- Fix a sign-checking bug in the BigInteger(..., Sign) constructors.

[bigint/bigint.git] / BigInteger.cc

diff --git a/BigInteger.cc b/BigInteger.cc
index 56f30ab..3b23aa1 100644 (file)
--- a/BigInteger.cc
+++ b/BigInteger.cc
@@ -13,11 +13,18 @@ void BigInteger::operator =(const BigInteger &x) {
 BigInteger::BigInteger(const Blk *b, Index blen, Sign s) : mag(b, blen) {
        switch (s) {
        case zero:
+               if (!mag.isZero())
+                       throw "BigInteger::BigInteger(const Blk *, Index, Sign): Cannot use a sign of zero with a nonzero magnitude";
+               sign = zero;
+               break;
        case positive:
        case negative:
+               // If the magnitude is zero, force the sign to zero.
                sign = mag.isZero() ? zero : s;
                break;
        default:
+               /* g++ seems to be optimizing out this case on the assumption
+                * that the sign is a valid member of the enumeration.  Oh well. */
                throw "BigInteger::BigInteger(const Blk *, Index, Sign): Invalid sign";
        }
 }
@@ -25,12 +32,19 @@ BigInteger::BigInteger(const Blk *b, Index blen, Sign s) : mag(b, blen) {
 BigInteger::BigInteger(const BigUnsigned &x, Sign s) : mag(x) {
        switch (s) {
        case zero:
+               if (!mag.isZero())
+                       throw "BigInteger::BigInteger(const BigUnsigned &, Sign): Cannot use a sign of zero with a nonzero magnitude";
+               sign = zero;
+               break;
        case positive:
        case negative:
+               // If the magnitude is zero, force the sign to zero.
                sign = mag.isZero() ? zero : s;
                break;
        default:
-               throw "BigInteger::BigInteger(Blk *, Index, Sign): Invalid sign";
+               /* g++ seems to be optimizing out this case on the assumption
+                * that the sign is a valid member of the enumeration.  Oh well. */
+               throw "BigInteger::BigInteger(const BigUnsigned &, Sign): Invalid sign";
        }
 }