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* 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;

}