diff options
Diffstat (limited to 'Objects/intobject.c')
| -rw-r--r-- | Objects/intobject.c | 42 |
1 files changed, 35 insertions, 7 deletions
diff --git a/Objects/intobject.c b/Objects/intobject.c index b420c128bd..0b746dee8d 100644 --- a/Objects/intobject.c +++ b/Objects/intobject.c @@ -557,6 +557,17 @@ int_mul(PyObject *v, PyObject *w) } } +/* Integer overflow checking for unary negation: on a 2's-complement + * box, -x overflows iff x is the most negative long. In this case we + * get -x == x. However, -x is undefined (by C) if x /is/ the most + * negative long (it's a signed overflow case), and some compilers care. + * So we cast x to unsigned long first. However, then other compilers + * warn about applying unary minus to an unsigned operand. Hence the + * weird "0-". + */ +#define UNARY_NEG_WOULD_OVERFLOW(x) \ + ((x) < 0 && (unsigned long)(x) == 0-(unsigned long)(x)) + /* Return type of i_divmod */ enum divmod_result { DIVMOD_OK, /* Correct result */ @@ -576,7 +587,7 @@ i_divmod(register long x, register long y, return DIVMOD_ERROR; } /* (-sys.maxint-1)/-1 is the only overflow case. */ - if (y == -1 && x < 0 && x == -x) + if (y == -1 && UNARY_NEG_WOULD_OVERFLOW(x)) return DIVMOD_OVERFLOW; xdivy = x / y; xmody = x - xdivy * y; @@ -744,10 +755,10 @@ int_pow(PyIntObject *v, PyIntObject *w, PyIntObject *z) static PyObject * int_neg(PyIntObject *v) { - register long a, x; + register long a; a = v->ob_ival; - x = -a; - if (a < 0 && x < 0) { + /* check for overflow */ + if (UNARY_NEG_WOULD_OVERFLOW(a)) { PyObject *o = PyLong_FromLong(a); if (o != NULL) { PyObject *result = PyNumber_Negative(o); @@ -756,7 +767,7 @@ int_neg(PyIntObject *v) } return NULL; } - return PyInt_FromLong(x); + return PyInt_FromLong(-a); } static PyObject * @@ -955,8 +966,25 @@ int_new(PyTypeObject *type, PyObject *args, PyObject *kwds) return PyInt_FromLong(0L); if (base == -909) return PyNumber_Int(x); - if (PyString_Check(x)) - return PyInt_FromString(PyString_AS_STRING(x), NULL, base); + if (PyString_Check(x)) { + /* Since PyInt_FromString doesn't have a length parameter, + * check here for possible NULs in the string. */ + char *string = PyString_AS_STRING(x); + if (strlen(string) != PyString_Size(x)) { + /* create a repr() of the input string, + * just like PyInt_FromString does */ + PyObject *srepr; + srepr = PyObject_Repr(x); + if (srepr == NULL) + return NULL; + PyErr_Format(PyExc_ValueError, + "invalid literal for int() with base %d: %s", + base, PyString_AS_STRING(srepr)); + Py_DECREF(srepr); + return NULL; + } + return PyInt_FromString(string, NULL, base); + } #ifdef Py_USING_UNICODE if (PyUnicode_Check(x)) return PyInt_FromUnicode(PyUnicode_AS_UNICODE(x), |