Experimental beginning of a change in the way rand-functions work.

This is only a _move around_ of code into functions.

5 files changed, 441 insertions, 283 deletions

diff --git a/ext/standard/Makefile.in b/ext/standard/Makefile.in
index 123e4cb110..628adea8a8 100644
--- a/ext/standard/Makefile.in
+++ b/ext/standard/Makefile.in
@@ -5,7 +5,7 @@ LTLIBRARY_SOURCES=\
 	dir.c dl.c dns.c exec.c file.c filestat.c flock_compat.c \
 	formatted_print.c fsock.c head.c html.c image.c info.c iptc.c lcg.c \
 	link.c mail.c math.c md5.c metaphone.c microtime.c pack.c pageinfo.c \
-        parsedate.c quot_print.c rand.c reg.c soundex.c string.c scanf.c \
+        parsedate.c quot_print.c rand.c rand_mt.c reg.c soundex.c string.c scanf.c \
 	syslog.c type.c uniqid.c url.c url_scanner.c var.c assert.c \
 	strnatcmp.c levenshtein.c incomplete_class.c url_scanner_ex.c \
 	ftp_fopen_wrapper.c http_fopen_wrapper.c php_fopen_wrapper.c credits.c
diff --git a/ext/standard/php_math.h b/ext/standard/php_math.h
index beef7dd160..71e7d40972 100644
--- a/ext/standard/php_math.h
+++ b/ext/standard/php_math.h
@@ -34,12 +34,6 @@ PHP_FUNCTION(log);
 PHP_FUNCTION(log10);
 PHP_FUNCTION(pow);
 PHP_FUNCTION(sqrt);
-PHP_FUNCTION(srand);
-PHP_FUNCTION(rand);
-PHP_FUNCTION(getrandmax);
-PHP_FUNCTION(mt_srand);
-PHP_FUNCTION(mt_rand);
-PHP_FUNCTION(mt_getrandmax);
 PHP_FUNCTION(abs);
 PHP_FUNCTION(ceil);
 PHP_FUNCTION(floor);
diff --git a/ext/standard/php_rand.h b/ext/standard/php_rand.h
index b4d7e991d0..0d20f84225 100644
--- a/ext/standard/php_rand.h
+++ b/ext/standard/php_rand.h
@@ -21,6 +21,41 @@
  */
 /* $Id$ */
 
+/* Layout implementation random functions
+ *
+ * The PHPAPI contains these functions:
+ * - long php_rand()
+ * - long php_rand_range(long min, long max)
+ * - void php_srand()
+ * - long php_getrandmax()
+ *
+ * Note that it is not possible to choose the algoritm. This is done to
+ * give the user the possibility to control all randomness by means of
+ * srand()/php.ini in a portable and consistent way.
+ *
+ * rand.c: (the only rand*.c file with PHP_API and PHP_FUNCTION functions)
+ *
+ * - PHP_FUNCTION([mt_]srand)
+ *   +-> void php_srand(void)
+ *   +-> void php_srand2(long seed, int alg)
+ *       +-> (rand_sys.c) long php_rand_sys()
+ *       +-> (rand_mt.c ) long php_rand_mt()
+ *
+ * - PHP_FUNCTION([mt_]rand)
+ *   +-> long php_rand()
+ *       +-> (rand_sys.c) long php_rand_sys()
+ *       +-> (rand_mt.c ) long php_rand_mt()
+ *   +-> long php_rand_range(long min, long max)
+ *       +-> calls php_rand()
+ *       
+ * - PHP_FUNCTION([mt_]getrandmax)
+ *   +-> PHPAPI long php_randmax(void)
+ *       +-> (rand_sys.c) long php_randmax_sys()
+ *       +-> (rand_mt.c ) long php_randmax_mt()
+ *   
+ *   --Jeroen
+ */
+
 #ifndef PHP_RAND_H
 #define	PHP_RAND_H
 
@@ -31,31 +66,66 @@
 #endif
 
 #if HAVE_LRAND48
-#define PHP_RAND_MAX 2147483647
+#define php_randmax_sys() 2147483647
 #else
-#define PHP_RAND_MAX RAND_MAX
+#define php_randmax_sys() RAND_MAX
 #endif
 
