/* Allocate a new int object with size digits.
Return NULL and set exception if we run out of memory. */
-#define MAX_LONG_DIGITS \
+#if SIZEOF_SIZE_T < 8
+# define MAX_LONG_DIGITS \
((PY_SSIZE_T_MAX - offsetof(PyLongObject, long_value.ob_digit))/sizeof(digit))
+#else
+/* Guarantee that the number of bits fits in int64_t.
+ This is more than an exbibyte, that is more than many of modern
+ architectures support in principle.
+ -1 is added to avoid overflow in _PyLong_Frexp(). */
+# define MAX_LONG_DIGITS ((INT64_MAX-1) / PyLong_SHIFT)
+#endif
PyLongObject *
_PyLong_New(Py_ssize_t size)
return _Py_bit_length((unsigned long)x);
}
-uint64_t
+int64_t
_PyLong_NumBits(PyObject *vv)
{
PyLongObject *v = (PyLongObject *)vv;
- uint64_t result = 0;
+ int64_t result = 0;
Py_ssize_t ndigits;
int msd_bits;
assert(ndigits == 0 || v->long_value.ob_digit[ndigits - 1] != 0);
if (ndigits > 0) {
digit msd = v->long_value.ob_digit[ndigits - 1];
- if ((uint64_t)(ndigits - 1) > UINT64_MAX / (uint64_t)PyLong_SHIFT)
- goto Overflow;
- result = (uint64_t)(ndigits - 1) * (uint64_t)PyLong_SHIFT;
+ assert(ndigits <= INT64_MAX / PyLong_SHIFT);
+ result = (int64_t)(ndigits - 1) * PyLong_SHIFT;
msd_bits = bit_length_digit(msd);
- if (UINT64_MAX - msd_bits < result)
- goto Overflow;
result += msd_bits;
}
return result;
-
- Overflow:
- /* Very unlikely. Such integer would require more than 2 exbibytes of RAM. */
- PyErr_SetString(PyExc_OverflowError, "int has too many bits "
- "to express in a 64-bit integer");
- return (uint64_t)-1;
}
PyObject *
/* Calculates the number of bits required for the *absolute* value
* of v. This does not take sign into account, only magnitude. */
- uint64_t nb = _PyLong_NumBits((PyObject *)v);
- if (nb == (uint64_t)-1) {
- res = -1;
- } else {
- /* Normally this would be((nb - 1) / 8) + 1 to avoid rounding up
- * multiples of 8 to the next byte, but we add an implied bit for
- * the sign and it cancels out. */
- res = (Py_ssize_t)(nb / 8) + 1;
- }
+ int64_t nb = _PyLong_NumBits((PyObject *)v);
+ assert(nb >= 0);
+ /* Normally this would be ((nb - 1) / 8) + 1 to avoid rounding up
+ * multiples of 8 to the next byte, but we add an implied bit for
+ * the sign and it cancels out. */
+ res = (Py_ssize_t)(nb / 8) + 1;
/* Two edge cases exist that are best handled after extracting the
* bits. These may result in us reporting overflow when the value
double
_PyLong_Frexp(PyLongObject *a, int64_t *e)
{
- Py_ssize_t a_size, shift_digits, shift_bits, x_size;
+ Py_ssize_t a_size, shift_digits, x_size;
+ int shift_bits;
int64_t a_bits;
/* See below for why x_digits is always large enough. */
digit rem;
*e = 0;
return 0.0;
}
- int msd_bits = bit_length_digit(a->long_value.ob_digit[a_size-1]);
- /* The following is an overflow-free version of the check
- "if ((a_size - 1) * PyLong_SHIFT + msd_bits > PY_SSIZE_T_MAX) ..." */
- if (a_size >= (INT64_MAX - 1) / PyLong_SHIFT + 1 &&
- (a_size > (INT64_MAX - 1) / PyLong_SHIFT + 1 ||
- msd_bits > (INT64_MAX - 1) % PyLong_SHIFT + 1))
- goto overflow;
- a_bits = (int64_t)(a_size - 1) * PyLong_SHIFT + msd_bits;
+ a_bits = _PyLong_NumBits((PyObject *)a);
/* Shift the first DBL_MANT_DIG + 2 bits of a into x_digits[0:x_size]
(shifting left if a_bits <= DBL_MANT_DIG + 2).
