Mega Code Archive
Create random strings, shuffle existing strings
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#include <time.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <getopt.h>
#include <unistd.h>
#include <stdlib.h>
#include <stddef.h>
#include <limits.h>
#define PACKAGE "strang"
#define VERSION "1.0.0"
void print_help(int exval);
int get_rand_val(int low, int high);
char *get_rand_str(int length);
char *strshuf(char *str);
unsigned time_seed(void);
int main(int argc, char *argv[]) {
char *str = NULL;
char *affix = NULL;
char *prefix = NULL;
int opt = 0;
int len = 0;
int number = 1;
while((opt = getopt(argc, argv, "hvn:l:p:a:s:")) != -1) {
switch(opt) {
case 'h':
print_help(0);
break;
case 'v':
fprintf(stdout, "%s %s\n", PACKAGE, VERSION);
exit(0);
break;
case 'n':
number = atoi(optarg);
break;
case 'l': /* string length (default=random) */
len = atoi(optarg);
break;
case 'p': /* prefix string with STR */
prefix = strdup(optarg);
break;
case 'a': /* affix string with STR */
affix = strdup(optarg);
break;
case 's': /* randomize string STR */
str = strdup(optarg);
break;
case ':':
fprintf(stderr, "%s: Error - Option `%c', needs an argument\n\n", PACKAGE, optopt);
print_help(1);
break;
case '?':
fprintf(stderr, "%s: Error - No such option: `%c'\n\n", PACKAGE, optopt);
print_help(1);
break;
} /* switch */
} /* while */
/* ! definitely not cryptographic secure ! */
srand((time_seed()));
for(; number > 0; number--) {
if(prefix != NULL)
printf("%s", prefix);
if(str != NULL)
printf("%s", strshuf(str));
else {
if(len != 0)
printf("%s", get_rand_str(len));
else
printf("%s", get_rand_str(get_rand_val(1, 20)));
}
if(affix != NULL)
printf("%s", affix);
printf("\n");
} /* for */
return 0;
}
char *strshuf(char *str) {
int pick = 0;
int len = 0;
int i = 0;
char tmp;
char *retval = NULL;
/* strip trailing newline */
if(str[strlen(str) - 1] == '\n')
str[strlen(str) - 1] = '\0';
len = strlen(str) - 1;
for(i = 0; i < len; i++) {
/* pick a random char out of input string */
pick = get_rand_val(1, len);
/* swap orig char with pick */
tmp = str[i];
str[i] = str[pick];
str[pick] = tmp;
}
retval = calloc(strlen(str) + 1, sizeof(char));
strcpy(retval, str);
return retval;
free(retval);
}
char *get_rand_str(int length) {
int value = 0;
char temp[1];
char *retval = NULL;
if((retval = calloc(length + 1, sizeof(char))) == NULL) {
fprintf(stderr, "%s: Error - calloc\n\n", PACKAGE);
return NULL;
}
for(; length > 0; length--) {
value = get_rand_val(97, 122);
temp[0] = value, temp[1] = '\0';
strcat(retval, temp);
}
return retval;
free(retval);
}
int get_rand_val(int low, int high) {
int k = 0;
double d = 0;
d = (double)rand() / ((double)RAND_MAX + 1);
k = (int)(d * (high - low + 1));
return(low + k);
}
/* ! definitely not cryptographic secure ! */
unsigned time_seed(void) {
int retval;
int fd;
if(open("/dev/urandom", O_RDONLY) == -1) {
retval = (((int)time(NULL)) & ((1 << 30) - 1)) + getpid();
} else {
read(fd, &retval, 4);
/* positive values only */
retval = abs(retval) + getpid();
close(fd);
}
return retval;
}
void print_help(int exval) {
printf("%s,%s generate random strings - shuffle existing strings\n", PACKAGE, VERSION);
printf("Usage: %s [-h] [-v] [-n INT] [-l INT] [-p STR] [-a STR] [-s STR]\n\n", PACKAGE);
printf(" Default:\n");
printf(" -h print this help and exit\n");
printf(" -v print version and exit\n\n");
printf(" Random:\n");
printf(" -n INT output number of strings, (default=1)\n");
printf(" -l INT string length, (default=random `1-10')\n");
printf(" -p STR prefix string with STR\n");
printf(" -a STR affix string with STR\n");
printf(" -s STR randomize string STR\n\n");
printf(" example : %s -s 'abcdef'\n", PACKAGE);
printf(" output : fceabd\n\n");
exit(exval);
}
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