1 /*
2 ** random.c - Random module
3 **
4 ** See Copyright Notice in mruby.h
5 */
6
7 #include <mruby.h>
8 #include <mruby/variable.h>
9 #include <mruby/class.h>
10 #include <mruby/data.h>
11 #include <mruby/array.h>
12 #include "mt19937ar.h"
13
14 #include <time.h>
15
16 static char const MT_STATE_KEY[] = "$mrb_i_mt_state";
17
18 static const struct mrb_data_type mt_state_type = {
19 MT_STATE_KEY, mrb_free,
20 };
21
22 static mrb_value mrb_random_rand(mrb_state *mrb, mrb_value self);
23 static mrb_value mrb_random_srand(mrb_state *mrb, mrb_value self);
24
25 static void
mt_srand(mt_state * t,unsigned long seed)26 mt_srand(mt_state *t, unsigned long seed)
27 {
28 mrb_random_init_genrand(t, seed);
29 }
30
31 static unsigned long
mt_rand(mt_state * t)32 mt_rand(mt_state *t)
33 {
34 return mrb_random_genrand_int32(t);
35 }
36
37 static double
mt_rand_real(mt_state * t)38 mt_rand_real(mt_state *t)
39 {
40 return mrb_random_genrand_real1(t);
41 }
42
43 static mrb_value
mrb_random_mt_srand(mrb_state * mrb,mt_state * t,mrb_value seed)44 mrb_random_mt_srand(mrb_state *mrb, mt_state *t, mrb_value seed)
45 {
46 if (mrb_nil_p(seed)) {
47 seed = mrb_fixnum_value((mrb_int)(time(NULL) + mt_rand(t)));
48 if (mrb_fixnum(seed) < 0) {
49 seed = mrb_fixnum_value(0 - mrb_fixnum(seed));
50 }
51 }
52
53 mt_srand(t, (unsigned) mrb_fixnum(seed));
54
55 return seed;
56 }
57
58 static mrb_value
mrb_random_mt_rand(mrb_state * mrb,mt_state * t,mrb_value max)59 mrb_random_mt_rand(mrb_state *mrb, mt_state *t, mrb_value max)
60 {
61 mrb_value value;
62
63 if (mrb_fixnum(max) == 0) {
64 value = mrb_float_value(mrb, mt_rand_real(t));
65 }
66 else {
67 value = mrb_fixnum_value(mt_rand(t) % mrb_fixnum(max));
68 }
69
70 return value;
71 }
72
73 static mrb_value
get_opt(mrb_state * mrb)74 get_opt(mrb_state* mrb)
75 {
76 mrb_value arg;
77
78 arg = mrb_nil_value();
79 mrb_get_args(mrb, "|o", &arg);
80
81 if (!mrb_nil_p(arg)) {
82 mrb_int i;
83
84 arg = mrb_to_int(mrb, arg);
85 i = mrb_fixnum(arg);
86 if (i < 0) {
87 arg = mrb_fixnum_value(0 - i);
88 }
89 }
90 return arg;
91 }
92
93 static mrb_value
get_random(mrb_state * mrb)94 get_random(mrb_state *mrb) {
95 return mrb_const_get(mrb,
96 mrb_obj_value(mrb_class_get(mrb, "Random")),
97 mrb_intern_lit(mrb, "DEFAULT"));
98 }
99
100 static mt_state *
get_random_state(mrb_state * mrb)101 get_random_state(mrb_state *mrb)
102 {
103 mrb_value random_val = get_random(mrb);
104 return DATA_GET_PTR(mrb, random_val, &mt_state_type, mt_state);
105 }
106
107 static mrb_value
mrb_random_g_rand(mrb_state * mrb,mrb_value self)108 mrb_random_g_rand(mrb_state *mrb, mrb_value self)
109 {
110 mrb_value random = get_random(mrb);
111 return mrb_random_rand(mrb, random);
112 }
113
114 static mrb_value
mrb_random_g_srand(mrb_state * mrb,mrb_value self)115 mrb_random_g_srand(mrb_state *mrb, mrb_value self)
116 {
117 mrb_value random = get_random(mrb);
118 return mrb_random_srand(mrb, random);
119 }
120
121 static mrb_value
mrb_random_init(mrb_state * mrb,mrb_value self)122 mrb_random_init(mrb_state *mrb, mrb_value self)
123 {
124 mrb_value seed;
125 mt_state *t;
126
