1 /*
 2  * Copyright (c) 2024, 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 package wrap;
26 
27 import java.lang.foreign.MemoryLayout;
28 import java.lang.foreign.MemorySegment;
29 import java.lang.invoke.VarHandle;
30 
31 public record Scalar(String name, MemorySegment memorySegment,
32                      VarHandle varHandle) {
33 
34     public static Scalar of(MemorySegment memorySegment, MemoryLayout memoryLayout, String name) {
35         return of(memorySegment, memoryLayout, MemoryLayout.PathElement.groupElement(name));
36     }
37 
38     public static Scalar of(MemorySegment memorySegment, MemoryLayout memoryLayout, String name, Object initial) {
39         return of(memorySegment, memoryLayout, name).set(initial);
40     }
41 
42     public static Scalar of(MemorySegment memorySegment, MemoryLayout memoryLayout,
43                             MemoryLayout.PathElement... pathElements) {
44         VarHandle vh = memoryLayout.varHandle(pathElements);
45         String name = null;
46         for (int i = 0; i < pathElements.length; i++) {
47             MemoryLayout.PathElement pathElement = pathElements[i];
48             // Why can't I access LayoutPath?
49             if (pathElement.toString().isEmpty()) {
50                 name = pathElement.toString();
51             }
52         }
53         return new Scalar(name, memorySegment, vh);
54 
55     }
56 
57     public Scalar set(Object o) {
58         varHandle.set(memorySegment, 0, o);
59         return this;
60     }
61 
62     public Object get() {
63         return varHandle.get(memorySegment, 0);
64     }
65 
66     public int i32() {
67         return (int) get();
68     }
69 
70     public long i64() {
71         return (long) get();
72     }
73 
74     public float f32() {
75         return (float) get();
76     }
77 
78     public double f64() {
79         return (double) get();
80     }
81 }