PythonExtra/extmod/modurandom.c

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/*
* 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/nlr.h"
#include "py/runtime.h"
#if MICROPY_PY_URANDOM
// Yasmarang random number generator
// by Ilya Levin
// http://www.literatecode.com/yasmarang
// Public Domain
STATIC uint32_t yasmarang_pad = 0xeda4baba, yasmarang_n = 69, yasmarang_d = 233;
STATIC uint8_t yasmarang_dat = 0;
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
STATIC mp_obj_t mod_urandom_getrandbits(mp_obj_t num_in) {
int n = mp_obj_get_int(num_in);
if (n > 32 || n == 0) {
nlr_raise(mp_obj_new_exception(&mp_type_ValueError));
}
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_urandom_getrandbits_obj, mod_urandom_getrandbits);
STATIC mp_obj_t mod_urandom_seed(mp_obj_t seed_in) {
mp_uint_t seed = mp_obj_get_int_truncated(seed_in);
yasmarang_pad = seed;
yasmarang_n = 69;
yasmarang_d = 233;
yasmarang_dat = 0;
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_urandom_seed_obj, mod_urandom_seed);
STATIC const mp_rom_map_elem_t mp_module_urandom_globals_table[] = {
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_urandom) },
{ MP_ROM_QSTR(MP_QSTR_getrandbits), MP_ROM_PTR(&mod_urandom_getrandbits_obj) },
{ MP_ROM_QSTR(MP_QSTR_seed), MP_ROM_PTR(&mod_urandom_seed_obj) },
};
STATIC MP_DEFINE_CONST_DICT(mp_module_urandom_globals, mp_module_urandom_globals_table);
const mp_obj_module_t mp_module_urandom = {
.base = { &mp_type_module },
.name = MP_QSTR_urandom,
.globals = (mp_obj_dict_t*)&mp_module_urandom_globals,
};
#endif //MICROPY_PY_URANDOM