phonebook_opt.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "phonebook_opt.h"

entry *findhash(char lastName[], hashtable *ht)
{
    int index = hash(lastName);
    entry *target = ht->list[index];
    if(ht->list[index]==NULL)
        return NULL;
    while(strcasecmp(lastName, target->lastName) == 0) {
        target = target->pNext;
    }
    return target;
}

void appendhash(char lastName[], hashtable *ht, pool *mem_pool)
{
    int index = hash(lastName);
    entry *temp;
    temp = mem_allocate(mem_pool);
    strcpy(temp->lastName, lastName);
    temp->pNext = ht->list[index];
    ht->list[index]=temp;
}

hashtable *Create_Hash_Table()
{
    hashtable *ht;
    ht = (hashtable *)malloc(sizeof(hashtable));
    ht->list = (entry **)malloc(sizeof(entry *)*TABLE_SIZE);
    for(int i=0; i<TABLE_SIZE; i++)
        ht->list[i]=NULL;
    return ht;
}

int hash(char lastName[])
{
    int i=0, sum=0;

    while(lastName[i] != '\0') {
        sum =  sum*3 + lastName[i];
        i++;
    }
    return sum % TABLE_SIZE;//Choose a prime to multiple the sum.
}

void create_pool(pool *mem_pool)
{
    mem_pool->start = (entry *) malloc(sizeof(entry)*350000);
    mem_pool->now = mem_pool->start;
    mem_pool->end = mem_pool->start + 350000;
}

entry *mem_allocate(pool *mem_pool)
{
    if(mem_pool->end == mem_pool->now)
        return NULL;
    mem_pool->now += 1;
    return (entry *)(mem_pool->now - 1);
}

void *mem_free(pool *mem_pool)
{
    mem_pool->now -= 1;
    return NULL;
}

void destroy_pool(pool *mem_pool)
{
    free(mem_pool->start);
    free(mem_pool);
}