1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
/*
* Copyright (c) 2003 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __INTMATH_HH__
#define __INTMATH_HH__
// Returns the prime number one less than n.
int PrevPrime(int n);
// Determine if a number is prime
template <class T>
inline bool
IsPrime(T n)
{
T i;
if (n == 2 || n == 3)
return true;
// Don't try every odd number to prove if it is a prime.
// Toggle between every 2nd and 4th number.
// (This is because every 6th odd number is divisible by 3.)
for (i = 5; i*i <= n; i += 6) {
if (((n % i) == 0 ) || ((n % (i + 2)) == 0) ) {
return false;
}
}
return true;
}
template <class T>
inline T
LeastSigBit(T n)
{
return n & ~(n - 1);
}
template <class T>
inline bool
IsPowerOf2(T n)
{
return n != 0 && LeastSigBit(n) == n;
}
template <class T>
inline int
FloorLog2(T x)
{
if (x == 0)
return -1;
int y = 0;
if (x & 0xffff0000) { y += 16; x >>= 16; }
if (x & 0x0000ff00) { y += 8; x >>= 8; }
if (x & 0x000000f0) { y += 4; x >>= 4; }
if (x & 0x0000000c) { y += 2; x >>= 2; }
if (x & 0x00000002) { y += 1; }
return y;
}
template <class T>
inline int
CeilLog2(T n)
{
return FloorLog2(n - 1) + 1;
}
template <class T>
inline T
FloorPow2(T n)
{
return (T)1 << FloorLog2(n);
}
template <class T>
inline T
CeilPow2(T n)
{
return (T)1 << CeilLog2(n);
}
inline bool
IsHex(char c)
{
return c >= '0' && c <= '9' ||
c >= 'A' && c <= 'F' ||
c >= 'a' && c <= 'f';
}
inline bool
IsOct(char c)
{
return c >= '0' && c <= '7';
}
inline bool
IsDec(char c)
{
return c >= '0' && c <= '9';
}
inline int
Hex2Int(char c)
{
if (c >= '0' && c <= '9')
return (c - '0');
if(c >= 'A' && c <= 'F')
return (c - 'A') + 10;
if (c >= 'a' && c <= 'f')
return (c - 'a') + 10;
return 0;
}
#endif // __INTMATH_HH__
|
