125 lines
2.8 KiB
Java
125 lines
2.8 KiB
Java
/*
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* Copyright (C) 2012 The Guava Authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.common.hash;
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import static com.google.common.base.Preconditions.checkNotNull;
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import static com.google.common.base.Preconditions.checkPositionIndexes;
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import java.nio.ByteBuffer;
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import java.nio.ByteOrder;
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import com.google.common.primitives.Chars;
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import com.google.common.primitives.Ints;
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import com.google.common.primitives.Longs;
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import com.google.common.primitives.Shorts;
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/**
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* Abstract {@link Hasher} that handles converting primitives to bytes using a
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* scratch {@code
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* ByteBuffer} and streams all bytes to a sink to compute the hash.
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*
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* @author Colin Decker
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*/
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abstract class AbstractByteHasher extends AbstractHasher {
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private final ByteBuffer scratch = ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN);
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/**
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* Updates this hasher with the given byte.
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*/
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protected abstract void update(byte b);
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/**
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* Updates this hasher with the given bytes.
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*/
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protected void update(byte[] b) {
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update(b, 0, b.length);
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}
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/**
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* Updates this hasher with {@code len} bytes starting at {@code off} in the
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* given buffer.
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*/
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protected void update(byte[] b, int off, int len) {
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for (int i = off; i < off + len; i++) {
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update(b[i]);
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}
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}
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@Override
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public Hasher putByte(byte b) {
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update(b);
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return this;
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}
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@Override
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public Hasher putBytes(byte[] bytes) {
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checkNotNull(bytes);
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update(bytes);
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return this;
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}
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@Override
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public Hasher putBytes(byte[] bytes, int off, int len) {
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checkPositionIndexes(off, off + len, bytes.length);
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update(bytes, off, len);
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return this;
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}
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/**
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* Updates the sink with the given number of bytes from the buffer.
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*/
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private Hasher update(int bytes) {
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try {
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update(scratch.array(), 0, bytes);
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} finally {
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scratch.clear();
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}
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return this;
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}
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@Override
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public Hasher putShort(short s) {
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scratch.putShort(s);
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return update(Shorts.BYTES);
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}
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@Override
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public Hasher putInt(int i) {
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scratch.putInt(i);
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return update(Ints.BYTES);
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}
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@Override
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public Hasher putLong(long l) {
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scratch.putLong(l);
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return update(Longs.BYTES);
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}
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@Override
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public Hasher putChar(char c) {
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scratch.putChar(c);
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return update(Chars.BYTES);
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}
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@Override
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public <T> Hasher putObject(T instance, Funnel<? super T> funnel) {
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funnel.funnel(instance, this);
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return this;
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}
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}
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