Added dnewlongobject(), function to convert double to long int.

diff --git a/Objects/longobject.c b/Objects/longobject.c
index badc3df0713c5349001e1844fef0663f1bd677f3..de7ff3985e26f9ccc65314fb0c2b661f626b7762 100644 (file)
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -28,8 +28,14 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 #include "allobjects.h"
 #include "longintrepr.h"
+#include <math.h>
 #include <assert.h>
 
+/* Forward: */
+extern object *long_mul PROTO((longobject *, object *));
+extern object *long_add PROTO((longobject *, object *));
+extern object *long_neg PROTO((longobject *));
+
 static int ticker;     /* XXX Could be shared with ceval? */
 
 #define INTRCHECK(block) \
@@ -87,6 +93,39 @@ newlongobject(ival)
        return (object *)v;
 }
 
+/* Create a new long int object from a C double */
+
+object *
+dnewlongobject(dval)
+       double dval;
+{
+       longobject *v;
+       double frac;
+       int i, ndig, expo, neg;
+       neg = 0;
+       if (dval < 0.0) {
+               neg = 1;
+               dval = -dval;
+       }
+       frac = frexp(dval, &expo); /* dval = frac*2**expo; 0.0 <= frac < 1.0 */
+       if (expo <= 0)
+               return newlongobject(0L);
+       ndig = (expo-1) / SHIFT + 1; /* Number of 'digits' in result */
+       v = alloclongobject(ndig);
+       if (v == NULL)
+               return NULL;
+       frac = ldexp(frac, (expo-1) % SHIFT + 1);
+       for (i = ndig; --i >= 0; ) {
+               long bits = (long)frac;
+               v->ob_digit[i] = bits;
+               frac = frac - (double)bits;
+               frac = ldexp(frac, SHIFT);
+       }
+       if (neg)
+               v->ob_size = -v->ob_size;
+       return (object *)v;
+}
+
 /* Get a C long int from a long int object.
    Returns -1 and sets an error condition if overflow occurs. */