*/
if (a_bits <= DBL_MANT_DIG + 2) {
shift_digits = (DBL_MANT_DIG + 2 - (Py_ssize_t)a_bits) / PyLong_SHIFT;
- shift_bits = (DBL_MANT_DIG + 2 - (Py_ssize_t)a_bits) % PyLong_SHIFT;
+ shift_bits = (DBL_MANT_DIG + 2 - (int)a_bits) % PyLong_SHIFT;
x_size = shift_digits;
rem = v_lshift(x_digits + x_size, a->long_value.ob_digit, a_size,
- (int)shift_bits);
+ shift_bits);
x_size += a_size;
x_digits[x_size++] = rem;
}
else {
shift_digits = (Py_ssize_t)((a_bits - DBL_MANT_DIG - 2) / PyLong_SHIFT);
- shift_bits = (Py_ssize_t)((a_bits - DBL_MANT_DIG - 2) % PyLong_SHIFT);
+ shift_bits = (int)((a_bits - DBL_MANT_DIG - 2) % PyLong_SHIFT);
rem = v_rshift(x_digits, a->long_value.ob_digit + shift_digits,
- a_size - shift_digits, (int)shift_bits);
+ a_size - shift_digits, shift_bits);
x_size = a_size - shift_digits;
/* For correct rounding below, we need the least significant
bit of x to be 'sticky' for this shift: if any of the bits
/* Rescale; make correction if result is 1.0. */
dx /= 4.0 * EXP2_DBL_MANT_DIG;
if (dx == 1.0) {
- if (a_bits == INT64_MAX)
- goto overflow;
+ assert(a_bits < INT64_MAX);
dx = 0.5;
a_bits += 1;
}
*e = a_bits;
return _PyLong_IsNegative(a) ? -dx : dx;
-
- overflow:
- /* exponent > PY_SSIZE_T_MAX */
- PyErr_SetString(PyExc_OverflowError,
- "huge integer: number of bits overflows a Py_ssize_t");
- *e = 0;
- return -1.0;
}
/* Get a C double from an int object. Rounds to the nearest double,
return (double)medium_value((PyLongObject *)v);
}
x = _PyLong_Frexp((PyLongObject *)v, &exponent);
- if ((x == -1.0 && PyErr_Occurred()) || exponent > DBL_MAX_EXP) {
+ assert(exponent >= 0);
+ assert(!PyErr_Occurred());
+ if (exponent > DBL_MAX_EXP) {
PyErr_SetString(PyExc_OverflowError,
"int too large to convert to float");
return -1.0;
return !_PyLong_IsZero(v);
}
-/* wordshift, remshift = divmod(shiftby, PyLong_SHIFT) */
-static int
-divmod_shift(PyObject *shiftby, Py_ssize_t *wordshift, digit *remshift)
-{
- assert(PyLong_Check(shiftby));
- assert(!_PyLong_IsNegative((PyLongObject *)shiftby));
- Py_ssize_t lshiftby = PyLong_AsSsize_t((PyObject *)shiftby);
- if (lshiftby >= 0) {
- *wordshift = lshiftby / PyLong_SHIFT;
- *remshift = lshiftby % PyLong_SHIFT;
- return 0;
- }
- /* PyLong_Check(shiftby) is true and shiftby is not negative, so it must
- be that PyLong_AsSsize_t raised an OverflowError. */
- assert(PyErr_ExceptionMatches(PyExc_OverflowError));
- PyErr_Clear();
- PyLongObject *wordshift_obj = divrem1((PyLongObject *)shiftby, PyLong_SHIFT, remshift);
- if (wordshift_obj == NULL) {
- return -1;
- }
- *wordshift = PyLong_AsSsize_t((PyObject *)wordshift_obj);
- Py_DECREF(wordshift_obj);
- if (*wordshift >= 0 && *wordshift < PY_SSIZE_T_MAX / (Py_ssize_t)sizeof(digit)) {
- return 0;
- }
- PyErr_Clear();
- /* Clip the value. With such large wordshift the right shift
- returns 0 and the left shift raises an error in _PyLong_New(). */
- *wordshift = PY_SSIZE_T_MAX / sizeof(digit);
- *remshift = 0;
- return 0;
-}
-
/* Inner function for both long_rshift and _PyLong_Rshift, shifting an
integer right by PyLong_SHIFT*wordshift + remshift bits.