127 seed = get_opt(mrb);
128
129 /* avoid memory leaks */
130 t = (mt_state*)DATA_PTR(self);
131 if (t) {
132 mrb_free(mrb, t);
133 }
134 mrb_data_init(self, NULL, &mt_state_type);
135
136 t = (mt_state *)mrb_malloc(mrb, sizeof(mt_state));
137 t->mti = N + 1;
138
139 seed = mrb_random_mt_srand(mrb, t, seed);
140 if (mrb_nil_p(seed)) {
141 t->has_seed = FALSE;
142 }
143 else {
144 mrb_assert(mrb_fixnum_p(seed));
145 t->has_seed = TRUE;
146 t->seed = mrb_fixnum(seed);
147 }
148
149 mrb_data_init(self, t, &mt_state_type);
150
151 return self;
152 }
153
154 static void
mrb_random_rand_seed(mrb_state * mrb,mt_state * t)155 mrb_random_rand_seed(mrb_state *mrb, mt_state *t)
156 {
157 if (!t->has_seed) {
158 mrb_random_mt_srand(mrb, t, mrb_nil_value());
159 }
160 }
161
162 static mrb_value
mrb_random_rand(mrb_state * mrb,mrb_value self)163 mrb_random_rand(mrb_state *mrb, mrb_value self)
164 {
165 mrb_value max;
166 mt_state *t = DATA_GET_PTR(mrb, self, &mt_state_type, mt_state);
167
168 max = get_opt(mrb);
169 mrb_random_rand_seed(mrb, t);
170 return mrb_random_mt_rand(mrb, t, max);
171 }
172
173 static mrb_value
mrb_random_srand(mrb_state * mrb,mrb_value self)174 mrb_random_srand(mrb_state *mrb, mrb_value self)
175 {
176 mrb_value seed;
177 mrb_value old_seed;
178 mt_state *t = DATA_GET_PTR(mrb, self, &mt_state_type, mt_state);
179
180 seed = get_opt(mrb);
181 seed = mrb_random_mt_srand(mrb, t, seed);
182 old_seed = t->has_seed? mrb_fixnum_value(t->seed) : mrb_nil_value();
183 if (mrb_nil_p(seed)) {
184 t->has_seed = FALSE;
185 }
186 else {
187 mrb_assert(mrb_fixnum_p(seed));
188 t->has_seed = TRUE;
189 t->seed = mrb_fixnum(seed);
190 }
191
192 return old_seed;
193 }
194
195 /*
196 * call-seq:
197 * ary.shuffle! -> ary
198 *
199 * Shuffles elements in self in place.
200 */
201
202 static mrb_value
mrb_ary_shuffle_bang(mrb_state * mrb,mrb_value ary)203 mrb_ary_shuffle_bang(mrb_state *mrb, mrb_value ary)
204 {
205 mrb_int i;
206 mt_state *random = NULL;
207
208 if (RARRAY_LEN(ary) > 1) {
209 mrb_get_args(mrb, "|d", &random, &mt_state_type);
210
211 if (random == NULL) {
212 random = get_random_state(mrb);
213 }
214 mrb_random_rand_seed(mrb, random);
215
216 mrb_ary_modify(mrb, mrb_ary_ptr(ary));
217
218 for (i = RARRAY_LEN(ary) - 1; i > 0; i--) {
219 mrb_int j;
220 mrb_value *ptr = RARRAY_PTR(ary);
221 mrb_value tmp;
222
223
224 j = mrb_fixnum(mrb_random_mt_rand(mrb, random, mrb_fixnum_value(RARRAY_LEN(ary))));
225
226 tmp = ptr[i];
227 ptr[i] = ptr[j];
228 ptr[j] = tmp;
229 }
230 }
231
232 return ary;
233 }
234
235 /*
236 * call-seq:
237 * ary.shuffle -> new_ary
238 *
239 * Returns a new array with elements of self shuffled.
240 */
241
242 static mrb_value
mrb_ary_shuffle(mrb_state * mrb,mrb_value ary)243 mrb_ary_shuffle(mrb_state *mrb, mrb_value ary)
244 {
245 mrb_value new_ary = mrb_ary_new_from_values(mrb, RARRAY_LEN(ary), RARRAY_PTR(ary));
246 mrb_ary_shuffle_bang(mrb, new_ary);
247
248 return new_ary;
249 }
250
251 /*
252 * call-seq:
253 * ary.sample -> obj
254 * ary.sample(n) -> new_ary
255 *
256 * Choose a random element or +n+ random elements from the array.
