revert bad commit.

1 files changed, 269 insertions, 226 deletions

diff --git a/ext/standard/rand.c b/ext/standard/rand.c
index a51ce4c940..4ac3bc0507 100644
--- a/ext/standard/rand.c
+++ b/ext/standard/rand.c
@@ -15,7 +15,8 @@
    | Authors: Rasmus Lerdorf <rasmus@lerdorf.on.ca>                       |
    |          Zeev Suraski <zeev@zend.com>                                |
    |          Pedro Melo <melo@ip.pt>                                     |
-   |          Jeroen van Wolffelaar <jeroen@php.net>                      |
+   |                                                                      |
+   | Based on code from: Shawn Cokus <Cokus@math.washington.edu>          |
    +----------------------------------------------------------------------+
  */
 /* $Id$ */
@@ -25,266 +26,302 @@
 #include "php.h"
 #include "php_math.h"
 #include "php_rand.h"
-#include "php_lcg.h"
-#include "php_ini.h"
-
-#include "zend_execute.h"
 
 #include "basic_functions.h"
 
-/* See php_rand.h for information about layout */
-
-/* an ARRAY of POINTERS, not vice versa */
-php_randgen_entry *php_randgen_entries[PHP_RAND_NUMRANDS];
-
-#define PHP_HAS_SRAND(which)	(php_randgen_entries[which] && php_randgen_entries[which]->srand)
-#define PHP_SRAND(which,seed)	((*(php_randgen_entries[which]->srand))(seed TSRMLS_CC))
-#define PHP_RAND(which)			((*(php_randgen_entries[which]->rand))(TSRMLS_C))
-#define PHP_RANDMAX(which)		(php_randgen_entries[which]->randmax)
-#define PHP_RAND_INISTR(which)	(php_randgen_entries[which]->ini_str)
-
-#define CURR_GEN BG(rand_generator_current)
-
-PHP_MINIT_FUNCTION(rand)
+/*
+   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 TSRMLS_DC)
 {
-	PHP_MINIT(rand_sys)(INIT_FUNC_ARGS_PASSTHRU);
-	PHP_MINIT(rand_mt)(INIT_FUNC_ARGS_PASSTHRU);
-	/* lcg not yet implemented */
-	php_randgen_entries[PHP_RAND_LCG] = NULL;
-
-	return SUCCESS;
+    /*
+       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);
 }
+/* }}} */
 
-/* TODO: check that this function is called on the start of each script
- * execution: not more often, not less often.
- *
- * Note that system rand is inherently thread-unsafe: A different thread can
- * always eat up some rand()'s, and thus nuking your expected sequence.
- * Another reason to use MT...
- */
-PHP_RINIT_FUNCTION(rand)
+static php_uint32 reloadMT(TSRMLS_D)
 {
-	register int i;
-
-	/* seed all number-generators */
-	/* FIXME: or seed relevant numgen on init/update ini-entry? */
-	for (i = 0 ; i < PHP_RAND_NUMRANDS ; i++) {
-		if (PHP_HAS_SRAND(i)) {
-#define SRAND_A_RANDOM_SEED ((long)time(0) * (long)getpid() * (long)(php_combined_lcg(TSRMLS_C) * 10000.0)) /* something with microtime? */
-			PHP_SRAND(i,SRAND_A_RANDOM_SEED);
-		}
-	}
+    register php_uint32 *p0=BG(state), *p2=BG(state)+2, *pM=BG(state)+M, s0, s1;
+    register int    j;
 
-	return SUCCESS;
-}
+    if(BG(left) < -1)
+        seedMT(4357U TSRMLS_CC);
 
-/* INI */
-static int randgen_str_to_int(char *str, int strlen)
-{
-	register int i;
+    BG(left)=N-1, BG(next)=BG(state)+1;
 
-	for (i = 0 ; i < PHP_RAND_NUMRANDS ; i++) {
-		if (!strcasecmp(str, PHP_RAND_INISTR(i)))
-			return i;
-	}
-	return -1;
-}
-	
-/* FIXME: check that this is called on initial ini-parsing too */
-/* FIXME: what if no ini-entry was present? */
-static PHP_INI_MH(OnUpdateRandGen)
-{
-	/* Set BG(rand_generator) to the correct integer value indicating
-	 * ini-setting */
-	BG(rand_generator) = randgen_str_to_int(new_value, new_value_length);
-	if (BG(rand_generator) == -1) {
-		/* FIXME: is this possible? What happens if this occurs during
-		 * ini-parsing at startup? */
-		php_error(E_WARNING,"Invalid value for random_number_generator: \"%s\"", new_value);
-		/* Fallback: */
-		BG(rand_generator) = PHP_RAND_DEFAULT;
-	}
-#ifdef DEBUG_RAND
-	printf("\nRAND-INI updated: %d\n",BG(rand_generator));
-#endif
-	return SUCCESS;
-}
+    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);
 
