;
194    final byte[] otherBytes = other.bytes;
195    for (int i = 0; i < size; i++) {
196      if (thisBytes[i] != otherBytes[i]) {
197        return false;
198      }
199    }
200
201    return true;
202  }
203
204  private volatile int hash = 0;
205
206  //@Override for compatibility with Java 1.3 code we can't use annotations
207  public int hashCode() {
208    int h = hash;
209
210    if (h == 0) {
211      final byte[] thisBytes = bytes;
212      final int size = bytes.length;
213
214      h = size;
215      for (int i = 0; i < size; i++) {
216        h = h * 31 + thisBytes[i];
217      }
218      if (h == 0) {
219        h = 1;
220      }
221
222      hash = h;
223    }
224
225    return h;
226  }
227}
228