com.scurrilous.circe.impl.AbstractStatefulHash Maven / Gradle / Ivy
/*******************************************************************************
* Copyright 2014 Trevor Robinson
*
* 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.scurrilous.circe.impl;
import java.nio.ByteBuffer;
import com.scurrilous.circe.StatefulHash;
/**
* Base implementation for stateful hash functions.
*/
public abstract class AbstractStatefulHash implements StatefulHash {
@Override
public boolean supportsUnsafe() {
return false;
}
@Override
public void update(byte[] input) {
updateUnchecked(input, 0, input.length);
}
@Override
public void update(byte[] input, int index, int length) {
if (length < 0)
throw new IllegalArgumentException();
if (index < 0 || index + length > input.length)
throw new IndexOutOfBoundsException();
updateUnchecked(input, index, length);
}
@Override
public void update(ByteBuffer input) {
final byte[] array;
final int index;
final int length = input.remaining();
if (input.hasArray()) {
array = input.array();
index = input.arrayOffset() + input.position();
input.position(input.limit());
} else {
// convert to unsafe access if possible
if (input.isDirect() && supportsUnsafe()) {
long address = DirectByteBufferAccessLoader.getAddress(input);
if (address != 0) {
address += input.position();
input.position(input.limit());
update(address, length);
return;
}
}
array = new byte[length];
index = 0;
input.get(array);
}
updateUnchecked(array, index, length);
}
@Override
public void update(long address, long length) {
throw new UnsupportedOperationException();
}
/**
* Updates the state of this hash function with the given range of the given
* input array. The index and length parameters have already been validated.
*
* @param input the input array
* @param index the starting index of the first input byte
* @param length the length of the input range
*/
protected abstract void updateUnchecked(byte[] input, int index, int length);
@Override
public byte[] getBytes() {
final byte[] array = new byte[length()];
writeBytes(array, 0, array.length);
return array;
}
@Override
public int getBytes(byte[] output, int index, int maxLength) {
if (maxLength < 0)
throw new IllegalArgumentException();
if (index < 0 || index + maxLength > output.length)
throw new IndexOutOfBoundsException();
final int length = Math.min(maxLength, length());
writeBytes(output, index, length);
return length;
}
/**
* Writes the output of this hash function into the given range of the given
* byte array. The inputs have already been validated.
*
* @param output the destination array for the output
* @param index the starting index of the first output byte
* @param length the number of bytes to write
*/
protected void writeBytes(byte[] output, int index, int length) {
long temp = getLong();
for (int i = 0; i < length; ++i) {
output[index + i] = (byte) temp;
temp >>>= 8;
}
}
@Override
public byte getByte() {
return (byte) getInt();
}
@Override
public short getShort() {
return (short) getInt();
}
}