#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#ifndef __FreeBSD__
#include <sys/time.h>
#include <time.h>
#endif

char *parse_range (char *dst, char *range)
{
    int i,j=0,k;
    for (i=0;i<strlen(range);i++) {
        if (i == 0) {
            if (range[i] == '-')
                dst[j++] = '-';
            else if (range[i+1] != '-')
                dst[j++] = range[i];
        }
        if (i > 0) {
            if (range[i] != '-' && (range[i-1] != '-' || i-1 == 0) && range[i+1] != '-')
                dst[j++] = range[i];
            if (range[i] != '-' && range[i-1] == '-' && range[i+1] == '-' && i-1 != 0)
                return NULL;
            if (range[i] != '-' && range[i-1] == '-' && i-1 != 0)
                continue;
        }
        if (range[i] != '-' && range[i+1] == '-') {
            if (range[i+2] == '-')
                return NULL;
            if (range[i+2] < range[i])
                return NULL;
            for (k = range[i]; k <= range[i+2]; k++)
                dst[j++] = k;
        }
    }

    dst[j] = '\0';
    return dst;
}

char *gen_rand_string (char *dst, char *range, int size)
{
    char text[512];
    int i;

    bzero(text,512);
    parse_range(text,range);

    for (i=0;i<size;i++)
        dst[i] = text[random() % (strlen(text))];
    dst[i] = '\0';

    return dst;
}

int main (int ac, char **av)
{
    char dst[512];
    if (ac != 3) {
        fprintf(stderr,"Usage: %s range len\n",av[0]);
        return 1;
    }
    int len = atoi(av[2]);
    char pass[len];

    parse_range(dst,av[1]);
#ifdef __FreeBSD__
    srandomdev();
#else
    unsigned long junk;
    struct timeval tv;
    gettimeofday(&tv,NULL);
    srandom(getpid() ^ tv.tv_sec ^ tv.tv_usec ^ junk);
#endif
    gen_rand_string(pass, dst, strtol(av[2],NULL,10));
    printf("%s\n",pass);
    return 0;
}