257 *
258 * The elements are chosen by using random and unique indices into the array
259 * in order to ensure that an element doesn't repeat itself unless the array
260 * already contained duplicate elements.
261 *
262 * If the array is empty the first form returns +nil+ and the second form
263 * returns an empty array.
264 */
265
266 static mrb_value
mrb_ary_sample(mrb_state * mrb,mrb_value ary)267 mrb_ary_sample(mrb_state *mrb, mrb_value ary)
268 {
269 mrb_int n = 0;
270 mrb_bool given;
271 mt_state *random = NULL;
272 mrb_int len;
273
274 mrb_get_args(mrb, "|i?d", &n, &given, &random, &mt_state_type);
275 if (random == NULL) {
276 random = get_random_state(mrb);
277 }
278 mrb_random_rand_seed(mrb, random);
279 mt_rand(random);
280 len = RARRAY_LEN(ary);
281 if (!given) { /* pick one element */
282 switch (len) {
283 case 0:
284 return mrb_nil_value();
285 case 1:
286 return RARRAY_PTR(ary)[0];
287 default:
288 return RARRAY_PTR(ary)[mt_rand(random) % len];
289 }
290 }
291 else {
292 mrb_value result;
293 mrb_int i, j;
294
295 if (n < 0) mrb_raise(mrb, E_ARGUMENT_ERROR, "negative sample number");
296 if (n > len) n = len;
297 result = mrb_ary_new_capa(mrb, n);
298 for (i=0; i<n; i++) {
299 mrb_int r;
300
301 for (;;) {
302 retry:
303 r = mt_rand(random) % len;
304
305 for (j=0; j<i; j++) {
306 if (mrb_fixnum(RARRAY_PTR(result)[j]) == r) {
307 goto retry; /* retry if duplicate */
308 }
309 }
310 break;
311 }
312 mrb_ary_push(mrb, result, mrb_fixnum_value(r));
313 }
314 for (i=0; i<n; i++) {
315 mrb_ary_set(mrb, result, i, RARRAY_PTR(ary)[mrb_fixnum(RARRAY_PTR(result)[i])]);
316 }
317 return result;
318 }
319 }
320
321
mrb_mruby_random_gem_init(mrb_state * mrb)322 void mrb_mruby_random_gem_init(mrb_state *mrb)
323 {
324 struct RClass *random;
325 struct RClass *array = mrb->array_class;
326
327 mrb_define_method(mrb, mrb->kernel_module, "rand", mrb_random_g_rand, MRB_ARGS_OPT(1));
328 mrb_define_method(mrb, mrb->kernel_module, "srand", mrb_random_g_srand, MRB_ARGS_OPT(1));
329
330 random = mrb_define_class(mrb, "Random", mrb->object_class);
331 MRB_SET_INSTANCE_TT(random, MRB_TT_DATA);
332 mrb_define_class_method(mrb, random, "rand", mrb_random_g_rand, MRB_ARGS_OPT(1));
333 mrb_define_class_method(mrb, random, "srand", mrb_random_g_srand, MRB_ARGS_OPT(1));
334
335 mrb_define_method(mrb, random, "initialize", mrb_random_init, MRB_ARGS_OPT(1));
336 mrb_define_method(mrb, random, "rand", mrb_random_rand, MRB_ARGS_OPT(1));
337 mrb_define_method(mrb, random, "srand", mrb_random_srand, MRB_ARGS_OPT(1));
338
339 mrb_define_method(mrb, array, "shuffle", mrb_ary_shuffle, MRB_ARGS_OPT(1));
340 mrb_define_method(mrb, array, "shuffle!", mrb_ary_shuffle_bang, MRB_ARGS_OPT(1));
341 mrb_define_method(mrb, array, "sample", mrb_ary_sample, MRB_ARGS_OPT(2));
342
343 mrb_const_set(mrb, mrb_obj_value(random), mrb_intern_lit(mrb, "DEFAULT"),
344 mrb_obj_new(mrb, random, 0, NULL));
345 }
346
mrb_mruby_random_gem_final(mrb_state * mrb)347 void mrb_mruby_random_gem_final(mrb_state *mrb)
348 {
349 }
350