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1   /*
2    * Copyright 2018 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   https://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.channel.unix;
17  
18  import io.netty.util.internal.PlatformDependent;
19  import io.netty.util.internal.UnstableApi;
20  
21  import java.nio.ByteBuffer;
22  import java.nio.ByteOrder;
23  
24  @UnstableApi
25  public final class Buffer {
26  
27      private Buffer() { }
28  
29      /**
30       * Free the direct {@link ByteBuffer}.
31       */
32      public static void free(ByteBuffer buffer) {
33          PlatformDependent.freeDirectBuffer(buffer);
34      }
35  
36      /**
37       * Returns a new {@link ByteBuffer} which has the same {@link ByteOrder} as the native order of the machine.
38       */
39      public static ByteBuffer allocateDirectWithNativeOrder(int capacity) {
40          return ByteBuffer.allocateDirect(capacity).order(
41                  PlatformDependent.BIG_ENDIAN_NATIVE_ORDER ? ByteOrder.BIG_ENDIAN : ByteOrder.LITTLE_ENDIAN);
42      }
43  
44      /**
45       * Returns the memory address of the given direct {@link ByteBuffer}.
46       */
47      public static long memoryAddress(ByteBuffer buffer) {
48          assert buffer.isDirect();
49          if (PlatformDependent.hasUnsafe()) {
50              return PlatformDependent.directBufferAddress(buffer);
51          }
52          return memoryAddress0(buffer);
53      }
54  
55      /**
56       * Returns the size of a pointer.
57       */
58      public static int addressSize() {
59          if (PlatformDependent.hasUnsafe()) {
60              return PlatformDependent.addressSize();
61          }
62          return addressSize0();
63      }
64  
65      // If Unsafe can not be used we will need to do JNI calls.
66      private static native int addressSize0();
67      private static native long memoryAddress0(ByteBuffer buffer);
68  }