/*
 * Copyright (C) 2017 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.checkPositionIndexes;

import com.google.errorprone.annotations.Immutable;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;

Skeleton implementation of HashFunction in terms of HashFunction.newHasher().

TODO(lowasser): make public

/** * Skeleton implementation of {@link HashFunction} in terms of {@link #newHasher()}. * * <p>TODO(lowasser): make public */
@Immutable abstract class AbstractHashFunction implements HashFunction { @Override public <T> HashCode hashObject(T instance, Funnel<? super T> funnel) { return newHasher().putObject(instance, funnel).hash(); } @Override public HashCode hashUnencodedChars(CharSequence input) { int len = input.length(); return newHasher(len * 2).putUnencodedChars(input).hash(); } @Override public HashCode hashString(CharSequence input, Charset charset) { return newHasher().putString(input, charset).hash(); } @Override public HashCode hashInt(int input) { return newHasher(4).putInt(input).hash(); } @Override public HashCode hashLong(long input) { return newHasher(8).putLong(input).hash(); } @Override public HashCode hashBytes(byte[] input) { return hashBytes(input, 0, input.length); } @Override public HashCode hashBytes(byte[] input, int off, int len) { checkPositionIndexes(off, off + len, input.length); return newHasher(len).putBytes(input, off, len).hash(); } @Override public HashCode hashBytes(ByteBuffer input) { return newHasher(input.remaining()).putBytes(input).hash(); } @Override public Hasher newHasher(int expectedInputSize) { checkArgument( expectedInputSize >= 0, "expectedInputSize must be >= 0 but was %s", expectedInputSize); return newHasher(); } }