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/* Long (arbitrary precision) integer object implementation */
/* XXX The functional organization of this file is terrible */
#include "Python.h"
#include "pycore_bitutils.h" // _Py_popcount32()
#include "pycore_initconfig.h" // _PyStatus_OK()
#include "pycore_call.h" // _PyObject_MakeTpCall
#include "pycore_freelist.h" // _Py_FREELIST_FREE, _Py_FREELIST_POP
#include "pycore_long.h" // _Py_SmallInts
#include "pycore_object.h" // _PyObject_Init()
#include "pycore_runtime.h" // _PY_NSMALLPOSINTS
#include "pycore_structseq.h" // _PyStructSequence_FiniBuiltin()
#include <float.h> // DBL_MANT_DIG
#include <stddef.h> // offsetof
#include "clinic/longobject.c.h"
/*[clinic input]
class int "PyObject *" "&PyLong_Type"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=ec0275e3422a36e3]*/
#define medium_value(x) ((stwodigits)_PyLong_CompactValue(x))
#define IS_SMALL_INT(ival) (-_PY_NSMALLNEGINTS <= (ival) && (ival) < _PY_NSMALLPOSINTS)
#define IS_SMALL_UINT(ival) ((ival) < _PY_NSMALLPOSINTS)
#define _MAX_STR_DIGITS_ERROR_FMT_TO_INT "Exceeds the limit (%d digits) for integer string conversion: value has %zd digits; use sys.set_int_max_str_digits() to increase the limit"
#define _MAX_STR_DIGITS_ERROR_FMT_TO_STR "Exceeds the limit (%d digits) for integer string conversion; use sys.set_int_max_str_digits() to increase the limit"
/* If defined, use algorithms from the _pylong.py module */
#define WITH_PYLONG_MODULE 1
// Forward declarations
static PyLongObject* long_neg(PyLongObject *v);
static PyLongObject *x_divrem(PyLongObject *, PyLongObject *, PyLongObject **);
static PyObject* long_long(PyObject *v);
static PyObject* long_lshift_int64(PyLongObject *a, int64_t shiftby);
static inline void
_Py_DECREF_INT(PyLongObject *op)
{
assert(PyLong_CheckExact(op));
_Py_DECREF_SPECIALIZED((PyObject *)op, _PyLong_ExactDealloc);
}
static inline int
is_medium_int(stwodigits x)
{
/* Take care that we are comparing unsigned values. */
twodigits x_plus_mask = ((twodigits)x) + PyLong_MASK;
return x_plus_mask < ((twodigits)PyLong_MASK) + PyLong_BASE;
}
static PyObject *
get_small_int(sdigit ival)
{
assert(IS_SMALL_INT(ival));
return (PyObject *)&_PyLong_SMALL_INTS[_PY_NSMALLNEGINTS + ival];
}
static PyLongObject *
maybe_small_long(PyLongObject *v)
{
if (v && _PyLong_IsCompact(v)) {
stwodigits ival = medium_value(v);
if (IS_SMALL_INT(ival)) {
_Py_DECREF_INT(v);
return (PyLongObject *)get_small_int((sdigit)ival);
}
}
return v;
}
/* For int multiplication, use the O(N**2) school algorithm unless
* both operands contain more than KARATSUBA_CUTOFF digits (this
* being an internal Python int digit, in base BASE).
*/
#define KARATSUBA_CUTOFF 70
#define KARATSUBA_SQUARE_CUTOFF (2 * KARATSUBA_CUTOFF)
/* For exponentiation, use the binary left-to-right algorithm unless the
^ exponent contains more than HUGE_EXP_CUTOFF bits. In that case, do
* (no more than) EXP_WINDOW_SIZE bits at a time. The potential drawback is
* that a table of 2**(EXP_WINDOW_SIZE - 1) intermediate results is
* precomputed.
*/
#define EXP_WINDOW_SIZE 5
#define EXP_TABLE_LEN (1 << (EXP_WINDOW_SIZE - 1))
/* Suppose the exponent has bit length e. All ways of doing this
* need e squarings. The binary method also needs a multiply for
* each bit set. In a k-ary method with window width w, a multiply
* for each non-zero window, so at worst (and likely!)
* ceiling(e/w). The k-ary sliding window method has the same
* worst case, but the window slides so it can sometimes skip
* over an all-zero window that the fixed-window method can't
* exploit. In addition, the windowing methods need multiplies
* to precompute a table of small powers.
