1 /*
2 * Copyright (c) 2019, 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.incubator.foreign;
28
29 import java.nio.ByteOrder;
30
31 /**
32 * This class defines useful layout constants. Some of the constants defined in this class are explicit in both
33 * size and byte order (see {@link #BITS_64_BE}), and can therefore be used to explicitly and unambiguously specify the
34 * contents of a memory segment. Other constants make implicit byte order assumptions (see
35 * {@link #JAVA_INT}); as such, these constants make it easy to interoperate with other serialization-centric APIs,
36 * such as {@link java.nio.ByteBuffer}.
37 */
38 public final class MemoryLayouts {
39
40 private MemoryLayouts() {
41 //just the one, please
42 }
43
44 /**
45 * A value layout constant with size of one byte, and byte order set to {@link ByteOrder#LITTLE_ENDIAN}.
46 */
47 public static final ValueLayout BITS_8_LE = MemoryLayout.ofValueBits(8, ByteOrder.LITTLE_ENDIAN);
48
49 /**
50 * A value layout constant with size of two bytes, and byte order set to {@link ByteOrder#LITTLE_ENDIAN}.
51 */
52 public static final ValueLayout BITS_16_LE = MemoryLayout.ofValueBits(16, ByteOrder.LITTLE_ENDIAN);
53
54 /**
55 * A value layout constant with size of four bytes, and byte order set to {@link ByteOrder#LITTLE_ENDIAN}.
56 */
57 public static final ValueLayout BITS_32_LE = MemoryLayout.ofValueBits(32, ByteOrder.LITTLE_ENDIAN);
58
59 /**
60 * A value layout constant with size of eight bytes, and byte order set to {@link ByteOrder#LITTLE_ENDIAN}.
61 */
62 public static final ValueLayout BITS_64_LE = MemoryLayout.ofValueBits(64, ByteOrder.LITTLE_ENDIAN);
63
64 /**
65 * A value layout constant with size of one byte, and byte order set to {@link ByteOrder#BIG_ENDIAN}.
66 */
67 public static final ValueLayout BITS_8_BE = MemoryLayout.ofValueBits(8, ByteOrder.BIG_ENDIAN);
68
69 /**
70 * A value layout constant with size of two bytes, and byte order set to {@link ByteOrder#BIG_ENDIAN}.
71 */
72 public static final ValueLayout BITS_16_BE = MemoryLayout.ofValueBits(16, ByteOrder.BIG_ENDIAN);
73
74 /**
75 * A value layout constant with size of four bytes, and byte order set to {@link ByteOrder#BIG_ENDIAN}.
76 */
77 public static final ValueLayout BITS_32_BE = MemoryLayout.ofValueBits(32, ByteOrder.BIG_ENDIAN);
78
79 /**
80 * A value layout constant with size of eight bytes, and byte order set to {@link ByteOrder#BIG_ENDIAN}.
81 */
82 public static final ValueLayout BITS_64_BE = MemoryLayout.ofValueBits(64, ByteOrder.BIG_ENDIAN);
83
84 /**
85 * A padding layout constant with size of one byte.
86 */
87 public static final MemoryLayout PAD_8 = MemoryLayout.ofPaddingBits(8);
88
89 /**
90 * A padding layout constant with size of two bytes.
91 */
92 public static final MemoryLayout PAD_16 = MemoryLayout.ofPaddingBits(16);
93
94 /**
95 * A padding layout constant with size of four bytes.
96 */
97 public static final MemoryLayout PAD_32 = MemoryLayout.ofPaddingBits(32);
98
99 /**
100 * A padding layout constant with size of eight bytes.
101 */
102 public static final MemoryLayout PAD_64 = MemoryLayout.ofPaddingBits(64);
103
104 /**
105 * A value layout constant whose size is the same as that of a Java {@code byte}, and byte order set to {@link ByteOrder#nativeOrder()}.
106 */
107 public static final ValueLayout JAVA_BYTE = MemoryLayout.ofValueBits(8, ByteOrder.nativeOrder());
108
109 /**
110 * A value layout constant whose size is the same as that of a Java {@code char}, and byte order set to {@link ByteOrder#nativeOrder()}.
111 */
112 public static final ValueLayout JAVA_CHAR = MemoryLayout.ofValueBits(16, ByteOrder.nativeOrder());
113
114 /**
115 * A value layout constant whose size is the same as that of a Java {@code short}, and byte order set to {@link ByteOrder#nativeOrder()}.
116 */
117 public static final ValueLayout JAVA_SHORT = MemoryLayout.ofValueBits(16, ByteOrder.nativeOrder());
118
119 /**
120 * A value layout constant whose size is the same as that of a Java {@code int}, and byte order set to {@link ByteOrder#nativeOrder()}.
121 */
122 public static final ValueLayout JAVA_INT = MemoryLayout.ofValueBits(32, ByteOrder.nativeOrder());
123
124 /**
125 * A value layout constant whose size is the same as that of a Java {@code long}, and byte order set to {@link ByteOrder#nativeOrder()}.
126 */
127 public static final ValueLayout JAVA_LONG = MemoryLayout.ofValueBits(64, ByteOrder.nativeOrder());
128
129 /**
130 * A value layout constant whose size is the same as that of a Java {@code float}, and byte order set to {@link ByteOrder#nativeOrder()}.
131 */
132 public static final ValueLayout JAVA_FLOAT = MemoryLayout.ofValueBits(32, ByteOrder.nativeOrder());
133
134 /**
135 * A value layout constant whose size is the same as that of a Java {@code double}, and byte order set to {@link ByteOrder#nativeOrder()}.
136 */
137 public static final ValueLayout JAVA_DOUBLE = MemoryLayout.ofValueBits(64, ByteOrder.nativeOrder());
138 }