Copy the KDE 3.5 branch to branches/trinity for new KDE 3.5 features.

BUG:215923


git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdeedu@1054174 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

1 files changed, 202 insertions, 0 deletions

diff --git a/kbruch/src/primenumber.cpp b/kbruch/src/primenumber.cpp
new file mode 100644
index 00000000..7eb3c700
--- /dev/null
+++ b/kbruch/src/primenumber.cpp
@@ -0,0 +1,202 @@
+/***************************************************************************
+                          primenumber.cpp  -  source code of class primenumber
+                             -------------------
+    begin                : Tue Nov 27 16:40:42 CET 2001
+    copyright            : (C) 2001 by Sebastian Stein
+    email                : seb.kde@hpfsc.de
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include <kdebug.h>
+#include "primenumber.h"
+
+/* ----- the global prime number vector ----- */
+UnsignedIntArray primenumber::prim_vector;
+
+/* ----- public member functions ----- */
+
+/*  constructor for class primenumber */
+primenumber::primenumber()
+{
+	/* if the vector is empty, we will add the first 2 prime numbers */
+	if (prim_vector.empty())
+	{
+#ifdef DEBUG
+		kdDebug() << "prim_vector is still empty" << endl;
+#endif
+
+		prim_vector.push_back(2);
+		prim_vector.push_back(3);
+	}
+	current_pos = prim_vector.begin();
+#ifdef DEBUG
+	kdDebug() << "constructor primenumber" << endl;
+#endif
+}
+
+/* destructor for class primenumber */
+primenumber::~primenumber()
+{
+#ifdef DEBUG
+	kdDebug() << "destructor primenumber" << endl;
+#endif
+}
+
+/* check, if the given number is a prime number;
+ * return 0 if no, 1 if yes */
+short primenumber::isPrimeNumber(uint number)
+{
+#ifdef DEBUG
+	kdDebug() << "primenumber::isPrimeNumber(" << number << ")" << endl;
+#endif
+	/* 0 is not a prime number */
+	if (number == 0)
+		return 0;
+
+	/* jump to the start of the vector */
+	move_first();
+
+	/* check, if we can find a divisor */
+	for (unsigned int dummy = get_first(); dummy < number; dummy = get_next())
+	{
+		if ((number % dummy == 0) && (dummy != number))
+			return 0; // the number is not a prime number
+
+		/* we found a prime number, because we only have to test the given 
+		 * number against all known prime numbers smaller square root of the 
+		 * number */
+		if (dummy * dummy > number)
+			return 1;
+	}
+
+	return 1; // the given number is a prime number
+}
+
+/* returns next prime number */
+unsigned int primenumber::get_next()
+{
+	/* if we do not know the next number, we have to find it first */
+	if (current_pos == prim_vector.end() ||
+	        ++current_pos == prim_vector.end())
+	{
+		/* we do not know the next prime number, so we have to find it */
+		find_next();
+		move_last();
+		return get_last(); /* return it */
+	}
+	else
+	{
+		/* we know the next prime number, set the pointer on it */
+		return *current_pos; /* return it */
+	}
+}
+
+/* returns the first prime number of the vector */
+unsigned int primenumber::get_first() const
+{
+	return *prim_vector.begin();
+}
+
+/* returns the last prime number in the vector */
+unsigned int primenumber::get_last() const
+{
+	return *(prim_vector.end() - 1);
+}
+
+/* returns currently selected prime number */
+unsigned int primenumber::get_current() const
+{
+	if (current_pos == prim_vector.end() + 1)
+		return get_last();
+	return *current_pos;
+}
+
+/* set current_pos to the first prime number */
+void primenumber::move_first()
+{
+	current_pos = prim_vector.begin();
+}
+
+/* set current_pos to the last prime number */
+void primenumber::move_last()
+{
+	current_pos = prim_vector.end() - 1;
+}
+
+/* move to the next prime number */
+void primenumber::move_forward()
+{
+	/* if we are at the end of prim_vector, we have to find a new number */
+	if (current_pos == prim_vector.end() ||
+	        ++current_pos == prim_vector.end())
+	{
+		find_next();
+		move_last();
+	}
+}
+
+/* move one prime number back */
+void primenumber::move_back()
+{
+	/* current_pos must be at least pointing to the first element
+	 * of our vector after this function */
+	if (current_pos != prim_vector.begin())
+		--current_pos;
+}
+
+/* displays the whole prim_vector on stdout; just for debugging */
+void primenumber::display_all()
+{
+	unsigned int dummy = 0; // count the numbers
+
+	/* looping through the complete vector */
+	for (current_pos = prim_vector.begin(); current_pos != prim_vector.end();
+	        current_pos++, dummy++)
+		kdDebug() << dummy << ": " << *current_pos << endl;
+
+	current_pos = prim_vector.end() - 1;
+}
+
+/* ----- private member functions ----- */
+
+/* finds next prime number and adds it to the vector */
+void primenumber::find_next()
+{
+	/* our new prime number, must be bigger then the last one */
+	unsigned int new_prim = *(prim_vector.end() - 1);
+
+	do
+	{
+		/* new prime number must be bigger as biggest known one */
+		new_prim += 2;
+		/* loop as long as we find a divisor for the new number */
+		for (current_pos = prim_vector.begin(); current_pos != prim_vector.end();
+		        current_pos++)
+			if ((new_prim % *current_pos == 0) || (new_prim < *current_pos))
+				break;
+
+		/* if we tried all known numbers and found no divisor, well,
+		 * we are happy to have found a new prime number
+		 *
+		 * we found a prime number, because we only have to test the given 
+		 * number against all known prime numbers smaller square root of the 
+		 * number */
+		if ((current_pos == prim_vector.end())
+				|| (*current_pos * *current_pos > new_prim))
+			break;
+	}
+	while(1);
+
+	/* add the new prime number to the vector */
+	prim_vector.push_back(new_prim);
+
+	current_pos = prim_vector.end() - 1;
+}