*
* For the sliding window method with width 5, 16 precomputation
* multiplies are needed. Assuming about half the exponent bits
* are set, then, the binary method needs about e/2 extra mults
* and the window method about 16 + e/5.
*
* The latter is smaller for e > 53 1/3. We don't have direct
* access to the bit length, though, so call it 60, which is a
* multiple of a long digit's max bit length (15 or 30 so far).
*/
#define HUGE_EXP_CUTOFF 60
#define SIGCHECK(PyTryBlock) \
do { \
if (PyErr_CheckSignals()) PyTryBlock \
} while(0)
/* Normalize (remove leading zeros from) an int object.
Doesn't attempt to free the storage--in most cases, due to the nature
of the algorithms used, this could save at most be one word anyway. */
static PyLongObject *
long_normalize(PyLongObject *v)
{
Py_ssize_t j = _PyLong_DigitCount(v);
Py_ssize_t i = j;
while (i > 0 && v->long_value.ob_digit[i-1] == 0)
--i;
if (i != j) {
if (i == 0) {
_PyLong_SetSignAndDigitCount(v, 0, 0);
}
else {
_PyLong_SetDigitCount(v, i);
}
}
return v;
}
/* Allocate a new int object with size digits.
Return NULL and set exception if we run out of memory. */
#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
static PyLongObject *
long_alloc(Py_ssize_t size)
{
assert(size >= 0);
PyLongObject *result = NULL;
if (size > (Py_ssize_t)MAX_LONG_DIGITS) {
PyErr_SetString(PyExc_OverflowError,
"too many digits in integer");
return NULL;
}
/* Fast operations for single digit integers (including zero)
* assume that there is always at least one digit present. */
Py_ssize_t ndigits = size ? size : 1;
if (ndigits == 1) {
result = (PyLongObject *)_Py_FREELIST_POP(PyLongObject, ints);
}
if (result == NULL) {
/* Number of bytes needed is: offsetof(PyLongObject, ob_digit) +
sizeof(digit)*size. Previous incarnations of this code used
sizeof() instead of the offsetof, but this risks being
incorrect in the presence of padding between the header
and the digits. */
result = PyObject_Malloc(offsetof(PyLongObject, long_value.ob_digit) +
ndigits*sizeof(digit));
if (!result) {
PyErr_NoMemory();
return NULL;
}
_PyObject_Init((PyObject*)result, &PyLong_Type);
}
_PyLong_SetSignAndDigitCount(result, size != 0, size);
/* The digit has to be initialized explicitly to avoid
* use-of-uninitialized-value. */
result->long_value.ob_digit[0] = 0;
return result;
}
PyLongObject *
_PyLong_New(Py_ssize_t size)
{
return long_alloc(size);
}
PyLongObject *
_PyLong_FromDigits(int negative, Py_ssize_t digit_count, digit *digits)
{
assert(digit_count >= 0);
if (digit_count == 0) {
return (PyLongObject *)_PyLong_GetZero();
}
PyLongObject *result = long_alloc(digit_count);
if (result == NULL) {
return NULL;
}
_PyLong_SetSignAndDigitCount(result, negative?-1:1, digit_count);
memcpy(result->long_value.ob_digit, digits, digit_count * sizeof(digit));
return result;
}
PyObject *
_PyLong_Copy(PyLongObject *src)
{
assert(src != NULL);
int sign;
if (_PyLong_IsCompact(src)) {
stwodigits ival = medium_value(src);
if (IS_SMALL_INT(ival)) {
return get_small_int((sdigit)ival);
}
sign = _PyLong_CompactSign(src);
}
else {
sign = _PyLong_NonCompactSign(src);
}
Py_ssize_t size = _PyLong_DigitCount(src);
PyLongObject *result = long_alloc(size);
if (result == NULL) {
return NULL;
}
_PyLong_SetSignAndDigitCount(result, sign, size);
memcpy(result->long_value.ob_digit, src->long_value.ob_digit,
