1 /*
2 * Copyright (c) 2016, 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 package jdk.jfr.internal;
27
28 import java.nio.ByteOrder;
29 import java.security.AccessController;
30 import sun.misc.Unsafe;
31
32 final class Bits { // package-private
33
34 private static final Unsafe unsafe = Unsafe.getUnsafe();
35 private static final boolean unalignedAccess = unaligned();
36 private static final boolean bigEndian = (ByteOrder.nativeOrder() == ByteOrder.BIG_ENDIAN);
37
38 private Bits() { }
39
40 private static boolean unaligned;
41 private static boolean unalignedKnown = false;
42
43 private static boolean unaligned() {
44 if (unalignedKnown)
45 return unaligned;
46 String arch = AccessController.doPrivileged(
47 new sun.security.action.GetPropertyAction("os.arch"));
48 unaligned = arch.equals("i386") || arch.equals("x86")
49 || arch.equals("amd64") || arch.equals("x86_64")
50 || arch.equals("ppc64") || arch.equals("ppc64le");
51 unalignedKnown = true;
52 return unaligned;
53 }
54
55 // -- Swapping --
56
57 private static short swap(short x) {
58 return Short.reverseBytes(x);
59 }
60
61 private static char swap(char x) {
62 return Character.reverseBytes(x);
63 }
64
65 private static int swap(int x) {
66 return Integer.reverseBytes(x);
67 }
68
69 private static long swap(long x) {
70 return Long.reverseBytes(x);
71 }
72
73 private static float swap(float x) {
74 return Float.intBitsToFloat(swap(Float.floatToIntBits(x)));
75 }
76
77 private static double swap(double x) {
78 return Double.longBitsToDouble(swap(Double.doubleToLongBits(x)));
79 }
80
81 // -- Alignment --
82
83 private static boolean isAddressAligned(long a, int datumSize) {
84 return (a & datumSize - 1) == 0;
85 }
86
87 // -- Primitives stored per byte
88
89 private static byte char1(char x) { return (byte)(x >> 8); }
90 private static byte char0(char x) { return (byte)(x ); }
91
92 private static byte short1(short x) { return (byte)(x >> 8); }
93 private static byte short0(short x) { return (byte)(x ); }
94
95 private static byte int3(int x) { return (byte)(x >> 24); }
96 private static byte int2(int x) { return (byte)(x >> 16); }
97 private static byte int1(int x) { return (byte)(x >> 8); }
98 private static byte int0(int x) { return (byte)(x ); }
99
100 private static byte long7(long x) { return (byte)(x >> 56); }
101 private static byte long6(long x) { return (byte)(x >> 48); }
102 private static byte long5(long x) { return (byte)(x >> 40); }
103 private static byte long4(long x) { return (byte)(x >> 32); }
104 private static byte long3(long x) { return (byte)(x >> 24); }
105 private static byte long2(long x) { return (byte)(x >> 16); }
106 private static byte long1(long x) { return (byte)(x >> 8); }
107 private static byte long0(long x) { return (byte)(x ); }
108
109 private static void putCharBigEndianUnaligned(long a, char x) {
110 putByte_(a , char1(x));
111 putByte_(a + 1, char0(x));
112 }
113
114 private static void putShortBigEndianUnaligned(long a, short x) {
115 putByte_(a , short1(x));
116 putByte_(a + 1, short0(x));
117 }
118
119 private static void putIntBigEndianUnaligned(long a, int x) {
120 putByte_(a , int3(x));
121 putByte_(a + 1, int2(x));
122 putByte_(a + 2, int1(x));
123 putByte_(a + 3, int0(x));
124 }
125
126 private static void putLongBigEndianUnaligned(long a, long x) {
127 putByte_(a , long7(x));
128 putByte_(a + 1, long6(x));
129 putByte_(a + 2, long5(x));
130 putByte_(a + 3, long4(x));
131 putByte_(a + 4, long3(x));
132 putByte_(a + 5, long2(x));
133 putByte_(a + 6, long1(x));
134 putByte_(a + 7, long0(x));
135 }
136
137 private static void putFloatBigEndianUnaligned(long a, float x) {
138 putIntBigEndianUnaligned(a, Float.floatToRawIntBits(x));
139 }
140
141 private static void putDoubleBigEndianUnaligned(long a, double x) {
142 putLongBigEndianUnaligned(a, Double.doubleToRawLongBits(x));
143 }
144
145 private static void putByte_(long a, byte b) {
146 unsafe.putByte(a, b);
147 }
148
149 private static void putBoolean_(long a, boolean x) {
150 unsafe.putBoolean(null, a, x);
151 }
152
153 private static void putChar_(long a, char x) {
154 unsafe.putChar(a, bigEndian ? x : swap(x));
155 }
156
157 private static void putShort_(long a, short x) {
158 unsafe.putShort(a, bigEndian ? x : swap(x));
159 }
160
161 private static void putInt_(long a, int x) {
162 unsafe.putInt(a, bigEndian ? x : swap(x));
163 }
164
165 private static void putLong_(long a, long x) {
166 unsafe.putLong(a, bigEndian ? x : swap(x));
167 }
168
169 private static void putFloat_(long a, float x) {
170 unsafe.putFloat(a, bigEndian ? x : swap(x));
171 }
172
173 private static void putDouble_(long a, double x) {
174 unsafe.putDouble(a, bigEndian ? x : swap(x));
175 }
176
177 // external api
178 static int putByte(long a, byte x) {
179 putByte_(a, x);
180 return Byte.BYTES;
181 }
182
183 static int putBoolean(long a, boolean x) {
184 putBoolean_(a, x);
185 return Byte.BYTES;
186 }
187
188 static int putChar(long a, char x) {
189 if (unalignedAccess || isAddressAligned(a, Character.BYTES)) {
190 putChar_(a, x);
191 return Character.BYTES;
192 }
193 putCharBigEndianUnaligned(a, x);
194 return Character.BYTES;
195 }
196
197 static int putShort(long a, short x) {
198 if (unalignedAccess || isAddressAligned(a, Short.BYTES)) {
199 putShort_(a, x);
200 return Short.BYTES;
201 }
202 putShortBigEndianUnaligned(a, x);
203 return Short.BYTES;
204 }
205
206 static int putInt(long a, int x) {
207 if (unalignedAccess || isAddressAligned(a, Integer.BYTES)) {
208 putInt_(a, x);
209 return Integer.BYTES;
210 }
211 putIntBigEndianUnaligned(a, x);
212 return Integer.BYTES;
213 }
214
215 static int putLong(long a, long x) {
216 if (unalignedAccess || isAddressAligned(a, Long.BYTES)) {
217 putLong_(a, x);
218 return Long.BYTES;
219 }
220 putLongBigEndianUnaligned(a, x);
221 return Long.BYTES;
222 }
223
224 static int putFloat(long a, float x) {
225 if (unalignedAccess || isAddressAligned(a, Float.BYTES)) {
226 putFloat_(a, x);
227 return Float.BYTES;
228 }
229 putFloatBigEndianUnaligned(a, x);
230 return Float.BYTES;
231 }
232
233 static int putDouble(long a, double x) {
234 if (unalignedAccess || isAddressAligned(a, Double.BYTES)) {
235 putDouble_(a, x);
236 return Double.BYTES;
237 }
238 putDoubleBigEndianUnaligned(a, x);
239 return Double.BYTES;
240 }
241 }