//===========================================================================
//                                      CRYPTOLOGY: VERNAM ASCII - Lower Case
//                                                           Nicholas Gessler
//                                                                 11/14/2008
//
//   Notes:  The decimal value of "a" is 97, thus if we subtract 97 from the
//           decimal values of the letters from "a" to "z" we have numbers
//           in the range from 1 to 26.
//           When we "extract" numeric values, we do so modulo 26.
//
//===========================================================================

#include <vcl.h>
#include <string.h>
#include <stddef.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
   : TForm(Owner)
{
}
//---------------------------------------------------------------------------

//===========================================================================
//                                                      DEFINES and VARIABLES
//===========================================================================

#define CLEAR 0
#define KEY 1
#define CIPHER 2

char c;             //?
char *str;          //?
int i;
int clearLength;
int keyLength;
int cipherLength;
int dec;
int clearArray[1000];
int keyArray[1000];
int cipherArray[1000];

//===========================================================================
//                                                                  FUNCTIONS
//===========================================================================

//================================================================ ENTER TEXT
void enter (int text) {
   switch (text) {
	  case CLEAR: {
		 Form1->MemoClearText->Font->Color = clRed;
		 char* clearText =
			new char[Form1->MemoClearText->Text.Length() + 1];
		 strcpy(clearText, Form1->MemoClearText->Text.t_str());
		 clearLength = StrLen(clearText);
         Form1->MemoClearASCII->Text = "";
         for (int i = 0; i < clearLength; i++) {
             Form1->EditClearTextLength->Text = clearLength;
			   char x = clearText[i];
			   if (i == 0) Form1->MemoClearASCII->Text =
				  Form1->MemoClearASCII->Text + " " + IntToStr(x-97);
			   else Form1->MemoClearASCII->Text =
				  Form1->MemoClearASCII->Text + ", " + IntToStr(x-97);
               clearArray[i] = clearText[i] - 97;
         }
         break;
      }
      case KEY: {
         Form1->MemoKeyText->Font->Color = clRed;
		 char* keyText =
			new char[Form1->MemoKeyText->Text.Length() + 1];
		 strcpy(keyText, Form1->MemoKeyText->Text.t_str());
         keyLength = StrLen(keyText);
         Form1->MemoKeyASCII->Text = "";
         for (int i = 0; i < keyLength; i++) {
             Form1->EditKeyTextLength->Text = keyLength;
			   char x = keyText[i];
			   if (i == 0)Form1->MemoKeyASCII->Text =
				  Form1->MemoKeyASCII->Text + " " + IntToStr(x-97);
			   else Form1->MemoKeyASCII->Text =
				  Form1->MemoKeyASCII->Text + ", " + IntToStr(x-97);
               keyArray[i] = keyText[i] - 97;
         }
         break;
      }
      case CIPHER: {
		 Form1->MemoCipherText->Font->Color = clRed;
		 char* cipherText =
			new char[Form1->MemoCipherText->Text.Length() + 1];
		 strcpy(cipherText, Form1->MemoCipherText->Text.t_str());
		 cipherLength = StrLen(cipherText);
         Form1->MemoCipherASCII->Text = "";
         for (int i = 0; i < cipherLength; i++) {
             Form1->EditCipherTextLength->Text = cipherLength;
			 char x = cipherText[i];
			 if (i == 0) Form1->MemoCipherASCII->Text =
				Form1->MemoCipherASCII->Text + " " + IntToStr(x-97);
			 else Form1->MemoCipherASCII->Text =
				Form1->MemoCipherASCII->Text + ", " + IntToStr(x-97);
			 cipherArray[i] = cipherText[i] - 97;
         }
         break;
      }
   }
}

