summaryrefslogtreecommitdiff
path: root/ext/standard/rand.c
diff options
context:
space:
mode:
Diffstat (limited to 'ext/standard/rand.c')
-rw-r--r--ext/standard/rand.c358
1 files changed, 0 insertions, 358 deletions
diff --git a/ext/standard/rand.c b/ext/standard/rand.c
deleted file mode 100644
index 72227af0fd..0000000000
--- a/ext/standard/rand.c
+++ /dev/null
@@ -1,358 +0,0 @@
-/*
- +----------------------------------------------------------------------+
- | 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> |
- | |
- | Based on code from: Shawn Cokus <Cokus@math.washington.edu> |
- +----------------------------------------------------------------------+
- */
-/* $Id$ */
-
-#include <stdlib.h>
-
-#include "php.h"
-#include "php_math.h"
-#include "php_rand.h"
-
-#include "basic_functions.h"
-
-/*
- This is the ``Mersenne Twister'' random number generator MT19937, which
- generates pseudorandom integers uniformly distributed in 0..(2^32 - 1)
- starting from any odd seed in 0..(2^32 - 1). This version is a recode
- by Shawn Cokus (Cokus@math.washington.edu) on March 8, 1998 of a version by
- Takuji Nishimura (who had suggestions from Topher Cooper and Marc Rieffel in
- July-August 1997).
-
- Effectiveness of the recoding (on Goedel2.math.washington.edu, a DEC Alpha
- running OSF/1) using GCC -O3 as a compiler: before recoding: 51.6 sec. to
- generate 300 million random numbers; after recoding: 24.0 sec. for the same
- (i.e., 46.5% of original time), so speed is now about 12.5 million random
- number generations per second on this machine.
-
- According to the URL <http://www.math.keio.ac.jp/~matumoto/emt.html>
- (and paraphrasing a bit in places), the Mersenne Twister is ``designed
- with consideration of the flaws of various existing generators,'' has
- a period of 2^19937 - 1, gives a sequence that is 623-dimensionally
- equidistributed, and ``has passed many stringent tests, including the
- die-hard test of G. Marsaglia and the load test of P. Hellekalek and
- S. Wegenkittl.'' It is efficient in memory usage (typically using 2506
- to 5012 bytes of static data, depending on data type sizes, and the code
- is quite short as well). It generates random numbers in batches of 624
- at a time, so the caching and pipelining of modern systems is exploited.
- It is also divide- and mod-free.
-
- This library is free software; you can redistribute it and/or modify it
- under the terms of the GNU Library General Public License as published by
- the Free Software Foundation (either version 2 of the License or, at your
- option, any later version). This library is distributed in the hope that
- it will be useful, but WITHOUT ANY WARRANTY, without even the implied
- warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
- the GNU Library General Public License for more details. You should have
- received a copy of the GNU Library General Public License along with this
- library; if not, write to the Free Software Foundation, Inc., 59 Temple
- Place, Suite 330, Boston, MA 02111-1307, USA.
-
- The code as Shawn received it included the following notice:
-
- Copyright (C) 1997 Makoto Matsumoto and Takuji Nishimura. When
- you use this, send an e-mail to <matumoto@math.keio.ac.jp> with
- an appropriate reference to your work.
-
- It would be nice to CC: <Cokus@math.washington.edu> when you write.
-
-
-
- php_uint32 must be an unsigned integer type capable of holding at least 32
- bits; exactly 32 should be fastest, but 64 is better on an Alpha with
- GCC at -O3 optimization so try your options and see what's best for you
-
- Melo: we should put some ifdefs here to catch those alphas...
-*/
-
-
-#define N MT_N /* length of state vector */
-#define M (397) /* a period parameter */
-#define K (0x9908B0DFU) /* a magic constant */
-#define hiBit(u) ((u) & 0x80000000U) /* mask all but highest bit of u */
-#define loBit(u) ((u) & 0x00000001U) /* mask all but lowest bit of u */
-#define loBits(u) ((u) & 0x7FFFFFFFU) /* mask the highest bit of u */
-#define mixBits(u, v) (hiBit(u)|loBits(v)) /* move hi bit of u to hi bit of v */
-
-#define MT_RAND_MAX ((long)(0x7FFFFFFF)) /* (1<<31) - 1 */
-
-/* {{{ seedMT
- */
-static void seedMT(php_uint32 seed BLS_DC)
-{
- /*
- We initialize state[0..(N-1)] via the generator
-
- x_new = (69069 * x_old) mod 2^32
-
- from Line 15 of Table 1, p. 106, Sec. 3.3.4 of Knuth's
- _The Art of Computer Programming_, Volume 2, 3rd ed.
-
- Notes (SJC): I do not know what the initial state requirements
- of the Mersenne Twister are, but it seems this seeding generator
- could be better. It achieves the maximum period for its modulus
- (2^30) iff x_initial is odd (p. 20-21, Sec. 3.2.1.2, Knuth); if
- x_initial can be even, you have sequences like 0, 0, 0, ...;
- 2^31, 2^31, 2^31, ...; 2^30, 2^30, 2^30, ...; 2^29, 2^29 + 2^31,
- 2^29, 2^29 + 2^31, ..., etc. so I force seed to be odd below.