-PHP_INI_BEGIN()
-	/* FIXME: default is hardcoded here, this is the second place */
-	PHP_INI_ENTRY("random_number_generator", "mt", PHP_INI_ALL, OnUpdateRandGen)
-PHP_INI_END()
+    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));
+}
 
-/* srand */
 
-/* FIXME: isn't used? */
-/* {{{ void php_srand(void) */
-static void php_srand(TSRMLS_D)
+static inline php_uint32 randomMT(void)
 {
-	CURR_GEN = BG(rand_generator);
-	PHP_SRAND(BG(rand_generator), SRAND_A_RANDOM_SEED);
-}
-/* }}} */
+    php_uint32 y;
+	TSRMLS_FETCH();
+
+    if(--BG(left) < 0)
+        return(reloadMT(TSRMLS_C));
 
-/* {{{ [mt_]srand common */
-#define pim_srand_common(name,type) 				\
-PHP_FUNCTION(name)							\
-{											\
-	zval **seed;								\
-	zval **alg;								\
-											\
-	switch (ZEND_NUM_ARGS()) {						\
-		case 0:										\
-			CURR_GEN = BG(rand_generator);	\
-			PHP_SRAND(BG(rand_generator), SRAND_A_RANDOM_SEED);	\
-			RETURN_TRUE;							\
-		case 1:										\
-			zend_get_parameters_ex(1, &seed);		\
-			convert_to_long_ex(seed);				\
-			CURR_GEN = type;		\
-			PHP_SRAND(type, Z_LVAL_PP(seed)); 		\
-			RETURN_TRUE;							\
-		case 2:										\
-			/* algorithm, seed is most logic, though it is the other way
-			 * around than current way... */		\
-			zend_get_parameters_ex(2, &alg, &seed);	\
-			convert_to_long_ex(seed);				\
-			convert_to_long_ex(alg);				\
-			if (0 > Z_LVAL_PP(alg) || Z_LVAL_PP(alg) >= PHP_RAND_NUMRANDS) {	\
-				php_error(E_WARNING, "%s(): There is no algorithm %d.", get_active_function_name(TSRMLS_C), Z_LVAL_PP(alg));		\
-				RETURN_FALSE;						\
-			}										\
-			if (!PHP_HAS_SRAND(Z_LVAL_PP(alg))) {	\
-				php_error(E_WARNING, "%s(): Algorithm %d does not support reproducable results.", get_active_function_name(TSRMLS_C), Z_LVAL_PP(alg));	\
-				RETURN_FALSE;						\
-			}										\
-			CURR_GEN = Z_LVAL_PP(alg);		\
-			PHP_SRAND(Z_LVAL_PP(alg), Z_LVAL_PP(seed)); 		\
-			RETURN_TRUE;							\
-		default:									\
-			WRONG_PARAM_COUNT;						\
-	}												\
+    y  = *BG(next)++;
+    y ^= (y >> 11);
+    y ^= (y <<  7) & 0x9D2C5680U;
+    y ^= (y << 15) & 0xEFC60000U;
+    return(y ^ (y >> 18));
 }
-/* }}} */
 
-/* {{{ proto bool srand(int seed)
+/* {{{ proto void srand(int seed)
    Seeds random number generator */
-pim_srand_common(srand,PHP_RAND_SYS)
-/* }}} */
+PHP_FUNCTION(srand)
+{
+	pval **arg;
 
-/* {{{ proto bool mt_srand(int seed)
-   Seeds random number generator */
-pim_srand_common(mt_srand,PHP_RAND_MT)
+	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);
+}
 /* }}} */
 
-/* rand */
-
-/* {{{ PHPAPI long php_rand(void) */
-PHPAPI long php_rand(TSRMLS_D)
+/* {{{ proto void mt_srand(int seed)
+   Seeds Mersenne Twister random number generator */
+PHP_FUNCTION(mt_srand)
 {
-	return PHP_RAND(CURR_GEN);
+	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);
 }
 /* }}} */
 
