php/archived-php-src
1
0
Fork 0
mirror of https://github.com/php/php-src.git synced 2026-04-11 10:03:18 +02:00
Code Issues Packages Projects Releases Wiki Activity

a bit of api cleanup... move range stuff into a macro (properly :)

Browse Source
This commit is contained in:
Sterling Hughes
2001-09-05 20:52:45 +00:00
parent 3a044786f8
commit 1b0f00d67f
1 changed files with 73 additions and 95 deletions
Download Patch File Download Diff File Expand all files Collapse all files

168
ext/standard/rand.c
View File

@@ -176,10 +176,9 @@ static php_uint32 reloadMT(TSRMLS_D)
}
static inline php_uint32 randomMT(void)
static inline php_uint32 randomMT(TSRMLS_D)
{
php_uint32 y;
TSRMLS_FETCH();
if(--BG(left) < 0)
return(reloadMT(TSRMLS_C));
@@ -195,13 +194,15 @@ static inline php_uint32 randomMT(void)
Seeds random number generator */
PHP_FUNCTION(srand)
{
pval **arg;
zval **seed;
if (ZEND_NUM_ARGS() != 1 || zend_get_parameters_ex(1, &arg) == FAILURE) {
if (ZEND_NUM_ARGS() != 1 ||
zend_get_parameters_ex(1, &seed) == FAILURE) {
WRONG_PARAM_COUNT;
}
convert_to_long_ex(arg);
php_srand((*arg)->value.lval);
convert_to_long_ex(seed);
php_srand(Z_LVAL_PP(seed));
}
/* }}} */
@@ -209,75 +210,67 @@ PHP_FUNCTION(srand)
Seeds Mersenne Twister random number generator */
PHP_FUNCTION(mt_srand)
{
pval **arg;
zval **seed;
if (ZEND_NUM_ARGS() != 1 || zend_get_parameters_ex(1, &arg) == FAILURE) {
if (ZEND_NUM_ARGS() != 1 ||
zend_get_parameters_ex(1, &seed) == FAILURE) {
WRONG_PARAM_COUNT;
}
convert_to_long_ex(arg);
seedMT((*arg)->value.lval TSRMLS_CC);
convert_to_long_ex(seed);
seedMT(Z_LVAL_PP(seed) TSRMLS_CC);
}
/* }}} */
/*
* 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
* Let n = the random number and n' = the mapped random number
*
* Then we have: n' = a + n(b-a)/M
*
* We have a problem here in that only n==M will get mapped to b which
# means the chances of getting b is much much less than getting any of
# the other values in the range. We can fix this by increasing our range
# artifically and using:
#
# n' = a + n(b-a+1)/M
*
# Now we only have a problem if n==M which would cause us to produce a
# number of b+1 which would be bad. So we bump M up by one to make sure
# this will never happen, and the final algorithm looks like this:
#
# n' = a + n(b-a+1)/(M+1)
*
* -RL
*/
#define RAND_RANGE(__n, __min, __max) \
(__min) + (int)((double)(__max) - (__min) + 1.0) * ((__n) / (PHP_RAND_MAX + 1.0))
/* {{{ proto int rand([int min, int max])
Returns a random number */
PHP_FUNCTION(rand)
{
pval **p_min=NULL, **p_max=NULL;
switch (ZEND_NUM_ARGS()) {
case 0:
break;
case 2:
if (zend_get_parameters_ex(2, &p_min, &p_max)==FAILURE) {
RETURN_FALSE;
}
convert_to_long_ex(p_min);
convert_to_long_ex(p_max);
if ((*p_max)->value.lval-(*p_min)->value.lval < 0) {
php_error(E_WARNING, "rand(): Invalid range: %ld..%ld", (*p_min)->value.lval, (*p_max)->value.lval);
} else if ((*p_max)->value.lval-(*p_min)->value.lval > PHP_RAND_MAX){
php3_error(E_WARNING, "rand(): Invalid range: %ld..%ld", (*p_min)->value.lval, (*p_max)->value.lval);
}
break;
default:
WRONG_PARAM_COUNT;
break;
}
return_value->type = IS_LONG;
zval **min;
zval **max;
long number;
int argc = ZEND_NUM_ARGS();
return_value->value.lval = php_rand();
if (argc != 0 && argc != 2 ||
