net.jpountz.util.UnsafeUtils Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of lz4 Show documentation
Java ports and bindings of the LZ4 compression algorithm and the xxHash hashing algorithm
There is a newer version: 1.5.0
package net.jpountz.util;

/*
 * 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.
 */

import static net.jpountz.util.Utils.NATIVE_BYTE_ORDER;

import java.lang.reflect.Field;
import java.nio.ByteOrder;

import sun.misc.Unsafe;

public enum UnsafeUtils {
  ;

  private static final Unsafe UNSAFE;
  private static final long BYTE_ARRAY_OFFSET;
  private static final int BYTE_ARRAY_SCALE;
  private static final long INT_ARRAY_OFFSET;
  private static final int INT_ARRAY_SCALE;
  private static final long SHORT_ARRAY_OFFSET;
  private static final int SHORT_ARRAY_SCALE;
  
  static {
    try {
      Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
      theUnsafe.setAccessible(true);
      UNSAFE = (Unsafe) theUnsafe.get(null);
      BYTE_ARRAY_OFFSET = UNSAFE.arrayBaseOffset(byte[].class);
      BYTE_ARRAY_SCALE = UNSAFE.arrayIndexScale(byte[].class);
      INT_ARRAY_OFFSET = UNSAFE.arrayBaseOffset(int[].class);
      INT_ARRAY_SCALE = UNSAFE.arrayIndexScale(int[].class);
      SHORT_ARRAY_OFFSET = UNSAFE.arrayBaseOffset(short[].class);
      SHORT_ARRAY_SCALE = UNSAFE.arrayIndexScale(short[].class);
    } catch (IllegalAccessException e) {
      throw new ExceptionInInitializerError("Cannot access Unsafe");
    } catch (NoSuchFieldException e) {
      throw new ExceptionInInitializerError("Cannot access Unsafe");
    } catch (SecurityException e) {
      throw new ExceptionInInitializerError("Cannot access Unsafe");
    }
  }

  public static void checkRange(byte[] buf, int off) {
    SafeUtils.checkRange(buf, off);
  }

  public static void checkRange(byte[] buf, int off, int len) {
    SafeUtils.checkRange(buf, off, len);
  }

  public static void checkLength(int len) {
    SafeUtils.checkLength(len);
  }

  public static byte readByte(byte[] src, int srcOff) {
    return UNSAFE.getByte(src, BYTE_ARRAY_OFFSET + BYTE_ARRAY_SCALE * srcOff);
  }

  public static void writeByte(byte[] src, int srcOff, byte value) {
    UNSAFE.putByte(src, BYTE_ARRAY_OFFSET + BYTE_ARRAY_SCALE * srcOff, (byte) value);
  }

  public static void writeByte(byte[] src, int srcOff, int value) {
    writeByte(src, srcOff, (byte) value);
  }

  public static long readLong(byte[] src, int srcOff) {
    return UNSAFE.getLong(src, BYTE_ARRAY_OFFSET + srcOff);
  }

  public static long readLongLE(byte[] src, int srcOff) {
    long i = readLong(src, srcOff);
    if (NATIVE_BYTE_ORDER == ByteOrder.BIG_ENDIAN) {
      i = Long.reverseBytes(i);
    }
    return i;
  }

  public static void writeLong(byte[] dest, int destOff, long value) {
    UNSAFE.putLong(dest, BYTE_ARRAY_OFFSET + destOff, value);
  }

  public static int readInt(byte[] src, int srcOff) {
    return UNSAFE.getInt(src, BYTE_ARRAY_OFFSET + srcOff);
  }

  public static int readIntLE(byte[] src, int srcOff) {
    int i = readInt(src, srcOff);
    if (NATIVE_BYTE_ORDER == ByteOrder.BIG_ENDIAN) {
      i = Integer.reverseBytes(i);
    }
    return i;
  }

  public static void writeInt(byte[] dest, int destOff, int value) {
    UNSAFE.putInt(dest, BYTE_ARRAY_OFFSET + destOff, value);
  }

  public static short readShort(byte[] src, int srcOff) {
    return UNSAFE.getShort(src, BYTE_ARRAY_OFFSET + srcOff);
  }

  public static int readShortLE(byte[] src, int srcOff) {
    short s = readShort(src, srcOff);
    if (NATIVE_BYTE_ORDER == ByteOrder.BIG_ENDIAN) {
      s = Short.reverseBytes(s);
    }
    return s & 0xFFFF;
  }

  public static void writeShort(byte[] dest, int destOff, short value) {
    UNSAFE.putShort(dest, BYTE_ARRAY_OFFSET + destOff, value);
  }

  public static void writeShortLE(byte[] buf, int off, int v) {
    writeByte(buf, off, (byte) v);
    writeByte(buf, off + 1, (byte) (v >>> 8));
  }

  public static int readInt(int[] src, int srcOff) {
    return UNSAFE.getInt(src, INT_ARRAY_OFFSET + INT_ARRAY_SCALE * srcOff);
  }

  public static void writeInt(int[] dest, int destOff, int value) {
    UNSAFE.putInt(dest, INT_ARRAY_OFFSET + INT_ARRAY_SCALE * destOff, value);
  }

  public static int readShort(short[] src, int srcOff) {
    return UNSAFE.getShort(src, SHORT_ARRAY_OFFSET + SHORT_ARRAY_SCALE * srcOff) & 0xFFFF;
  }

  public static void writeShort(short[] dest, int destOff, int value) {
    UNSAFE.putShort(dest, SHORT_ARRAY_OFFSET + SHORT_ARRAY_SCALE * destOff, (short) value);
  }
}