1 files changed, 98 insertions, 0 deletions
diff --git a/OpenSim/Framework/PrimeNumberHelper.cs b/OpenSim/Framework/PrimeNumberHelper.cs
new file mode 100644
index 0000000..e4bf615
--- /dev/null
+++ b/OpenSim/Framework/PrimeNumberHelper.cs
@@ -0,0 +1,98 @@
+// --------------------------------------------------------------------------------------------------------------------
+// <copyright company="" file="PrimeNumberHelper.cs">
+//   
+// </copyright>
+// <summary>
+//   
+// </summary>
+// 
+// --------------------------------------------------------------------------------------------------------------------
+using System;
+namespace OpenSim.Framework
+{
+    /// <summary>
+    /// Utility class that is used to find small prime numbers and test is number prime number.
+    /// </summary>
+    public static class PrimeNumberHelper
+    {
+        /// <summary>
+        /// Precalculated prime numbers. 
+        /// </summary>
+        private static readonly int[] Primes = new int[]
+                                                   {
+                                                       3, 7, 11, 17, 23, 29, 37, 47, 59, 71, 89, 107, 131, 163, 197, 239,
+                                                       293, 353, 431, 521, 631, 761, 919, 1103, 1327, 1597, 1931, 2333,
+                                                       2801, 3371, 4049, 4861, 5839, 7013, 8419, 10103, 12143, 14591,
+                                                       17519, 21023, 25229, 30293, 36353, 43627, 52361, 62851, 75431,
+                                                       90523, 108631, 130363, 156437, 187751, 225307, 270371, 324449,
+                                                       389357, 467237, 560689, 672827, 807403, 968897, 1162687, 1395263,
+                                                       1674319, 2009191, 2411033, 2893249, 3471899, 4166287, 4999559,
+                                                       5999471, 7199369
+                                                   };
+        /// <summary>
+        /// Get prime number that is equal or larger than <see cref="min"/>.
+        /// </summary>
+        /// <param name="min">
+        /// Minimal returned prime number.
+        /// </param>
+        /// <returns>
+        /// Primer number that is equal or larger than <see cref="min"/>. If <see cref="min"/> is too large, return -1.
+        /// </returns>
+        public static int GetPrime( int min )
+        {
+            if( min <= 2 )
+                return 2;
+            if( Primes[ Primes.Length - 1 ] < min )
+            {
+                for( int i = min | 1 ; i < 0x7FFFFFFF ; i += 2 )
+                {
+                    if( IsPrime( i ) )
+                        return i;
+                }
+                return -1;
+            }
+            for( int i = Primes.Length - 2 ; i >= 0 ; i-- )
+            {
+                if( min == Primes[ i ] )
+                    return min;
+                if( min > Primes[ i ] )
+                    return Primes[ i + 1 ];
+            }
+            return 2;
+        }
+        /// <summary>
+        /// Just basic Sieve of Eratosthenes prime number test.
+        /// </summary>
+        /// <param name="candinate">
+        /// Number that is tested.
+        /// </param>
+        /// <returns>
+        /// true, if <see cref="candinate"/> is prime number; otherwise false.
+        /// </returns>
+        public static bool IsPrime( int candinate )
+        {
+            if( (candinate & 1) == 0 )
+                // Even number - only prime if 2
+                return candinate == 2;
+            int upperBound = (int) Math.Sqrt( candinate );
+            for( int i = 3 ; i < upperBound ; i += 2 )
+            {
+                if( candinate % i == 0 )
+                    return false;
+            }
+            return true;
+        }
+    }
+}

diff --git a/OpenSim/Framework/PrimeNumberHelper.cs b/OpenSim/Framework/PrimeNumberHelper.cs new file mode 100644 index 0000000..e4bf615 --- /dev/null +++ b/OpenSim/Framework/PrimeNumberHelper.cs
@@ -0,0 +1,98 @@
	1	// --------------------------------------------------------------------------------------------------------------------
	2	// <copyright company="" file="PrimeNumberHelper.cs">
	3	//
	4	// </copyright>
	5	// <summary>
	6	//
	7	// </summary>
	8	//
	9	// --------------------------------------------------------------------------------------------------------------------
	10
	11	using System;
	12
	13	namespace OpenSim.Framework
	14	{
	15	/// <summary>
	16	/// Utility class that is used to find small prime numbers and test is number prime number.
	17	/// </summary>
	18	public static class PrimeNumberHelper
	19	{
	20	/// <summary>
	21	/// Precalculated prime numbers.
	22	/// </summary>
	23	private static readonly int[] Primes = new int[]
	24	{
	25	3, 7, 11, 17, 23, 29, 37, 47, 59, 71, 89, 107, 131, 163, 197, 239,
	26	293, 353, 431, 521, 631, 761, 919, 1103, 1327, 1597, 1931, 2333,
	27	2801, 3371, 4049, 4861, 5839, 7013, 8419, 10103, 12143, 14591,
	28	17519, 21023, 25229, 30293, 36353, 43627, 52361, 62851, 75431,
	29	90523, 108631, 130363, 156437, 187751, 225307, 270371, 324449,
	30	389357, 467237, 560689, 672827, 807403, 968897, 1162687, 1395263,
	31	1674319, 2009191, 2411033, 2893249, 3471899, 4166287, 4999559,
	32	5999471, 7199369
	33	};
	34
	35	/// <summary>
	36	/// Get prime number that is equal or larger than <see cref="min"/>.
	37	/// </summary>
	38	/// <param name="min">
	39	/// Minimal returned prime number.
	40	/// </param>
	41	/// <returns>
	42	/// Primer number that is equal or larger than <see cref="min"/>. If <see cref="min"/> is too large, return -1.
	43	/// </returns>
	44	public static int GetPrime( int min )
	45	{
	46	if( min <= 2 )
	47	return 2;
	48
	49	if( Primes[ Primes.Length - 1 ] < min )
	50	{
	51	for( int i = min \| 1 ; i < 0x7FFFFFFF ; i += 2 )
	52	{
	53	if( IsPrime( i ) )
	54	return i;
	55	}
	56
	57	return -1;
	58	}
	59
	60	for( int i = Primes.Length - 2 ; i >= 0 ; i-- )
	61	{
	62	if( min == Primes[ i ] )
	63	return min;
	64
	65	if( min > Primes[ i ] )
	66	return Primes[ i + 1 ];
	67	}
	68
	69	return 2;
	70	}
	71
	72	/// <summary>
	73	/// Just basic Sieve of Eratosthenes prime number test.
	74	/// </summary>
	75	/// <param name="candinate">
	76	/// Number that is tested.
	77	/// </param>
	78	/// <returns>
	79	/// true, if <see cref="candinate"/> is prime number; otherwise false.
	80	/// </returns>
	81	public static bool IsPrime( int candinate )
	82	{
	83	if( (candinate & 1) == 0 )
	84
	85	// Even number - only prime if 2
	86	return candinate == 2;
	87
	88	int upperBound = (int) Math.Sqrt( candinate );
	89	for( int i = 3 ; i < upperBound ; i += 2 )
	90	{
	91	if( candinate % i == 0 )
	92	return false;
	93	}
	94
	95	return true;
	96	}
	97	}
	98	}