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/*
** random.c - Random module
**
** See Copyright Notice in mruby.h
*/
#include <mruby.h>
#include <mruby/variable.h>
#include <mruby/class.h>
#include <mruby/data.h>
#include <mruby/array.h>
#include "mt19937ar.h"
#include <time.h>
static char const MT_STATE_KEY[] = "$mrb_i_mt_state";
static const struct mrb_data_type mt_state_type = {
MT_STATE_KEY, mrb_free,
};
static mrb_value mrb_random_rand(mrb_state *mrb, mrb_value self);
static mrb_value mrb_random_srand(mrb_state *mrb, mrb_value self);
static void
mt_srand(mt_state *t, unsigned long seed)
{
mrb_random_init_genrand(t, seed);
}
static unsigned long
mt_rand(mt_state *t)
{
return mrb_random_genrand_int32(t);
}
static double
mt_rand_real(mt_state *t)
{
return mrb_random_genrand_real1(t);
}
static mrb_value
mrb_random_mt_srand(mrb_state *mrb, mt_state *t, mrb_value seed)
{
if (mrb_nil_p(seed)) {
seed = mrb_fixnum_value((mrb_int)(time(NULL) + mt_rand(t)));
if (mrb_fixnum(seed) < 0) {
seed = mrb_fixnum_value(0 - mrb_fixnum(seed));
}
}
mt_srand(t, (unsigned) mrb_fixnum(seed));
return seed;
}
static mrb_value
mrb_random_mt_rand(mrb_state *mrb, mt_state *t, mrb_value max)
{
mrb_value value;
if (mrb_fixnum(max) == 0) {
value = mrb_float_value(mrb, mt_rand_real(t));
}
else {
value = mrb_fixnum_value(mt_rand(t) % mrb_fixnum(max));
}
return value;
}
static mrb_value
get_opt(mrb_state* mrb)
{
mrb_value arg;
arg = mrb_nil_value();
mrb_get_args(mrb, "|o", &arg);
if (!mrb_nil_p(arg)) {
arg = mrb_check_convert_type(mrb, arg, MRB_TT_FIXNUM, "Fixnum", "to_int");
if (mrb_nil_p(arg)) {
mrb_raise(mrb, E_ARGUMENT_ERROR, "invalid argument type");
}
if (mrb_fixnum(arg) < 0) {
arg = mrb_fixnum_value(0 - mrb_fixnum(arg));
}
}
return arg;
}
static mrb_value
get_random(mrb_state *mrb) {
return mrb_const_get(mrb,
mrb_obj_value(mrb_class_get(mrb, "Random")),
mrb_intern_lit(mrb, "DEFAULT"));
}
static mt_state *
get_random_state(mrb_state *mrb)
{
mrb_value random_val = get_random(mrb);
return DATA_GET_PTR(mrb, random_val, &mt_state_type, mt_state);
}
static mrb_value
mrb_random_g_rand(mrb_state *mrb, mrb_value self)
{
mrb_value random = get_random(mrb);
return mrb_random_rand(mrb, random);
}
static mrb_value
mrb_random_g_srand(mrb_state *mrb, mrb_value self)
{
mrb_value random = get_random(mrb);
return mrb_random_srand(mrb, random);
}
static mrb_value
mrb_random_init(mrb_state *mrb, mrb_value self)
{
mrb_value seed;
mt_state *t;
seed = get_opt(mrb);
/* avoid memory leaks */
t = (mt_state*)DATA_PTR(self);
if (t) {
mrb_free(mrb, t);
}
mrb_data_init(self, NULL, &mt_state_type);
t = (mt_state *)mrb_malloc(mrb, sizeof(mt_state));
t->mti = N + 1;
seed = mrb_random_mt_srand(mrb, t, seed);
if (mrb_nil_p(seed)) {
t->has_seed = FALSE;
}
else {
mrb_assert(mrb_fixnum_p(seed));
t->has_seed = TRUE;
t->seed = mrb_fixnum(seed);
}
mrb_data_init(self, t, &mt_state_type);
return self;
}
static void
mrb_random_rand_seed(mrb_state *mrb, mt_state *t)
{
if (!t->has_seed) {
mrb_random_mt_srand(mrb, t, mrb_nil_value());
}
}
static mrb_value
mrb_random_rand(mrb_state *mrb, mrb_value self)
{
mrb_value max;
mt_state *t = DATA_GET_PTR(mrb, self, &mt_state_type, mt_state);
max = get_opt(mrb);
mrb_random_rand_seed(mrb, t);
return mrb_random_mt_rand(mrb, t, max);
}
static mrb_value
mrb_random_srand(mrb_state *mrb, mrb_value self)
{
mrb_value seed;
mrb_value old_seed;
mt_state *t = DATA_GET_PTR(mrb, self, &mt_state_type, mt_state);
seed = get_opt(mrb);
seed = mrb_random_mt_srand(mrb, t, seed);
old_seed = t->has_seed? mrb_fixnum_value(t->seed) : mrb_nil_value();
if (mrb_nil_p(seed)) {
t->has_seed = FALSE;
}
else {
mrb_assert(mrb_fixnum_p(seed));
t->has_seed = TRUE;
t->seed = mrb_fixnum(seed);
}
return old_seed;
}
/*
* call-seq:
* ary.shuffle! -> ary
*
* Shuffles elements in self in place.
