-
Notifications
You must be signed in to change notification settings - Fork 110
/
Uuids.java
70 lines (60 loc) · 2.27 KB
/
Uuids.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
/*
* Copyright (C) 2018 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.caliper.util;
import static com.google.common.base.Preconditions.checkArgument;
import java.io.EOFException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;
import java.util.UUID;
/** Utility for converting {@code UUID}s to bytes and back. */
public final class Uuids {
/** The number of bytes in a {@code UUID}. */
private static final int UUID_BYTES = 16;
private Uuids() {}
/** Returns a buffer containing the 16 bytes of the given UUID. */
public static ByteBuffer toBytes(UUID uuid) {
ByteBuffer buf = ByteBuffer.allocate(UUID_BYTES);
buf.putLong(uuid.getMostSignificantBits());
buf.putLong(uuid.getLeastSignificantBits());
buf.flip();
return buf;
}
/** Writes the bytes of the given UUID to the given channel. */
public static void writeToChannel(UUID uuid, WritableByteChannel channel) throws IOException {
ByteBuffer buf = toBytes(uuid);
while (buf.hasRemaining()) {
channel.write(buf);
}
}
/** Returns a UUID created from the first 16 bytes of the given buffer. */
public static UUID fromBytes(ByteBuffer buf) {
checkArgument(buf.remaining() >= UUID_BYTES);
return new UUID(buf.getLong(), buf.getLong());
}
/** Reads the next 16 bytes from the given channel as a UUID. */
public static UUID readFromChannel(ReadableByteChannel channel) throws IOException {
ByteBuffer buf = ByteBuffer.allocate(UUID_BYTES);
while (buf.hasRemaining()) {
if (channel.read(buf) == -1) {
throw new EOFException("unexpected EOF while reading UUID");
}
}
buf.flip();
return fromBytes(buf);
}
}