71 lines
1.7 KiB
C
71 lines
1.7 KiB
C
/*
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* @Author: jiejie
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* @Github: https://github.com/jiejieTop
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* @Date: 2020-01-09 19:25:05
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* @LastEditTime: 2020-06-16 14:50:33
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* @Description: the code belongs to jiejie, please keep the author information and source code according to the license.
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*/
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#include <stdlib.h>
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#include "random.h"
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#include "platform_timer.h"
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#include "platform_memory.h"
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static unsigned int last_seed = 1;
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static int do_random(unsigned int seed)
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{
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srand(seed);
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return rand();
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}
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int random_number(void)
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{
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unsigned int seed = (unsigned int) platform_timer_now();
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last_seed += (seed >> ((seed ^ last_seed) % 3));
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return do_random(last_seed ^ seed);
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}
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// random number range interval [min, max)
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int random_number_range(unsigned int min, unsigned int max)
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{
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return (random_number() % (max - min)) + min;
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}
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char *random_string(unsigned int len)
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{
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unsigned int i, flag, seed, random;
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char *str = platform_memory_alloc((size_t)(len + 1));
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if (NULL == str)
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return NULL;
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seed = (unsigned int) random_number();
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seed += (unsigned int) ((size_t)str ^ seed);
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random = (unsigned int)do_random(seed);
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for (i = 0; i < len; i++) {
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random = do_random(seed ^ random);
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flag = (unsigned int)random % 3;
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switch (flag) {
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case 0:
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str[i] = 'A' + do_random(random ^ (i & flag)) % 26;
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break;
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case 1:
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str[i] = 'a' + do_random(random ^ (i & flag)) % 26;
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break;
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case 2:
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str[i] = '0' + do_random(random ^ (i & flag)) % 10;
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break;
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default:
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str[i] = 'x';
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break;
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}
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random += ((0xb433e5c6 ^ random) << (i & flag));
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}
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str[len] = '\0';
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return str;
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}
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