diff options
author | Tom Tromey <tromey@redhat.com> | 2003-02-17 23:15:56 +0000 |
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committer | Tom Tromey <tromey@redhat.com> | 2003-02-17 23:15:56 +0000 |
commit | 26087ec05570ea81ad20150d73837ba2bdcf1c9d (patch) | |
tree | 35d5e391639faaa1e89876f1f38fff1b0b7cbec8 /java/math | |
parent | a0eb645f0a0f6a68d2963aaf45538e4356483a90 (diff) | |
download | classpath-26087ec05570ea81ad20150d73837ba2bdcf1c9d.tar.gz |
2003-02-17 Raif S. Naffah <raif@fl.net.au>
* java/math/BigInteger.java (euclidInv): Return array of
`BigInteger's. Changed all callers.
Diffstat (limited to 'java/math')
-rw-r--r-- | java/math/BigInteger.java | 33 |
1 files changed, 15 insertions, 18 deletions
diff --git a/java/math/BigInteger.java b/java/math/BigInteger.java index f72429046..6a17cf3b7 100644 --- a/java/math/BigInteger.java +++ b/java/math/BigInteger.java @@ -1017,9 +1017,8 @@ public class BigInteger extends Number implements Comparable return xy; } - private static final void euclidInv(BigInteger a, BigInteger b, - BigInteger prevDiv, BigInteger xy0, - BigInteger xy1, BigInteger xy2) + private static final BigInteger[] euclidInv(BigInteger a, BigInteger b, + BigInteger prevDiv) { if (b.isZero()) throw new ArithmeticException("not invertible"); @@ -1028,20 +1027,20 @@ public class BigInteger extends Number implements Comparable { // Success: values are indeed invertible! // Bottom of the recursion reached; start unwinding. - // WARNING: xy1 is, and xy0 may be, a shared BI! - xy0 = neg(prevDiv); - xy1 = ONE; - return; + return new BigInteger[] { neg(prevDiv), ONE }; } + 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); - xy0 = new BigInteger(xyInt[0]); // non-shared BI - xy1 = new BigInteger(xyInt[1]); // non-shared BI + result = new BigInteger[] { // non-shared BI + new BigInteger(xyInt[0]), + new BigInteger(xyInt[1]) + }; } else { @@ -1051,15 +1050,13 @@ public class BigInteger extends Number implements Comparable // quot and rem may not be in canonical form. ensure rem.canonicalize(); quot.canonicalize(); - euclidInv(b, rem, quot, xy0, xy1, xy2); + result = euclidInv(b, rem, quot); } - // xy2 is just temp storage for intermediate results in the following - // calculation. This saves us a bit of space over having a BigInteger - // allocated at every level of this recursive method. - xy2 = xy0; - xy0 = add(xy1, times(xy2, prevDiv), -1); - xy1 = xy2; + BigInteger t = result[0]; + result[0] = add(result[1], times(t, prevDiv), -1); + result[1] = t; + return result; } public BigInteger modInverse(BigInteger y) @@ -1129,8 +1126,8 @@ public class BigInteger extends Number implements Comparable quot.canonicalize(); BigInteger xy0 = new BigInteger(); BigInteger xy1 = new BigInteger(); - euclidInv(y, rem, quot, xy0, xy1, result); - result = swapped ? xy0 : xy1; + BigInteger[] xy = euclidInv(y, rem, quot); + result = swapped ? xy[0] : xy[1]; // Result can't be negative, so make it positive by adding the // original modulus, y (which is now x if they were swapped). |