51 lines
1.5 KiB
C
51 lines
1.5 KiB
C
#include "stdio.h"
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#include "stdlib.h"
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#include "limits.h"
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#include "sodium.h"
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#include "strtoui.h"
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/**
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* Maps a number that is between i_min and i_max to the range o_min and o_max
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*/
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int map(int i, int i_min, int i_max, int o_min, int o_max) {
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double r = (double)(o_max - o_min) / (double)(i_max - i_min);
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int j = (double) (i - i_min) * r + o_min;
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return j;
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}
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int main(int argc, char *argv[]) {
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//if doesnt have any argument just show a usage info
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if(argc == 1) {
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puts("Usage:\tchars [length]");
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puts("\t0 > lenght > UINT_MAX");
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puts("Description:");
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puts("\t Generates a random string with the specified length");
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exit(EXIT_SUCCESS);
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}
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//read the length argument and parse it to a an unsigned int
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unsigned int len;
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enum strtoui_error error = strtoui(&len, argv[1], 10);
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if(error == STRTOUI_OVERFLOW){
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fputs("The input is too big\n", stderr);
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exit(EXIT_FAILURE);
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}else if(error == STRTOUI_UNDERFLOW) {
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fputs("The input must be bigger than 0\n", stderr);
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exit(EXIT_FAILURE);
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}else if(error == STRTOUI_INCONVERTIBLE) {
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fputs("The input isn't valid\n", stderr);
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exit(EXIT_FAILURE);
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}
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//prints random numbers in the bounds specified as chars
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char lower_bound = 0x20;
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char upper_bound= 0x7e;
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for(int i = 0; i < len; i++) {
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int random = randombytes_uniform(upper_bound);
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printf("%c", map(random, 0, upper_bound, lower_bound, upper_bound));
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}
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printf("\n");
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exit(EXIT_SUCCESS);
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}
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