1 /*
2 * Copyright (c) 2016, 2018, 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.jfr.internal;
27
28 import jdk.internal.misc.Unsafe;
29
30 final class Bits { // package-private
31
32 private static final Unsafe unsafe = Unsafe.getUnsafe();
33 private static final boolean unalignedAccess = unsafe.unalignedAccess();
34 private static final boolean bigEndian = unsafe.isBigEndian();
35
36 private Bits() { }
37
38 // -- Swapping --
39
40 private static short swap(short x) {
41 return Short.reverseBytes(x);
42 }
43
44 private static char swap(char x) {
45 return Character.reverseBytes(x);
46 }
47
48 private static int swap(int x) {
49 return Integer.reverseBytes(x);
50 }
51
52 private static long swap(long x) {
53 return Long.reverseBytes(x);
54 }
55
56 private static float swap(float x) {
57 return Float.intBitsToFloat(swap(Float.floatToIntBits(x)));
58 }
59
60 private static double swap(double x) {
61 return Double.longBitsToDouble(swap(Double.doubleToLongBits(x)));
62 }
63
64 // -- Alignment --
65
66 private static boolean isAddressAligned(long a, int datumSize) {
67 return (a & datumSize - 1) == 0;
68 }
69
70 // -- Primitives stored per byte
71
72 private static byte char1(char x) { return (byte)(x >> 8); }
73 private static byte char0(char x) { return (byte)(x ); }
74
75 private static byte short1(short x) { return (byte)(x >> 8); }
76 private static byte short0(short x) { return (byte)(x ); }
77
78 private static byte int3(int x) { return (byte)(x >> 24); }
79 private static byte int2(int x) { return (byte)(x >> 16); }
80 private static byte int1(int x) { return (byte)(x >> 8); }
81 private static byte int0(int x) { return (byte)(x ); }
82
83 private static byte long7(long x) { return (byte)(x >> 56); }
84 private static byte long6(long x) { return (byte)(x >> 48); }
85 private static byte long5(long x) { return (byte)(x >> 40); }
86 private static byte long4(long x) { return (byte)(x >> 32); }
87 private static byte long3(long x) { return (byte)(x >> 24); }
88 private static byte long2(long x) { return (byte)(x >> 16); }
89 private static byte long1(long x) { return (byte)(x >> 8); }
90 private static byte long0(long x) { return (byte)(x ); }
91
92 private static void putCharBigEndianUnaligned(long a, char x) {
93 putByte_(a , char1(x));
94 putByte_(a + 1, char0(x));
95 }
96
97 private static void putShortBigEndianUnaligned(long a, short x) {
98 putByte_(a , short1(x));
99 putByte_(a + 1, short0(x));
100 }
101
102 private static void putIntBigEndianUnaligned(long a, int x) {
103 putByte_(a , int3(x));
104 putByte_(a + 1, int2(x));
105 putByte_(a + 2, int1(x));
106 putByte_(a + 3, int0(x));
107 }
108
109 private static void putLongBigEndianUnaligned(long a, long x) {
110 putByte_(a , long7(x));
111 putByte_(a + 1, long6(x));
112 putByte_(a + 2, long5(x));
113 putByte_(a + 3, long4(x));
114 putByte_(a + 4, long3(x));
115 putByte_(a + 5, long2(x));
116 putByte_(a + 6, long1(x));
117 putByte_(a + 7, long0(x));
118 }
119
120 private static void putFloatBigEndianUnaligned(long a, float x) {
121 putIntBigEndianUnaligned(a, Float.floatToRawIntBits(x));
122 }
123
124 private static void putDoubleBigEndianUnaligned(long a, double x) {
125 putLongBigEndianUnaligned(a, Double.doubleToRawLongBits(x));
126 }
127
128 private static void putByte_(long a, byte b) {
129 unsafe.putByte(a, b);
130 }
131
132 private static void putBoolean_(long a, boolean x) {
133 unsafe.putBoolean(null, a, x);
134 }
135
136 private static void putChar_(long a, char x) {
137 unsafe.putChar(a, bigEndian ? x : swap(x));
138 }
139
140 private static void putShort_(long a, short x) {
141 unsafe.putShort(a, bigEndian ? x : swap(x));
142 }
143
144 private static void putInt_(long a, int x) {
145 unsafe.putInt(a, bigEndian ? x : swap(x));
146 }
147
148 private static void putLong_(long a, long x) {
149 unsafe.putLong(a, bigEndian ? x : swap(x));
150 }
151
152 private static void putFloat_(long a, float x) {
153 unsafe.putFloat(a, bigEndian ? x : swap(x));
154 }
155
156 private static void putDouble_(long a, double x) {
157 unsafe.putDouble(a, bigEndian ? x : swap(x));
158 }
159
160 // external api
161 static int putByte(long a, byte x) {
162 putByte_(a, x);
163 return Byte.BYTES;
164 }
165
166 static int putBoolean(long a, boolean x) {
167 putBoolean_(a, x);
168 return Byte.BYTES;
169 }
170
171 static int putChar(long a, char x) {
172 if (unalignedAccess || isAddressAligned(a, Character.BYTES)) {
173 putChar_(a, x);
174 return Character.BYTES;
175 }
176 putCharBigEndianUnaligned(a, x);
177 return Character.BYTES;
178 }
179
180 static int putShort(long a, short x) {
181 if (unalignedAccess || isAddressAligned(a, Short.BYTES)) {
182 putShort_(a, x);
183 return Short.BYTES;
184 }
185 putShortBigEndianUnaligned(a, x);
186 return Short.BYTES;
187 }
188
189 static int putInt(long a, int x) {
190 if (unalignedAccess || isAddressAligned(a, Integer.BYTES)) {
191 putInt_(a, x);
192 return Integer.BYTES;
193 }
194 putIntBigEndianUnaligned(a, x);
195 return Integer.BYTES;
196 }
197
198 static int putLong(long a, long x) {
199 if (unalignedAccess || isAddressAligned(a, Long.BYTES)) {
200 putLong_(a, x);
201 return Long.BYTES;
202 }
203 putLongBigEndianUnaligned(a, x);
204 return Long.BYTES;
205 }
206
207 static int putFloat(long a, float x) {
208 if (unalignedAccess || isAddressAligned(a, Float.BYTES)) {
209 putFloat_(a, x);
210 return Float.BYTES;
211 }
212 putFloatBigEndianUnaligned(a, x);
213 return Float.BYTES;
214 }
215
216 static int putDouble(long a, double x) {
217 if (unalignedAccess || isAddressAligned(a, Double.BYTES)) {
218 putDouble_(a, x);
219 return Double.BYTES;
220 }
221 putDoubleBigEndianUnaligned(a, x);
222 return Double.BYTES;
223 }
224 }