php-src/ext/standard/lcg.c
Peter Kokot 8d3f8ca12a Remove unused Git attributes ident
The $Id$ keywords were used in Subversion where they can be substituted
with filename, last revision number change, last changed date, and last
user who changed it.

In Git this functionality is different and can be done with Git attribute
ident. These need to be defined manually for each file in the
.gitattributes file and are afterwards replaced with 40-character
hexadecimal blob object name which is based only on the particular file
contents.

This patch simplifies handling of $Id$ keywords by removing them since
they are not used anymore.
2018-07-25 00:53:25 +02:00

134 lines
3.1 KiB
C

/*
+----------------------------------------------------------------------+
| PHP Version 7 |
+----------------------------------------------------------------------+
| Copyright (c) 1997-2018 The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 3.01 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
| available through the world-wide-web at the following url: |
| http://www.php.net/license/3_01.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> |
+----------------------------------------------------------------------+
*/
#include "php.h"
#include "php_lcg.h"
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef PHP_WIN32
#include "win32/time.h"
#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
static void lcg_seed(void);
PHPAPI double php_combined_lcg(void) /* {{{ */
{
int32_t q;
int32_t z;
if (!LCG(seeded)) {
lcg_seed();
}
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(void) /* {{{ */
{
struct timeval tv;
if (gettimeofday(&tv, NULL) == 0) {
LCG(s1) = tv.tv_sec ^ (tv.tv_usec<<11);
} else {
LCG(s1) = 1;
}
#ifdef ZTS
LCG(s2) = (zend_long) tsrm_thread_id();
#else
LCG(s2) = (zend_long) getpid();
#endif
/* Add entropy to s2 by calling gettimeofday() again */
if (gettimeofday(&tv, NULL) == 0) {
LCG(s2) ^= (tv.tv_usec<<11);
}
LCG(seeded) = 1;
}
/* }}} */
static void lcg_init_globals(php_lcg_globals *lcg_globals_p) /* {{{ */
{
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;
}
/* }}} */
/* {{{ proto float lcg_value()
Returns a value from the combined linear congruential generator */
PHP_FUNCTION(lcg_value)
{
if (zend_parse_parameters_none() == FAILURE) {
return;
}
RETURN_DOUBLE(php_combined_lcg());
}
/* }}} */
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
* vim600: sw=4 ts=4 fdm=marker
* vim<600: sw=4 ts=4
*/