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