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
|
/*
+----------------------------------------------------------------------+
| PHP Version 4 |
+----------------------------------------------------------------------+
| Copyright (c) 1997-2003 The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 2.02 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
| available at through the world-wide-web at |
| http://www.php.net/license/2_02.txt. |
| If you did not receive a copy of the PHP license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| license@php.net so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Author: Sascha Schumann <sascha@schumann.cx> |
+----------------------------------------------------------------------+
*/
/* $Id$ */
#include "php.h"
#include "php_lcg.h"
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef PHP_WIN32
#include "win32/time.h"
#elif defined(NETWARE)
#ifdef NEW_LIBC
#include <sys/timeval.h>
#else
#include "netware/time_nw.h"
#endif
#else
#include <sys/time.h>
#endif
#ifdef ZTS
int lcg_globals_id;
#else
static php_lcg_globals lcg_globals;
#endif
#ifdef PHP_WIN32
#include <process.h>
#endif
/*
* combinedLCG() returns a pseudo random number in the range of (0, 1).
* The function combines two CGs with periods of
* 2^31 - 85 and 2^31 - 249. The period of this function
* is equal to the product of both primes.
*/
#define MODMULT(a, b, c, m, s) q = s/a;s=b*(s-a*q)-c*q;if(s<0)s+=m
PHPAPI double php_combined_lcg(TSRMLS_D)
{
php_int32 q;
php_int32 z;
MODMULT(53668, 40014, 12211, 2147483563L, LCG(s1));
MODMULT(52774, 40692, 3791, 2147483399L, LCG(s2));
z = LCG(s1) - LCG(s2);
if (z < 1) {
z += 2147483562;
}
return z * 4.656613e-10;
}
static void lcg_seed(TSRMLS_D)
{
struct timeval tv;
if (gettimeofday(&tv, NULL) == 0) {
LCG(s1) = tv.tv_sec ^ (~tv.tv_usec);
} else {
LCG(s1) = 1;
}
#ifdef ZTS
LCG(s2) = (long) tsrm_thread_id();
#else
LCG(s2) = (long) getpid();
#endif
LCG(seeded) = 1;
}
static void lcg_init_globals(php_lcg_globals *lcg_globals_p TSRMLS_DC)
{
LCG(seeded) = 0;
}
PHP_MINIT_FUNCTION(lcg)
{
#ifdef ZTS
ts_allocate_id(&lcg_globals_id, sizeof(php_lcg_globals), (ts_allocate_ctor) lcg_init_globals, NULL);
#else
lcg_init_globals(&lcg_globals);
#endif
return SUCCESS;
}
PHP_RINIT_FUNCTION(lcg)
{
if (!LCG(seeded)) {
lcg_seed(TSRMLS_C);
}
return SUCCESS;
}
/* {{{ proto float lcg_value()
Returns a value from the combined linear congruential generator */
PHP_FUNCTION(lcg_value)
{
RETURN_DOUBLE(php_combined_lcg(TSRMLS_C));
}
/* }}} */
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
* vim600: sw=4 ts=4 fdm=marker
* vim<600: sw=4 ts=4
*/
|
