/****************************************************************************

* dictionary.c

*

* Computer Science 50

* Problem Set 6

*

* Implements a dictionary's functionality.

***************************************************************************/

#include <stdbool.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "dictionary.h"

#define ALPHABETS 27

// Trie node

typedef struct trieNode {

bool isLeaf;

struct trieNode *child[ALPHABETS];

} trieNode;

// Prototypes

trieNode *getNode(void);

void insertInTrie(char*);

int getRelativePos(char);

bool inTrie(const char*);

bool deleteNode(trieNode*);

// Global variables

trieNode *rootNode;

size_t dictionarySize = 0;

int mc = 0;

/*

* Returns true if word is in dictionary else false.

*/

bool

check(const char *word)

{

char lower[LENGTH];

int i;

for (i = 0; i < strlen(word); ++i)

if(word[i] >= 'A' && word[i] <= 'Z') lower[i] = (char) word[i] + 32;

else lower[i] = (char) word[i];

lower[i] = '\0';

return inTrie(lower);

}

/*

* Loads dictionary into memory. Returns true if successful else false.

*/

bool

load(const char *dictionary)

{

char *word = NULL;

size_t len = 0;

FILE *fp = fopen(dictionary, "r");

if (fp == NULL) return false;

rootNode = getNode();

while (getline(&word, &len, fp) != -1) {

if (word[strlen(word) - 1] == '\n') word[strlen(word) - 1] = '\0'; // remove new line character

insertInTrie(word);

}

free(word);

fclose(fp);

return true;

}

/*

* Returns number of words in dictionary if loaded else 0 if not yet loaded.

*/

unsigned int

size(void)

{

return dictionarySize;

}

/*

* Unloads dictionary from memory. Returns true if successful else false.

*/

bool

unload(void)

{

return deleteNode(rootNode);

}

/*

* Get new node

*/

trieNode *getNode() {

trieNode *T = (trieNode *) malloc(sizeof(trieNode));

T -> isLeaf = false;

for (int i = 0; i < ALPHABETS; ++i)

T -> child[i] = NULL;

return T;

}

/*

* returns the pos relative to 'a'

*/

int getRelativePos(char ch) {

return (ch == '\'') ? 27 : ch % 'a';

}

void insertInTrie(char *word) {

trieNode *temp, *node = rootNode;

for (int i = 0; i < strlen(word); ++i)

{

int pos = getRelativePos(word[i]);

if (node -> child[pos] == NULL) {

temp = getNode();

node -> child[pos] = temp;

node = temp;

} else {

node = node -> child[pos];

}

}

node -> isLeaf = true;

++dictionarySize;

}

bool inTrie(const char *word) {

trieNode *node = rootNode;

for (int i = 0; i < strlen(word); ++i)

{

int pos = getRelativePos(word[i]);

if (node -> child[pos] == NULL)

return false;

node = node -> child[pos];

}

if (node -> isLeaf) return true;

else return false;

}

bool deleteNode(trieNode *node) {

if (node == NULL) return true;

for (int i = 0; i < ALPHABETS; ++i)

if (node -> child[i] != NULL) deleteNode

(node -> child[i]);

free(node);

return true;

}