size * sizeof(digit));
return (PyObject *)result;
}
static PyObject *
_PyLong_FromMedium(sdigit x)
{
assert(!IS_SMALL_INT(x));
assert(is_medium_int(x));
PyLongObject *v = (PyLongObject *)_Py_FREELIST_POP(PyLongObject, ints);
if (v == NULL) {
v = PyObject_Malloc(sizeof(PyLongObject));
if (v == NULL) {
PyErr_NoMemory();
return NULL;
}
_PyObject_Init((PyObject*)v, &PyLong_Type);
}
digit abs_x = x < 0 ? -x : x;
_PyLong_SetSignAndDigitCount(v, x<0?-1:1, 1);
v->long_value.ob_digit[0] = abs_x;
return (PyObject*)v;
}
static PyObject *
_PyLong_FromLarge(stwodigits ival)
{
twodigits abs_ival;
int sign;
assert(!is_medium_int(ival));
if (ival < 0) {
/* negate: can't write this as abs_ival = -ival since that
invokes undefined behaviour when ival is LONG_MIN */
abs_ival = 0U-(twodigits)ival;
sign = -1;
}
else {
abs_ival = (twodigits)ival;
sign = 1;
}
/* Must be at least two digits */
assert(abs_ival >> PyLong_SHIFT != 0);
twodigits t = abs_ival >> (PyLong_SHIFT * 2);
Py_ssize_t ndigits = 2;
while (t) {
++ndigits;
t >>= PyLong_SHIFT;
}
PyLongObject *v = long_alloc(ndigits);
if (v != NULL) {
digit *p = v->long_value.ob_digit;
_PyLong_SetSignAndDigitCount(v, sign, ndigits);
t = abs_ival;
while (t) {
*p++ = Py_SAFE_DOWNCAST(
t & PyLong_MASK, twodigits, digit);
t >>= PyLong_SHIFT;
}
}
return (PyObject *)v;
}
/* Create a new int object from a C word-sized int */
static inline PyLongObject *
_PyLong_FromSTwoDigits(stwodigits x)
{
if (IS_SMALL_INT(x)) {
return (PyLongObject*)get_small_int((sdigit)x);
}
assert(x != 0);
if (is_medium_int(x)) {
return (PyLongObject*)_PyLong_FromMedium((sdigit)x);
}
return (PyLongObject*)_PyLong_FromLarge(x);
}
/* If a freshly-allocated int is already shared, it must
be a small integer, so negating it must go to PyLong_FromLong */
Py_LOCAL_INLINE(void)
_PyLong_Negate(PyLongObject **x_p)
{
PyLongObject *x;
x = (PyLongObject *)*x_p;
if (Py_REFCNT(x) == 1) {
_PyLong_FlipSign(x);
return;
}
*x_p = _PyLong_FromSTwoDigits(-medium_value(x));
Py_DECREF(x);
}
/* Create a new int object from a C long int */
PyObject *
PyLong_FromLong(long ival)
{
PyLongObject *v;
unsigned long abs_ival, t;
int ndigits;
/* Handle small and medium cases. */
if (IS_SMALL_INT(ival)) {
return get_small_int((sdigit)ival);
}
if (-(long)PyLong_MASK <= ival && ival <= (long)PyLong_MASK) {
return _PyLong_FromMedium((sdigit)ival);
}
/* Count digits (at least two - smaller cases were handled above). */
abs_ival = ival < 0 ? 0U-(unsigned long)ival : (unsigned long)ival;
/* Do shift in two steps to avoid possible undefined behavior. */
t = abs_ival >> PyLong_SHIFT >> PyLong_SHIFT;
ndigits = 2;
while (t) {
++ndigits;
t >>= PyLong_SHIFT;
}
/* Construct output value. */
v = long_alloc(ndigits);
if (v != NULL) {
digit *p = v->long_value.ob_digit;
_PyLong_SetSignAndDigitCount(v, ival < 0 ? -1 : 1, ndigits);
t = abs_ival;
while (t) {
*p++ = (digit)(t & PyLong_MASK);
t >>= PyLong_SHIFT;
}
}
return (PyObject *)v;
}
#define PYLONG_FROM_UINT(INT_TYPE, ival) \
do { \
if (IS_SMALL_UINT(ival)) { \
return get_small_int((sdigit)(ival)); \
} \
if ((ival) <= PyLong_MASK) { \
return _PyLong_FromMedium((sdigit)(ival)); \
} \
/* Do shift in two steps to avoid possible undefined behavior. */ \
INT_TYPE t = (ival) >> PyLong_SHIFT >> PyLong_SHIFT; \
/* Count the number of Python digits. */ \
