//Charles Pierse
//11510667

package Lexical_Analyzer;


import java.util.Arrays;

public class HashTable {

	private int MAX_INTEGER = 512;
	private char MAX_CHARACTER = 4096;
	private int[] num_array = new int[MAX_INTEGER];
	private char[] char_array = new char[MAX_CHARACTER];
	private int counter1 = -1;
	private int counter2 = 0;
	private int prime_counter = 0;
	private int hash_code = 0 ;



	public void array_fill() {


		Arrays.fill(num_array, -1);
		Arrays.fill(char_array, '~');

	}

	public int store_next_character(char nextChar, int h_slot){
		char_array[counter2] = nextChar;

		int prime_Arr[] =
				{13001,13003,13007,13009,13033,13037,13043,13049,13063,13093,13099,
				13103,13109,13121,13127,13147,13151,13159,13163,13171,13177,13183,13187,13217,13219};
		int ascii_num = nextChar;
		hash_code = ascii_num*prime_Arr[prime_counter];

		prime_counter++;
		counter2++;
		return ((h_slot + hash_code)%MAX_INTEGER);
	}

	public int determine_slot(int h_slot) {
		if (num_array[h_slot] == -1)
		{

			num_array[h_slot] =  counter1 +1;
			char_array[counter2 +1] ='~';
			counter1 = counter2;
			counter2 = counter2 +1;
			if (h_slot!=136){ //this ignores printing the id at start for the stoplexer
				System.out.println("<id," + h_slot+">");
			}


		}
		else if (match_check(num_array[h_slot], counter1+1) == true ){

			counter2 = counter1 + 1;


		}
		else if (match_check(num_array[h_slot], counter1+1)  == false){ //collision has occured,
			//find new hash slot

			h_slot = h_slot + 1;
			if (h_slot >511){   //if we incremented the hash_slot and
				//it goes over the int array size reset it to 0
				h_slot = 0;
			}
			determine_slot(h_slot);




		}
		for ( int dupl_counter = counter2; char_array[dupl_counter] != '~'; dupl_counter++){
			//this cleans out duplicate id's in the char_array
			char_array[dupl_counter] = '~';
		}
		prime_counter= 0;
		return h_slot;

	}


	public boolean match_check(int index1, int index2){

		int temp_pos = 0;

		while(char_array[index1+ temp_pos]!='~' && char_array[index2 +temp_pos] != '~'){

			if (char_array[index1+temp_pos] != char_array[index2 + temp_pos]){
				return false;
			}
			temp_pos = temp_pos + 1;
		}

		if(char_array[index1 + temp_pos]!='~'||char_array[index2+temp_pos] != '~'){
			return false;
		}

		else{

			return true;

		}

	}
//	public static void main(String[] args){ // this was my testing stub for this class
//
//		HashTable table = new HashTable();
//		table.array_fill();
//
//		String tester = "bog~bogota~bog~";
//
//		for(Character c: tester.toCharArray()) {
//
//			if ((c>='A') && (c<='Z') || (c>='a') && (c<='z')){
//				table.store_next_character(c);
//			}
//
//			else {
//
//				table.determine_slot();
//
//			}
//
//			System.out.println(new String(table.char_array).substring(0, 200));
//		}
//	}
}