-
- Even if x_initial is odd, if x_initial is 1 mod 4 then
-
- the lowest bit of x is always 1,
- the next-to-lowest bit of x is always 0,
- the 2nd-from-lowest bit of x alternates ... 0 1 0 1 0 1 0 1 ... ,
- the 3rd-from-lowest bit of x 4-cycles ... 0 1 1 0 0 1 1 0 ... ,
- the 4th-from-lowest bit of x has the 8-cycle ... 0 0 0 1 1 1 1 0 ... ,
- ...
-
- and if x_initial is 3 mod 4 then
-
- the lowest bit of x is always 1,
- the next-to-lowest bit of x is always 1,
- the 2nd-from-lowest bit of x alternates ... 0 1 0 1 0 1 0 1 ... ,
- the 3rd-from-lowest bit of x 4-cycles ... 0 0 1 1 0 0 1 1 ... ,
- the 4th-from-lowest bit of x has the 8-cycle ... 0 0 1 1 1 1 0 0 ... ,
- ...
-
- The generator's potency (min. s>=0 with (69069-1)^s = 0 mod 2^32) is
- 16, which seems to be alright by p. 25, Sec. 3.2.1.3 of Knuth. It
- also does well in the dimension 2..5 spectral tests, but it could be
- better in dimension 6 (Line 15, Table 1, p. 106, Sec. 3.3.4, Knuth).
-
- Note that the random number user does not see the values generated
- here directly since reloadMT() will always munge them first, so maybe
- none of all of this matters. In fact, the seed values made here could
- even be extra-special desirable if the Mersenne Twister theory says
- so-- that's why the only change I made is to restrict to odd seeds.
- */
-
- register php_uint32 x = (seed | 1U) & 0xFFFFFFFFU, *s = BG(state);
- register int j;
-
- for(BG(left)=0, *s++=x, j=N; --j;
- *s++ = (x*=69069U) & 0xFFFFFFFFU);
-}
-/* }}} */
-
-static php_uint32 reloadMT(BLS_D)
-{
- register php_uint32 *p0=BG(state), *p2=BG(state)+2, *pM=BG(state)+M, s0, s1;
- register int j;
-
- if(BG(left) < -1)
- seedMT(4357U BLS_CC);
-
- BG(left)=N-1, BG(next)=BG(state)+1;
-
- for(s0=BG(state)[0], s1=BG(state)[1], j=N-M+1; --j; s0=s1, s1=*p2++)
- *p0++ = *pM++ ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
-
- for(pM=BG(state), j=M; --j; s0=s1, s1=*p2++)
- *p0++ = *pM++ ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
-
- s1=BG(state)[0], *p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
- s1 ^= (s1 >> 11);
- s1 ^= (s1 << 7) & 0x9D2C5680U;
- s1 ^= (s1 << 15) & 0xEFC60000U;
- return(s1 ^ (s1 >> 18));
-}
-
-
-static inline php_uint32 randomMT(void)
-{
- php_uint32 y;
- BLS_FETCH();
-
- if(--BG(left) < 0)
- return(reloadMT(BLS_C));
-
- y = *BG(next)++;
- y ^= (y >> 11);
- y ^= (y << 7) & 0x9D2C5680U;
- y ^= (y << 15) & 0xEFC60000U;
- return(y ^ (y >> 18));
-}
-
-/* {{{ proto void srand(int seed)
- Seeds random number generator */
-PHP_FUNCTION(srand)
-{
- pval **arg;
-
- if (ZEND_NUM_ARGS() != 1 || zend_get_parameters_ex(1, &arg) == FAILURE) {
- WRONG_PARAM_COUNT;
- }
- convert_to_long_ex(arg);
- php_srand((*arg)->value.lval);
-}
-/* }}} */
-
-/* {{{ proto void mt_srand(int seed)
- Seeds Mersenne Twister random number generator */
-PHP_FUNCTION(mt_srand)
-{
- pval **arg;
- BLS_FETCH();
-
- if (ZEND_NUM_ARGS() != 1 || zend_get_parameters_ex(1, &arg) == FAILURE) {
- WRONG_PARAM_COUNT;
- }
- convert_to_long_ex(arg);
- seedMT((*arg)->value.lval BLS_CC);
-}
-/* }}} */
-
-/* {{{ 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;
-
- return_value->value.lval = php_rand();
-
- /*
- * 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));
- }
-}
-/* }}} */
-
-/* {{{ proto int mt_rand([int min, int max])
- 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;
- }
-
- return_value->type = IS_LONG;
- /*
- * Melo: hmms.. randomMT() returns 32 random bits...
- * Yet, the previous php_rand only returns 31 at most.
- * So I put a right shift to loose the lsb. It *seems*
- * better than clearing the msb.
- * 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));
- }
-}
-/* }}} */
-
-/* {{{ proto int getrandmax(void)
- Returns the maximum value a random number can have */
-PHP_FUNCTION(getrandmax)
-{
- return_value->type = IS_LONG;
- return_value->value.lval = PHP_RAND_MAX;
-}
-/* }}} */
-
-/* {{{ proto int mt_getrandmax(void)
- Returns the maximum value a random number from Mersenne Twister can have */
-PHP_FUNCTION(mt_getrandmax)
-{
- 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 */
-}
-/* }}} */
-
-/*
- * 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
- */
View Lorry Controller Status