dictionary.c

// Implements a dictionary's functionality
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>

#include "dictionary.h"



// Represents a node in a hash table
typedef struct node
{
    char word[LENGTH + 1];
    struct node *next;
}
node;

// Number of buckets in hash table
const unsigned int N = 50000;
int count=0;

// Hash table
node *table[N];

void free_linkedlist(node *cursor);

// Returns true if word is in dictionary else false
bool check(const char *word)
{
    node *head=table[hash(word)];

    node *cursor=head;
    while(cursor != NULL)
    {
        if(strcasecmp(cursor->word,word)==1){
            return true;
        }
        else
        {
            cursor=cursor->next;
        }
    }
    return false;

}

// Hashes word to a number
size_t precision=2;
unsigned int hash(const char *word)
{
    return ((*(size_t*)word)>>precision) % N;
}


// Loads dictionary into memory, returning true if successful else false
bool load(const char *dictionary)
{
    // open dictionary file
    FILE* dicfile = fopen(dictionary,"r");
    if(dicfile==NULL){
        printf("couldnt open dictionary file\n");
        return false;
    }
    char word[LENGTH+1]={'\0'};
    //read strings from file till EOF.
    while(fscanf(dicfile,"%s",word)==1)
    {
        node* new_node=malloc(sizeof(node));
        if(new_node== NULL){

            unload();
            return false;
        }
        //copy word into node structure
        strcpy(new_node->word,word);
        int key=hash(new_node->word);
        if(!table[key]){
            table[key]=new_node;
            count++;
        }
        else
        {
            new_node->next=table[key];
            table[key]=new_node;
            count++;
        }



    }
    return true;


}

// Returns number of words in dictionary if loaded else 0 if not yet loaded
unsigned int size(void)
{
    // TODO
    return count;
}

// Unloads dictionary from memory, returning true if successful else false
bool unload(void)
{
    for(int i=0; i<N; i++)
    {
        free_linkedlist(table[i]);
    }
    return true;
}

void free_linkedlist(node *cursor)
{

    while(cursor != NULL)
    {
        node *temp=cursor;
        cursor=cursor->next;
        free(temp);
    }
}