hashtab.c

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#include "global.h"

int hash_char(char * key)
{
        int temp = 0;
        int i = 0;

        while (key[i] != '\0') {
                temp = ((temp << SHIFT) + key[i]) % SIZE;
                ++i;
        }

        return temp;
}


int hash_int(int connfd)
{
	return (connfd*2+3)%SIZE;
}

/*initialize the two hash tables*/
void init_hash_tab()
{
	int i;
	for(i = 0; i < SIZE; i++) {
		hash_table[i] = NULL;
		addr_table[i] = NULL;
	}
}

/*insert a record into the hash_table table*/
bucket_list hash_insert(char * name)
{
        int h = hash_char(name);
        bucket_list l =  hash_table[h];

	l = (bucket_list) malloc(sizeof(struct bucket_list_rec));
	if(l == NULL) {
		log_err("malloc fails!\n");
	}
	l->name = name;
	l->connfd = -1;
	l->next = hash_table[h];
	hash_table[h] = l; 
	return l;
}


/*insert a record into the addr_table table*/
addr_list addr_insert(int connfd)
{
        int h = hash_int(connfd);
        addr_list a = addr_table[h];

	a = (addr_list)malloc(sizeof(struct addr_list_rec));
	if(a == NULL) {
		log_err("malloc fails!\n");
	}
	a->name = NULL;
	a->connfd = connfd;
	a->next = addr_table[h];
	addr_table[h] = a; 
	return a;
}



/*lookup a record from the hash_table table*/
bucket_list hash_lookup(char * name)
{
        int h = hash_char(name);
        bucket_list l =  hash_table[h];

        while((l != NULL) && (strcmp(name,l->name) != 0))
                l = l->next;

        if(l == NULL) return (bucket_list)0;
        else return l;
}


/*lookup a record from the addr_table table*/
addr_list addr_lookup(int connfd)
{
        int h = hash_int(connfd);
        addr_list a =  addr_table[h];

        while((a != NULL) && (connfd != a->connfd))
                a = a->next;

        if(a == NULL) return (addr_list)0;
        else return a;
}