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// Copyright 2017 Google Inc.
//
// 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.google.crypto.tink.subtle;
/**
* Immutable Wrapper around a byte array.
*
* <p>Wrap a bytearray so it prevents callers from modifying its contents. It does this by making a
* copy upon initialization, and also makes a copy if the underlying bytes are requested.
*
* @since 1.0.0
*/
public final class ImmutableByteArray {
/**
* @param data the byte array to be wrapped.
* @return an immutable wrapper around the provided bytes.
*/
public static ImmutableByteArray of(final byte[] data) {
if (data == null) {
return null;
} else {
return of(data, 0, data.length);
}
}
/**
* Wrap an immutable byte array over a slice of a bytearray
*
* @param data the byte array to be wrapped.
* @param start the starting index of the slice
* @param len the length of the slice. start + len must be less than the length of the array.
* @return an immutable wrapper around the bytes in the slice from {@code start} to {@code start +
* len}
*/
public static ImmutableByteArray of(final byte[] data, final int start, final int len) {
return new ImmutableByteArray(data, start, len);
}
/** @return a copy of the bytes wrapped by this object. */
public byte[] getBytes() {
byte[] result = new byte[data.length];
System.arraycopy(data, 0, result, 0, data.length);
return result;
}
/** @return the length of the bytes wrapped by this object. */
public int getLength() {
return data.length;
}
private ImmutableByteArray(final byte[] buf, final int start, final int len) {
data = new byte[len];
System.arraycopy(buf, start, data, 0, len);
}
private final byte[] data;
}