package net.jpountz.xxhash;
import java.util.zip.Checksum;
/*
* 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.
*/
/**
* Streaming interface for {@link XXHash64}.
* <p>
* This API is compatible with the {@link XXHash64 block API} and the following
* code samples are equivalent:
* <pre class="prettyprint">
* long hash(XXHashFactory xxhashFactory, byte[] buf, int off, int len, long seed) {
* return xxhashFactory.hash64().hash(buf, off, len, seed);
* }
* </pre>
* <pre class="prettyprint">
* long hash(XXHashFactory xxhashFactory, byte[] buf, int off, int len, long seed) {
* StreamingXXHash64 sh64 = xxhashFactory.newStreamingHash64(seed);
* sh64.update(buf, off, len);
* return sh64.getValue();
* }
* </pre>
* <p>
* Instances of this class are <b>not</b> thread-safe.
*/
public abstract class StreamingXXHash64 {
interface Factory {
StreamingXXHash64 newStreamingHash(long seed);
}
final long seed;
StreamingXXHash64(long seed) {
this.seed = seed;
}
/**
* Get the value of the checksum.
*/
public abstract long getValue();
/**
* Update the value of the hash with buf[off:off+len].
*/
public abstract void update(byte[] buf, int off, int len);
/**
* Reset this instance to the state it had right after instantiation. The
* seed remains unchanged.
*/
public abstract void reset();
@Override
public String toString() {
return getClass().getSimpleName() + "(seed=" + seed + ")";
}
/**
* Return a {@link Checksum} view of this instance. Modifications to the view
* will modify this instance too and vice-versa.
*/
public final Checksum asChecksum() {
return new Checksum() {
@Override
public long getValue() {
return StreamingXXHash64.this.getValue();
}
@Override
public void reset() {
StreamingXXHash64.this.reset();
}
@Override
public void update(int b) {
StreamingXXHash64.this.update(new byte[] {(byte) b}, 0, 1);
}
@Override
public void update(byte[] b, int off, int len) {
StreamingXXHash64.this.update(b, off, len);
}
@Override
public String toString() {
return StreamingXXHash64.this.toString();
}
};
}
}