1 /*
2 * Copyright (C) 2017 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.checkArgument;
18 import static com.google.common.base.Preconditions.checkPositionIndexes;
19
20 import com.google.errorprone.annotations.Immutable;
21 import java.nio.ByteBuffer;
22 import java.nio.charset.Charset;
23 import org.checkerframework.checker.nullness.qual.Nullable;
24
25 /**
26 * Skeleton implementation of {@link HashFunction} in terms of {@link #newHasher()}.
27 *
28 * <p>TODO(lowasser): make public
29 */
30 @Immutable
31 @ElementTypesAreNonnullByDefault
32 abstract class AbstractHashFunction implements HashFunction {
33 @Override
34 public <T extends @Nullable Object> HashCode hashObject(
35 @ParametricNullness T instance, Funnel<? super T> funnel) {
36 return newHasher().putObject(instance, funnel).hash();
37 }
38
39 @Override
40 public HashCode hashUnencodedChars(CharSequence input) {
41 int len = input.length();
42 return newHasher(len * 2).putUnencodedChars(input).hash();
43 }
44
45 @Override
46 public HashCode hashString(CharSequence input, Charset charset) {
47 return newHasher().putString(input, charset).hash();
48 }
49
50 @Override
51 public HashCode hashInt(int input) {
52 return newHasher(4).putInt(input).hash();
53 }
54
55 @Override
56 public HashCode hashLong(long input) {
57 return newHasher(8).putLong(input).hash();
58 }
59
60 @Override
61 public HashCode hashBytes(byte[] input) {
62 return hashBytes(input, 0, input.length);
63 }
64
65 @Override
66 public HashCode hashBytes(byte[] input, int off, int len) {
67 checkPositionIndexes(off, off + len, input.length);
68 return newHasher(len).putBytes(input, off, len).hash();
69 }
70
71 @Override
72 public HashCode hashBytes(ByteBuffer input) {
73 return newHasher(input.remaining()).putBytes(input).hash();
74 }
75
76 @Override
77 public Hasher newHasher(int expectedInputSize) {
78 checkArgument(
79 expectedInputSize >= 0, "expectedInputSize must be >= 0 but was %s", expectedInputSize);
80 return newHasher();
81 }
82 }