Py_ssize_t ndigits = 2; \
while (t) { \
++ndigits; \
t >>= PyLong_SHIFT; \
} \
PyLongObject *v = long_alloc(ndigits); \
if (v == NULL) { \
return NULL; \
} \
digit *p = v->long_value.ob_digit; \
while ((ival)) { \
*p++ = (digit)((ival) & PyLong_MASK); \
(ival) >>= PyLong_SHIFT; \
} \
return (PyObject *)v; \
} while(0)
/* Create a new int object from a C unsigned long int */
PyObject *
PyLong_FromUnsignedLong(unsigned long ival)
{
PYLONG_FROM_UINT(unsigned long, ival);
}
/* Create a new int object from a C unsigned long long int. */
PyObject *
PyLong_FromUnsignedLongLong(unsigned long long ival)
{
PYLONG_FROM_UINT(unsigned long long, ival);
}
/* Create a new int object from a C size_t. */
PyObject *
PyLong_FromSize_t(size_t ival)
{
PYLONG_FROM_UINT(size_t, ival);
}
/* Create a new int object from a C double */
PyObject *
PyLong_FromDouble(double dval)
{
/* Try to get out cheap if this fits in a long. When a finite value of real
* floating type is converted to an integer type, the value is truncated
* toward zero. If the value of the integral part cannot be represented by
* the integer type, the behavior is undefined. Thus, we must check that
* value is in range (LONG_MIN - 1, LONG_MAX + 1). If a long has more bits
* of precision than a double, casting LONG_MIN - 1 to double may yield an
* approximation, but LONG_MAX + 1 is a power of two and can be represented
* as double exactly (assuming FLT_RADIX is 2 or 16), so for simplicity
* check against [-(LONG_MAX + 1), LONG_MAX + 1).
*/
const double int_max = (unsigned long)LONG_MAX + 1;
if (-int_max < dval && dval < int_max) {
return PyLong_FromLong((long)dval);
}
PyLongObject *v;
double frac;
int i, ndig, expo, neg;
neg = 0;
if (isinf(dval)) {
PyErr_SetString(PyExc_OverflowError,
"cannot convert float infinity to integer");
return NULL;
}
if (isnan(dval)) {
PyErr_SetString(PyExc_ValueError,
"cannot convert float NaN to integer");
return NULL;
}
if (dval < 0.0) {
neg = 1;
dval = -dval;
}
frac = frexp(dval, &expo); /* dval = frac*2**expo; 0.0 <= frac < 1.0 */
assert(expo > 0);
ndig = (expo-1) / PyLong_SHIFT + 1; /* Number of 'digits' in result */
v = long_alloc(ndig);
if (v == NULL)
return NULL;
frac = ldexp(frac, (expo-1) % PyLong_SHIFT + 1);
for (i = ndig; --i >= 0; ) {
digit bits = (digit)frac;
v->long_value.ob_digit[i] = bits;
frac = frac - (double)bits;
frac = ldexp(frac, PyLong_SHIFT);
}
if (neg) {
_PyLong_FlipSign(v);
}
return (PyObject *)v;
}
/* Checking for overflow in PyLong_AsLong is a PITA since C doesn't define
* anything about what happens when a signed integer operation overflows,
* and some compilers think they're doing you a favor by being "clever"
* then. The bit pattern for the largest positive signed long is
* (unsigned long)LONG_MAX, and for the smallest negative signed long
* it is abs(LONG_MIN), which we could write -(unsigned long)LONG_MIN.
* However, some other compilers warn about applying unary minus to an
* unsigned operand. Hence the weird "0-".
*/
#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 an int object or any object that has an __index__
method.
On overflow, return -1 and set *overflow to 1 or -1 depending on the sign of
the result. Otherwise *overflow is 0.
For other errors (e.g., TypeError), return -1 and set an error condition.
In this case *overflow will be 0.
