Simple hashmap for IPs

main.c

#include <stdio.h>
#include <time.h>

#include "compat.h"
#include "smap.h"

int
main()
{
    struct smap map;
    time_t t = time(NULL);
    
    smap_init(&map, 200);
    for (int i = 0; i < 10000; i++) {
        smap_insert(&map, "10.11.12.1", t);
        smap_insert(&map, "10.11.12.2", t);
        smap_insert(&map, "10.11.12.3", t);
        smap_insert(&map, "10.11.12.4", t);
        smap_insert(&map, "10.11.12.5", t);
        smap_insert(&map, "10.11.12.6", t);
        smap_insert(&map, "10.11.12.7", t);
        smap_insert(&map, "10.11.12.9", t);
        smap_insert(&map, "10.11.12.10", t);
        smap_insert(&map, "10.11.12.11", t);
        smap_insert(&map, "10.11.12.12", t);
        smap_insert(&map, "10.11.12.13", t);
        smap_insert(&map, "10.11.12.14", t);
        smap_insert(&map, "10.11.12.15", t);
        smap_insert(&map, "10.11.12.16", t);
        smap_insert(&map, "10.11.12.17", t);
        smap_insert(&map, "10.11.12.18", t);
        smap_insert(&map, "10.11.12.19", t);
        smap_insert(&map, "10.11.12.20", t);
        smap_insert(&map, "10.11.12.21", t);
        smap_insert(&map, "10.11.12.22", t);
        smap_insert(&map, "10.11.12.23", t);
        smap_insert(&map, "10.11.12.24", t);
        smap_insert(&map, "10.11.12.25", t);
        smap_insert(&map, "10.11.12.26", t);
        smap_insert(&map, "10.11.12.27", t);
        smap_insert(&map, "10.11.12.28", t);
        smap_insert(&map, "10.11.12.29", t);
        smap_insert(&map, "10.11.12.30", t);
        smap_insert(&map, "10.11.12.31", t);

        smap_get(&map, "10.11.12.1");
        smap_get(&map, "10.11.12.2");
        smap_get(&map, "10.11.12.3");
        smap_get(&map, "10.11.12.4");
        smap_get(&map, "10.11.12.5");
        smap_get(&map, "10.11.12.6");
        smap_get(&map, "10.11.12.7");
        smap_get(&map, "10.11.12.8");
        smap_get(&map, "10.11.12.9");
        smap_get(&map, "10.11.12.10");
        smap_get(&map, "10.11.12.11");
        smap_get(&map, "10.11.12.12");
        smap_get(&map, "10.11.12.13");
        smap_get(&map, "10.11.12.14");
        smap_get(&map, "10.11.12.15");
        smap_get(&map, "10.11.12.16");
        smap_get(&map, "10.11.12.17");
        smap_get(&map, "10.11.12.18");
        smap_get(&map, "10.11.12.19");
        smap_get(&map, "10.11.12.20");
        smap_get(&map, "10.11.12.21");
        smap_get(&map, "10.11.12.22");
        smap_get(&map, "10.11.12.23");
        smap_get(&map, "10.11.12.24");
        smap_get(&map, "10.11.12.25");
        smap_get(&map, "10.11.12.26");
    }
    if (smap_empty(&map) == 0)
        printf("EMPTY!\n");
    
    smap_clear(&map);

    smap_free(&map);
    return 0;
}

smap.c

#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "compat.h"
#include "smap.h"

static int hash(char*, size_t);
static int exists(struct smap*, int);

void
smap_init(struct smap* map, unsigned int size)
{
    map->entry = calloc(size, sizeof(struct entry));
    if (map->entry == NULL)
        return;

    map->size = size;
    map->count = 0;
}

void
smap_free(struct smap* map)
{
        free(map->entry);
}

int
hash(char* ip, size_t map_size)
{
    int hash = 0;
    long long temp = 0;
    const char *errstr = NULL;
    char **ap, *ips[4], *wip, *wwip;

    wip = strdup(ip);
    if (wip == NULL)
        return -1;
  
    wwip = wip;
    
    for (ap = ips; ap <= &ips[3] &&
        (*ap = strsep(&wip, ".")) != NULL;) {
            if (**ap != '\0')
                ap++;    
    }

    for (int i = 0; i <= 3; i++) {
        temp = strtonum(ips[i], 0, 255, &errstr);
        if (errstr != NULL) {
            return -1;
        }
        hash += temp;
    }
    
    hash += 127;
    hash %= map_size;
    
    free(wwip);
    wwip = NULL;
    
    return hash;
}

int
smap_insert (struct smap *map, char* ip, time_t time)
{
    int h = hash(ip, map->size);
    int nc = map->count;
    
    if (exists(map, h) == 0)
        nc++; 

    map->entry[h].value = time;
    strlcpy(map->entry[h].ip, ip, 33);
    map->count = nc;
    
    return 0;
}

//0 = doesnt exist
//1 = exists
int
exists(struct smap *map, int hash)
{
    if (strncmp(map->entry[hash].ip, "0", 33) == 0)
        return 0;

    return 1;
}

int
smap_contains(struct smap *map, char* ip)
{
    int h = hash(ip, map->size);
    return exists(map, h);
}



struct entry*
smap_get(struct smap *map, char* ip)
{
    int h = hash(ip, map->size);

    if (exists(map, h) == 0)
        return NULL;

    return &(map->entry[h]);
}

int
smap_empty(struct smap *map)
{
    return (map->count == 0);
}

void
smap_clear(struct smap *map)
{
    memset(map->entry, 0, map->size * sizeof(struct entry));   
}

smap.h

#ifndef SMAP_H
#define SMAP_H

struct entry {
        char ip[33];
        time_t value;
};

struct smap {
        size_t size;
        unsigned int count;
        struct entry* entry;
};

void smap_init(struct smap*, unsigned int);
void smap_free(struct smap*);

int smap_empty(struct smap*);
int smap_insert(struct smap*, char*, time_t);

struct entry* smap_get(struct smap*, char*);
void smap_clear(struct smap*);


#endif