net.jpountz.xxhash.StreamingXXHash64JNI Maven / Gradle / Ivy
package net.jpountz.xxhash;
/*
* 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.
*/
/**
* Fast {@link StreamingXXHash64} implemented with JNI bindings.
* The methods are synchronized to avoid a race condition
* between freeing the native memory in finalize() and using it in
* reset(), getValue(), and update(). Note that GC can call finalize()
* after calling checkState() and before using XXHashJNI if the caller
* does not retain a reference to this object.
*/
final class StreamingXXHash64JNI extends StreamingXXHash64 {
static class Factory implements StreamingXXHash64.Factory {
public static final StreamingXXHash64.Factory INSTANCE = new Factory();
@Override
public StreamingXXHash64 newStreamingHash(long seed) {
return new StreamingXXHash64JNI(seed);
}
}
private long state;
StreamingXXHash64JNI(long seed) {
super(seed);
state = XXHashJNI.XXH64_init(seed);
}
private void checkState() {
if (state == 0) {
throw new AssertionError("Already finalized");
}
}
@Override
public synchronized void reset() {
checkState();
XXHashJNI.XXH64_free(state);
state = XXHashJNI.XXH64_init(seed);
}
@Override
public synchronized long getValue() {
checkState();
return XXHashJNI.XXH64_digest(state);
}
@Override
public synchronized void update(byte[] bytes, int off, int len) {
checkState();
XXHashJNI.XXH64_update(state, bytes, off, len);
}
@Override
public synchronized void close() {
if (state != 0) {
super.close();
XXHashJNI.XXH64_free(state);
state = 0;
}
}
@Override
protected synchronized void finalize() throws Throwable {
super.finalize();
if (state != 0) {
// free memory
XXHashJNI.XXH64_free(state);
state = 0;
}
}
}