+/*
+ * Melo: it could be 2^^32 but we only use 2^^31 to maintain
+ * compatibility with the previous php_rand
+ */
+#define php_randmax_mt() ((long)(0x7FFFFFFF)) /* 2^^31 - 1 */
+
+PHP_FUNCTION(srand);
+PHP_FUNCTION(rand);
+PHP_FUNCTION(getrandmax);
+PHP_FUNCTION(mt_srand);
+PHP_FUNCTION(mt_rand);
+PHP_FUNCTION(mt_getrandmax);
+
+PHPAPI long php_rand(void);
+PHPAPI long php_rand_range(long min, long max);
+PHPAPI long php_randmax(void);
+long php_rand_mt(void);
+void php_srand_mt(long seed TSRMLS_DC);
+
 /* Define rand Function wrapper */
 #ifdef HAVE_RANDOM
-#define php_rand() random()
+#define php_rand_sys() random()
 #else
 #ifdef HAVE_LRAND48
-#define php_rand() lrand48()
+#define php_rand_sys() lrand48()
 #else
-#define php_rand() rand()
+#define php_rand_sys() rand()
 #endif
 #endif
 
 /* Define srand Function wrapper */
 #ifdef HAVE_SRANDOM
-#define php_srand(seed) srandom((unsigned int)seed)
+#define php_srand_sys(seed) srandom((unsigned int)seed)
 #else
 #ifdef HAVE_SRAND48
-#define php_srand(seed) srand48((long)seed)
+#define php_srand_sys(seed) srand48((long)seed)
 #else
-#define php_srand(seed) srand((unsigned int)seed)
+#define php_srand_sys(seed) srand((unsigned int)seed)
 #endif
 #endif
 
+/* Define random generator constants */
+#define RAND_SYS 1
+#define RAND_MT  2
+
+/* BC */
+#define PHP_RAND_MAX php_randmax()
+
 #endif	/* PHP_RAND_H */
+
+/*
+ * Local variables:
+ * tab-width: 4
+ * c-basic-offset: 4
+ * End:
+ * vim600: fdm=marker
+ * vim: sw=4 ts=4 tw=78
+ */
diff --git a/ext/standard/rand.c b/ext/standard/rand.c
index 4ac3bc0507..5e1c39fbdc 100644
--- a/ext/standard/rand.c
+++ b/ext/standard/rand.c
@@ -15,8 +15,6 @@
    | 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>          |
    +----------------------------------------------------------------------+
  */
 /* $Id$ */
@@ -27,301 +25,183 @@
 #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...
-*/
+#include "zend_execute.h"
 
+#include "basic_functions.h"
 
-#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 */
+/* See php_rand.h for information about layout */
 
-#define MT_RAND_MAX ((long)(0x7FFFFFFF)) /* (1<<31) - 1 */
+/* srand */
 
-/* {{{ seedMT
- */
-static void seedMT(php_uint32 seed TSRMLS_DC)
+/* {{{ PHPAPI void php_srand(void) */
+PHPAPI void php_srand(void)
 {
-    /*
-       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);
+	/* php_srand_2( 1e6d * microtime() , protocol-specified-in-php.ini ) */
+	php_error(E_ERROR,"Not yet implemented");
 }
 /* }}} */
 
-static php_uint32 reloadMT(TSRMLS_D)
+/* {{{ void php_srand2(long seed, int alg) */
+static inline void php_srand2(long seed, int alg)
 {
-    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 TSRMLS_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));
+	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;
+	}
 }
+/* }}} */
 
-
-static inline php_uint32 randomMT(void)
-{
-    php_uint32 y;
-	TSRMLS_FETCH();
-
-    if(--BG(left) < 0)
-        return(reloadMT(TSRMLS_C));
-
-    y  = *BG(next)++;
-    y ^= (y >> 11);
-    y ^= (y <<  7) & 0x9D2C5680U;
-    y ^= (y << 15) & 0xEFC60000U;
-    return(y ^ (y >> 18));
+/* {{{ [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 */
-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);
-}
+pim_srand_common(srand,RAND_SYS)
 /* }}} */
 
