1/*
2Copyright (C) 1999-2007 The Botan Project. All rights reserved.
3
4Redistribution and use in source and binary forms, for any use, with or without
5modification, is permitted provided that the following conditions are met:
6
71. Redistributions of source code must retain the above copyright notice, this
8list of conditions, and the following disclaimer.
9
102. Redistributions in binary form must reproduce the above copyright notice,
11this list of conditions, and the following disclaimer in the documentation
12and/or other materials provided with the distribution.
13
14THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) "AS IS" AND ANY EXPRESS OR IMPLIED
15WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
16MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.
17
18IN NO EVENT SHALL THE AUTHOR(S) OR CONTRIBUTOR(S) BE LIABLE FOR ANY DIRECT,
19INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
20BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
22LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
23OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
24ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25*/
26// LICENSEHEADER_END
27namespace QCA { // WRAPNS_LINE
28/*************************************************
29 * Bit/Word Operations Source File *
30 * (C) 1999-2007 The Botan Project *
31 *************************************************/
32
33} // WRAPNS_LINE
34#include <botan/bit_ops.h>
35namespace QCA { // WRAPNS_LINE
36
37namespace Botan {
38
39/*************************************************
40 * XOR arrays together *
41 *************************************************/
42void xor_buf(byte data[], const byte mask[], u32bit length)
43{
44 while (length >= 8) {
45 data[0] ^= mask[0];
46 data[1] ^= mask[1];
47 data[2] ^= mask[2];
48 data[3] ^= mask[3];
49 data[4] ^= mask[4];
50 data[5] ^= mask[5];
51 data[6] ^= mask[6];
52 data[7] ^= mask[7];
53 data += 8;
54 mask += 8;
55 length -= 8;
56 }
57 for (u32bit j = 0; j != length; ++j)
58 data[j] ^= mask[j];
59}
60
61void xor_buf(byte out[], const byte in[], const byte mask[], u32bit length)
62{
63 while (length >= 8) {
64 out[0] = in[0] ^ mask[0];
65 out[1] = in[1] ^ mask[1];
66 out[2] = in[2] ^ mask[2];
67 out[3] = in[3] ^ mask[3];
68 out[4] = in[4] ^ mask[4];
69 out[5] = in[5] ^ mask[5];
70 out[6] = in[6] ^ mask[6];
71 out[7] = in[7] ^ mask[7];
72 in += 8;
73 out += 8;
74 mask += 8;
75 length -= 8;
76 }
77 for (u32bit j = 0; j != length; ++j)
78 out[j] = in[j] ^ mask[j];
79}
80
81/*************************************************
82 * Return true iff arg is 2**n for some n > 0 *
83 *************************************************/
84bool power_of_2(u64bit arg)
85{
86 if (arg == 0 || arg == 1)
87 return false;
88 if ((arg & (arg - 1)) == 0)
89 return true;
90 return false;
91}
92
93/*************************************************
94 * Return the index of the highest set bit *
95 *************************************************/
96u32bit high_bit(u64bit n)
97{
98 for (u32bit count = 64; count > 0; --count)
99 if ((n >> (count - 1)) & 0x01)
100 return count;
101 return 0;
102}
103
104/*************************************************
105 * Return the index of the lowest set bit *
106 *************************************************/
107u32bit low_bit(u64bit n)
108{
109 for (u32bit count = 0; count != 64; ++count)
110 if ((n >> count) & 0x01)
111 return (count + 1);
112 return 0;
113}
114
115/*************************************************
116 * Return the number of significant bytes in n *
117 *************************************************/
118u32bit significant_bytes(u64bit n)
119{
120 for (u32bit j = 0; j != 8; ++j)
121 if (get_byte(byte_num: j, input: n))
122 return 8 - j;
123 return 0;
124}
125
126/*************************************************
127 * Return the Hamming weight of n *
128 *************************************************/
129u32bit hamming_weight(u64bit n)
130{
131 u32bit weight = 0;
132 for (u32bit j = 0; j != 64; ++j)
133 if ((n >> j) & 0x01)
134 ++weight;
135 return weight;
136}
137
138}
139} // WRAPNS_LINE
140

source code of qca/src/botantools/botan/bit_ops.cpp