| /* |
| * Copyright (C) 2011 The Guava Authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except |
| * in compliance with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software distributed under the License |
| * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express |
| * or implied. See the License for the specific language governing permissions and limitations under |
| * the License. |
| */ |
| |
| package com.google.common.hash; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static com.google.common.base.Preconditions.checkNotNull; |
| |
| import com.google.errorprone.annotations.Immutable; |
| import java.nio.ByteBuffer; |
| import java.nio.charset.Charset; |
| |
| /** |
| * An abstract composition of multiple hash functions. {@linkplain #newHasher()} delegates to the |
| * {@code Hasher} objects of the delegate hash functions, and in the end, they are used by |
| * {@linkplain #makeHash(Hasher[])} that constructs the final {@code HashCode}. |
| * |
| * @author Dimitris Andreou |
| */ |
| @Immutable |
| abstract class AbstractCompositeHashFunction extends AbstractHashFunction { |
| |
| @SuppressWarnings("Immutable") // array not modified after creation |
| final HashFunction[] functions; |
| |
| AbstractCompositeHashFunction(HashFunction... functions) { |
| for (HashFunction function : functions) { |
| checkNotNull(function); |
| } |
| this.functions = functions; |
| } |
| |
| /** |
| * Constructs a {@code HashCode} from the {@code Hasher} objects of the functions. Each of them |
| * has consumed the entire input and they are ready to output a {@code HashCode}. The order of the |
| * hashers are the same order as the functions given to the constructor. |
| */ |
| // this could be cleaner if it passed HashCode[], but that would create yet another array... |
| /* protected */ abstract HashCode makeHash(Hasher[] hashers); |
| |
| @Override |
| public Hasher newHasher() { |
| Hasher[] hashers = new Hasher[functions.length]; |
| for (int i = 0; i < hashers.length; i++) { |
| hashers[i] = functions[i].newHasher(); |
| } |
| return fromHashers(hashers); |
| } |
| |
| @Override |
| public Hasher newHasher(int expectedInputSize) { |
| checkArgument(expectedInputSize >= 0); |
| Hasher[] hashers = new Hasher[functions.length]; |
| for (int i = 0; i < hashers.length; i++) { |
| hashers[i] = functions[i].newHasher(expectedInputSize); |
| } |
| return fromHashers(hashers); |
| } |
| |
| private Hasher fromHashers(final Hasher[] hashers) { |
| return new Hasher() { |
| @Override |
| public Hasher putByte(byte b) { |
| for (Hasher hasher : hashers) { |
| hasher.putByte(b); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putBytes(byte[] bytes) { |
| for (Hasher hasher : hashers) { |
| hasher.putBytes(bytes); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putBytes(byte[] bytes, int off, int len) { |
| for (Hasher hasher : hashers) { |
| hasher.putBytes(bytes, off, len); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putBytes(ByteBuffer bytes) { |
| int pos = bytes.position(); |
| for (Hasher hasher : hashers) { |
| bytes.position(pos); |
| hasher.putBytes(bytes); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putShort(short s) { |
| for (Hasher hasher : hashers) { |
| hasher.putShort(s); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putInt(int i) { |
| for (Hasher hasher : hashers) { |
| hasher.putInt(i); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putLong(long l) { |
| for (Hasher hasher : hashers) { |
| hasher.putLong(l); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putFloat(float f) { |
| for (Hasher hasher : hashers) { |
| hasher.putFloat(f); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putDouble(double d) { |
| for (Hasher hasher : hashers) { |
| hasher.putDouble(d); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putBoolean(boolean b) { |
| for (Hasher hasher : hashers) { |
| hasher.putBoolean(b); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putChar(char c) { |
| for (Hasher hasher : hashers) { |
| hasher.putChar(c); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putUnencodedChars(CharSequence chars) { |
| for (Hasher hasher : hashers) { |
| hasher.putUnencodedChars(chars); |
| } |
| return this; |
| } |
| |
| @Override |
| public Hasher putString(CharSequence chars, Charset charset) { |
| for (Hasher hasher : hashers) { |
| hasher.putString(chars, charset); |
| } |
| return this; |
| } |
| |
| @Override |
| public <T> Hasher putObject(T instance, Funnel<? super T> funnel) { |
| for (Hasher hasher : hashers) { |
| hasher.putObject(instance, funnel); |
| } |
| return this; |
| } |
| |
| @Override |
| public HashCode hash() { |
| return makeHash(hashers); |
| } |
| }; |
| } |
| |
| private static final long serialVersionUID = 0L; |
| } |