From: Sebastien Pouliot <sebastien@ximian.com>
Date: Thu, 5 Jul 2007 15:21:01 +0000 (-0000)
Subject: 2007-07-05  Sebastien Pouliot  <sebastien@ximian.com>
X-Git-Url: http://wien.tomnetworks.com/gitweb/?a=commitdiff_plain;h=f1ef8e4bc5621b7e418bc2c1df5eeb4ed756dfaa;p=mono.git

2007-07-05  Sebastien Pouliot  <sebastien@ximian.com>

	* PrimalityTests.cs: Added Test method that select which algorithm,
	SPP or RabinMillerTest, to use based on the prime-candidate size.
	Removed previous workaround (as this is both a workaround and a good
	fix ;-).


svn path=/trunk/mcs/; revision=81398
---

diff --git a/mcs/class/Mono.Security/Mono.Math.Prime/ChangeLog b/mcs/class/Mono.Security/Mono.Math.Prime/ChangeLog
index 9385c06bc4f..7ac31c94324 100644
--- a/mcs/class/Mono.Security/Mono.Math.Prime/ChangeLog
+++ b/mcs/class/Mono.Security/Mono.Math.Prime/ChangeLog
@@ -1,3 +1,10 @@
+2007-07-05  Sebastien Pouliot  <sebastien@ximian.com> 
+
+	* PrimalityTests.cs: Added Test method that select which algorithm, 
+	SPP or RabinMillerTest, to use based on the prime-candidate size. 
+	Removed previous workaround (as this is both a workaround and a good
+	fix ;-).
+
 2007-07-05  Sebastien Pouliot  <sebastien@ximian.com>
 
 	* PrimalityTests.cs: Rewritten RabinMillerTest to be closer to the 
diff --git a/mcs/class/Mono.Security/Mono.Math.Prime/PrimalityTests.cs b/mcs/class/Mono.Security/Mono.Math.Prime/PrimalityTests.cs
index 12d9a392b7c..d5bf8fa849a 100644
--- a/mcs/class/Mono.Security/Mono.Math.Prime/PrimalityTests.cs
+++ b/mcs/class/Mono.Security/Mono.Math.Prime/PrimalityTests.cs
@@ -92,6 +92,15 @@ namespace Mono.Math.Prime {
 			}
 		}
 
+		public static bool Test (BigInteger n, ConfidenceFactor confidence)
+		{
+			// Rabin-Miller fails with smaller primes (at least with our BigInteger code)
+			if (n.BitCount () < 100)
+				return SmallPrimeSppTest (n, confidence);
+			else
+				return RabinMillerTest (n, confidence);
+		}
+
 		/// <summary>
 		///     Probabilistic prime test based on Rabin-Miller's test
 		/// </summary>
@@ -128,10 +137,7 @@ namespace Mono.Math.Prime {
 			
 			// Applying optimization from HAC section 4.50 (base == 2)
 			// not a really random base but an interesting (and speedy) one
-			BigInteger y = null;
-			// FIXME: sadly there a bug that makes this fails for "small" big integers
-			if (n.BitCount () > 100)
-				y = mr.Pow (2, r);
+			BigInteger y = mr.Pow (2, r);
 
 			// still here ? start at round 1 (round 0 was a == 2)
 			for (int round = 0; round < t; round++) {