Fix Issue 13391 - Allow division of BigInt by long/ulong

dlang · Aug 31, 2014 · 5862d71 · 5862d71
1 parent 5fb71bb
commit 5862d71
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Showing 2 changed files with 54 additions and 2 deletions.
diff --git a/std/bigint.d b/std/bigint.d
@@ -163,8 +163,14 @@ public:
         else static if (op=="/")
         {
             assert(y!=0, "Division by zero");
-            static assert(!is(T == long) && !is(T == ulong));
-            data = BigUint.divInt(data, cast(uint)u);
+            static if (T.sizeof <= uint.sizeof)
+            {
+                data = BigUint.divInt(data, cast(uint)u);
+            }
+            else
+            {
+                data = BigUint.divInt(data, u);
+            }
             sign = data.isZero() ? false : sign ^ (y < 0);
         }
         else static if (op=="%")
@@ -994,3 +1000,34 @@ unittest // 11583
     BigInt x = 0;
     assert((x > 0) == false);
 }
+
+unittest // 13391
+{
+    BigInt x1 = "123456789";
+    BigInt x2 = "123456789123456789";
+    BigInt x3 = "123456789123456789123456789";
+
+    import std.typetuple : TypeTuple;
+    foreach (T; TypeTuple!(byte, ubyte, short, ushort, int, uint, long, ulong))
+    {
+        assert((x1 * T.max) / T.max == x1);
+        assert((x2 * T.max) / T.max == x2);
+        assert((x3 * T.max) / T.max == x3);
+    }
+
+    assert(x1 / -123456789 == -1);
+    assert(x1 / 123456789U == 1);
+    assert(x1 / -123456789L == -1);
+    assert(x1 / 123456789UL == 1);
+    assert(x2 / -123456789123456789L == -1);
+    assert(x2 / 123456789123456789UL == 1);
+
+    assert(x1 / uint.max == 0);
+    assert(x1 / ulong.max == 0);
+    assert(x2 / ulong.max == 0);
+
+    x1 /= 123456789UL;
+    assert(x1 == 1);
+    x2 /= 123456789123456789UL;
+    assert(x2 == 1);
+}
diff --git a/std/internal/math/biguintcore.d b/std/internal/math/biguintcore.d
@@ -597,6 +597,21 @@ public:
         return BigUint(removeLeadingZeros(assumeUnique(result)));
     }
 
+    static BigUint divInt(T)(BigUint x, T y) pure nothrow
+    if ( is(Unqual!T == ulong) )
+    {
+        if (y <= uint.max)
+            return divInt!uint(x, cast(uint)y);
+        if (x.data.length < 2)
+            return BigUint(ZERO);
+        uint hi = cast(uint)(y >>> 32);
+        uint lo = cast(uint)(y & 0xFFFF_FFFF);
+        immutable uint[2] z = [lo, hi];
+        BigDigit[] result = new BigDigit[x.data.length - z.length + 1];
+        divModInternal(result, null, x.data, z[]);
+        return BigUint(removeLeadingZeros(assumeUnique(result)));
+    }
+
     // return x % y
     static uint modInt(T)(BigUint x, T y_) pure if ( is(Unqual!T == uint) )
     {