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

	dictionary.c

	Started by Jeff Ondich on 5/8/97
	Last modified 5/9/97

	Implementation for a simple dictionary
	data type.

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

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


/***************************************************
	InitializeDictionary returns TRUE if d is
	non-NULL and initialization is successful,
	FALSE otherwise.
 ***************************************************/

boolean InitializeDictionary( Dictionary *d )
{
	if( d != NULL )
	{
		d->nWords = 0;
		d->entry = (Word *)malloc( sizeof(Word) * MAX_WORDS );
		if( d->entry == NULL )
			return( FALSE );
		
		return( TRUE );
	}
	else
		return( FALSE );
}


/***************************************************
	AddToDictionary returns FALSE if d or newWord
	is NULL, if the dictionary is already full,
	or if adding to the dictionary fails.
	Otherwise, AddToDictionary adds newWord
	to the dictionary and returns TRUE.
 ***************************************************/

boolean AddToDictionary( Dictionary *d, char *newWord )
{
	int		i;

	if( d == NULL  ||  newWord == NULL  ||  d->nWords >= MAX_WORDS )
		return( FALSE );

  /* Shift words down to make space for the new word. */
	for( i=d->nWords-1; i >= 0  &&  strcmp( newWord, d->entry[i] ) < 0; i-- )
		strcpy( d->entry[i+1], d->entry[i] );

  /* Put the new word in its place.  Prevent the new word from
     overflowing its array by using strncpy(). */
	strncpy( d->entry[i+1], newWord, MAX_WORD_LENGTH );
	d->entry[i+1][MAX_WORD_LENGTH-1] = '\0';

  /* Update word count. */
	(d->nWords)++;

	return( TRUE );
}


/***************************************************
	IsInDictionary returns TRUE if d and searchWord
	are non-NULL and searchWord is in the dictionary.
	Otherwise, IsInDictionary returns FALSE.
	
	This implementation of IsInDictionary uses
	a binary search on a sorted array of strings.
 ***************************************************/

boolean IsInDictionary( Dictionary *d, char *searchWord )
{
	int		left, right, middle, comparison;

	if( d == NULL )
		return( FALSE );

	left = 0;
	right = d->nWords - 1;
	while( left <= right )
	{
		middle = (right + left) / 2;
		comparison = strcmp( searchWord, d->entry[middle] );
		if( comparison == 0 )
			return( TRUE );
		
		else if( comparison > 0 )
			left = middle + 1;
		
		else
			right = middle - 1;
	}

	return( FALSE );
}


/***************************************************
	PrintDictionary prints out the dictionary
	in whatever form is appropriate for
	debugging.
 ***************************************************/

void PrintDictionary( FILE *f, Dictionary *d )
{
	int		i;

	if( d != NULL  &&  f != NULL )
	{
		fprintf( f, "\nDictionary:\n" );
		for( i=0; i < d->nWords; i++ )
			fprintf( f, "\t%s\n", d->entry[i] );
		fprintf( f, "End of Dictionary.\n\n" );
	}
}