table.c

#include <stdio.h>
#include "hash.h"

typedef struct tableElem_t *tableElem;

struct H_hashTable_t {
  tableElem *table;
  int size;
};

struct tableElem_t {
  void *data;
  char *key;
  tableElem next;
};


int hash(char *key, int size);
tableElem TableElem(void *data, char *key, tableElem next);

void H_insert(H_hashTable h, char *key, void *data)
{
	int hashval = hash(key, h->size);
	h->table[hashval] = TableElem((void *)data, key, h->table[hashval]);  
}

void *H_find(H_hashTable h, char *key)
{
	tableElem tmp = h->table[hash(key,h->size)];

	while (tmp && strcmp(key, tmp->key) != 0)
		tmp = tmp->next;
	if (tmp == NULL)
		return (NULL);
	return (tmp->data);
}

void H_delete(H_hashTable h, char *key)
{
	int index;
	tableElem tmp;

	index = hash(key, h->size);
	if (h->table[index] != NULL)
	{
		if (strcmp(h->table[index]->key, key) == 0)
			h->table[index] = h->table[index]->next;   /* Memory Leak */
		else
		{
			for(tmp = h->table[index]; tmp->next != NULL &&
				strcmp(tmp->next->key, key) != 0; tmp = tmp->next);
			if (tmp->next) 
				tmp->next = tmp->next->next;
		}
	}
}

int hash(char *key, int size)
{
	unsigned int hashval = 0;
	int retval;

	for ( ; key[0]; key++)
		hashval = (hashval << 5) +  key[0];
	retval = hashval % size;
	return (retval);
}

H_hashTable H_HashTable(int size)
{
	int i;
	H_hashTable retval = (H_hashTable) malloc(sizeof(*retval));

	retval->size = size;
	retval->table = malloc_checked(size * sizeof(tableElem *));
	for (i = 0; i < size; i++)
		retval->table[i] = NULL;
	return (retval);
}

tableElem TableElem(void *data, char *key, tableElem next)
{
	tableElem retval = malloc_checked(sizeof(*retval));

	retval->data = data;
	retval->key = key;
	retval->next = next;
	return (retval);
}