From 8022ab5725540b6ae71e1f353a3ff4ba72d31646 Mon Sep 17 00:00:00 2001
From: Stefan Suhren <suhren.stefan@fh-swf.de>
Date: Tue, 14 Apr 2015 14:19:11 +0200
Subject: Enigmafied the Caesar chipher

---
 src/crypt/cryptclasscaesar.cpp | 69 +++++++++++++++++-------------------------
 src/crypt/cryptclasscaesar.h   |  3 +-
 2 files changed, 29 insertions(+), 43 deletions(-)

(limited to 'src')

diff --git a/src/crypt/cryptclasscaesar.cpp b/src/crypt/cryptclasscaesar.cpp
index c9942a8..e2fdf50 100644
--- a/src/crypt/cryptclasscaesar.cpp
+++ b/src/crypt/cryptclasscaesar.cpp
@@ -1,11 +1,12 @@
 #include "cryptclasscaesar.h"
 
-const int CryptClassCaesar::LOWERBOUND = 0x30;
-const int CryptClassCaesar::UPPERBOUND = 0x7A;
+const int CryptClassCaesar::LOWERBOUND = 'A';
+const int CryptClassCaesar::UPPERBOUND = 'Z';
 
 CryptClassCaesar::CryptClassCaesar()
 {
-    oldKey = -1;
+    mapOffset = 0;
+    buildMap();
 }
 
 CryptClassCaesar::~CryptClassCaesar()
@@ -16,11 +17,10 @@ CryptClassCaesar::~CryptClassCaesar()
 void CryptClassCaesar::encrypt()
 {
     qDebug("CryptClassCaesar::encrypt");
-    buildMap();
 
+    m_clearText = m_clearText.toUpper();
     m_cryptText.clear();
-
-    m_clearText = stripUmlauts(m_clearText);
+    mapOffset = 0;
 
     int spaceCount = 0;
 
@@ -28,7 +28,8 @@ void CryptClassCaesar::encrypt()
     {
         if (m_clearText[i] >= (char) LOWERBOUND && m_clearText[i] <= (char) UPPERBOUND)
         {
-            m_cryptText.append(substitutionsMap[m_clearText[i]]);
+            m_cryptText.append(substitutionsMap[LOWERBOUND + (((m_clearText[i] - LOWERBOUND)
+                                                + mapOffset++) % (26))]);
 
             if (!(++spaceCount % 5))
             {
@@ -42,57 +43,43 @@ void CryptClassCaesar::encrypt()
 void CryptClassCaesar::decrypt()
 {
     qDebug("CryptClassCaesar::decrypt");
-    buildMap();
 
-    m_clearText.clear();
+    int tmp = 0;
+
+    m_cryptText = m_cryptText.toUpper();
 
-    m_cryptText = stripUmlauts(m_cryptText);
+    m_clearText.clear();
+    mapOffset = 0;
 
     for (int i = 0; i < m_cryptText.size(); i++)
     {
         if (m_cryptText[i] >= (char) LOWERBOUND && m_cryptText[i] <= (char) UPPERBOUND)
         {
-            m_clearText.append(substitutionsMap.key(m_cryptText[i]));
+            tmp = ((substitutionsMap.key(m_cryptText[i]) - LOWERBOUND) - mapOffset++) %
+                  (26);
+
+            if (tmp < 0)
+            {
+                //Because tmp is negative adding it to UPPERBOUND subtracts it
+                //Also plus 1 because -1 is the highest negative number
+                m_clearText.append(UPPERBOUND + tmp + 1);
+            }
+            else
+            {
+                m_clearText.append(LOWERBOUND + tmp);
+            }
         }
     }
 }
 
 void CryptClassCaesar::buildMap()
 {
-    bool ok = false;
-
-    if (oldKey == getKey().toInt(&ok))
-    {
-        if (ok == false)
-        {
-            QMessageBox::warning(NULL, "Key invalid",
-                                 "The key for Ceasar should only be a number.");
-        }
-
-        return;
-    }
-
-    oldKey = getKey().toInt();
+    char tmp[] = "EKMFLGDQVZNTOWYHXUSPAIBRCJ";
 
     substitutionsMap.clear();
 
     for (int i = 0; i <= (UPPERBOUND - LOWERBOUND); i++)
     {
-        substitutionsMap.insert((char)(LOWERBOUND + i),
-                                (char)(LOWERBOUND + (i + oldKey) % (UPPERBOUND - LOWERBOUND)));
-
+        substitutionsMap.insert((char)(LOWERBOUND + i), tmp[i]);
     }
 }
-
-QByteArray CryptClassCaesar::stripUmlauts(QByteArray umlautText)
-{
-    umlautText.replace(QByteArray("ß"), QByteArray("SS"));
-
-    umlautText = umlautText.toUpper();
-
-    umlautText.replace(QByteArray("Ä"), QByteArray("AE"));
-    umlautText.replace(QByteArray("Ö"), QByteArray("OE"));
-    umlautText.replace(QByteArray("Ü"), QByteArray("UE"));
-
-    return umlautText;
-}
diff --git a/src/crypt/cryptclasscaesar.h b/src/crypt/cryptclasscaesar.h
index 899136b..95fc479 100644
--- a/src/crypt/cryptclasscaesar.h
+++ b/src/crypt/cryptclasscaesar.h
@@ -20,12 +20,11 @@ public:
 private:
     void buildMap();
 
-    int oldKey;
+    int mapOffset;
     QMap<char, char> substitutionsMap;
 
     const static int LOWERBOUND;
     const static int UPPERBOUND;
-    QByteArray stripUmlauts(QByteArray umlautText);
 };
 
 #endif // CRYPTCLASSCAESAR_H
-- 
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