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ByteArrayProxy.java
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112 lines (96 loc) · 3.23 KB
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/*
* Copyright © 2016-2025 The LmdbJava Open Source Project
*
* 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 org.lmdbjava;
import static java.lang.Math.min;
import static java.util.Objects.requireNonNull;
import static org.lmdbjava.Library.RUNTIME;
import java.util.Arrays;
import java.util.Comparator;
import jnr.ffi.Pointer;
import jnr.ffi.provider.MemoryManager;
/**
* Byte array proxy.
*
* <p>{@link Env#create(org.lmdbjava.BufferProxy)}.
*/
public final class ByteArrayProxy extends BufferProxy<byte[]> {
/** The byte array proxy. Guaranteed to never be null. */
public static final BufferProxy<byte[]> PROXY_BA = new ByteArrayProxy();
private static final MemoryManager MEM_MGR = RUNTIME.getMemoryManager();
private ByteArrayProxy() {}
/**
* Lexicographically compare two byte arrays.
*
* @param o1 left operand (required)
* @param o2 right operand (required)
* @return as specified by {@link Comparable} interface
*/
public static int compareLexicographically(final byte[] o1, final byte[] o2) {
requireNonNull(o1);
requireNonNull(o2);
if (o1 == o2) {
return 0;
}
final int minLength = min(o1.length, o2.length);
for (int i = 0; i < minLength; i++) {
final int lw = Byte.toUnsignedInt(o1[i]);
final int rw = Byte.toUnsignedInt(o2[i]);
final int result = Integer.compareUnsigned(lw, rw);
if (result != 0) {
return result;
}
}
return o1.length - o2.length;
}
@Override
protected byte[] allocate() {
return new byte[0];
}
@Override
protected void deallocate(final byte[] buff) {
// byte arrays cannot be allocated
}
@Override
protected byte[] getBytes(final byte[] buffer) {
return Arrays.copyOf(buffer, buffer.length);
}
@Override
public Comparator<byte[]> getComparator(final DbiFlagSet dbiFlagSet) {
return ByteArrayProxy::compareLexicographically;
}
@Override
protected Pointer in(final byte[] buffer, final Pointer ptr) {
final Pointer pointer = MEM_MGR.allocateDirect(buffer.length);
pointer.put(0, buffer, 0, buffer.length);
ptr.putLong(STRUCT_FIELD_OFFSET_SIZE, buffer.length);
ptr.putAddress(STRUCT_FIELD_OFFSET_DATA, pointer.address());
return pointer;
}
@Override
protected Pointer in(final byte[] buffer, final int size, final Pointer ptr) {
// cannot reserve for byte arrays
return null;
}
@Override
protected byte[] out(final byte[] buffer, final Pointer ptr) {
final long addr = ptr.getAddress(STRUCT_FIELD_OFFSET_DATA);
final int size = (int) ptr.getLong(STRUCT_FIELD_OFFSET_SIZE);
final Pointer pointer = MEM_MGR.newPointer(addr, size);
final byte[] bytes = new byte[size];
pointer.get(0, bytes, 0, size);
return bytes;
}
}