2 * netsniff-ng - the packet sniffing beast
3 * By Daniel Borkmann <daniel@netsniff-ng.org>
4 * Copyright 2009, 2010 Daniel Borkmann.
5 * Copyright (C) 1997-2004, Makoto Matsumoto, Takuji Nishimura, and
6 * Eric Landry; All rights reserved. (3-clause BSD license)
7 * Daniel Borkmann: Refactored, added initialization functions.
8 * Subject to the GPL, version 2.
9 * Reference: M. Matsumoto and T. Nishimura, "Mersenne Twister:
10 * A 623-Dimensionally Equidistributed Uniform Pseudo-Random Number
11 * Generator", ACM Transactions on Modeling and Computer Simulation,
12 * Vol. 8, No. 1, January 1998, pp 3--30.
28 #define MATRIX_A 0x9908b0dfUL
29 #define UPPER_MASK 0x80000000UL
30 #define LOWER_MASK 0x7fffffffUL
32 static unsigned long x
[N
];
33 static unsigned long *p0
, *p1
, *pm
;
35 void mt_init_by_seed_rand(unsigned long s
)
38 x
[0] = s
& 0xffffffffUL
;
39 for (i
= 1; i
< N
; ++i
) {
40 x
[i
] = (1812433253UL * (x
[i
- 1] ^ (x
[i
- 1] >> 30)) + i
) &
48 void mt_init_by_seed_time(void)
50 mt_init_by_seed_rand((unsigned long) time(NULL
));
53 void mt_init_by_seed_array(unsigned long key
[], int len
)
56 mt_init_by_seed_rand(19650218UL);
59 for (k
= (N
> len
? N
: len
); k
; --k
) {
61 x
[i
] = ((x
[i
] ^ ((x
[i
- 1] ^ (x
[i
- 1] >> 30)) *
62 1664525UL)) + key
[j
] + j
) & 0xffffffffUL
;
70 for (k
= N
- 1; k
; --k
) {
72 x
[i
] = ((x
[i
] ^ ((x
[i
- 1] ^ (x
[i
- 1] >> 30)) *
73 1566083941UL)) - i
) & 0xffffffffUL
;
82 void mt_init_by_seed_rand_array(void)
85 unsigned long k
[LEN_INIT
];
86 srand((unsigned int) time(NULL
));
87 for (i
= 0; i
< LEN_INIT
; i
++)
89 mt_init_by_seed_array(k
, LEN_INIT
);
92 void mt_init_by_random_device(void)
95 unsigned long k
[LEN_INIT
];
96 fd
= open_or_die("/dev/random", O_RDONLY
);
97 read_or_die(fd
, k
, sizeof(unsigned long) * LEN_INIT
);
99 mt_init_by_seed_array(k
, LEN_INIT
);
102 unsigned long mt_rand_int32(void)
104 /* Interval [0,0xffffffff] */
108 mt_init_by_seed_rand(5489UL);
109 /* Twisted feedback */
110 y
= *p0
= *pm
++ ^ (((*p0
& UPPER_MASK
) | (*p1
& LOWER_MASK
)) >> 1) ^
111 (-(*p1
& 1) & MATRIX_A
);
119 y
^= y
<< 7 & 0x9d2c5680UL
;
120 y
^= y
<< 15 & 0xefc60000UL
;
125 long mt_rand_int31(void)
127 /* Interval [0,0x7fffffff] */
128 return (long) mt_rand_int32() >> 1;
131 double mt_rand_real1(void)
133 /* Interval [0,1]; Divided by 2^32-1 */
134 return mt_rand_int32() * (1.0 / 4294967295.0);
137 double mt_rand_real2(void)
139 /* Interval [0,1); Divided by 2^32 */
140 return mt_rand_int32() * (1.0 / 4294967296.0);
143 double mt_rand_real3(void)
145 /* Interval (0,1); Divided by 2^32 */
146 return (((double) mt_rand_int32()) + 0.5) * (1.0 / 4294967296.0);
149 double mt_rand_res53(void)
151 /* 53-bit random number on the real interval [0,1) */
152 unsigned long a
= mt_rand_int32() >> 5, b
= mt_rand_int32() >> 6;
153 return (a
* 67108864.0 + b
) * (1.0 / 9007199254740992.0);