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|
/*
+----------------------------------------------------------------------+
| PHP version 4.0 |
+----------------------------------------------------------------------+
| Copyright (c) 1997-2001 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. |
+----------------------------------------------------------------------+
| Authors: Rasmus Lerdorf <rasmus@lerdorf.on.ca> |
| Zeev Suraski <zeev@zend.com> |
| Pedro Melo <melo@ip.pt> |
+----------------------------------------------------------------------+
*/
/* $Id$ */
#include <stdlib.h>
#include "php.h"
#include "php_math.h"
#include "php_rand.h"
#include "zend_execute.h"
#include "basic_functions.h"
/* See php_rand.h for information about layout */
/* srand */
/* {{{ PHPAPI void php_srand(void) */
PHPAPI void php_srand(void)
{
/* php_srand_2( 1e6d * microtime() , protocol-specified-in-php.ini ) */
php_error(E_ERROR,"Not yet implemented");
}
/* }}} */
/* {{{ void php_srand2(long seed, int alg) */
static inline void php_srand2(long seed, int alg)
{
switch (alg) {
case RAND_SYS:
php_srand_sys(seed);
return;
case RAND_MT:
php_srand_mt(seed TSRMLS_CC);
return;
default:
php_error(E_ERROR,"Bug, please report (php_srand2-%d)",alg);
return;
}
}
/* }}} */
/* {{{ [mt_]srand common */
#define pim_srand_common(name,type) \
PHP_FUNCTION(name) \
{ \
zval **arg; \
\
if (ZEND_NUM_ARGS() != 1) { \
WRONG_PARAM_COUNT; \
} \
zend_get_parameters_ex(1, &arg); \
convert_to_long_ex(arg); \
\
php_srand2((*arg)->value.lval, type); \
}
/* }}} */
/* {{{ proto void srand(int seed)
Seeds random number generator */
pim_srand_common(srand,RAND_SYS)
/* }}} */
/* {{{ proto void mt_srand(int seed)
Seeds random number generator */
pim_srand_common(mt_srand,RAND_MT)
/* }}} */
/* rand */
/* {{{ PHPAPI long php_rand(void) */
PHPAPI long php_rand(void)
{
/* algorithm = BG(current_alg) */
return php_rand_sys();
}
/* }}} */
/* {{{ macro: php_map_a_range */
#define php_map_a_range(number,min,max,MAX) { \
/*
* A bit of tricky math here. We want to avoid using a modulus because
* that simply tosses the high-order bits and might skew the distribution
* of random values over the range. Instead we map the range directly.
*
* We need to map the range from 0...M evenly to the range a...b
* Expressed in real numbers, this becomes:
*
* [0,M+1[ mapped to [a,b+1[
*
* Let n = the random number and n' = the mapped random number
* So the formula needs to be:
*
* n' = a + n((b+1)-a)/(m+1)
*
* This isn't perfect, because n only takes integer values. So when a..b
* spans a significant portion of 0..M, some numbers have nearly twice as
* much chance. But since twice a very small chance is still a very small
* chance, it's ignored.
*
* --Rasmus and Jeroen
*/ \
if ((max) < (min)) { \
php_error(E_WARNING, "%s(): Invalid range: %ld..%ld (minimum can't be larger than maximum)", \
get_active_function_name(TSRMLS_C), (min), (max)); \
} else if ( (max) - (min) > (MAX) ) { \
/* TODO: this can done better, get two numbers and combine... */ \
php_error(E_WARNING, "%s(): Invalid range: %ld..%ld (can't give that much randomness)", \
get_active_function_name(TSRMLS_C), (min), (max)); \
} \
(number) = (min) + (int) ((double)((max)-(min)+1) * (number)/(MAX+1.0)); \
}
/* }}} */
/* {{{ long php_rand_range2(long min, long max, int alg)
* Temporary hack function */
static inline long php_rand_range2(long min, long max, int alg)
{
long number;
switch (alg) {
case RAND_SYS:
number = php_rand_sys();
php_map_a_range(number,min,max,php_randmax_sys());
return number;
case RAND_MT:
number = php_rand_mt();
php_map_a_range(number,min,max,php_randmax_mt());
return number;
default:
php_error(E_ERROR,"Bug, please report (php_rand_range2-%d)",alg);
return;
}
}
/* }}} */
/* {{{ PHPAPI long php_rand_range(long min, long max) */
PHPAPI long php_rand_range(long min, long max)
{
/* will be php.ini & srand aware */
return php_rand_range2(min,max,RAND_SYS);
}
/* }}} */
/* {{{ [mt_]rand common */
#define PHP_FUNCTION_RAND(name,type,lowertype) \
PHP_FUNCTION(name) \
{ \
zval **min, **max; \
\
switch (ZEND_NUM_ARGS()) { \
case 0: \
RETURN_LONG(php_rand_##lowertype()); \
case 2: \
if (zend_get_parameters_ex(2, &min, &max)==FAILURE) { \
RETURN_FALSE; \
} \
convert_to_long_ex(min); \
convert_to_long_ex(max); \
RETURN_LONG(php_rand_range2(Z_LVAL_PP(min), \
Z_LVAL_PP(max), type)); \
default: \
WRONG_PARAM_COUNT; \
break; \
} \
}
/* }}} */
/* {{{ proto int rand([int min, int max])
Returns a random number */
PHP_FUNCTION_RAND(rand,RAND_SYS,sys)
/* }}} */
/* {{{ proto int mt_rand([int min, int max])
Returns a random number by means of Mersenne Twister */
PHP_FUNCTION_RAND(mt_rand,RAND_MT,mt)
/* }}} */
/* getrandmax */
/* {{{ PHPAPI long php_randmax(void)
Returns the maximum value a random number can have */
PHPAPI long php_randmax(void)
{
/* Get current algorithm */
return php_randmax_sys();
}
/* }}} */
/* {{{ proto int getrandmax(void)
Returns the maximum value a random number can have */
PHP_FUNCTION(getrandmax)
{
if (ZEND_NUM_ARGS() != 0) {
WRONG_PARAM_COUNT;
}
RETURN_LONG( php_randmax_sys() );
}
/* }}} */
/* {{{ proto int mt_getrandmax(void)
Returns the maximum value a random number can have */
PHP_FUNCTION(mt_getrandmax)
{
if (ZEND_NUM_ARGS() != 0) {
WRONG_PARAM_COUNT;
}
RETURN_LONG( php_randmax_mt() );
}
/* }}} */
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
* vim600: sw=4 ts=4 tw=78 fdm=marker
* vim<600: sw=4 ts=4 tw=78
*/
|