*/
long
PyLong_AsLongAndOverflow(PyObject *vv, int *overflow)
{
/* This version by Tim Peters */
PyLongObject *v;
unsigned long x, prev;
long res;
Py_ssize_t i;
int sign;
int do_decref = 0; /* if PyNumber_Index was called */
*overflow = 0;
if (vv == NULL) {
PyErr_BadInternalCall();
return -1;
}
if (PyLong_Check(vv)) {
v = (PyLongObject *)vv;
}
else {
v = (PyLongObject *)_PyNumber_Index(vv);
if (v == NULL)
return -1;
do_decref = 1;
}
if (_PyLong_IsCompact(v)) {
#if SIZEOF_LONG < SIZEOF_SIZE_T
Py_ssize_t tmp = _PyLong_CompactValue(v);
if (tmp < LONG_MIN) {
*overflow = -1;
res = -1;
}
else if (tmp > LONG_MAX) {
*overflow = 1;
res = -1;
}
else {
res = (long)tmp;
}
#else
res = _PyLong_CompactValue(v);
#endif
}
else {
res = -1;
i = _PyLong_DigitCount(v);
sign = _PyLong_NonCompactSign(v);
x = 0;
while (--i >= 0) {
prev = x;
x = (x << PyLong_SHIFT) | v->long_value.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(v);
}
return res;
}
/* Get a C long int from an int object or any object that has an __index__
method. Return -1 and set an error 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 C int from an int object or any object that has an __index__
method. Return -1 and set an error if overflow occurs. */
int
PyLong_AsInt(PyObject *obj)
{
int overflow;
long result = PyLong_AsLongAndOverflow(obj, &overflow);
if (overflow || result > INT_MAX || result < INT_MIN) {
/* XXX: could be cute and give a different
message for overflow == -1 */
PyErr_SetString(PyExc_OverflowError,
"Python int too large to convert to C int");
return -1;
}
return (int)result;
}
/* Get a Py_ssize_t from an int object.
Returns -1 and sets an error condition if overflow occurs. */
Py_ssize_t
PyLong_AsSsize_t(PyObject *vv) {
PyLongObject *v;
size_t x, prev;
Py_ssize_t i;
int sign;
if (vv == NULL) {
PyErr_BadInternalCall();
return -1;
}
if (!PyLong_Check(vv)) {
PyErr_SetString(PyExc_TypeError, "an integer is required");
return -1;
}
v = (PyLongObject *)vv;
if (_PyLong_IsCompact(v)) {
return _PyLong_CompactValue(v);
}
i = _PyLong_DigitCount(v);
sign = _PyLong_NonCompactSign(v);
x = 0;
while (--i >= 0) {
prev = x;
x = (x << PyLong_SHIFT) | v->long_value.ob_digit[i];
if ((x >> PyLong_SHIFT) != prev)
goto overflow;
}
/* Haven't lost any bits, but casting to a signed type requires
* extra care (see comment above).
*/
if (x <= (size_t)PY_SSIZE_T_MAX) {
return (Py_ssize_t)x * sign;
}
else if (sign < 0 && x == PY_ABS_SSIZE_T_MIN) {
return PY_SSIZE_T_MIN;
}
/* else overflow */
overflow:
PyErr_SetString(PyExc_OverflowError,
"Python int too large to convert to C ssize_t");
return -1;
}
/* Get a C unsigned long int from an int object.
Returns -1 and sets an error condition if overflow occurs. */
unsigned long
PyLong_AsUnsignedLong(PyObject *vv)
{
PyLongObject *v;
unsigned long x, prev;
Py_ssize_t i;
if (vv == NULL) {
PyErr_BadInternalCall();
return (unsigned long)-1;
}
if (!PyLong_Check(vv)) {
PyErr_SetString(PyExc_TypeError, "an integer is required");
return (unsigned long)-1;
}
v = (PyLongObject *)vv;
if (_PyLong_IsNonNegativeCompact(v)) {
#if SIZEOF_LONG < SIZEOF_SIZE_T
size_t tmp = (size_t)_PyLong_CompactValue(v);
unsigned long res = (unsigned long)tmp;
if (res != tmp) {
goto overflow;
}
return res;
#else
return (unsigned long)(size_t)_PyLong_CompactValue(v);
#endif
}
if (_PyLong_IsNegative(v)) {
PyErr_SetString(PyExc_OverflowError,
"can't convert negative value to unsigned int");
return (unsigned long) -1;
}
i = _PyLong_DigitCount(v);
x = 0;
