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 @SuppressWarnings("unchecked")
57 public final L withoutName() {
58 return name.isPresent() ? dup(byteAlignment(), Optional.empty()) : (L) this;
59 }
60
61 public final Optional<String> name() {
62 return name;
63 }
64
65 public L withByteAlignment(long byteAlignment) {
66 return dup(byteAlignment, name);
67 }
68
69 public final long byteAlignment() {
70 return byteAlignment;
71 }
72
73 public final long byteSize() {
74 return byteSize;
75 }
76
77 public boolean hasNaturalAlignment() {
78 return byteSize == byteAlignment;
79 }
80
81 // the following methods have to copy the same Javadoc as in MemoryLayout, or subclasses will just show
82 // the Object methods javadoc
83
84 /**
85 * {@return the hash code value for this layout}
86 */
87 @Override
88 public int hashCode() {
89 return Objects.hash(name, byteSize, byteAlignment);
90 }
91
92 /**
93 * Compares the specified object with this layout for equality. Returns {@code true} if and only if the specified
94 * object is also a layout, and it is equal to this layout. Two layouts are considered equal if they are of
95 * the same kind, have the same size, name and alignment constraints. Furthermore, depending on the layout kind, additional
96 * conditions must be satisfied:
97 * <ul>
98 * <li>two value layouts are considered equal if they have the same {@linkplain ValueLayout#order() order},
99 * and {@linkplain ValueLayout#carrier() carrier}</li>
100 * <li>two sequence layouts are considered equal if they have the same element count (see {@link SequenceLayout#elementCount()}), and
101 * if their element layouts (see {@link SequenceLayout#elementLayout()}) are also equal</li>
102 * <li>two group layouts are considered equal if they are of the same type (see {@link StructLayout},
103 * {@link UnionLayout}) and if their member layouts (see {@link GroupLayout#memberLayouts()}) are also equal</li>
104 * </ul>
105 *
106 * @param other the object to be compared for equality with this layout.
107 * @return {@code true} if the specified object is equal to this layout.
108 */
109 @Override
110 public boolean equals(Object other) {
111 return other instanceof AbstractLayout<?> otherLayout &&
112 name.equals(otherLayout.name) &&
113 byteSize == otherLayout.byteSize &&
114 byteAlignment == otherLayout.byteAlignment;
115 }
116
117 /**
118 * {@return the string representation of this layout}
119 */
120 @Override
121 public abstract String toString();
122
123 abstract L dup(long byteAlignment, Optional<String> name);
124
125 String decorateLayoutString(String s) {
126 if (name().isPresent()) {
127 s = String.format("%s(%s)", s, name().get());
128 }
129 if (!hasNaturalAlignment()) {
130 s = byteAlignment() + "%" + s;
131 }
132 return s;
133 }
134
135 private static long requirePowerOfTwoAndGreaterOrEqualToOne(long value) {
136 if (!Utils.isPowerOfTwo(value) || // value must be a power of two
137 value < 1) { // value must be greater or equal to 1
138 throw new IllegalArgumentException("Invalid alignment: " + value);
139 }
140 return value;
141 }
142
143 }