/
random.c
1433 lines (1290 loc) · 35.4 KB
/
random.c
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/**********************************************************************
random.c -
$Author$
created at: Fri Dec 24 16:39:21 JST 1993
Copyright (C) 1993-2007 Yukihiro Matsumoto
**********************************************************************/
/*
This is based on trimmed version of MT19937. To get the original version,
contact <http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html>.
The original copyright notice follows.
A C-program for MT19937, with initialization improved 2002/2/10.
Coded by Takuji Nishimura and Makoto Matsumoto.
This is a faster version by taking Shawn Cokus's optimization,
Matthe Bellew's simplification, Isaku Wada's real version.
Before using, initialize the state by using init_genrand(mt, seed)
or init_by_array(mt, init_key, key_length).
Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
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.
Any feedback is very welcome.
http://www.math.keio.ac.jp/matumoto/emt.html
email: matumoto@math.keio.ac.jp
*/
#include "ruby/ruby.h"
#include <limits.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#include <math.h>
#include <errno.h>
#ifdef _WIN32
# if !defined(_WIN32_WINNT) || _WIN32_WINNT < 0x0400
# undef _WIN32_WINNT
# define _WIN32_WINNT 0x400
# undef __WINCRYPT_H__
# endif
#include <wincrypt.h>
#endif
typedef int int_must_be_32bit_at_least[sizeof(int) * CHAR_BIT < 32 ? -1 : 1];
/* Period parameters */
#define N 624
#define M 397
#define MATRIX_A 0x9908b0dfU /* constant vector a */
#define UMASK 0x80000000U /* most significant w-r bits */
#define LMASK 0x7fffffffU /* least significant r bits */
#define MIXBITS(u,v) ( ((u) & UMASK) | ((v) & LMASK) )
#define TWIST(u,v) ((MIXBITS((u),(v)) >> 1) ^ ((v)&1U ? MATRIX_A : 0U))
enum {MT_MAX_STATE = N};
struct MT {
/* assume int is enough to store 32bits */
unsigned int state[N]; /* the array for the state vector */
unsigned int *next;
int left;
};
#define genrand_initialized(mt) ((mt)->next != 0)
#define uninit_genrand(mt) ((mt)->next = 0)
/* initializes state[N] with a seed */
static void
init_genrand(struct MT *mt, unsigned int s)
{
int j;
mt->state[0] = s & 0xffffffffU;
for (j=1; j<N; j++) {
mt->state[j] = (1812433253U * (mt->state[j-1] ^ (mt->state[j-1] >> 30)) + j);
/* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
/* In the previous versions, MSBs of the seed affect */
/* only MSBs of the array state[]. */
/* 2002/01/09 modified by Makoto Matsumoto */
mt->state[j] &= 0xffffffff; /* for >32 bit machines */
}
mt->left = 1;
mt->next = mt->state + N;
}
/* initialize by an array with array-length */
/* init_key is the array for initializing keys */
/* key_length is its length */
/* slight change for C++, 2004/2/26 */
static void
init_by_array(struct MT *mt, unsigned int init_key[], int key_length)
{
int i, j, k;
init_genrand(mt, 19650218U);
i=1; j=0;
k = (N>key_length ? N : key_length);
for (; k; k--) {
mt->state[i] = (mt->state[i] ^ ((mt->state[i-1] ^ (mt->state[i-1] >> 30)) * 1664525U))
+ init_key[j] + j; /* non linear */
mt->state[i] &= 0xffffffffU; /* for WORDSIZE > 32 machines */
i++; j++;