*/
static mrb_value
mrb_ary_shuffle_bang(mrb_state *mrb, mrb_value ary)
{
mrb_int i;
mt_state *random = NULL;
if (RARRAY_LEN(ary) > 1) {
mrb_get_args(mrb, "|d", &random, &mt_state_type);
if (random == NULL) {
random = get_random_state(mrb);
}
mrb_random_rand_seed(mrb, random);
mrb_ary_modify(mrb, mrb_ary_ptr(ary));
for (i = RARRAY_LEN(ary) - 1; i > 0; i--) {
mrb_int j;
mrb_value *ptr = RARRAY_PTR(ary);
mrb_value tmp;
j = mrb_fixnum(mrb_random_mt_rand(mrb, random, mrb_fixnum_value(RARRAY_LEN(ary))));
tmp = ptr[i];
ptr[i] = ptr[j];
ptr[j] = tmp;
}
}
return ary;
}
/*
* call-seq:
* ary.shuffle -> new_ary
*
* Returns a new array with elements of self shuffled.
*/
static mrb_value
mrb_ary_shuffle(mrb_state *mrb, mrb_value ary)
{
mrb_value new_ary = mrb_ary_new_from_values(mrb, RARRAY_LEN(ary), RARRAY_PTR(ary));
mrb_ary_shuffle_bang(mrb, new_ary);
return new_ary;
}
/*
* call-seq:
* ary.sample -> obj
* ary.sample(n) -> new_ary
*
* Choose a random element or +n+ random elements from the array.
*
* The elements are chosen by using random and unique indices into the array
* in order to ensure that an element doesn't repeat itself unless the array
* already contained duplicate elements.
*
* If the array is empty the first form returns +nil+ and the second form
* returns an empty array.
*/
static mrb_value
mrb_ary_sample(mrb_state *mrb, mrb_value ary)
{
mrb_int n = 0;
mrb_bool given;
mt_state *random = NULL;
mrb_int len;
mrb_get_args(mrb, "|i?d", &n, &given, &random, &mt_state_type);
if (random == NULL) {
random = get_random_state(mrb);
}
mrb_random_rand_seed(mrb, random);
mt_rand(random);
len = RARRAY_LEN(ary);
if (!given) { /* pick one element */
switch (len) {
case 0:
return mrb_nil_value();
case 1:
return RARRAY_PTR(ary)[0];
default:
return RARRAY_PTR(ary)[mt_rand(random) % len];
}
}
else {
mrb_value result;
mrb_int i, j;
if (n < 0) mrb_raise(mrb, E_ARGUMENT_ERROR, "negative sample number");
if (n > len) n = len;
result = mrb_ary_new_capa(mrb, n);
for (i=0; i<n; i++) {
mrb_int r;
for (;;) {
retry:
r = mt_rand(random) % len;
for (j=0; j<i; j++) {
if (mrb_fixnum(RARRAY_PTR(result)[j]) == r) {
goto retry; /* retry if duplicate */
}
}
break;
}
mrb_ary_push(mrb, result, mrb_fixnum_value(r));
}
for (i=0; i<n; i++) {
mrb_ary_set(mrb, result, i, RARRAY_PTR(ary)[mrb_fixnum(RARRAY_PTR(result)[i])]);
}
return result;
}
}
void mrb_mruby_random_gem_init(mrb_state *mrb)
{
struct RClass *random;
struct RClass *array = mrb->array_class;
mrb_define_method(mrb, mrb->kernel_module, "rand", mrb_random_g_rand, MRB_ARGS_OPT(1));
mrb_define_method(mrb, mrb->kernel_module, "srand", mrb_random_g_srand, MRB_ARGS_OPT(1));
random = mrb_define_class(mrb, "Random", mrb->object_class);
MRB_SET_INSTANCE_TT(random, MRB_TT_DATA);
mrb_define_class_method(mrb, random, "rand", mrb_random_g_rand, MRB_ARGS_OPT(1));
mrb_define_class_method(mrb, random, "srand", mrb_random_g_srand, MRB_ARGS_OPT(1));
mrb_define_method(mrb, random, "initialize", mrb_random_init, MRB_ARGS_OPT(1));
mrb_define_method(mrb, random, "rand", mrb_random_rand, MRB_ARGS_OPT(1));
mrb_define_method(mrb, random, "srand", mrb_random_srand, MRB_ARGS_OPT(1));
mrb_define_method(mrb, array, "shuffle", mrb_ary_shuffle, MRB_ARGS_OPT(1));
mrb_define_method(mrb, array, "shuffle!", mrb_ary_shuffle_bang, MRB_ARGS_OPT(1));
mrb_define_method(mrb, array, "sample", mrb_ary_sample, MRB_ARGS_OPT(2));
mrb_const_set(mrb, mrb_obj_value(random), mrb_intern_lit(mrb, "DEFAULT"),
mrb_obj_new(mrb, random, 0, NULL));
}
void mrb_mruby_random_gem_final(mrb_state *mrb)
{
}