Issue #7528: Backport PyLong_AsLongAndOverflow from py3k to trunk.
Thanks Case Van Horsen for the patch.
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 8bdb283..b0170d2 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -223,53 +223,123 @@
#define PY_ABS_LONG_MIN (0-(unsigned long)LONG_MIN)
#define PY_ABS_SSIZE_T_MIN (0-(size_t)PY_SSIZE_T_MIN)
-/* Get a C long int from a long int object.
- Returns -1 and sets an error condition if overflow occurs. */
+/* Get a C long int from a Python long or Python int object.
+ On overflow, returns -1 and sets *overflow to 1 or -1 depending
+ on the sign of the result. Otherwise *overflow is 0.
+
+ For other errors (e.g., type error), returns -1 and sets an error
+ condition.
+*/
long
-PyLong_AsLong(PyObject *vv)
+PyLong_AsLongAndOverflow(PyObject *vv, int *overflow)
{
/* This version by Tim Peters */
register PyLongObject *v;
unsigned long x, prev;
+ long res;
Py_ssize_t i;
int sign;
+ int do_decref = 0; /* if nb_int was called */
- if (vv == NULL || !PyLong_Check(vv)) {
- if (vv != NULL && PyInt_Check(vv))
- return PyInt_AsLong(vv);
+ *overflow = 0;
+ if (vv == NULL) {
PyErr_BadInternalCall();
return -1;
}
- v = (PyLongObject *)vv;
- i = v->ob_size;
- sign = 1;
- x = 0;
- if (i < 0) {
- sign = -1;
- i = -(i);
- }
- while (--i >= 0) {
- prev = x;
- x = (x << PyLong_SHIFT) | v->ob_digit[i];
- if ((x >> PyLong_SHIFT) != prev)
- goto overflow;
- }
- /* Haven't lost any bits, but casting to long requires extra care
- * (see comment above).
- */
- if (x <= (unsigned long)LONG_MAX) {
- return (long)x * sign;
- }
- else if (sign < 0 && x == PY_ABS_LONG_MIN) {
- return LONG_MIN;
- }
- /* else overflow */
- overflow:
- PyErr_SetString(PyExc_OverflowError,
- "long int too large to convert to int");
- return -1;
+ if(PyInt_Check(vv))
+ return PyInt_AsLong(vv);
+
+ if (!PyLong_Check(vv)) {
+ PyNumberMethods *nb;
+ nb = vv->ob_type->tp_as_number;
+ if (nb == NULL || nb->nb_int == NULL) {
+ PyErr_SetString(PyExc_TypeError,
+ "an integer is required");
+ return -1;
+ }
+ vv = (*nb->nb_int) (vv);
+ if (vv == NULL)
+ return -1;
+ do_decref = 1;
+ if(PyInt_Check(vv)) {
+ res = PyInt_AsLong(vv);
+ goto exit;
+ }
+ if (!PyLong_Check(vv)) {
+ Py_DECREF(vv);
+ PyErr_SetString(PyExc_TypeError,
+ "nb_int should return int object");
+ return -1;
+ }
+ }
+
+ res = -1;
+ v = (PyLongObject *)vv;
+ i = Py_SIZE(v);
+
+ switch (i) {
+ case -1:
+ res = -(sdigit)v->ob_digit[0];
+ break;
+ case 0:
+ res = 0;
+ break;
+ case 1:
+ res = v->ob_digit[0];
+ break;
+ default:
+ sign = 1;
+ x = 0;
+ if (i < 0) {
+ sign = -1;
+ i = -(i);
+ }
+ while (--i >= 0) {
+ prev = x;
+ x = (x << PyLong_SHIFT) + v->ob_digit[i];
+ if ((x >> PyLong_SHIFT) != prev) {
+ *overflow = sign;
+ goto exit;
+ }
+ }
+ /* Haven't lost any bits, but casting to long requires extra
+ * care (see comment above).
+ */
+ if (x <= (unsigned long)LONG_MAX) {
+ res = (long)x * sign;
+ }
+ else if (sign < 0 && x == PY_ABS_LONG_MIN) {
+ res = LONG_MIN;
+ }
+ else {
+ *overflow = sign;
+ /* res is already set to -1 */
+ }
+ }
+ exit:
+ if (do_decref) {
+ Py_DECREF(vv);
+ }
+ return res;
+}
+
+/* Get a C long int from a long int object.
+ Returns -1 and sets an error condition if overflow occurs. */
+
+long
+PyLong_AsLong(PyObject *obj)
+{
+ int overflow;
+ long result = PyLong_AsLongAndOverflow(obj, &overflow);
+ if (overflow) {
+ /* XXX: could be cute and give a different
+ message for overflow == -1 */
+ PyErr_SetString(PyExc_OverflowError,
+ "Python int too large to convert to C long");
+ }
+ return result;
}
/* Get a Py_ssize_t from a long int object.