Make math commutative/correct for Long/MIN_VALUE

Signed-off-by: Stuart Halloway <[email protected]>

Author: trptcolin

src/jvm/clojure/lang/BigInt.java

@@ -144,7 +144,8 @@ public BigInt add(BigInt y) {
 public BigInt multiply(BigInt y) {
     if ((bipart == null) && (y.bipart == null)) {
         long ret = lpart * y.lpart;
-            if (y.lpart == 0 || ret / y.lpart == lpart)
+            if (y.lpart == 0 ||
+                (ret / y.lpart == lpart && lpart != Long.MIN_VALUE))
                 return BigInt.valueOf(ret);
         }
     return BigInt.fromBigInteger(this.toBigInteger().multiply(y.toBigInteger()));

src/jvm/clojure/lang/Numbers.java

@@ -444,6 +444,8 @@ final public Number multiply(Number x, Number y){
 
 	final public Number multiplyP(Number x, Number y){
 		long lx = x.longValue(), ly = y.longValue();
+    if (lx == Long.MIN_VALUE && ly < 0)
+      return BIGINT_OPS.multiply(x, y);
 		long ret = lx * ly;
 		if (ly != 0 && ret/ly != lx)
 			return BIGINT_OPS.multiply(x, y);
@@ -1747,13 +1749,17 @@ static public Number decP(long x){
 
 
 static public long multiply(long x, long y){
+  if (x == Long.MIN_VALUE && y < 0)
+		return throwIntOverflow();
 	long ret = x * y;
 	if (y != 0 && ret/y != x)
 		return throwIntOverflow();
 	return ret;
 }
 
 static public Number multiplyP(long x, long y){
+  if (x == Long.MIN_VALUE && y < 0)
+		return multiplyP((Number)x,(Number)y);
 	long ret = x * y;
 	if (y != 0 && ret/y != x)
 		return multiplyP((Number)x,(Number)y);

test/clojure/test_clojure/numbers.clj

@@ -214,6 +214,17 @@
 
   (is (> (* 3 (int (/ Integer/MAX_VALUE 2.0))) Integer/MAX_VALUE)) )  ; no overflow
 
+(deftest test-multiply-longs-at-edge
+  (are [x] (= x 9223372036854775808N)
+       (*' -1 Long/MIN_VALUE)
+       (*' Long/MIN_VALUE -1)
+       (* -1N Long/MIN_VALUE)
+       (* Long/MIN_VALUE -1N)
+       (* -1 (bigint Long/MIN_VALUE))
+       (* (bigint Long/MIN_VALUE) -1))
+  (is (thrown? ArithmeticException (* Long/MIN_VALUE -1)))
+  (is (thrown? ArithmeticException (* -1 Long/MIN_VALUE))))
+
 (deftest test-ratios-simplify-to-ints-where-appropriate
   (testing "negative denominator (assembla #275)"
     (is (integer? (/ 1 -1/2)))