if (i>=N) { mt->state[0] = mt->state[N-1]; i=1; }
if (j>=key_length) j=0;
}
for (k=N-1; k; k--) {
mt->state[i] = (mt->state[i] ^ ((mt->state[i-1] ^ (mt->state[i-1] >> 30)) * 1566083941U))
- i; /* non linear */
mt->state[i] &= 0xffffffffU; /* for WORDSIZE > 32 machines */
i++;
if (i>=N) { mt->state[0] = mt->state[N-1]; i=1; }
}
mt->state[0] = 0x80000000U; /* MSB is 1; assuring non-zero initial array */
}
static void
next_state(struct MT *mt)
{
unsigned int *p = mt->state;
int j;
mt->left = N;
mt->next = mt->state;
for (j=N-M+1; --j; p++)
*p = p[M] ^ TWIST(p[0], p[1]);
for (j=M; --j; p++)
*p = p[M-N] ^ TWIST(p[0], p[1]);
*p = p[M-N] ^ TWIST(p[0], mt->state[0]);
}
/* generates a random number on [0,0xffffffff]-interval */
static unsigned int
genrand_int32(struct MT *mt)
{
/* mt must be initialized */
unsigned int y;
if (--mt->left <= 0) next_state(mt);
y = *mt->next++;
/* Tempering */
y ^= (y >> 11);
y ^= (y << 7) & 0x9d2c5680;
y ^= (y << 15) & 0xefc60000;
y ^= (y >> 18);
return y;
}
/* generates a random number on [0,1) with 53-bit resolution*/
static double
genrand_real(struct MT *mt)
{
/* mt must be initialized */
unsigned int a = genrand_int32(mt)>>5, b = genrand_int32(mt)>>6;
return(a*67108864.0+b)*(1.0/9007199254740992.0);
}
/* generates a random number on [0,1] with 53-bit resolution*/
static double int_pair_to_real_inclusive(unsigned int a, unsigned int b);
static double
genrand_real2(struct MT *mt)
{
/* mt must be initialized */
unsigned int a = genrand_int32(mt), b = genrand_int32(mt);
return int_pair_to_real_inclusive(a, b);
}
/* These real versions are due to Isaku Wada, 2002/01/09 added */
#undef N
#undef M
typedef struct {
VALUE seed;
struct MT mt;
} rb_random_t;
#define DEFAULT_SEED_CNT 4
static rb_random_t default_rand;
static VALUE rand_init(struct MT *mt, VALUE vseed);
static VALUE random_seed(void);
static rb_random_t *
rand_start(rb_random_t *r)
{
struct MT *mt = &r->mt;
if (!genrand_initialized(mt)) {
r->seed = rand_init(mt, random_seed());
}
return r;
}
static struct MT *
default_mt(void)
{
return &rand_start(&default_rand)->mt;
}
unsigned int
rb_genrand_int32(void)
{
struct MT *mt = default_mt();
return genrand_int32(mt);
}
double
rb_genrand_real(void)
{
struct MT *mt = default_mt();
return genrand_real(mt);
}
#define BDIGITS(x) (RBIGNUM_DIGITS(x))
#define BITSPERDIG (SIZEOF_BDIGITS*CHAR_BIT)
#define BIGRAD ((BDIGIT_DBL)1 << BITSPERDIG)
#define DIGSPERINT (SIZEOF_INT/SIZEOF_BDIGITS)
#define BIGUP(x) ((BDIGIT_DBL)(x) << BITSPERDIG)
#define BIGDN(x) RSHIFT((x),BITSPERDIG)
#define BIGLO(x) ((BDIGIT)((x) & (BIGRAD-1)))
#define BDIGMAX ((BDIGIT)-1)
#define roomof(n, m) (int)(((n)+(m)-1) / (m))
#define numberof(array) (int)(sizeof(array) / sizeof((array)[0]))
#define SIZEOF_INT32 (31/CHAR_BIT + 1)
static double
int_pair_to_real_inclusive(unsigned int a, unsigned int b)
{
VALUE x = rb_big_new(roomof(64, BITSPERDIG), 1);
VALUE m = rb_big_new(roomof(53, BITSPERDIG), 1);
BDIGIT *xd = BDIGITS(x);
int i = 0;
double r;
xd[i++] = (BDIGIT)b;
#if BITSPERDIG < 32
xd[i++] = (BDIGIT)(b >> BITSPERDIG);
#endif
xd[i++] = (BDIGIT)a;
#if BITSPERDIG < 32
xd[i++] = (BDIGIT)(a >> BITSPERDIG);
#endif
xd = BDIGITS(m);
#if BITSPERDIG < 53
MEMZERO(xd, BDIGIT, roomof(53, BITSPERDIG) - 1);
