1 /*
2 * This file is part of the MicroPython project, http://micropython.org/
3 *
4 * The MIT License (MIT)
5 *
6 * Copyright (c) 2016 Paul Sokolovsky
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this software and associated documentation files (the "Software"), to deal
10 * in the Software without restriction, including without limitation the rights
11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12 * copies of the Software, and to permit persons to whom the Software is
13 * furnished to do so, subject to the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24 * THE SOFTWARE.
25 */
26
27 #include <assert.h>
28 #include <string.h>
29
30 #include "py/runtime.h"
31
32 #if MICROPY_PY_URANDOM
33
34 // Work out if the seed will be set on import or not.
35 #if MICROPY_MODULE_BUILTIN_INIT && defined(MICROPY_PY_URANDOM_SEED_INIT_FUNC)
36 #define SEED_ON_IMPORT (1)
37 #else
38 #define SEED_ON_IMPORT (0)
39 #endif
40
41 // Yasmarang random number generator
42 // by Ilya Levin
43 // http://www.literatecode.com/yasmarang
44 // Public Domain
45
46 #if !MICROPY_ENABLE_DYNRUNTIME
47 #if SEED_ON_IMPORT
48 // If the state is seeded on import then keep these variables in the BSS.
49 STATIC uint32_t yasmarang_pad, yasmarang_n, yasmarang_d;
50 STATIC uint8_t yasmarang_dat;
51 #else
52 // Without seed-on-import these variables must be initialised via the data section.
53 STATIC uint32_t yasmarang_pad = 0xeda4baba, yasmarang_n = 69, yasmarang_d = 233;
54 STATIC uint8_t yasmarang_dat = 0;
55 #endif
56 #endif
57
yasmarang(void)58 STATIC uint32_t yasmarang(void) {
59 yasmarang_pad += yasmarang_dat + yasmarang_d * yasmarang_n;
60 yasmarang_pad = (yasmarang_pad << 3) + (yasmarang_pad >> 29);
61 yasmarang_n = yasmarang_pad | 2;
62 yasmarang_d ^= (yasmarang_pad << 31) + (yasmarang_pad >> 1);
63 yasmarang_dat ^= (char)yasmarang_pad ^ (yasmarang_d >> 8) ^ 1;
64
65 return yasmarang_pad ^ (yasmarang_d << 5) ^ (yasmarang_pad >> 18) ^ (yasmarang_dat << 1);
66 } /* yasmarang */
67
68 // End of Yasmarang
69
70 #if MICROPY_PY_URANDOM_EXTRA_FUNCS
71
72 // returns an unsigned integer below the given argument
73 // n must not be zero
yasmarang_randbelow(uint32_t n)74 STATIC uint32_t yasmarang_randbelow(uint32_t n) {
75 uint32_t mask = 1;
76 while ((n & mask) < n) {
77 mask = (mask << 1) | 1;
78 }
79 uint32_t r;
80 do {
81 r = yasmarang() & mask;
82 } while (r >= n);
83 return r;
84 }
85
86 #endif
87
mod_urandom_getrandbits(mp_obj_t num_in)88 STATIC mp_obj_t mod_urandom_getrandbits(mp_obj_t num_in) {
89 int n = mp_obj_get_int(num_in);
90 if (n > 32 || n < 0) {
91 mp_raise_ValueError(MP_ERROR_TEXT("bits must be 32 or less"));
92 }
93 if (n == 0) {
94 return MP_OBJ_NEW_SMALL_INT(0);
95 }
96 uint32_t mask = ~0;
97 // Beware of C undefined behavior when shifting by >= than bit size
98 mask >>= (32 - n);
99 return mp_obj_new_int_from_uint(yasmarang() & mask);
100 }
101 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_urandom_getrandbits_obj, mod_urandom_getrandbits);
102
mod_urandom_seed(size_t n_args,const mp_obj_t * args)103 STATIC mp_obj_t mod_urandom_seed(size_t n_args, const mp_obj_t *args) {
104 mp_uint_t seed;
105 if (n_args == 0 || args[0] == mp_const_none) {
106 #ifdef MICROPY_PY_URANDOM_SEED_INIT_FUNC
107 seed = MICROPY_PY_URANDOM_SEED_INIT_FUNC;
108 #else
109 mp_raise_ValueError(MP_ERROR_TEXT("no default seed"));
110 #endif
111 } else {
112 seed = mp_obj_get_int_truncated(args[0]);
113 }
114 yasmarang_pad = seed;
115 yasmarang_n = 69;
116 yasmarang_d = 233;
117 yasmarang_dat = 0;
118 return mp_const_none;
119 }
120 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_urandom_seed_obj, 0, 1, mod_urandom_seed);
121
122 #if MICROPY_PY_URANDOM_EXTRA_FUNCS
123
mod_urandom_randrange(size_t n_args,const mp_obj_t * args)124 STATIC mp_obj_t mod_urandom_randrange(size_t n_args, const mp_obj_t *args) {
125 mp_int_t start = mp_obj_get_int(args[0]);
126 if (n_args == 1) {
127 // range(stop)
128 if (start > 0) {
129 return mp_obj_new_int(yasmarang_randbelow(start));
130 } else {
131 goto error;
132 }
133 } else {
134 mp_int_t stop = mp_obj_get_int(args[1]);
135 if (n_args == 2) {
136 // range(start, stop)
137 if (start < stop) {
138 return mp_obj_new_int(start + yasmarang_randbelow(stop - start));
139 } else {
