diff options
Diffstat (limited to 'ext/standard/rand.c')
| -rw-r--r-- | ext/standard/rand.c | 325 |
1 files changed, 11 insertions, 314 deletions
diff --git a/ext/standard/rand.c b/ext/standard/rand.c index 708e0c376e..0b804fa5aa 100644 --- a/ext/standard/rand.c +++ b/ext/standard/rand.c @@ -25,35 +25,15 @@ */ /* $Id$ */ -#include <stdlib.h> - #include "php.h" -#include "php_math.h" #include "php_rand.h" - -#include "basic_functions.h" - - -/* SYSTEM RAND FUNCTIONS */ +#include "php_mt_rand.h" /* {{{ php_srand */ PHPAPI void php_srand(zend_long seed) { -#ifdef ZTS - BG(rand_seed) = (unsigned int) seed; -#else -# if defined(HAVE_SRANDOM) - srandom((unsigned int) seed); -# elif defined(HAVE_SRAND48) - srand48(seed); -# else - srand((unsigned int) seed); -# endif -#endif - - /* Seed only once */ - BG(rand_is_seeded) = 1; + php_mt_srand(seed); } /* }}} */ @@ -61,314 +41,31 @@ PHPAPI void php_srand(zend_long seed) */ PHPAPI zend_long php_rand(void) { - zend_long ret; - - if (!BG(rand_is_seeded)) { - php_srand(GENERATE_SEED()); - } - -#ifdef ZTS - ret = php_rand_r(&BG(rand_seed)); -#else -# if defined(HAVE_RANDOM) - ret = random(); -# elif defined(HAVE_LRAND48) - ret = lrand48(); -# else - ret = rand(); -# endif -#endif - - return ret; -} -/* }}} */ - - -/* MT RAND FUNCTIONS */ - -/* - The following php_mt_...() functions are based on a C++ class MTRand by - Richard J. Wagner. For more information see the web page at - http://www-personal.engin.umich.edu/~wagnerr/MersenneTwister.html - - Mersenne Twister random number generator -- a C++ class MTRand - Based on code by Makoto Matsumoto, Takuji Nishimura, and Shawn Cokus - Richard J. Wagner v1.0 15 May 2003 rjwagner@writeme.com - - The Mersenne Twister is an algorithm for generating random numbers. It - was designed with consideration of the flaws in various other generators. - The period, 2^19937-1, and the order of equidistribution, 623 dimensions, - are far greater. The generator is also fast; it avoids multiplication and - division, and it benefits from caches and pipelines. For more information - see the inventors' web page at http://www.math.keio.ac.jp/~matumoto/emt.html - - Reference - M. Matsumoto and T. Nishimura, "Mersenne Twister: A 623-Dimensionally - Equidistributed Uniform Pseudo-Random Number Generator", ACM Transactions on - Modeling and Computer Simulation, Vol. 8, No. 1, January 1998, pp 3-30. - - Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura, - Copyright (C) 2000 - 2003, Richard J. Wagner - All rights reserved. - - Redistribution and use in source and binary forms, with or without - modification, are permitted provided that the following conditions - are met: - - 1. Redistributions of source code must retain the above copyright - notice, this list of conditions and the following disclaimer. - - 2. Redistributions in binary form must reproduce the above copyright - notice, this list of conditions and the following disclaimer in the - documentation and/or other materials provided with the distribution. - - 3. The names of its contributors may not be used to endorse or promote - products derived from this software without specific prior written - permission. - - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR - A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR - CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, - EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, - PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR - PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF - LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING - NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS - SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -*/ - -#define N MT_N /* length of state vector */ -#define M (397) /* a period parameter */ -#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 twist(m,u,v) (m ^ (mixBits(u,v)>>1) ^ ((php_uint32)(-(php_int32)(loBit(u))) & 0x9908b0dfU)) - -/* {{{ php_mt_initialize - */ -static inline void php_mt_initialize(php_uint32 seed, php_uint32 *state) -{ - /* Initialize generator state with seed - See Knuth TAOCP Vol 2, 3rd Ed, p.106 for multiplier. - In previous versions, most significant bits (MSBs) of the seed affect - only MSBs of the state array. Modified 