1 /*
2 * Copyright (c) 2019, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 *
25 */
26
27 package jdk.internal.foreign;
28
29 import jdk.incubator.foreign.MemorySegment;
30 import jdk.internal.access.JavaNioAccess;
31 import jdk.internal.access.SharedSecrets;
32 import jdk.internal.access.foreign.UnmapperProxy;
33 import jdk.internal.misc.Unsafe;
34 import sun.nio.ch.FileChannelImpl;
35 import sun.security.action.GetBooleanAction;
36
37 import java.io.IOException;
38 import java.nio.ByteBuffer;
39 import java.nio.channels.FileChannel;
40 import java.nio.file.OpenOption;
41 import java.nio.file.Path;
42 import java.nio.file.StandardOpenOption;
43 import java.util.function.Supplier;
44
45 /**
46 * This class contains misc helper functions to support creation of memory segments.
47 */
48 public final class Utils {
49
50 private static Unsafe unsafe = Unsafe.getUnsafe();
51
52 // The maximum alignment supported by malloc - typically 16 on
53 // 64-bit platforms and 8 on 32-bit platforms.
54 private final static long MAX_ALIGN = Unsafe.ADDRESS_SIZE == 4 ? 8 : 16;
55
56 private static final JavaNioAccess javaNioAccess = SharedSecrets.getJavaNioAccess();
57
58 private static final boolean skipZeroMemory = GetBooleanAction.privilegedGetProperty("jdk.internal.foreign.skipZeroMemory");
59
60 public static long alignUp(long n, long alignment) {
61 return (n + alignment - 1) & -alignment;
62 }
63
64 public static long bitsToBytesOrThrow(long bits, Supplier<RuntimeException> exFactory) {
65 if (bits % 8 == 0) {
66 return bits / 8;
67 } else {
68 throw exFactory.get();
69 }
70 }
71
72 // segment factories
73
74 public static MemorySegment makeNativeSegment(long bytesSize, long alignmentBytes) {
75 long alignedSize = bytesSize;
76
77 if (alignmentBytes > MAX_ALIGN) {
78 alignedSize = bytesSize + (alignmentBytes - 1);
79 }
80
81 long buf = unsafe.allocateMemory(alignedSize);
82 if (!skipZeroMemory) {
83 unsafe.setMemory(buf, alignedSize, (byte)0);
84 }
85 long alignedBuf = Utils.alignUp(buf, alignmentBytes);
86 MemoryScope scope = new MemoryScope(null, () -> unsafe.freeMemory(buf));
87 MemorySegment segment = new MemorySegmentImpl(buf, null, alignedSize, 0, Thread.currentThread(), scope);
88 if (alignedBuf != buf) {
89 long delta = alignedBuf - buf;
90 segment = segment.asSlice(delta, bytesSize);
91 }
92 return segment;
93 }
94
95 public static MemorySegment makeArraySegment(byte[] arr) {
96 return makeArraySegment(arr, arr.length, Unsafe.ARRAY_BYTE_BASE_OFFSET, Unsafe.ARRAY_BYTE_INDEX_SCALE);
97 }
98
99 public static MemorySegment makeArraySegment(char[] arr) {
100 return makeArraySegment(arr, arr.length, Unsafe.ARRAY_CHAR_BASE_OFFSET, Unsafe.ARRAY_CHAR_INDEX_SCALE);
101 }
102
103 public static MemorySegment makeArraySegment(short[] arr) {
104 return makeArraySegment(arr, arr.length, Unsafe.ARRAY_SHORT_BASE_OFFSET, Unsafe.ARRAY_SHORT_INDEX_SCALE);
105 }
106
107 public static MemorySegment makeArraySegment(int[] arr) {
108 return makeArraySegment(arr, arr.length, Unsafe.ARRAY_INT_BASE_OFFSET, Unsafe.ARRAY_INT_INDEX_SCALE);
109 }
110
111 public static MemorySegment makeArraySegment(float[] arr) {
112 return makeArraySegment(arr, arr.length, Unsafe.ARRAY_FLOAT_BASE_OFFSET, Unsafe.ARRAY_FLOAT_INDEX_SCALE);
113 }
114
115 public static MemorySegment makeArraySegment(long[] arr) {
116 return makeArraySegment(arr, arr.length, Unsafe.ARRAY_LONG_BASE_OFFSET, Unsafe.ARRAY_LONG_INDEX_SCALE);
117 }
118
119 public static MemorySegment makeArraySegment(double[] arr) {
120 return makeArraySegment(arr, arr.length, Unsafe.ARRAY_DOUBLE_BASE_OFFSET, Unsafe.ARRAY_DOUBLE_INDEX_SCALE);
121 }
122
123 private static MemorySegment makeArraySegment(Object arr, int size, int base, int scale) {
124 MemoryScope scope = new MemoryScope(null, null);
125 return new MemorySegmentImpl(base, arr, size * scale, 0, Thread.currentThread(), scope);
126 }
127
128 public static MemorySegment makeBufferSegment(ByteBuffer bb) {
129 long bbAddress = javaNioAccess.getBufferAddress(bb);
130 Object base = javaNioAccess.getBufferBase(bb);
131
132 int pos = bb.position();
133 int limit = bb.limit();
134
135 MemoryScope bufferScope = new MemoryScope(bb, null);
136 return new MemorySegmentImpl(bbAddress + pos, base, limit - pos, 0, Thread.currentThread(), bufferScope);
137 }
138
139 // create and map a file into a fresh segment
140 public static MemorySegment makeMappedSegment(Path path, long bytesSize, FileChannel.MapMode mapMode) throws IOException {
141 if (bytesSize <= 0) throw new IllegalArgumentException("Requested bytes size must be > 0.");
142 try (FileChannelImpl channelImpl = (FileChannelImpl)FileChannel.open(path, openOptions(mapMode))) {
143 UnmapperProxy unmapperProxy = channelImpl.mapInternal(mapMode, 0L, bytesSize);
144 MemoryScope scope = new MemoryScope(null, unmapperProxy::unmap);
145 return new MemorySegmentImpl(unmapperProxy.address(), null, bytesSize, 0, Thread.currentThread(), scope);
146 }
147 }
148
149 private static OpenOption[] openOptions(FileChannel.MapMode mapMode) {
150 if (mapMode == FileChannel.MapMode.READ_ONLY) {
151 return new OpenOption[] { StandardOpenOption.READ };
152 } else if (mapMode == FileChannel.MapMode.READ_WRITE || mapMode == FileChannel.MapMode.PRIVATE) {
153 return new OpenOption[] { StandardOpenOption.READ, StandardOpenOption.WRITE };
154 } else {
155 throw new UnsupportedOperationException("Unsupported map mode: " + mapMode);
156 }
157 }
158 }