#endif
xd[53 / BITSPERDIG] = 1 << 53 % BITSPERDIG;
xd[0] |= 1;
x = rb_big_mul(x, m);
if (FIXNUM_P(x)) {
#if CHAR_BIT * SIZEOF_LONG > 64
r = (double)(FIX2ULONG(x) >> 64);
#else
return 0.0;
#endif
}
else {
#if 64 % BITSPERDIG == 0
long len = RBIGNUM_LEN(x);
xd = BDIGITS(x);
MEMMOVE(xd, xd + 64 / BITSPERDIG, BDIGIT, len - 64 / BITSPERDIG);
MEMZERO(xd + len - 64 / BITSPERDIG, BDIGIT, 64 / BITSPERDIG);
r = rb_big2dbl(x);
#else
x = rb_big_rshift(x, INT2FIX(64));
if (FIXNUM_P(x)) {
r = (double)FIX2ULONG(x);
}
else {
r = rb_big2dbl(x);
}
#endif
}
return ldexp(r, -53);
}
VALUE rb_cRandom;
#define id_minus '-'
#define id_plus '+'
static ID id_rand, id_bytes;
/* :nodoc: */
static void
random_mark(void *ptr)
{
rb_gc_mark(((rb_random_t *)ptr)->seed);
}
static void
random_free(void *ptr)
{
if (ptr != &default_rand)
xfree(ptr);
}
static size_t
random_memsize(const void *ptr)
{
return ptr ? sizeof(rb_random_t) : 0;
}
static const rb_data_type_t random_data_type = {
"random",
{
random_mark,
random_free,
random_memsize,
},
};
static rb_random_t *
get_rnd(VALUE obj)
{
rb_random_t *ptr;
TypedData_Get_Struct(obj, rb_random_t, &random_data_type, ptr);
return ptr;
}
static rb_random_t *
try_get_rnd(VALUE obj)
{
if (obj == rb_cRandom) {
return rand_start(&default_rand);
}
if (!rb_typeddata_is_kind_of(obj, &random_data_type)) return NULL;
return DATA_PTR(obj);
}
/* :nodoc: */
static VALUE
random_alloc(VALUE klass)
{
rb_random_t *rnd;
VALUE obj = TypedData_Make_Struct(klass, rb_random_t, &random_data_type, rnd);
rnd->seed = INT2FIX(0);
return obj;
}
static VALUE
rand_init(struct MT *mt, VALUE vseed)
{
volatile VALUE seed;
long blen = 0;
long fixnum_seed;
int i, j, len;
unsigned int buf0[SIZEOF_LONG / SIZEOF_INT32 * 4], *buf = buf0;
seed = rb_to_int(vseed);
switch (TYPE(seed)) {
case T_FIXNUM:
len = 1;
fixnum_seed = FIX2LONG(seed);
if (fixnum_seed < 0)
fixnum_seed = -fixnum_seed;
buf[0] = (unsigned int)(fixnum_seed & 0xffffffff);
#if SIZEOF_LONG > SIZEOF_INT32
if ((long)(int32_t)fixnum_seed != fixnum_seed) {
if ((buf[1] = (unsigned int)(fixnum_seed >> 32)) != 0) ++len;
}
#endif
break;
case T_BIGNUM:
blen = RBIGNUM_LEN(seed);
if (blen == 0) {
len = 1;
}
else {
if (blen > MT_MAX_STATE * SIZEOF_INT32 / SIZEOF_BDIGITS)
blen = MT_MAX_STATE * SIZEOF_INT32 / SIZEOF_BDIGITS;
len = roomof((int)blen * SIZEOF_BDIGITS, SIZEOF_INT32);
}
/* allocate ints for init_by_array */
if (len > numberof(buf0)) buf = ALLOC_N(unsigned int, len);
memset(buf, 0, len * sizeof(*buf));
len = 0;
for (i = (int)(blen-1); 0 <= i; i--) {
j = i * SIZEOF_BDIGITS / SIZEOF_INT32;
#if SIZEOF_BDIGITS < SIZEOF_INT32
buf[j] <<= BITSPERDIG;
#endif
buf[j] |= RBIGNUM_DIGITS(seed)[i];
if (!len && buf[j]) len = j;
}
++len;
break;
default:
rb_raise(rb_eTypeError, "failed to convert %s into Integer",
rb_obj_classname(vseed));
}
if (len <= 1) {
init_genrand(mt, buf[0]);
}
else {
if (buf[len-1] == 1) /* remove leading-zero-guard */
len--;
init_by_array(mt, buf, len);
}
if (buf != buf0) xfree(buf);
return seed;
}
/*
* call-seq:
* Random.new(seed = Random.new_seed) -> prng
*
* Creates a new PRNG using +seed+ to set the initial state. If +seed+ is
* omitted, the generator is initialized with Random.new_seed.
