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longobject.c
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3590 lines (3222 loc) · 106 KB
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/* Long (arbitrary precision) integer object implementation */
/* XXX The functional organization of this file is terrible */
#include "Python.h"
#include "longintrepr.h"
#include <ctype.h>
/* For long multiplication, use the O(N**2) school algorithm unless
* both operands contain more than KARATSUBA_CUTOFF digits (this
* being an internal Python long digit, in base PyLong_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 FIVEARY_CUTOFF digits.
* In that case, do 5 bits at a time. The potential drawback is that
* a table of 2**5 intermediate results is computed.
*/
#define FIVEARY_CUTOFF 8
#define ABS(x) ((x) < 0 ? -(x) : (x))
#undef MIN
#undef MAX
#define MAX(x, y) ((x) < (y) ? (y) : (x))
#define MIN(x, y) ((x) > (y) ? (y) : (x))
/* Forward */
static PyLongObject *long_normalize(PyLongObject *);
static PyLongObject *mul1(PyLongObject *, wdigit);
static PyLongObject *muladd1(PyLongObject *, wdigit, wdigit);
static PyLongObject *divrem1(PyLongObject *, digit, digit *);
#define SIGCHECK(PyTryBlock) \
if (--_Py_Ticker < 0) { \
_Py_Ticker = _Py_CheckInterval; \
if (PyErr_CheckSignals()) PyTryBlock \
}
/* Normalize (remove leading zeros from) a long 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(register PyLongObject *v)
{
Py_ssize_t j = ABS(Py_SIZE(v));
Py_ssize_t i = j;
while (i > 0 && v->ob_digit[i-1] == 0)
--i;
if (i != j)
Py_SIZE(v) = (Py_SIZE(v) < 0) ? -(i) : i;
return v;
}
/* Allocate a new long int object with size digits.
Return NULL and set exception if we run out of memory. */
PyLongObject *
_PyLong_New(Py_ssize_t size)
{
if (size > PY_SSIZE_T_MAX) {
PyErr_NoMemory();
return NULL;
}
/* coverity[ampersand_in_size] */
/* XXX(nnorwitz): This can overflow --
PyObject_NEW_VAR / _PyObject_VAR_SIZE need to detect overflow */
return PyObject_NEW_VAR(PyLongObject, &PyLong_Type, size);
}
PyObject *
_PyLong_Copy(PyLongObject *src)
{
PyLongObject *result;
Py_ssize_t i;
assert(src != NULL);
i = src->ob_size;
if (i < 0)
i = -(i);
result = _PyLong_New(i);
if (result != NULL) {
result->ob_size = src->ob_size;
while (--i >= 0)
result->ob_digit[i] = src->ob_digit[i];
}
return (PyObject *)result;
}
/* Create a new long int object from a C long int */
PyObject *
PyLong_FromLong(long ival)
{
PyLongObject *v;
unsigned long abs_ival;
unsigned long t; /* unsigned so >> doesn't propagate sign bit */
int ndigits = 0;
int negative = 0;
if (ival < 0) {
/* if LONG_MIN == -LONG_MAX-1 (true on most platforms) then
ANSI C says that the result of -ival is undefined when ival
== LONG_MIN. Hence the following workaround. */
abs_ival = (unsigned long)(-1-ival) + 1;
negative = 1;
}
else {
abs_ival = (unsigned long)ival;
}
/* Count the number of Python digits.
We used to pick 5 ("big enough for anything"), but that's a
waste of time and space given that 5*15 = 75 bits are rarely
needed. */
t = abs_ival;
while (t) {
++ndigits;
t >>= PyLong_SHIFT;
}
v = _PyLong_New(ndigits);
if (v != NULL) {
digit *p = v->ob_digit;
v->ob_size = negative ? -ndigits : ndigits;
t = abs_ival;
while (t) {
*p++ = (digit)(t & PyLong_MASK);
t >>= PyLong_SHIFT;
}
}
return (PyObject *)v;
}
/* Create a new long int object from a C unsigned long int */
PyObject *
PyLong_FromUnsignedLong(unsigned long ival)
{
PyLongObject *v;
unsigned long t;
int ndigits = 0;
/* Count the number of Python digits. */
t = (unsigned long)ival;
while (t) {
++ndigits;
t >>= PyLong_SHIFT;
}
v = _PyLong_New(ndigits);
if (v != NULL) {
digit *p = v->ob_digit;
Py_SIZE(v) = ndigits;
while (ival) {
*p++ = (digit)(ival & PyLong_MASK);
ival >>= PyLong_SHIFT;
}
}
return (PyObject *)v;
}
/* Create a new long int object from a C double */
PyObject *
PyLong_FromDouble(double dval)
{
PyLongObject *v;
double frac;
int i, ndig, expo, neg;
neg = 0;
if (Py_IS_INFINITY(dval)) {
PyErr_SetString(PyExc_OverflowError,
"cannot convert float infinity to integer");
return NULL;
}
if (Py_IS_NAN(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 */
if (expo <= 0)
return PyLong_FromLong(0L);
ndig = (expo-1) / PyLong_SHIFT + 1; /* Number of 'digits' in result */
v = _PyLong_New(ndig);
if (v == NULL)
return NULL;
frac = ldexp(frac, (expo-1) % PyLong_SHIFT + 1);
for (i = ndig; --i >= 0; ) {
long bits = (long)frac;
v->ob_digit[i] = (digit) bits;
frac = frac - (double)bits;
frac = ldexp(frac, PyLong_SHIFT);
}
if (neg)
Py_SIZE(v) = -(Py_SIZE(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 postive 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 a long int object.
