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
26package java.io;
27
28/**
29 * Utility methods for packing/unpacking primitive values in/out of byte arrays
30 * using big-endian byte ordering.
31 */
32class Bits {
33
34    /*
35     * Methods for unpacking primitive values from byte arrays starting at
36     * given offsets.
37     */
38
39    static boolean getBoolean(byte[] b, int off) {
40        return b[off] != 0;
41    }
42
43    static char getChar(byte[] b, int off) {
44        return (char) ((b[off + 1] & 0xFF) +
45                       (b[off] << 8));
46    }
47
48    static short getShort(byte[] b, int off) {
49        return (short) ((b[off + 1] & 0xFF) +
50                        (b[off] << 8));
51    }
52
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
60    static float getFloat(byte[] b, int off) {
61        return Float.intBitsToFloat(getInt(b, off));
62    }
63
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
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
84    static void putBoolean(byte[] b, int off, boolean val) {
85        b[off] = (byte) (val ? 1 : 0);
86    }
87
88    static void putChar(byte[] b, int off, char val) {
89        b[off + 1] = (byte) (val      );
90        b[off    ] = (byte) (val >>> 8);
91    }
92
93    static void putShort(byte[] b, int off, short val) {
94        b[off + 1] = (byte) (val      );
95        b[off    ] = (byte) (val >>> 8);
96    }
97
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
105    static void putFloat(byte[] b, int off, float val) {
106        putInt(b, off,  Float.floatToIntBits(val));
107    }
108
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
120    static void putDouble(byte[] b, int off, double val) {
121        putLong(b, off, Double.doubleToLongBits(val));
122    }
123}
124