1 /*
2 * Copyright (c) 2019, 2023, 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 package jdk.internal.foreign.layout;
27
28 import jdk.internal.foreign.Utils;
29
30 import java.lang.foreign.GroupLayout;
31 import java.lang.foreign.MemoryLayout;
32 import java.lang.foreign.SequenceLayout;
33 import java.lang.foreign.StructLayout;
34 import java.lang.foreign.UnionLayout;
35 import java.lang.foreign.ValueLayout;
36 import java.util.Objects;
37 import java.util.Optional;
38
39 public abstract sealed class AbstractLayout<L extends AbstractLayout<L> & MemoryLayout>
40 permits AbstractGroupLayout, PaddingLayoutImpl, SequenceLayoutImpl, ValueLayouts.AbstractValueLayout {
41
42 private final long byteSize;
43 private final long byteAlignment;
44 private final Optional<String> name;
45
46 AbstractLayout(long byteSize, long byteAlignment, Optional<String> name) {
47 this.byteSize = MemoryLayoutUtil.requireByteSizeValid(byteSize, true);
48 this.byteAlignment = requirePowerOfTwoAndGreaterOrEqualToOne(byteAlignment);
49 this.name = Objects.requireNonNull(name);
50 }
51
52 public final L withName(String name) {
53 return dup(byteAlignment(), Optional.of(name));
54 }
55
56 public final L withoutName() {
57 return dup(byteAlignment(), Optional.empty());
58 }
59
60 public final Optional<String> name() {
61 return name;
62 }
63
64 public L withByteAlignment(long byteAlignment) {
65 return dup(byteAlignment, name);
66 }
67
68 public final long byteAlignment() {
69 return byteAlignment;
70 }
71
72 public final long byteSize() {
73 return byteSize;
74 }
75
76 public boolean hasNaturalAlignment() {
77 return byteSize == byteAlignment;
78 }
79
80 // the following methods have to copy the same Javadoc as in MemoryLayout, or subclasses will just show
81 // the Object methods javadoc
82
83 /**
84 * {@return the hash code value for this layout}
85 */
86 @Override
87 public int hashCode() {
88 return Objects.hash(name, byteSize, byteAlignment);
89 }
90
91 /**
92 * Compares the specified object with this layout for equality. Returns {@code true} if and only if the specified
93 * object is also a layout, and it is equal to this layout. Two layouts are considered equal if they are of
94 * the same kind, have the same size, name and alignment constraints. Furthermore, depending on the layout kind, additional
95 * conditions must be satisfied:
96 * <ul>
97 * <li>two value layouts are considered equal if they have the same {@linkplain ValueLayout#order() order},
98 * and {@linkplain ValueLayout#carrier() carrier}</li>
99 * <li>two sequence layouts are considered equal if they have the same element count (see {@link SequenceLayout#elementCount()}), and
100 * if their element layouts (see {@link SequenceLayout#elementLayout()}) are also equal</li>
101 * <li>two group layouts are considered equal if they are of the same type (see {@link StructLayout},
102 * {@link UnionLayout}) and if their member layouts (see {@link GroupLayout#memberLayouts()}) are also equal</li>
103 * </ul>
104 *
105 * @param other the object to be compared for equality with this layout.
106 * @return {@code true} if the specified object is equal to this layout.
107 */
108 @Override
109 public boolean equals(Object other) {
110 return other instanceof AbstractLayout<?> otherLayout &&
111 name.equals(otherLayout.name) &&
112 byteSize == otherLayout.byteSize &&
113 byteAlignment == otherLayout.byteAlignment;
114 }
115
116 /**
117 * {@return the string representation of this layout}
118 */
119 @Override
120 public abstract String toString();
121
122 abstract L dup(long byteAlignment, Optional<String> name);
123
124 String decorateLayoutString(String s) {
125 if (name().isPresent()) {
126 s = String.format("%s(%s)", s, name().get());
127 }
128 if (!hasNaturalAlignment()) {
129 s = byteAlignment() + "%" + s;
130 }
131 return s;
132 }
133
134 private static long requirePowerOfTwoAndGreaterOrEqualToOne(long value) {
135 if (!Utils.isPowerOfTwo(value) || // value must be a power of two
136 value < 1) { // value must be greater or equal to 1
137 throw new IllegalArgumentException("Invalid alignment: " + value);
138 }
139 return value;
140 }
141
142 }