zend_get_parameters_ex(argc, &min, &max) == FAILURE) {
WRONG_PARAM_COUNT;
}
/*
* 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
* Let n = the random number and n' = the mapped random number
*
* Then we have: n' = a + n(b-a)/M
*
* We have a problem here in that only n==M will get mapped to b which
# means the chances of getting b is much much less than getting any of
# the other values in the range. We can fix this by increasing our range
# artifically and using:
#
# n' = a + n(b-a+1)/M
*
# Now we only have a problem if n==M which would cause us to produce a
# number of b+1 which would be bad. So we bump M up by one to make sure
# this will never happen, and the final algorithm looks like this:
#
# n' = a + n(b-a+1)/(M+1)
*
* -RL
*/
if (p_min && p_max) { /* implement range */
return_value->value.lval = (*p_min)->value.lval +
(int)((double)((*p_max)->value.lval - (*p_min)->value.lval + 1.0) * return_value->value.lval/(PHP_RAND_MAX+1.0));
number = php_rand();
if (argc == 2) {
number = RAND_RANGE(number, Z_LVAL_PP(min), Z_LVAL_PP(max));
}
RETURN_LONG(number);
}
/* }}} */
@@ -285,29 +278,16 @@ PHP_FUNCTION(rand)
Returns a random number from Mersenne Twister */
PHP_FUNCTION(mt_rand)
{
pval **p_min=NULL, **p_max=NULL;
switch (ZEND_NUM_ARGS()) {
case 0:
break;
case 2:
if (zend_get_parameters_ex(2, &p_min, &p_max)==FAILURE) {
RETURN_FALSE;
}
convert_to_long_ex(p_min);
convert_to_long_ex(p_max);
if ((*p_max)->value.lval-(*p_min)->value.lval <= 0) {
php_error(E_WARNING, "mt_rand(): Invalid range: %ld..%ld", (*p_min)->value.lval, (*p_max)->value.lval);
}else if ((*p_max)->value.lval-(*p_min)->value.lval > MT_RAND_MAX){
php3_error(E_WARNING, "mt_rand(): Invalid range: %ld..%ld", (*p_min)->value.lval, (*p_max)->value.lval);
}
break;
default:
WRONG_PARAM_COUNT;
break;
zval **min;
zval **max;
long number;
int argc = ZEND_NUM_ARGS();
if (argc != 0 && argc != 2 ||
zend_get_parameters_ex(argc, &min, &max) == FAILURE) {
WRONG_PARAM_COUNT;
}
return_value->type = IS_LONG;
/*
* Melo: hmms.. randomMT() returns 32 random bits...
* Yet, the previous php_rand only returns 31 at most.
@@ -316,12 +296,12 @@ PHP_FUNCTION(mt_rand)
* Update:
* I talked with Cokus via email and it won't ruin the algorithm
*/
return_value->value.lval = (long)(randomMT() >> 1);
if (p_min && p_max) { /* implement range */
return_value->value.lval = (*p_min)->value.lval +
(long)((double)((*p_max)->value.lval - (*p_min)->value.lval + 1.0) * return_value->value.lval/(MT_RAND_MAX+1.0));
number = (long) (randomMT(TSRMLS_C) >> 1);
if (argc == 2) {
number = RAND_RANGE(number, Z_LVAL_PP(min), Z_LVAL_PP(max));
}
RETURN_LONG(number);
}
/* }}} */
@@ -333,8 +313,7 @@ PHP_FUNCTION(getrandmax)
WRONG_PARAM_COUNT;
}
return_value->type = IS_LONG;
return_value->value.lval = PHP_RAND_MAX;
RETURN_LONG(PHP_RAND_MAX);
}
/* }}} */
@@ -346,12 +325,11 @@ PHP_FUNCTION(mt_getrandmax)
WRONG_PARAM_COUNT;
}
return_value->type = IS_LONG;
/*
* Melo: it could be 2^^32 but we only use 2^^31 to maintain
* compatibility with the previous php_rand
*/
return_value->value.lval = MT_RAND_MAX; /* 2^^31 */
RETURN_LONG(MT_RAND_MAX); /* 2^^31 */
}
/* }}} */
@@ -360,6 +338,6 @@ PHP_FUNCTION(mt_getrandmax)
* 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
* vim600: noet sw=4 ts=4 tw=78 fdm=marker
* vim<600: noet sw=4 ts=4 tw=78
*/