*
* See Random.srand for more information on the use of seed values.
*/
static VALUE
random_init(int argc, VALUE *argv, VALUE obj)
{
VALUE vseed;
rb_random_t *rnd = get_rnd(obj);
if (argc == 0) {
rb_check_frozen(obj);
vseed = random_seed();
}
else {
rb_scan_args(argc, argv, "01", &vseed);
rb_check_copyable(obj, vseed);
}
rnd->seed = rand_init(&rnd->mt, vseed);
return obj;
}
#define DEFAULT_SEED_LEN (DEFAULT_SEED_CNT * (int)sizeof(int))
#if defined(S_ISCHR) && !defined(DOSISH)
# define USE_DEV_URANDOM 1
#else
# define USE_DEV_URANDOM 0
#endif
static void
fill_random_seed(unsigned int seed[DEFAULT_SEED_CNT])
{
static int n = 0;
struct timeval tv;
#if USE_DEV_URANDOM
int fd;
struct stat statbuf;
#elif defined(_WIN32)
HCRYPTPROV prov;
#endif
memset(seed, 0, DEFAULT_SEED_LEN);
#if USE_DEV_URANDOM
if ((fd = rb_cloexec_open("/dev/urandom", O_RDONLY
#ifdef O_NONBLOCK
|O_NONBLOCK
#endif
#ifdef O_NOCTTY
|O_NOCTTY
#endif
, 0)) >= 0) {
rb_update_max_fd(fd);
if (fstat(fd, &statbuf) == 0 && S_ISCHR(statbuf.st_mode)) {
if (read(fd, seed, DEFAULT_SEED_LEN) < DEFAULT_SEED_LEN) {
/* abandon */;
}
}
close(fd);
}
#elif defined(_WIN32)
if (CryptAcquireContext(&prov, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) {
CryptGenRandom(prov, DEFAULT_SEED_LEN, (void *)seed);
CryptReleaseContext(prov, 0);
}
#endif
gettimeofday(&tv, 0);
seed[0] ^= tv.tv_usec;
seed[1] ^= (unsigned int)tv.tv_sec;
#if SIZEOF_TIME_T > SIZEOF_INT
seed[0] ^= (unsigned int)((time_t)tv.tv_sec >> SIZEOF_INT * CHAR_BIT);
#endif
seed[2] ^= getpid() ^ (n++ << 16);
seed[3] ^= (unsigned int)(VALUE)&seed;
#if SIZEOF_VOIDP > SIZEOF_INT
seed[2] ^= (unsigned int)((VALUE)&seed >> SIZEOF_INT * CHAR_BIT);
#endif
}
static VALUE
make_seed_value(const void *ptr)
{
const long len = DEFAULT_SEED_LEN/SIZEOF_BDIGITS;
BDIGIT *digits;
NEWOBJ(big, struct RBignum);
OBJSETUP(big, rb_cBignum, T_BIGNUM);
RBIGNUM_SET_SIGN(big, 1);
rb_big_resize((VALUE)big, len + 1);
digits = RBIGNUM_DIGITS(big);
MEMCPY(digits, ptr, char, DEFAULT_SEED_LEN);
/* set leading-zero-guard if need. */
digits[len] =
#if SIZEOF_INT32 / SIZEOF_BDIGITS > 1
digits[len-2] <= 1 && digits[len-1] == 0
#else
digits[len-1] <= 1
#endif
? 1 : 0;
return rb_big_norm((VALUE)big);
}
/*
* call-seq: Random.new_seed -> integer
*
* Returns an arbitrary seed value. This is used by Random.new
* when no seed value is specified as an argument.