140 goto error;
141 }
142 } else {
143 // range(start, stop, step)
144 mp_int_t step = mp_obj_get_int(args[2]);
145 mp_int_t n;
146 if (step > 0) {
147 n = (stop - start + step - 1) / step;
148 } else if (step < 0) {
149 n = (stop - start + step + 1) / step;
150 } else {
151 goto error;
152 }
153 if (n > 0) {
154 return mp_obj_new_int(start + step * yasmarang_randbelow(n));
155 } else {
156 goto error;
157 }
158 }
159 }
160
161 error:
162 mp_raise_ValueError(NULL);
163 }
164 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_urandom_randrange_obj, 1, 3, mod_urandom_randrange);
165
mod_urandom_randint(mp_obj_t a_in,mp_obj_t b_in)166 STATIC mp_obj_t mod_urandom_randint(mp_obj_t a_in, mp_obj_t b_in) {
167 mp_int_t a = mp_obj_get_int(a_in);
168 mp_int_t b = mp_obj_get_int(b_in);
169 if (a <= b) {
170 return mp_obj_new_int(a + yasmarang_randbelow(b - a + 1));
171 } else {
172 mp_raise_ValueError(NULL);
173 }
174 }
175 STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_urandom_randint_obj, mod_urandom_randint);
176
mod_urandom_choice(mp_obj_t seq)177 STATIC mp_obj_t mod_urandom_choice(mp_obj_t seq) {
178 mp_int_t len = mp_obj_get_int(mp_obj_len(seq));
179 if (len > 0) {
180 return mp_obj_subscr(seq, mp_obj_new_int(yasmarang_randbelow(len)), MP_OBJ_SENTINEL);
181 } else {
182 mp_raise_type(&mp_type_IndexError);
183 }
184 }
185 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_urandom_choice_obj, mod_urandom_choice);
186
187 #if MICROPY_PY_BUILTINS_FLOAT
188
189 // returns a number in the range [0..1) using Yasmarang to fill in the fraction bits
yasmarang_float(void)190 STATIC mp_float_t yasmarang_float(void) {
191 mp_float_union_t u;
192 u.p.sgn = 0;
193 u.p.exp = (1 << (MP_FLOAT_EXP_BITS - 1)) - 1;
194 if (MP_FLOAT_FRAC_BITS <= 32) {
195 u.p.frc = yasmarang();
196 } else {
197 u.p.frc = ((uint64_t)yasmarang() << 32) | (uint64_t)yasmarang();
198 }
199 return u.f - 1;
200 }
201
mod_urandom_random(void)202 STATIC mp_obj_t mod_urandom_random(void) {
203 return mp_obj_new_float(yasmarang_float());
204 }
205 STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_urandom_random_obj, mod_urandom_random);
206
mod_urandom_uniform(mp_obj_t a_in,mp_obj_t b_in)207 STATIC mp_obj_t mod_urandom_uniform(mp_obj_t a_in, mp_obj_t b_in) {
208 mp_float_t a = mp_obj_get_float(a_in);
209 mp_float_t b = mp_obj_get_float(b_in);
210 return mp_obj_new_float(a + (b - a) * yasmarang_float());
211 }
212 STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_urandom_uniform_obj, mod_urandom_uniform);
213
214 #endif
215
216 #endif // MICROPY_PY_URANDOM_EXTRA_FUNCS
217
218 #if SEED_ON_IMPORT
mod_urandom___init__()219 STATIC mp_obj_t mod_urandom___init__() {
220 // This module may be imported by more than one name so need to ensure
221 // that it's only ever seeded once.
222 static bool seeded = false;
223 if (!seeded) {
224 seeded = true;
225 mod_urandom_seed(0, NULL);
226 }
227 return mp_const_none;
228 }
229 STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_urandom___init___obj, mod_urandom___init__);
230 #endif
231
232 #if !MICROPY_ENABLE_DYNRUNTIME
233 STATIC const mp_rom_map_elem_t mp_module_urandom_globals_table[] = {
234 { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_urandom) },
235 #if SEED_ON_IMPORT
236 { MP_ROM_QSTR(MP_QSTR___init__), MP_ROM_PTR(&mod_urandom___init___obj) },
237 #endif
238 { MP_ROM_QSTR(MP_QSTR_getrandbits), MP_ROM_PTR(&mod_urandom_getrandbits_obj) },
239 { MP_ROM_QSTR(MP_QSTR_seed), MP_ROM_PTR(&mod_urandom_seed_obj) },
240 #if MICROPY_PY_URANDOM_EXTRA_FUNCS
241 { MP_ROM_QSTR(MP_QSTR_randrange), MP_ROM_PTR(&mod_urandom_randrange_obj) },
242 { MP_ROM_QSTR(MP_QSTR_randint), MP_ROM_PTR(&mod_urandom_randint_obj) },
243 { MP_ROM_QSTR(MP_QSTR_choice), MP_ROM_PTR(&mod_urandom_choice_obj) },
244 #if MICROPY_PY_BUILTINS_FLOAT
245 { MP_ROM_QSTR(MP_QSTR_random), MP_ROM_PTR(&mod_urandom_random_obj) },
246 { MP_ROM_QSTR(MP_QSTR_uniform), MP_ROM_PTR(&mod_urandom_uniform_obj) },
247 #endif
248 #endif
249 };
250
251 STATIC MP_DEFINE_CONST_DICT(mp_module_urandom_globals, mp_module_urandom_globals_table);
252
253 const mp_obj_module_t mp_module_urandom = {
254 .base = { &mp_type_module },
255 .globals = (mp_obj_dict_t *)&mp_module_urandom_globals,
256 };
257 #endif
258
259 #endif // MICROPY_PY_URANDOM
260