dev.cel.common.values.CelByteString Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of runtime Show documentation
Common Expression Language Runtime for Java
The newest version!
// Copyright 2023 Google LLC
//
// 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
//
//      https://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 dev.cel.common.values;

import com.google.common.base.Preconditions;
import com.google.errorprone.annotations.Immutable;
import java.util.Arrays;

/** CelByteString is an immutable sequence of a byte array. */
@Immutable
@SuppressWarnings("Immutable") // We make defensive copies on the byte array.
public final class CelByteString {
  private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
  public static final CelByteString EMPTY = new CelByteString(EMPTY_BYTE_ARRAY);

  private final byte[] data;

  private volatile int hash = 0;

  public static CelByteString of(byte[] buffer) {
    Preconditions.checkNotNull(buffer);
    if (buffer.length == 0) {
      return EMPTY;
    }
    return new CelByteString(buffer);
  }

  public int size() {
    return data.length;
  }

  public boolean isEmpty() {
    return data.length == 0;
  }

  public byte[] toByteArray() {
    int size = size();
    if (size == 0) {
      return EMPTY_BYTE_ARRAY;
    }

    return Arrays.copyOf(data, size);
  }

  private CelByteString(byte[] buffer) {
    data = Arrays.copyOf(buffer, buffer.length);
  }

  @Override
  public boolean equals(Object o) {
    if (o == this) {
      return true;
    }

    if (!(o instanceof CelByteString)) {
      return false;
    }

    return Arrays.equals(data, ((CelByteString) o).data);
  }

  /**
   * Note that we do not use Arrays.hashCode directly due to its implementation using 31 as an odd
   * prime, which is outdated and is more prone to hash collisions. This code is very similar to
   * what AutoValue generates.
   */
  @Override
  public int hashCode() {
    if (hash == 0) {
      int h = 1;
      h *= 1000003;
      h ^= Arrays.hashCode(data);
      if (h == 0) {
        h = 1;
      }
      hash = h;
    }

    return hash;
  }
}