9 Jan 2002 by Makoto Matsumoto. */ - - register php_uint32 *s = state; - register php_uint32 *r = state; - register int i = 1; - - *s++ = seed & 0xffffffffU; - for( ; i < N; ++i ) { - *s++ = ( 1812433253U * ( *r ^ (*r >> 30) ) + i ) & 0xffffffffU; - r++; - } -} -/* }}} */ - -/* {{{ php_mt_reload - */ -static inline void php_mt_reload(void) -{ - /* Generate N new values in state - Made clearer and faster by Matthew Bellew (matthew.bellew@home.com) */ - - register php_uint32 *state = BG(state); - register php_uint32 *p = state; - register int i; - - for (i = N - M; i--; ++p) - *p = twist(p[M], p[0], p[1]); - for (i = M; --i; ++p) - *p = twist(p[M-N], p[0], p[1]); - *p = twist(p[M-N], p[0], state[0]); - BG(left) = N; - BG(next) = state; -} -/* }}} */ - -/* {{{ php_mt_srand - */ -PHPAPI void php_mt_srand(php_uint32 seed) -{ - /* Seed the generator with a simple uint32 */ - php_mt_initialize(seed, BG(state)); - php_mt_reload(); - - /* Seed only once */ - BG(mt_rand_is_seeded) = 1; -} -/* }}} */ - -/* {{{ php_mt_rand - */ -PHPAPI php_uint32 php_mt_rand(void) -{ - /* Pull a 32-bit integer from the generator state - Every other access function simply transforms the numbers extracted here */ - - register php_uint32 s1; - - if (BG(left) == 0) { - php_mt_reload(); - } - --BG(left); - - s1 = *BG(next)++; - s1 ^= (s1 >> 11); - s1 ^= (s1 << 7) & 0x9d2c5680U; - s1 ^= (s1 << 15) & 0xefc60000U; - return ( s1 ^ (s1 >> 18) ); -} -/* }}} */ - -/* {{{ proto void srand([int seed]) - Seeds random number generator */ -PHP_FUNCTION(srand) -{ - zend_long seed = 0; - - if (zend_parse_parameters(ZEND_NUM_ARGS(), "|l", &seed) == FAILURE) - return; - - if (ZEND_NUM_ARGS() == 0) - seed = GENERATE_SEED(); - - php_srand(seed); -} -/* }}} */ - -/* {{{ proto void mt_srand([int seed]) - Seeds Mersenne Twister random number generator */ -PHP_FUNCTION(mt_srand) -{ - zend_long seed = 0; - - if (zend_parse_parameters(ZEND_NUM_ARGS(), "|l", &seed) == FAILURE) - return; - - if (ZEND_NUM_ARGS() == 0) - seed = GENERATE_SEED(); - - php_mt_srand(seed); -} -/* }}} */ - - -/* - * 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 - # artificially 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 - */ - -/* {{{ proto int rand([int min, int max]) - Returns a random number */ -PHP_FUNCTION(rand) -{ - zend_long min; - zend_long max; - zend_long number; - int argc = ZEND_NUM_ARGS(); - - if (argc != 0 && zend_parse_parameters(argc, "ll", &min, &max) == FAILURE) - return; - - number = php_rand(); - if (argc == 2) { - RAND_RANGE(number, min, max, PHP_RAND_MAX); - } - - RETURN_LONG(number); + return php_mt_rand(); } /* }}} */ /* {{{ proto int mt_rand([int min, int max]) Returns a random number from Mersenne Twister */ -PHP_FUNCTION(mt_rand) +PHP_FUNCTION(rand) { zend_long min; zend_long max; - zend_long number; - int argc = ZEND_NUM_ARGS(); + int argc = ZEND_NUM_ARGS(); - if (argc != 0) { - if (zend_parse_parameters(argc, "ll", &min, &max) == FAILURE) { - return; - } else if (max < min) { - php_error_docref(NULL, E_WARNING, "max(" ZEND_LONG_FMT ") is smaller than min(" ZEND_LONG_FMT ")", max, min); - RETURN_FALSE; - } + if (argc == 0) { + RETURN_LONG(php_mt_rand() >> 1); } - if (!BG(mt_rand_is_seeded)) { - php_mt_srand(GENERATE_SEED()); - } - - /* - * 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 - */ - number = (zend_long) (php_mt_rand() >> 1); - if (argc == 2) { - RAND_RANGE(number, min, max, PHP_MT_RAND_MAX); - } - - RETURN_LONG(number); -} -/* }}} */ - -/* {{{ proto int getrandmax(void) - Returns the maximum value a random number can have */ -PHP_FUNCTION(getrandmax) -{ - if (zend_parse_parameters_none() == FAILURE) { + if (zend_parse_parameters(argc, "ll", &min, &max) == FAILURE) { return; } - RETURN_LONG(PHP_RAND_MAX); -} -/* }}} */ - -/* {{{ proto int mt_getrandmax(void) - Returns the maximum value a random number from Mersenne Twister can have */ -PHP_FUNCTION(mt_getrandmax) -{ - if (zend_parse_parameters_none() == FAILURE) { - return; + if (max < min) { + RETURN_LONG(php_mt_rand_common(max, min)); } - /* - * Melo: it could be 2^^32 but we only use 2^^31 to maintain - * compatibility with the previous php_rand - */ - RETURN_LONG(PHP_MT_RAND_MAX); /* 2^^31 */ + RETURN_LONG(php_mt_rand_common(min, max)); } /* }}} */ |