djb.c

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>

/* Generic hash function (a popular one from Bernstein).
 * I tested a few and this was the best. */
uint32_t dictGenHashFunction(const uint8_t *buf, int len) {
    uint32_t hash = 5381;

    while (len--)
        hash = ((hash << 5) + hash) + (*buf++); /* hash * 33 + c */
    return hash;
}

int main(int argc, char **argv) {
    if (argc < 2) {
        printf("Usage: djb <str>...");
        return 1;
    }

    for (int i = 1; i < argc; i++) {
        uint8_t *arg = malloc(strlen(argv[i]) * sizeof(uint8_t));
        strncpy((uint8_t *)arg, argv[i], strlen(argv[i])+1);
        printf("%u %s\n", dictGenHashFunction(arg, strlen(arg)), arg);
    }
    return 0;
}