//============================================================== EXTRACT TEXT
void extract (int text) {
   switch (text) {
	  case CLEAR: {
		 Form1->MemoClearText->Font->Color = clBlue;
		 if (cipherLength <= keyLength) {
			Form1->MemoClearText->Text = "";
			Form1->MemoClearASCII->Text = "";
			for (int i = 0; i < cipherLength; i++) {
			   clearArray[i] = cipherArray[i] - keyArray[i];
			   if (clearArray[i] > 25) clearArray[i] -= 26;
			   if (clearArray[i] < 0) clearArray[i] += 26;
			   if (i == 0) Form1->MemoClearASCII->Text
				  = Form1->MemoClearASCII->Text
				  + " " + IntToStr(clearArray[i]);
			   else Form1->MemoClearASCII->Text
				  = Form1->MemoClearASCII->Text
				  + ", " + IntToStr(clearArray[i]);
			   c = clearArray[i] + 97;
			   Form1->MemoClearText->Text
				  = Form1->MemoClearText->Text + c;
            }
		 }
         else Form1->MemoClearText->Text = "Key Length Too Short";
		 break;
	  }
	  case KEY: {
		 Form1->MemoKeyText->Font->Color = clBlue;
		 if (clearLength == cipherLength) {
			Form1->MemoKeyText->Text = "";
			Form1->MemoKeyASCII->Text = "";
			for (int i = 0; i < cipherLength; i++) {
			   keyArray[i] = cipherArray[i] - clearArray[i];
			   if (keyArray[i] > 25) keyArray[i] -= 26;
			   if (keyArray[i] < 0) keyArray[i] += 26;
			   if (i == 0) Form1->MemoKeyASCII->Text =
				  Form1->MemoKeyASCII->Text
				  + " " + IntToStr(keyArray[i]);
			   else Form1->MemoKeyASCII->Text =
				  Form1->MemoKeyASCII->Text
				  + ", " + IntToStr(keyArray[i]);
			   c = keyArray[i] + 97;
			   Form1->MemoKeyText->Text
				  = Form1->MemoKeyText->Text + c;
			}
		 }
		 else Form1->MemoKeyText->Text = "Clear and Cipher Lengths Unequal";
		 break;
	  }
	  case CIPHER: {
		 Form1->MemoCipherText->Font->Color = clBlue;
		 if (clearLength <= keyLength) {
			Form1->MemoCipherText->Text = "";
			Form1->MemoCipherASCII->Text = "";
			for (int i = 0; i < clearLength; i++) {
			   cipherArray[i] = clearArray[i] + keyArray[i];
			   if (cipherArray[i] > 25) cipherArray[i] -= 26;
			   if (cipherArray[i] < 0) cipherArray[i] += 26;
			   if (i == 0) Form1->MemoCipherASCII->Text =
				  Form1->MemoCipherASCII->Text
				  + " " + IntToStr(cipherArray[i]);
			   else Form1->MemoCipherASCII->Text =
				  Form1->MemoCipherASCII->Text
				  + ", " + IntToStr(cipherArray[i]);
               c = cipherArray[i] + 97;
               Form1->MemoCipherText->Text
                  = Form1->MemoCipherText->Text + c;
            }
         }
         else Form1->MemoCipherText->Text = "Key Length Too Short";
         break;
      }
   }
}

//===========================================================================
//                                                             EVENT HANDLERS
//===========================================================================

//-------------------------------------------------------- ENTER CLEAR BUTTON
void __fastcall TForm1::ButtonEnterClearClick(TObject *Sender)
{
   enter(CLEAR);
}

//---------------------------------------------------------- ENTER KEY BUTTON
void __fastcall TForm1::ButtonEnterKeyClick(TObject *Sender)
{
   enter(KEY);
}

//------------------------------------------------------- ENTER CIPHER BUTTON
void __fastcall TForm1::ButtonEnterCipherClick(TObject *Sender)
{
   enter(CIPHER);
}

//------------------------------------------------------ EXTRACT CLEAR BUTTON
void __fastcall TForm1::ButtonExtractClearClick(TObject *Sender)
{
   extract(CLEAR);
}

//-------------------------------------------------------- EXTRACT KEY BUTTON
void __fastcall TForm1::ButtonExtractKeyClick(TObject *Sender)
{
   extract(KEY);
}

//----------------------------------------------------- EXTRACT CIPHER BUTTON
void __fastcall TForm1::ButtonExtractCipherClick(TObject *Sender)
{
   extract(CIPHER);
}

//---------------------------------------------------- MEMO CLEAR TEXT CHANGE
void __fastcall TForm1::MemoClearTextChange(TObject *Sender)
{
   MemoClearText->Font->Color = clGray;
}

//------------------------------------------------------ MEMO KEY TEXT CHANGE
void __fastcall TForm1::MemoKeyTextChange(TObject *Sender)
{
   MemoKeyText->Font->Color = clGray;
}

//--------------------------------------------------- MEMO CIPHER TEXT CHANGE
void __fastcall TForm1::MemoCipherTextChange(TObject *Sender)
{
   MemoCipherText->Font->Color = clGray;
}