*
* Random.new_seed #=> 115032730400174366788466674494640623225
*/
static VALUE
random_seed(void)
{
unsigned int buf[DEFAULT_SEED_CNT];
fill_random_seed(buf);
return make_seed_value(buf);
}
/*
* call-seq: prng.seed -> integer
*
* Returns the seed value used to initialize the generator. This may be used to
* initialize another generator with the same state at a later time, causing it
* to produce the same sequence of numbers.
*
* prng1 = Random.new(1234)
* prng1.seed #=> 1234
* prng1.rand(100) #=> 47
*
* prng2 = Random.new(prng1.seed)
* prng2.rand(100) #=> 47
*/
static VALUE
random_get_seed(VALUE obj)
{
return get_rnd(obj)->seed;
}
/* :nodoc: */
static VALUE
random_copy(VALUE obj, VALUE orig)
{
rb_random_t *rnd1, *rnd2;
struct MT *mt;
if (!OBJ_INIT_COPY(obj, orig)) return obj;
rnd1 = get_rnd(obj);
rnd2 = get_rnd(orig);
mt = &rnd1->mt;
*rnd1 = *rnd2;
mt->next = mt->state + numberof(mt->state) - mt->left + 1;
return obj;
}
static VALUE
mt_state(const struct MT *mt)
{
VALUE bigo = rb_big_new(sizeof(mt->state) / sizeof(BDIGIT), 1);
BDIGIT *d = RBIGNUM_DIGITS(bigo);
int i;
for (i = 0; i < numberof(mt->state); ++i) {
unsigned int x = mt->state[i];
#if SIZEOF_BDIGITS < SIZEOF_INT32
int j;
for (j = 0; j < SIZEOF_INT32 / SIZEOF_BDIGITS; ++j) {
*d++ = BIGLO(x);
x = BIGDN(x);
}
#else
*d++ = (BDIGIT)x;
#endif
}
return rb_big_norm(bigo);
}
/* :nodoc: */
static VALUE
random_state(VALUE obj)
{
rb_random_t *rnd = get_rnd(obj);
return mt_state(&rnd->mt);
}
/* :nodoc: */
static VALUE
random_s_state(VALUE klass)
{
return mt_state(&default_rand.mt);
}
/* :nodoc: */
static VALUE
random_left(VALUE obj)
{
rb_random_t *rnd = get_rnd(obj);
return INT2FIX(rnd->mt.left);
}
/* :nodoc: */
static VALUE
random_s_left(VALUE klass)
{
return INT2FIX(default_rand.mt.left);
}
/* :nodoc: */
static VALUE
random_dump(VALUE obj)
{
rb_random_t *rnd = get_rnd(obj);
VALUE dump = rb_ary_new2(3);
rb_ary_push(dump, mt_state(&rnd->mt));
rb_ary_push(dump, INT2FIX(rnd->mt.left));
rb_ary_push(dump, rnd->seed);
return dump;
}
/* :nodoc: */
static VALUE
random_load(VALUE obj, VALUE dump)
{
rb_random_t *rnd = get_rnd(obj);
struct MT *mt = &rnd->mt;
VALUE state, left = INT2FIX(1), seed = INT2FIX(0);
VALUE *ary;
unsigned long x;
rb_check_copyable(obj, dump);
Check_Type(dump, T_ARRAY);
ary = RARRAY_PTR(dump);
switch (RARRAY_LEN(dump)) {
case 3:
seed = ary[2];
case 2:
left = ary[1];
case 1:
state = ary[0];
break;
default:
rb_raise(rb_eArgError, "wrong dump data");
}
memset(mt->state, 0, sizeof(mt->state));
if (FIXNUM_P(state)) {
x = FIX2ULONG(state);
mt->state[0] = (unsigned int)x;
#if SIZEOF_LONG / SIZEOF_INT >= 2
mt->state[1] = (unsigned int)(x >> BITSPERDIG);
#endif
#if SIZEOF_LONG / SIZEOF_INT >= 3
mt->state[2] = (unsigned int)(x >> 2 * BITSPERDIG);
#endif
#if SIZEOF_LONG / SIZEOF_INT >= 4
mt->state[3] = (unsigned int)(x >> 3 * BITSPERDIG);
#endif
}
else {
BDIGIT *d;
long len;
Check_Type(state, T_BIGNUM);
len = RBIGNUM_LEN(state);
if (len > roomof(sizeof(mt->state), SIZEOF_BDIGITS)) {
len = roomof(sizeof(mt->state), SIZEOF_BDIGITS);
}
#if SIZEOF_BDIGITS < SIZEOF_INT
else if (len % DIGSPERINT) {
d = RBIGNUM_DIGITS(state) + len;
# if DIGSPERINT == 2
--len;
x = *--d;
# else
x = 0;
do {
x = (x << BITSPERDIG) | *--d;
} while (--len % DIGSPERINT);
# endif
mt->state[len / DIGSPERINT] = (unsigned int)x;
}
#endif
if (len > 0) {
d = BDIGITS(state) + len;
do {
--len;
x = *--d;
# if DIGSPERINT == 2
--len;