wordshift should be nonnegative. */
static PyObject *
long_rshift(PyObject *a, PyObject *b)
{
- Py_ssize_t wordshift;
- digit remshift;
+ int64_t shiftby;
CHECK_BINOP(a, b);
if (_PyLong_IsZero((PyLongObject *)a)) {
return PyLong_FromLong(0);
}
- if (divmod_shift(b, &wordshift, &remshift) < 0)
- return NULL;
- return long_rshift1((PyLongObject *)a, wordshift, remshift);
+ if (PyLong_AsInt64(b, &shiftby) < 0) {
+ if (!PyErr_ExceptionMatches(PyExc_OverflowError)) {
+ return NULL;
+ }
+ PyErr_Clear();
+ if (_PyLong_IsNegative((PyLongObject *)a)) {
+ return PyLong_FromLong(-1);
+ }
+ else {
+ return PyLong_FromLong(0);
+ }
+ }
+ return _PyLong_Rshift(a, shiftby);
}
/* Return a >> shiftby. */
PyObject *
-_PyLong_Rshift(PyObject *a, uint64_t shiftby)
+_PyLong_Rshift(PyObject *a, int64_t shiftby)
{
Py_ssize_t wordshift;
digit remshift;
assert(PyLong_Check(a));
+ assert(shiftby >= 0);
if (_PyLong_IsZero((PyLongObject *)a)) {
return PyLong_FromLong(0);
}
-#if PY_SSIZE_T_MAX <= UINT64_MAX / PyLong_SHIFT
- if (shiftby > (uint64_t)PY_SSIZE_T_MAX * PyLong_SHIFT) {
+#if PY_SSIZE_T_MAX <= INT64_MAX / PyLong_SHIFT
+ if (shiftby > (int64_t)PY_SSIZE_T_MAX * PyLong_SHIFT) {
if (_PyLong_IsNegative((PyLongObject *)a)) {
return PyLong_FromLong(-1);
}
static PyObject *
long_lshift(PyObject *a, PyObject *b)
{
- Py_ssize_t wordshift;
- digit remshift;
+ int64_t shiftby;
CHECK_BINOP(a, b);
if (_PyLong_IsZero((PyLongObject *)a)) {
return PyLong_FromLong(0);
}
- if (divmod_shift(b, &wordshift, &remshift) < 0)
+ if (PyLong_AsInt64(b, &shiftby) < 0) {
+ if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
+ PyErr_SetString(PyExc_OverflowError,
+ "too many digits in integer");
+ }
return NULL;
- return long_lshift1((PyLongObject *)a, wordshift, remshift);
+ }
+ return _PyLong_Lshift(a, shiftby);
}
/* Return a << shiftby. */
PyObject *
-_PyLong_Lshift(PyObject *a, uint64_t shiftby)
+_PyLong_Lshift(PyObject *a, int64_t shiftby)
{
Py_ssize_t wordshift;
digit remshift;
assert(PyLong_Check(a));
+ assert(shiftby >= 0);
if (_PyLong_IsZero((PyLongObject *)a)) {
return PyLong_FromLong(0);
}
-#if PY_SSIZE_T_MAX <= UINT64_MAX / PyLong_SHIFT
- if (shiftby > (uint64_t)PY_SSIZE_T_MAX * PyLong_SHIFT) {
+#if PY_SSIZE_T_MAX <= INT64_MAX / PyLong_SHIFT
+ if (shiftby > (int64_t)PY_SSIZE_T_MAX * PyLong_SHIFT) {
PyErr_SetString(PyExc_OverflowError,
"too many digits in integer");
return NULL;
int_bit_length_impl(PyObject *self)
/*[clinic end generated code: output=fc1977c9353d6a59 input=e4eb7a587e849a32]*/
{
- uint64_t nbits = _PyLong_NumBits(self);
- if (nbits == (uint64_t)-1) {
- return NULL;
- }
- return PyLong_FromUnsignedLongLong(nbits);
+ int64_t nbits = _PyLong_NumBits(self);
+ assert(nbits >= 0);
+ assert(!PyErr_Occurred());
+ return PyLong_FromInt64(nbits);
}
static int
PyLongObject *z = (PyLongObject *)self;
Py_ssize_t ndigits = _PyLong_DigitCount(z);
- Py_ssize_t bit_count = 0;
+ int64_t bit_count = 0;
- /* Each digit has up to PyLong_SHIFT ones, so the accumulated bit count
- from the first PY_SSIZE_T_MAX/PyLong_SHIFT digits can't overflow a
- Py_ssize_t. */
- Py_ssize_t ndigits_fast = Py_MIN(ndigits, PY_SSIZE_T_MAX/PyLong_SHIFT);
- for (Py_ssize_t i = 0; i < ndigits_fast; i++) {
+ for (Py_ssize_t i = 0; i < ndigits; i++) {
bit_count += popcount_digit(z->long_value.ob_digit[i]);
}
- PyObject *result = PyLong_FromSsize_t(bit_count);
- if (result == NULL) {
- return NULL;
- }
-
- /* Use Python integers if bit_count would overflow. */
- for (Py_ssize_t i = ndigits_fast; i < ndigits; i++) {
- PyObject *x = PyLong_FromLong(popcount_digit(z->long_value.ob_digit[i]));
- if (x == NULL) {
- goto error;
- }
- PyObject *y = long_add((PyLongObject *)result, (PyLongObject *)x);
- Py_DECREF(x);
- if (y == NULL) {
- goto error;
- }
- Py_SETREF(result, y);
- }
-
- return result;
-
- error:
- Py_DECREF(result);
- return NULL;
+ return PyLong_FromInt64(bit_count);
}
/*[clinic input]
projects / thirdparty / Python / cpython.git / commitdiff
