1 /*
2  * Copyright (c) 2001, 2010, 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 java.io;
27 
28 /**
29  * Utility methods for packing/unpacking primitive values in/out of byte arrays
30  * using big-endian byte ordering.
31  */
32 class Bits {
33 
34     /*
35      * Methods for unpacking primitive values from byte arrays starting at
36      * given offsets.
37      */
38 
getBoolean(byte[] b, int off)39     static boolean getBoolean(byte[] b, int off) {
40         return b[off] != 0;
41     }
42 
getChar(byte[] b, int off)43     static char getChar(byte[] b, int off) {
44         return (char) ((b[off + 1] & 0xFF) +
45                        (b[off] << 8));
46     }
47 
getShort(byte[] b, int off)48     static short getShort(byte[] b, int off) {
49         return (short) ((b[off + 1] & 0xFF) +
50                         (b[off] << 8));
51     }
52 
getInt(byte[] b, int off)53     static int getInt(byte[] b, int off) {
54         return ((b[off + 3] & 0xFF)      ) +
55                ((b[off + 2] & 0xFF) <<  8) +
56                ((b[off + 1] & 0xFF) << 16) +
57                ((b[off    ]       ) << 24);
58     }
59 
getFloat(byte[] b, int off)60     static float getFloat(byte[] b, int off) {
61         return Float.intBitsToFloat(getInt(b, off));
62     }
63 
getLong(byte[] b, int off)64     static long getLong(byte[] b, int off) {
65         return ((b[off + 7] & 0xFFL)      ) +
66                ((b[off + 6] & 0xFFL) <<  8) +
67                ((b[off + 5] & 0xFFL) << 16) +
68                ((b[off + 4] & 0xFFL) << 24) +
69                ((b[off + 3] & 0xFFL) << 32) +
70                ((b[off + 2] & 0xFFL) << 40) +
71                ((b[off + 1] & 0xFFL) << 48) +
72                (((long) b[off])      << 56);
73     }
74 
getDouble(byte[] b, int off)75     static double getDouble(byte[] b, int off) {
76         return Double.longBitsToDouble(getLong(b, off));
77     }
78 
79     /*
80      * Methods for packing primitive values into byte arrays starting at given
81      * offsets.
82      */
83 
putBoolean(byte[] b, int off, boolean val)84     static void putBoolean(byte[] b, int off, boolean val) {
85         b[off] = (byte) (val ? 1 : 0);
86     }
87 
putChar(byte[] b, int off, char val)88     static void putChar(byte[] b, int off, char val) {
89         b[off + 1] = (byte) (val      );
90         b[off    ] = (byte) (val >>> 8);
91     }
92 
putShort(byte[] b, int off, short val)93     static void putShort(byte[] b, int off, short val) {
94         b[off + 1] = (byte) (val      );
95         b[off    ] = (byte) (val >>> 8);
96     }
97 
putInt(byte[] b, int off, int val)98     static void putInt(byte[] b, int off, int val) {
99         b[off + 3] = (byte) (val       );
100         b[off + 2] = (byte) (val >>>  8);
101         b[off + 1] = (byte) (val >>> 16);
102         b[off    ] = (byte) (val >>> 24);
103     }
104 
putFloat(byte[] b, int off, float val)105     static void putFloat(byte[] b, int off, float val) {
106         putInt(b, off,  Float.floatToIntBits(val));
107     }
108 
putLong(byte[] b, int off, long val)109     static void putLong(byte[] b, int off, long val) {
110         b[off + 7] = (byte) (val       );
111         b[off + 6] = (byte) (val >>>  8);
112         b[off + 5] = (byte) (val >>> 16);
113         b[off + 4] = (byte) (val >>> 24);
114         b[off + 3] = (byte) (val >>> 32);
115         b[off + 2] = (byte) (val >>> 40);
116         b[off + 1] = (byte) (val >>> 48);
117         b[off    ] = (byte) (val >>> 56);
118     }
119 
putDouble(byte[] b, int off, double val)120     static void putDouble(byte[] b, int off, double val) {
121         putLong(b, off, Double.doubleToLongBits(val));
122     }
123 }
124