x = (x << BITSPERDIG) | *--d;
# elif SIZEOF_BDIGITS < SIZEOF_INT
do {
x = (x << BITSPERDIG) | *--d;
} while (--len % DIGSPERINT);
# endif
mt->state[len / DIGSPERINT] = (unsigned int)x;
} while (len > 0);
}
}
x = NUM2ULONG(left);
if (x > numberof(mt->state)) {
rb_raise(rb_eArgError, "wrong value");
}
mt->left = (unsigned int)x;
mt->next = mt->state + numberof(mt->state) - x + 1;
rnd->seed = rb_to_int(seed);
return obj;
}
/*
* call-seq:
* srand(number = Random.new_seed) -> old_seed
*
* Seeds the system pseudo-random number generator, Random::DEFAULT, with
* +number+. The previous seed value is returned.
*
* If +number+ is omitted, seeds the generator using a source of entropy
* provided by the operating system, if available (/dev/urandom on Unix systems
* or the RSA cryptographic provider on Windows), which is then combined with
* the time, the process id, and a sequence number.
*
* srand may be used to ensure repeatable sequences of pseudo-random numbers
* between different runs of the program. By setting the seed to a known value,
* programs can be made deterministic during testing.
*
* srand 1234 # => 268519324636777531569100071560086917274
* [ rand, rand ] # => [0.1915194503788923, 0.6221087710398319]
* [ rand(10), rand(1000) ] # => [4, 664]
* srand 1234 # => 1234
* [ rand, rand ] # => [0.1915194503788923, 0.6221087710398319]
*/
static VALUE
rb_f_srand(int argc, VALUE *argv, VALUE obj)
{
VALUE seed, old;
rb_random_t *r = &default_rand;
rb_secure(4);
if (argc == 0) {
seed = random_seed();
}
else {
rb_scan_args(argc, argv, "01", &seed);
}
old = r->seed;
r->seed = rand_init(&r->mt, seed);
return old;
}
static unsigned long
make_mask(unsigned long x)
{
x = x | x >> 1;
x = x | x >> 2;
x = x | x >> 4;
x = x | x >> 8;
x = x | x >> 16;
#if 4 < SIZEOF_LONG
x = x | x >> 32;
#endif
return x;
}
static unsigned long
limited_rand(struct MT *mt, unsigned long limit)
{
/* mt must be initialized */
int i;
unsigned long val, mask;
if (!limit) return 0;
mask = make_mask(limit);
retry:
val = 0;
for (i = SIZEOF_LONG/SIZEOF_INT32-1; 0 <= i; i--) {
if ((mask >> (i * 32)) & 0xffffffff) {
val |= (unsigned long)genrand_int32(mt) << (i * 32);
val &= mask;
if (limit < val)
goto retry;
}
}
return val;
}
static VALUE
limited_big_rand(struct MT *mt, struct RBignum *limit)
{
/* mt must be initialized */
unsigned long mask, lim, rnd;
struct RBignum *val;
long i, len;
int boundary;
len = (RBIGNUM_LEN(limit) * SIZEOF_BDIGITS + 3) / 4;
val = (struct RBignum *)rb_big_clone((VALUE)limit);
RBIGNUM_SET_SIGN(val, 1);
#if SIZEOF_BDIGITS == 2
# define BIG_GET32(big,i) \
(RBIGNUM_DIGITS(big)[(i)*2] | \
((i)*2+1 < RBIGNUM_LEN(big) ? \
(RBIGNUM_DIGITS(big)[(i)*2+1] << 16) : \
0))
# define BIG_SET32(big,i,d) \
((RBIGNUM_DIGITS(big)[(i)*2] = (d) & 0xffff), \
((i)*2+1 < RBIGNUM_LEN(big) ? \
(RBIGNUM_DIGITS(big)[(i)*2+1] = (d) >> 16) : \
0))
#else
/* SIZEOF_BDIGITS == 4 */
# define BIG_GET32(big,i) (RBIGNUM_DIGITS(big)[(i)])
# define BIG_SET32(big,i,d) (RBIGNUM_DIGITS(big)[(i)] = (d))
#endif
retry:
mask = 0;
boundary = 1;
for (i = len-1; 0 <= i; i--) {
lim = BIG_GET32(limit, i);
mask = mask ? 0xffffffff : make_mask(lim);
if (mask) {
rnd = genrand_int32(mt) & mask;
if (boundary) {
if (lim < rnd)
goto retry;
if (rnd < lim)
boundary = 0;
}
}
else {
rnd = 0;
}
BIG_SET32(val, i, (BDIGIT)rnd);
}
return rb_big_norm((VALUE)val);
}
/*
* Returns random unsigned long value in [0, +limit+].
