Coverage Summary for Class: AbstractByteHasher (com.google.common.hash)

1 /*
2  * Copyright (C) 2012 The Guava Authors
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5  * in compliance with the License. You may obtain a copy of the License at
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software distributed under the License
10  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11  * or implied. See the License for the specific language governing permissions and limitations under
12  * the License.
13  */
14 
15 package com.google.common.hash;
16 
17 import static com.google.common.base.Preconditions.checkNotNull;
18 import static com.google.common.base.Preconditions.checkPositionIndexes;
19 
20 import com.google.common.primitives.Chars;
21 import com.google.common.primitives.Ints;
22 import com.google.common.primitives.Longs;
23 import com.google.common.primitives.Shorts;
24 import com.google.errorprone.annotations.CanIgnoreReturnValue;
25 import java.nio.ByteBuffer;
26 import java.nio.ByteOrder;
27 
28 /**
29  * Abstract {@link Hasher} that handles converting primitives to bytes using a scratch {@code
30  * ByteBuffer} and streams all bytes to a sink to compute the hash.
31  *
32  * @author Colin Decker
33  */
34 @CanIgnoreReturnValue
35 @ElementTypesAreNonnullByDefault
36 abstract class AbstractByteHasher extends AbstractHasher {
37   private final ByteBuffer scratch = ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN);
38 
39   /** Updates this hasher with the given byte. */
40   protected abstract void update(byte b);
41 
42   /** Updates this hasher with the given bytes. */
43   protected void update(byte[] b) {
44     update(b, 0, b.length);
45   }
46 
47   /** Updates this hasher with {@code len} bytes starting at {@code off} in the given buffer. */
48   protected void update(byte[] b, int off, int len) {
49     for (int i = off; i < off + len; i++) {
50       update(b[i]);
51     }
52   }
53 
54   /** Updates this hasher with bytes from the given buffer. */
55   protected void update(ByteBuffer b) {
56     if (b.hasArray()) {
57       update(b.array(), b.arrayOffset() + b.position(), b.remaining());
58       Java8Compatibility.position(b, b.limit());
59     } else {
60       for (int remaining = b.remaining(); remaining > 0; remaining--) {
61         update(b.get());
62       }
63     }
64   }
65 
66   /** Updates the sink with the given number of bytes from the buffer. */
67   private Hasher update(int bytes) {
68     try {
69       update(scratch.array(), 0, bytes);
70     } finally {
71       Java8Compatibility.clear(scratch);
72     }
73     return this;
74   }
75 
76   @Override
77   public Hasher putByte(byte b) {
78     update(b);
79     return this;
80   }
81 
82   @Override
83   public Hasher putBytes(byte[] bytes) {
84     checkNotNull(bytes);
85     update(bytes);
86     return this;
87   }
88 
89   @Override
90   public Hasher putBytes(byte[] bytes, int off, int len) {
91     checkPositionIndexes(off, off + len, bytes.length);
92     update(bytes, off, len);
93     return this;
94   }
95 
96   @Override
97   public Hasher putBytes(ByteBuffer bytes) {
98     update(bytes);
99     return this;
100   }
101 
102   @Override
103   public Hasher putShort(short s) {
104     scratch.putShort(s);
105     return update(Shorts.BYTES);
106   }
107 
108   @Override
109   public Hasher putInt(int i) {
110     scratch.putInt(i);
111     return update(Ints.BYTES);
112   }
113 
114   @Override
115   public Hasher putLong(long l) {
116     scratch.putLong(l);
117     return update(Longs.BYTES);
118   }
119 
120   @Override
121   public Hasher putChar(char c) {
122     scratch.putChar(c);
123     return update(Chars.BYTES);
124   }
125 }