-/* {{{ PHPAPI double php_drand(void) 
- *      returns a double in the range [0,1) */
-PHPAPI double php_drand(TSRMLS_D)
+/* {{{ proto int rand([int min, int max])
+   Returns a random number */
+PHP_FUNCTION(rand)
 {
-	return  (double)php_rand(TSRMLS_C) /
-			(double)(PHP_RANDMAX(CURR_GEN)+1.0);
-}
-/* }}} */
+	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();
 
-/* {{{ macro: PHP_RAND_RANGE */
-#define PHP_RAND_RANGE(which,min,max,result) {  \
     /*
      * 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
-     */								\
-	(result) = PHP_RAND(which);		\
-	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) > PHP_RANDMAX(which) ) { \
-		/* 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)); \
-	} \
-	(result) = (min) + (long) ((double)((max)-(min)+1) * (result)/(PHP_RANDMAX(which)+1.0)); \
-}
-/* }}} */
-
-/* {{{ PHPAPI long php_rand_range(long min, long max) */
-PHPAPI long php_rand_range(long min, long max TSRMLS_DC)
-{
-	register long result;
-
-	PHP_RAND_RANGE(CURR_GEN, min, max, result);
-	return result;
-}
-/* }}} */
-
-/* {{{ [mt_]rand common */
-#define PHP_FUNCTION_RAND(name,which)								\
-PHP_FUNCTION(name)													\
-{																	\
-	zval **min, **max;												\
-																	\
-	switch (ZEND_NUM_ARGS()) {										\
-		case 0:														\
-			RETURN_LONG(PHP_RAND(which));							\
-		case 2:														\
-			if (zend_get_parameters_ex(2, &min, &max)==FAILURE) {	\
-				RETURN_FALSE;										\
-			}														\
-			convert_to_long_ex(min);								\
-			convert_to_long_ex(max);								\
-			Z_TYPE_P(return_value) = IS_LONG;						\
-			PHP_RAND_RANGE(which, Z_LVAL_PP(min), 					\
-					Z_LVAL_PP(max), Z_LVAL_P(return_value));		\
-			return;													\
-		default:													\
-			WRONG_PARAM_COUNT;										\
-			break;													\
-	}																\
+     * 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 rand([int min, int max]) 
-   Returns a random number */
-PHP_FUNCTION_RAND(rand,PHP_RAND_SYS)
-/* }}} */
-
-/* {{{ proto int mt_rand([int min, int max]) 
-   Returns a random number by means of Mersenne Twister */
-PHP_FUNCTION_RAND(mt_rand,PHP_RAND_MT)
-/* }}} */
-
-/* getrandmax */
-
-/* {{{ PHPAPI long php_randmax(void)
-   Returns the maximum value a random number can have */
-PHPAPI long php_randmax(TSRMLS_D)
+/* {{{ proto int mt_rand([int min, int max])
+   Returns a random number from Mersenne Twister */
+PHP_FUNCTION(mt_rand)
 {
-	return PHP_RANDMAX(CURR_GEN);
+	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));
+	}
 }
 /* }}} */
 
@@ -296,19 +333,25 @@ PHP_FUNCTION(getrandmax)
 		WRONG_PARAM_COUNT;
 	}
 
-	RETURN_LONG( php_randmax(TSRMLS_C));
+	return_value->type = IS_LONG;
+	return_value->value.lval = PHP_RAND_MAX;
 }
 /* }}} */
 
 /* {{{ proto int mt_getrandmax(void)
-   Returns the maximum value a random number can have */
+   Returns the maximum value a random number from Mersenne Twister can have */
 PHP_FUNCTION(mt_getrandmax)
 {
 	if (ZEND_NUM_ARGS() != 0) {
 		WRONG_PARAM_COUNT;
 	}
 
-	RETURN_LONG( php_randmax(TSRMLS_C) );
+	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 */
 }
 /* }}} */
 
@@ -318,5 +361,5 @@ PHP_FUNCTION(mt_getrandmax)
  * c-basic-offset: 4
  * End:
  * vim600: sw=4 ts=4 tw=78 fdm=marker
- * vim: sw=4 ts=4 tw=78
+ * vim<600: sw=4 ts=4 tw=78
  */