add docs and some hashmap code

src/hashmap.c

@@ -7,18 +7,41 @@ void hm_init(struct hashmap *map) {
 
 	for (size_t i = 0; i < HASHMAP_MAX_CLIENTS; ++i) {
 		map[i].sockfd = -1;
+		map[i].next = NULL;
 	}
 }
 
 void hm_insert(struct hashmap *map, int sockfd, struct sockaddr_storage *sas) {
 	int index = hash(sockfd);
-	map[index].sockfd = sockfd;
-	map[index].sas = *sas;
 
-    // I should check the collisions
+	if (map[index].sockfd == -1) {
+		map[index].sockfd = sockfd;
+		map[index].sas = *sas;
+	} else {
+		/* Go through the linked list and append the new item */
+		struct hashmap *p;
+		for (p = &map[index]; p->next != NULL; p = p->next);
+		struct hashmap *new = malloc(sizeof(struct hashmap));
+		new->sockfd = sockfd;
+		new->sas = *sas;
+		new->next = NULL;
+
+		p->next = new;
+	}
 }
 
 struct hashmap *hm_lookup(struct hashmap *map, int sockfd) {
 	int index = hash(sockfd);
-	return &map[index];
+
+	if (map[index].sockfd != sockfd) {
+		struct hashmap *p;
+		for (p = map[index].next; p->sockfd != sockfd; p = p->next);
+		return p;
+	} else {
+		return &map[index];
+	}
+
+	return NULL;
 }
+
+void hm_free(struct hashmap *map) {}