while (--i >= 0) {
prev = x;
x = (x << PyLong_SHIFT) | v->long_value.ob_digit[i];
if ((x >> PyLong_SHIFT) != prev) {
goto overflow;
}
}
return x;
overflow:
PyErr_SetString(PyExc_OverflowError,
"Python int too large to convert "
"to C unsigned long");
return (unsigned long) -1;
}
/* Get a C size_t from an int object. Returns (size_t)-1 and sets
an error condition if overflow occurs. */
size_t
PyLong_AsSize_t(PyObject *vv)
{
PyLongObject *v;
size_t x, prev;
Py_ssize_t i;
if (vv == NULL) {
PyErr_BadInternalCall();
return (size_t) -1;
}
if (!PyLong_Check(vv)) {
PyErr_SetString(PyExc_TypeError, "an integer is required");
return (size_t)-1;
}
v = (PyLongObject *)vv;
if (_PyLong_IsNonNegativeCompact(v)) {
return (size_t)_PyLong_CompactValue(v);
}
if (_PyLong_IsNegative(v)) {
PyErr_SetString(PyExc_OverflowError,
"can't convert negative value to size_t");
return (size_t) -1;
}
i = _PyLong_DigitCount(v);
x = 0;
while (--i >= 0) {
prev = x;
x = (x << PyLong_SHIFT) | v->long_value.ob_digit[i];
if ((x >> PyLong_SHIFT) != prev) {
PyErr_SetString(PyExc_OverflowError,
"Python int too large to convert to C size_t");
return (size_t) -1;
}
}
return x;
}
/* Get a C unsigned long int from an int object, ignoring the high bits.
Returns -1 and sets an error condition if an error occurs. */
static unsigned long
_PyLong_AsUnsignedLongMask(PyObject *vv)
{
PyLongObject *v;
unsigned long x;
Py_ssize_t i;
if (vv == NULL || !PyLong_Check(vv)) {
PyErr_BadInternalCall();
return (unsigned long) -1;
}
v = (PyLongObject *)vv;
if (_PyLong_IsCompact(v)) {
#if SIZEOF_LONG < SIZEOF_SIZE_T
return (unsigned long)(size_t)_PyLong_CompactValue(v);
#else
return (unsigned long)(long)_PyLong_CompactValue(v);
#endif
}
i = _PyLong_DigitCount(v);
int sign = _PyLong_NonCompactSign(v);
x = 0;
while (--i >= 0) {
x = (x << PyLong_SHIFT) | v->long_value.ob_digit[i];
}
return x * sign;
}
unsigned long
PyLong_AsUnsignedLongMask(PyObject *op)
{
PyLongObject *lo;
unsigned long val;
if (op == NULL) {
PyErr_BadInternalCall();
return (unsigned long)-1;
}
if (PyLong_Check(op)) {
return _PyLong_AsUnsignedLongMask(op);
}
lo = (PyLongObject *)_PyNumber_Index(op);
if (lo == NULL)
return (unsigned long)-1;
val = _PyLong_AsUnsignedLongMask((PyObject *)lo);
Py_DECREF(lo);
return val;
}
int
PyLong_IsPositive(PyObject *obj)
{
assert(obj != NULL);
if (!PyLong_Check(obj)) {
PyErr_Format(PyExc_TypeError, "expected int, got %T", obj);
return -1;
}
return _PyLong_IsPositive((PyLongObject *)obj);
}
int
PyLong_IsNegative(PyObject *obj)
{
assert(obj != NULL);
if (!PyLong_Check(obj)) {
PyErr_Format(PyExc_TypeError, "expected int, got %T", obj);
return -1;
}
return _PyLong_IsNegative((PyLongObject *)obj);
}
int
PyLong_IsZero(PyObject *obj)
{
assert(obj != NULL);
if (!PyLong_Check(obj)) {
PyErr_Format(PyExc_TypeError, "expected int, got %T", obj);
return -1;
}
return _PyLong_IsZero((PyLongObject *)obj);
}
static int
long_sign(PyObject *vv)
{
assert(vv != NULL);
assert(PyLong_Check(vv));
PyLongObject *v = (PyLongObject *)vv;
if (_PyLong_IsCompact(v)) {
return _PyLong_CompactSign(v);
}
return _PyLong_NonCompactSign(v);
}
int
_PyLong_Sign(PyObject *vv)
{
return long_sign(vv);
}
int
PyLong_GetSign(PyObject *vv, int *sign)
{
if (!PyLong_Check(vv)) {
PyErr_Format(PyExc_TypeError, "expect int, got %T", vv);
return -1;
}
*sign = long_sign(vv);
return 0;
}
static int
bit_length_digit(digit x)
{
// digit can be larger than unsigned long, but only PyLong_SHIFT bits
// of it will be ever used.
