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Diffstat (limited to 'extmod/modrandom.c')
| -rw-r--r-- | extmod/modrandom.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/extmod/modrandom.c b/extmod/modrandom.c new file mode 100644 index 0000000000..1c697aec70 --- /dev/null +++ b/extmod/modrandom.c @@ -0,0 +1,261 @@ +/* + * This file is part of the MicroPython project, http://micropython.org/ + * + * The MIT License (MIT) + * + * Copyright (c) 2016 Paul Sokolovsky + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include <assert.h> +#include <string.h> + +#include "py/runtime.h" + +#if MICROPY_PY_RANDOM + +// Work out if the seed will be set on import or not. +#if MICROPY_MODULE_BUILTIN_INIT && defined(MICROPY_PY_RANDOM_SEED_INIT_FUNC) +#define SEED_ON_IMPORT (1) +#else +#define SEED_ON_IMPORT (0) +#endif + +// Yasmarang random number generator +// by Ilya Levin +// http://www.literatecode.com/yasmarang +// Public Domain + +#if !MICROPY_ENABLE_DYNRUNTIME +#if SEED_ON_IMPORT +// If the state is seeded on import then keep these variables in the BSS. +STATIC uint32_t yasmarang_pad, yasmarang_n, yasmarang_d; +STATIC uint8_t yasmarang_dat; +#else +// Without seed-on-import these variables must be initialised via the data section. +STATIC uint32_t yasmarang_pad = 0xeda4baba, yasmarang_n = 69, yasmarang_d = 233; +STATIC uint8_t yasmarang_dat = 0; +#endif +#endif + +STATIC uint32_t yasmarang(void) { + yasmarang_pad += yasmarang_dat + yasmarang_d * yasmarang_n; + yasmarang_pad = (yasmarang_pad << 3) + (yasmarang_pad >> 29); + yasmarang_n = yasmarang_pad | 2; + yasmarang_d ^= (yasmarang_pad << 31) + (yasmarang_pad >> 1); + yasmarang_dat ^= (char)yasmarang_pad ^ (yasmarang_d >> 8) ^ 1; + + return yasmarang_pad ^ (yasmarang_d << 5) ^ (yasmarang_pad >> 18) ^ (yasmarang_dat << 1); +} /* yasmarang */ + +// End of Yasmarang + +#if MICROPY_PY_RANDOM_EXTRA_FUNCS + +// returns an unsigned integer below the given argument +// n must not be zero +STATIC uint32_t yasmarang_randbelow(uint32_t n) { + uint32_t mask = 1; + while ((n & mask) < n) { + mask = (mask << 1) | 1; + } + uint32_t r; + do { + r = yasmarang() & mask; + } while (r >= n); + return r; +} + +#endif + +STATIC mp_obj_t mod_random_getrandbits(mp_obj_t num_in) { + int n = mp_obj_get_int(num_in); + if (n > 32 || n < 0) { + mp_raise_ValueError(MP_ERROR_TEXT("bits must be 32 or less")); + } + if (n == 0) { + return MP_OBJ_NEW_SMALL_INT(0); + } + uint32_t mask = ~0; + // Beware of C undefined behavior when shifting by >= than bit size + mask >>= (32 - n); + return mp_obj_new_int_from_uint(yasmarang() & mask); +} +STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_random_getrandbits_obj, mod_random_getrandbits); + +STATIC mp_obj_t mod_random_seed(size_t n_args, const mp_obj_t *args) { + mp_uint_t seed; + if (n_args == 0 || args[0] == mp_const_none) { + #ifdef MICROPY_PY_RANDOM_SEED_INIT_FUNC + seed = MICROPY_PY_RANDOM_SEED_INIT_FUNC; + #else + mp_raise_ValueError(MP_ERROR_TEXT("no default seed")); + #endif + } else { + seed = mp_obj_get_int_truncated(args[0]); + } + yasmarang_pad = seed; + yasmarang_n = 69; + yasmarang_d = 233; + yasmarang_dat = 0; + return mp_const_none; +} +STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_random_seed_obj, 0, 1, mod_random_seed); + +#if MICROPY_PY_RANDOM_EXTRA_FUNCS + +STATIC mp_obj_t mod_random_randrange(size_t n_args, const mp_obj_t *args) { + mp_int_t start = mp_obj_get_int(args[0]); + if (n_args == 1) { + // range(stop) + if (start > 0) { + return mp_obj_new_int(yasmarang_randbelow(start)); + } else { + goto error; + } + } else { + mp_int_t stop = mp_obj_get_int(args[1]); + if (n_args == 2) { + // range(start, stop) + if (start < stop) { + return mp_obj_new_int(start + yasmarang_randbelow(stop - start)); + } else { + goto error; + } + } else { + // range(start, stop, step) + mp_int_t step = mp_obj_get_int(args[2]); + mp_int_t n; + if (step > 0) { + n = (stop - start + step - 1) / step; + } else if (step < 0) { + n = (stop - start + step + 1) / step; + } else { + goto error; + } + if (n > 0) { + return mp_obj_new_int(start + step * yasmarang_randbelow(n)); + } else { + goto error; + } + } + } + +error: + mp_raise_ValueError(NULL); +} +STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_random_randrange_obj, 1, 3, mod_random_randrange); + +STATIC mp_obj_t mod_random_randint(mp_obj_t a_in, mp_obj_t b_in) { + mp_int_t a = mp_obj_get_int(a_in); + mp_int_t b = mp_obj_get_int(b_in); + if (a <= b) { + return mp_obj_new_int(a + yasmarang_randbelow(b - a + 1)); + } else { + mp_raise_ValueError(NULL); + } +} +STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_random_randint_obj, mod_random_randint); + +STATIC mp_obj_t mod_random_choice(mp_obj_t seq) { + mp_int_t len = mp_obj_get_int(mp_obj_len(seq)); + if (len > 0) { + return mp_obj_subscr(seq, mp_obj_new_int(yasmarang_randbelow(len)), MP_OBJ_SENTINEL); + } else { + mp_raise_type(&mp_type_IndexError); + } +} +STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_random_choice_obj, mod_random_choice); + +#if MICROPY_PY_BUILTINS_FLOAT + +// returns a number in the range [0..1) using Yasmarang to fill in the fraction bits +STATIC mp_float_t yasmarang_float(void) { + mp_float_union_t u; + u.p.sgn = 0; + u.p.exp = (1 << (MP_FLOAT_EXP_BITS - 1)) - 1; + if (MP_FLOAT_FRAC_BITS <= 32) { + u.p.frc = yasmarang(); + } else { + u.p.frc = ((uint64_t)yasmarang() << 32) | (uint64_t)yasmarang(); + } + return u.f - 1; +} + +STATIC mp_obj_t mod_random_random(void) { + return mp_obj_new_float(yasmarang_float()); +} +STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_random_random_obj, mod_random_random); + +STATIC mp_obj_t mod_random_uniform(mp_obj_t a_in, mp_obj_t b_in) { + mp_float_t a = mp_obj_get_float(a_in); + mp_float_t b = mp_obj_get_float(b_in); + return mp_obj_new_float(a + (b - a) * yasmarang_float()); +} +STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_random_uniform_obj, mod_random_uniform); + +#endif + +#endif // MICROPY_PY_RANDOM_EXTRA_FUNCS + +#if SEED_ON_IMPORT +STATIC mp_obj_t mod_random___init__(void) { + // This module may be imported by more than one name so need to ensure + // that it's only ever seeded once. + static bool seeded = false; + if (!seeded) { + seeded = true; + mod_random_seed(0, NULL); + } + return mp_const_none; +} +STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_random___init___obj, mod_random___init__); +#endif + +#if !MICROPY_ENABLE_DYNRUNTIME +STATIC const mp_rom_map_elem_t mp_module_random_globals_table[] = { + { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_random) }, + #if SEED_ON_IMPORT + { MP_ROM_QSTR(MP_QSTR___init__), MP_ROM_PTR(&mod_random___init___obj) }, + #endif + { MP_ROM_QSTR(MP_QSTR_getrandbits), MP_ROM_PTR(&mod_random_getrandbits_obj) }, + { MP_ROM_QSTR(MP_QSTR_seed), MP_ROM_PTR(&mod_random_seed_obj) }, + #if MICROPY_PY_RANDOM_EXTRA_FUNCS + { MP_ROM_QSTR(MP_QSTR_randrange), MP_ROM_PTR(&mod_random_randrange_obj) }, + { MP_ROM_QSTR(MP_QSTR_randint), MP_ROM_PTR(&mod_random_randint_obj) }, + { MP_ROM_QSTR(MP_QSTR_choice), MP_ROM_PTR(&mod_random_choice_obj) }, + #if MICROPY_PY_BUILTINS_FLOAT + { MP_ROM_QSTR(MP_QSTR_random), MP_ROM_PTR(&mod_random_random_obj) }, + { MP_ROM_QSTR(MP_QSTR_uniform), MP_ROM_PTR(&mod_random_uniform_obj) }, + #endif + #endif +}; + +STATIC MP_DEFINE_CONST_DICT(mp_module_random_globals, mp_module_random_globals_table); + +const mp_obj_module_t mp_module_random = { + .base = { &mp_type_module }, + .globals = (mp_obj_dict_t *)&mp_module_random_globals, +}; + +MP_REGISTER_MODULE(MP_QSTR_random, mp_module_random); +#endif + +#endif // MICROPY_PY_RANDOM |