Patch: FYI: BigInteger again

[Tom Tromey]

I'm checking this in to 3.3, 3.4, and Classpath.

Raif updated his patch to remove a couple unused variables (leaving
those in was my fault) and also to be a bit more efficient.

Tom

Index: ChangeLog
from  Raif S. Naffah <raif@fl.net.au>

	* java/math/BigInteger.java (euclidInv): Take result array as an
	argument.  Updated all callers.
	(modInverse): Removed unused variables.

Index: java/math/BigInteger.java
===================================================================
RCS file: /cvsroot/classpath/classpath/java/math/BigInteger.java,v
retrieving revision 1.18
diff -u -r1.18 BigInteger.java
--- java/math/BigInteger.java 17 Feb 2003 23:15:56 -0000 1.18
+++ java/math/BigInteger.java 18 Feb 2003 17:28:02 -0000
@@ -1017,8 +1017,8 @@
     return xy;
   }
 
-  private static final BigInteger[] euclidInv(BigInteger a, BigInteger b,
-					      BigInteger prevDiv)
+  private static final void euclidInv(BigInteger a, BigInteger b,
+                                      BigInteger prevDiv, BigInteger[] xy)
   {
     if (b.isZero())
       throw new ArithmeticException("not invertible");
@@ -1027,20 +1027,19 @@
       {
 	// Success:  values are indeed invertible!
 	// Bottom of the recursion reached; start unwinding.
-	return new BigInteger[] { neg(prevDiv), ONE };
+	xy[0] = neg(prevDiv);
+        xy[1] = ONE;
+	return;
       }
 
-    BigInteger[] result;
     // Recursion happens in the following conditional!
 
     // If a just contains an int, then use integer math for the rest.
     if (a.words == null)
       {
         int[] xyInt = euclidInv(b.ival, a.ival % b.ival, a.ival / b.ival);
-	result = new BigInteger[] { // non-shared BI
-	  new BigInteger(xyInt[0]),
-	  new BigInteger(xyInt[1])
-	};
+	xy[0] = new BigInteger(xyInt[0]);
+        xy[1] = new BigInteger(xyInt[1]);
       }
     else
       {
@@ -1050,13 +1049,12 @@
         // quot and rem may not be in canonical form. ensure
         rem.canonicalize();
         quot.canonicalize();
-	result = euclidInv(b, rem, quot);
+	euclidInv(b, rem, quot, xy);
       }
 
-    BigInteger t = result[0];
-    result[0] = add(result[1], times(t, prevDiv), -1);
-    result[1] = t;
-    return result;
+    BigInteger t = xy[0];
+    xy[0] = add(xy[1], times(t, prevDiv), -1);
+    xy[1] = t;
   }
 
   public BigInteger modInverse(BigInteger y)
@@ -1124,9 +1122,8 @@
         // quot and rem may not be in canonical form. ensure
         rem.canonicalize();
         quot.canonicalize();
-        BigInteger xy0 = new BigInteger();
-        BigInteger xy1 = new BigInteger();
-	BigInteger[] xy = euclidInv(y, rem, quot);
+	BigInteger[] xy = new BigInteger[2];
+	euclidInv(y, rem, quot, xy);
 	result = swapped ? xy[0] : xy[1];
 
 	// Result can't be negative, so make it positive by adding the