 /* {{{ proto void mt_srand(int seed)
-   Seeds Mersenne Twister random number generator */
-PHP_FUNCTION(mt_srand)
-{
-	pval **arg;
-
-	if (ZEND_NUM_ARGS() != 1 || zend_get_parameters_ex(1, &arg) == FAILURE) {
-		WRONG_PARAM_COUNT;
-	}
-	convert_to_long_ex(arg);
-	seedMT((*arg)->value.lval TSRMLS_CC);
-}
+   Seeds random number generator */
+pim_srand_common(mt_srand,RAND_MT)
 /* }}} */
 
-/* {{{ 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;
+/* rand */
 
-	return_value->value.lval = php_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) 
      *
-     * 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));     
-	}
+	 *  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)); \
 }
 /* }}} */
 
-/* {{{ proto int mt_rand([int min, int max])
-   Returns a random number from Mersenne Twister */
-PHP_FUNCTION(mt_rand)
+/* {{{ 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)
 {
-	pval **p_min=NULL, **p_max=NULL;
+	long number;
 	
-	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;
+	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:
-			WRONG_PARAM_COUNT;
-			break;
+			php_error(E_ERROR,"Bug, please report (php_rand_range2-%d)",alg);
+			return;
 	}
-			
-	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));
-	}
+/* {{{ 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();
 }
 /* }}} */
 
@@ -333,25 +213,19 @@ PHP_FUNCTION(getrandmax)
 		WRONG_PARAM_COUNT;
 	}
 
-	return_value->type = IS_LONG;
-	return_value->value.lval = PHP_RAND_MAX;
+	RETURN_LONG( php_randmax_sys() );
 }
 /* }}} */
 
 /* {{{ proto int mt_getrandmax(void)
-   Returns the maximum value a random number from Mersenne Twister can have */
+   Returns the maximum value a random number can have */
 PHP_FUNCTION(mt_getrandmax)
 {
 	if (ZEND_NUM_ARGS() != 0) {
 		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( php_randmax_mt() );
 }
 /* }}} */
 
diff --git a/ext/standard/rand_mt.c b/ext/standard/rand_mt.c
new file mode 100644
index 0000000000..bb0114951f
--- /dev/null
+++ b/ext/standard/rand_mt.c
@@ -0,0 +1,220 @@
+/*
+   +----------------------------------------------------------------------+
+   | 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_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 MIX_AND_RETURN(var) {             \
+    (var) ^= ((var) >> 11);               \
+    (var) ^= ((var) <<  7) & 0x9D2C5680U; \
+    (var) ^= ((var) << 15) & 0xEFC60000U; \
+    (var) ^= ((var) >> 18);               \
+	/*
+	 * Melo: hmms.. these are 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
+	 *
+	 * Jeroen: moved this to end of php_rand_mt and php_rand_mt_reload
+	 */                                   \
+	return (long)((var) >> 1);            \
+}
+
+/* {{{ void php_srand_mt(long seed)
+ */
+void php_srand_mt(long seed TSRMLS_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 = ((php_uint32)seed | 1U) & 0xFFFFFFFFU, *s = BG(state);
+    register int    j;
+
+    for(BG(left)=0, *s++=x, j=N; --j;
+        *s++ = (x*=69069U) & 0xFFFFFFFFU);
+}
+/* }}} */
+
+/* {{{ long php_rand_mt_reload(void) [internal function]
+ * Generates a new batch of random numbers, and returns the first of it */
+static inline long php_rand_mt_reload(TSRMLS_D)
+{
+    register php_uint32 *p0=BG(state), *p2=BG(state)+2, *pM=BG(state)+M, s0, s1;
+    register int    j;
+
+    if(BG(left) < -1)
+        php_srand_mt(4357U TSRMLS_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);
+	MIX_AND_RETURN(s1);
+}
+/*}}}*/
+
+/* {{{ long php_rand_mt(void) */
+long php_rand_mt(void)
+{
+    php_uint32 y;
+	TSRMLS_FETCH();
+
+    if(--BG(left) < 0)
+        return(php_rand_mt_reload(TSRMLS_C));
+
+    y  = *BG(next)++;
+	MIX_AND_RETURN(y);
+}
+/* }}} */
+
+/* {{{ long php_randmax_mt(void) */
+
+/* in php_rand.h */
+
+/* }}} */
+
+/*
+ * 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
+ */