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81 lines
1.7 KiB
C
81 lines
1.7 KiB
C
/**
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* Copyright (C) 2015 Kaspar Schleiser <kaspar@schleiser.de>
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup sys_random
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* @{
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* @file
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*
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* @brief Glue-code for tinymt32
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*
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* See https://github.com/MersenneTwister-Lab/TinyMT for details.
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*
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* @author Kaspar Schleiser <kaspar@schleiser.de>
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* @}
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*/
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#include <stdint.h>
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#include <string.h>
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#include "tinymt32/tinymt32.h"
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#define _ALIGNMENT_MASK (sizeof(uint32_t) - 1)
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/* fits size to byte alignment */
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static inline uint8_t *_align(uint8_t *buf)
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{
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return (uint8_t *)(((size_t) buf + _ALIGNMENT_MASK) & ~(_ALIGNMENT_MASK));
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}
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static tinymt32_t _random;
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void random_init(uint32_t seed)
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{
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tinymt32_init(&_random, seed);
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}
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uint32_t random_uint32(void)
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{
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return tinymt32_generate_uint32(&_random);
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}
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void random_bytes(uint8_t *buf, size_t size)
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{
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size_t iter = size;
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size_t diff = _align(buf) - buf;
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uint32_t tmp;
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/* Fill first <4 unaligned bytes */
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if (diff) {
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tmp = tinymt32_generate_uint32(&_random);
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if (diff > size) {
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diff = size;
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}
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memcpy(buf, &tmp, diff);
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iter -= diff;
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}
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/* Fill aligned bytes */
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while (iter >= sizeof(uint32_t)) {
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*((uint32_t *) buf) = tinymt32_generate_uint32(&_random);
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buf += sizeof(uint32_t);
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iter -= sizeof(uint32_t);
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}
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/* Fill last bytes */
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if (iter) {
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tmp = tinymt32_generate_uint32(&_random);
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memcpy(buf, &tmp, iter);
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}
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}
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void random_init_by_array(uint32_t init_key[], int key_length)
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{
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tinymt32_init_by_array(&_random, init_key, key_length);
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}
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