| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you 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.apache.impala.util; |
| |
| import java.lang.reflect.Field; |
| import java.security.AccessController; |
| import java.security.PrivilegedAction; |
| |
| import sun.misc.Unsafe; |
| |
| @SuppressWarnings("restriction") |
| /** |
| * Utility class to access unsafe methods. |
| */ |
| public class UnsafeUtil { |
| // object to allow us to use unsafe APIs. This lets us read native memory without |
| // copies and not have to switch back and forth between little endian and big endian. |
| public static final Unsafe UNSAFE; |
| |
| // This is the offset to the start of the array data. (There's some bytes |
| // before the array data like the size and other java stuff). |
| private static final int BYTE_ARRAY_DATA_OFFSET; |
| |
| static { |
| UNSAFE = (Unsafe) AccessController.doPrivileged( |
| new PrivilegedAction<Object>() { |
| @Override |
| public Object run() { |
| try { |
| Field f = Unsafe.class.getDeclaredField("theUnsafe"); |
| f.setAccessible(true); |
| return f.get(null); |
| } catch (NoSuchFieldException e) { |
| throw new Error(); |
| } catch (IllegalAccessException e) { |
| throw new Error(); |
| } |
| } |
| }); |
| |
| BYTE_ARRAY_DATA_OFFSET = UNSAFE.arrayBaseOffset(byte[].class); |
| } |
| |
| // Copies src[srcOffset, srcOffset + len) into dst. |
| public static void Copy(long dst, byte[] src, int srcOffset, int len) { |
| UNSAFE.copyMemory(src, BYTE_ARRAY_DATA_OFFSET + srcOffset, null, dst, len); |
| } |
| |
| // Copies src[0, len) into dst[dstOffset, dstOffset + len). |
| public static void Copy(byte[] dst, int dstOffset, long src, int len) { |
| UNSAFE.copyMemory(null, src, dst, dstOffset + BYTE_ARRAY_DATA_OFFSET, len); |
| } |
| } |