static_assert(PyLong_SHIFT <= sizeof(unsigned long) * 8,
"digit is larger than unsigned long");
return _Py_bit_length((unsigned long)x);
}
int64_t
_PyLong_NumBits(PyObject *vv)
{
PyLongObject *v = (PyLongObject *)vv;
int64_t result = 0;
Py_ssize_t ndigits;
int msd_bits;
assert(v != NULL);
assert(PyLong_Check(v));
ndigits = _PyLong_DigitCount(v);
assert(ndigits == 0 || v->long_value.ob_digit[ndigits - 1] != 0);
if (ndigits > 0) {
digit msd = v->long_value.ob_digit[ndigits - 1];
assert(ndigits <= INT64_MAX / PyLong_SHIFT);
result = (int64_t)(ndigits - 1) * PyLong_SHIFT;
msd_bits = bit_length_digit(msd);
result += msd_bits;
}
return result;
}
PyObject *
_PyLong_FromByteArray(const unsigned char* bytes, size_t n,
int little_endian, int is_signed)
{
const unsigned char* pstartbyte; /* LSB of bytes */
int incr; /* direction to move pstartbyte */
const unsigned char* pendbyte; /* MSB of bytes */
size_t numsignificantbytes; /* number of bytes that matter */
Py_ssize_t ndigits; /* number of Python int digits */
PyLongObject* v; /* result */
Py_ssize_t idigit = 0; /* next free index in v->long_value.ob_digit */
if (n == 0)
return PyLong_FromLong(0L);
if (little_endian) {
pstartbyte = bytes;
pendbyte = bytes + n - 1;
incr = 1;
}
else {
pstartbyte = bytes + n - 1;
pendbyte = bytes;
incr = -1;
}
if (is_signed)
is_signed = *pendbyte >= 0x80;
/* Compute numsignificantbytes. This consists of finding the most
significant byte. Leading 0 bytes are insignificant if the number
is positive, and leading 0xff bytes if negative. */
{
size_t i;
const unsigned char* p = pendbyte;
const int pincr = -incr; /* search MSB to LSB */
const unsigned char insignificant = is_signed ? 0xff : 0x00;
for (i = 0; i < n; ++i, p += pincr) {
if (*p != insignificant)
break;
}
numsignificantbytes = n - i;
/* 2's-comp is a bit tricky here, e.g. 0xff00 == -0x0100, so
actually has 2 significant bytes. OTOH, 0xff0001 ==
-0x00ffff, so we wouldn't *need* to bump it there; but we
do for 0xffff = -0x0001. To be safe without bothering to
check every case, bump it regardless. */
if (is_signed && numsignificantbytes < n)
++numsignificantbytes;
}
/* How many Python int digits do we need? We have
8*numsignificantbytes bits, and each Python int digit has
PyLong_SHIFT bits, so it's the ceiling of the quotient. */
/* catch overflow before it happens */
if (numsignificantbytes > (PY_SSIZE_T_MAX - PyLong_SHIFT) / 8) {
PyErr_SetString(PyExc_OverflowError,
"byte array too long to convert to int");
return NULL;
}
ndigits = (numsignificantbytes * 8 + PyLong_SHIFT - 1) / PyLong_SHIFT;
v = long_alloc(ndigits);
if (v == NULL)
return NULL;
/* Copy the bits over. The tricky parts are computing 2's-comp on
the fly for signed numbers, and dealing with the mismatch between
8-bit bytes and (probably) 15-bit Python digits.*/
{
size_t i;
twodigits carry = 1; /* for 2's-comp calculation */
twodigits accum = 0; /* sliding register */
unsigned int accumbits = 0; /* number of bits in accum */
const unsigned char* p = pstartbyte;
for (i = 0; i < numsignificantbytes; ++i, p += incr) {
twodigits thisbyte = *p;
/* Compute correction for 2's comp, if needed. */
if (is_signed) {
thisbyte = (0xff ^ thisbyte) + carry;
carry = thisbyte >> 8;
thisbyte &= 0xff;
}
/* Because we're going LSB to MSB, thisbyte is
You can’t perform that action at this time.