*
* Note that +limit+ is included, and the range of the argument and the
* return value depends on environments.
*/
unsigned long
rb_genrand_ulong_limited(unsigned long limit)
{
return limited_rand(default_mt(), limit);
}
unsigned int
rb_random_int32(VALUE obj)
{
rb_random_t *rnd = try_get_rnd(obj);
if (!rnd) {
#if SIZEOF_LONG * CHAR_BIT > 32
VALUE lim = ULONG2NUM(0x100000000UL);
#elif defined HAVE_LONG_LONG
VALUE lim = ULL2NUM((LONG_LONG)0xffffffff+1);
#else
VALUE lim = rb_big_plus(ULONG2NUM(0xffffffff), INT2FIX(1));
#endif
return (unsigned int)NUM2ULONG(rb_funcall2(obj, id_rand, 1, &lim));
}
return genrand_int32(&rnd->mt);
}
double
rb_random_real(VALUE obj)
{
rb_random_t *rnd = try_get_rnd(obj);
if (!rnd) {
VALUE v = rb_funcall2(obj, id_rand, 0, 0);
double d = NUM2DBL(v);
if (d < 0.0 || d >= 1.0) {
rb_raise(rb_eRangeError, "random number too big %g", d);
}
return d;
}
return genrand_real(&rnd->mt);
}
/*
* call-seq: prng.bytes(size) -> a_string
*
* Returns a random binary string containing +size+ bytes.
*
* random_string = Random.new.bytes(10) # => "\xD7:R\xAB?\x83\xCE\xFAkO"
* random_string.size # => 10
*/
static VALUE
random_bytes(VALUE obj, VALUE len)
{
return rb_random_bytes(obj, NUM2LONG(rb_to_int(len)));
}
VALUE
rb_random_bytes(VALUE obj, long n)
{
rb_random_t *rnd = try_get_rnd(obj);
VALUE bytes;
char *ptr;
unsigned int r, i;
if (!rnd) {
VALUE len = LONG2NUM(n);
return rb_funcall2(obj, id_bytes, 1, &len);
}
bytes = rb_str_new(0, n);
ptr = RSTRING_PTR(bytes);
for (; n >= SIZEOF_INT32; n -= SIZEOF_INT32) {
r = genrand_int32(&rnd->mt);
i = SIZEOF_INT32;
do {
*ptr++ = (char)r;
r >>= CHAR_BIT;
} while (--i);
}
if (n > 0) {
r = genrand_int32(&rnd->mt);
do {
*ptr++ = (char)r;
r >>= CHAR_BIT;
} while (--n);
}
return bytes;
}
static VALUE
range_values(VALUE vmax, VALUE *begp, VALUE *endp, int *exclp)
{
VALUE end, r;
if (!rb_range_values(vmax, begp, &end, exclp)) return Qfalse;
if (endp) *endp = end;
if (!rb_respond_to(end, id_minus)) return Qfalse;
r = rb_funcall2(end, id_minus, 1, begp);
if (NIL_P(r)) return Qfalse;
return r;
}