Returns -1 and sets an error condition if overflow occurs. */
long
PyLong_AsLong(PyObject *vv)
{
/* This version by Tim Peters */
register PyLongObject *v;
unsigned long x, prev;
Py_ssize_t i;
int sign;
if (vv == NULL || !PyLong_Check(vv)) {
if (vv != NULL && PyInt_Check(vv))
return PyInt_AsLong(vv);
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;
}
/* Get a Py_ssize_t from a long int object.
Returns -1 and sets an error condition if overflow occurs. */
Py_ssize_t
PyLong_AsSsize_t(PyObject *vv) {
register PyLongObject *v;
size_t x, prev;
Py_ssize_t i;
int sign;
if (vv == NULL || !PyLong_Check(vv)) {
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 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,
"long int too large to convert to int");
return -1;
}
/* Get a C unsigned long int from a long int object.
Returns -1 and sets an error condition if overflow occurs. */
unsigned long
PyLong_AsUnsignedLong(PyObject *vv)
{
register PyLongObject *v;
unsigned long x, prev;
Py_ssize_t i;
if (vv == NULL || !PyLong_Check(vv)) {
if (vv != NULL && PyInt_Check(vv)) {
long val = PyInt_AsLong(vv);
if (val < 0) {
PyErr_SetString(PyExc_OverflowError,
"can't convert negative value to unsigned long");
return (unsigned long) -1;
}
return val;
}
PyErr_BadInternalCall();
return (unsigned long) -1;
}
v = (PyLongObject *)vv;
i = Py_SIZE(v);
x = 0;
if (i < 0) {
PyErr_SetString(PyExc_OverflowError,
"can't convert negative value to unsigned long");
return (unsigned long) -1;
}
while (--i >= 0) {
prev = x;
x = (x << PyLong_SHIFT) + v->ob_digit[i];
if ((x >> PyLong_SHIFT) != prev) {
PyErr_SetString(PyExc_OverflowError,
"long int too large to convert");
return (unsigned long) -1;
}
}
return x;
}
/* Get a C unsigned long int from a long int object, ignoring the high bits.
Returns -1 and sets an error condition if an error occurs. */
unsigned long
PyLong_AsUnsignedLongMask(PyObject *vv)
{
register PyLongObject *v;
unsigned long x;
Py_ssize_t i;
int sign;
if (vv == NULL || !PyLong_Check(vv)) {
if (vv != NULL && PyInt_Check(vv))
return PyInt_AsUnsignedLongMask(vv);
PyErr_BadInternalCall();
return (unsigned long) -1;
}
v = (PyLongObject *)vv;
i = v->ob_size;
sign = 1;
x = 0;
if (i < 0) {
sign = -1;
i = -i;
}
while (--i >= 0) {
x = (x << PyLong_SHIFT) + v->ob_digit[i];
}
return x * sign;
}
int
_PyLong_Sign(PyObject *vv)
{
PyLongObject *v = (PyLongObject *)vv;
assert(v != NULL);
assert(PyLong_Check(v));
return Py_SIZE(v) == 0 ? 0 : (Py_SIZE(v) < 0 ? -1 : 1);
}
size_t
_PyLong_NumBits(PyObject *vv)
{
PyLongObject *v = (PyLongObject *)vv;
size_t result = 0;
Py_ssize_t ndigits;
assert(v != NULL);
assert(PyLong_Check(v));
ndigits = ABS(Py_SIZE(v));
assert(ndigits == 0 || v->ob_digit[ndigits - 1] != 0);
if (ndigits > 0) {
digit msd = v->ob_digit[ndigits - 1];
result = (ndigits - 1) * PyLong_SHIFT;
if (result / PyLong_SHIFT != (size_t)(ndigits - 1))
goto Overflow;
do {
++result;
if (result == 0)
goto Overflow;
msd >>= 1;
} while (msd);
}
return result;
Overflow:
PyErr_SetString(PyExc_OverflowError, "long has too many bits "
"to express in a platform size_t");
return (size_t)-1;
}
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 */
size_t ndigits; /* number of Python long digits */
PyLongObject* v; /* result */
int idigit = 0; /* next free index in v->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 insignficant 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 insignficant = is_signed ? 0xff : 0x00;
for (i = 0; i < n; ++i, p += pincr) {
if (*p != insignficant)
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 long digits do we need? We have
8*numsignificantbytes bits, and each Python long digit has PyLong_SHIFT
bits, so it's the ceiling of the quotient. */
ndigits = (numsignificantbytes * 8 + PyLong_SHIFT - 1) / PyLong_SHIFT;
if (ndigits > (size_t)INT_MAX)
return PyErr_NoMemory();
v = _PyLong_New((int)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
more significant than what's already in accum,
so needs to be prepended to accum. */
accum |= (twodigits)thisbyte << accumbits;
accumbits += 8;
if (accumbits >= PyLong_SHIFT) {
/* There's enough to fill a Python digit. */
assert(idigit < (int)ndigits);
v->ob_digit[idigit] = (digit)(accum & PyLong_MASK);
++idigit;
accum >>= PyLong_SHIFT;
accumbits -= PyLong_SHIFT;
assert(accumbits < PyLong_SHIFT);
}
}
assert(accumbits < PyLong_SHIFT);
if (accumbits) {
assert(idigit < (int)ndigits);
v->ob_digit[idigit] = (digit)accum;
++idigit;
}
}
Py_SIZE(v) = is_signed ? -idigit : idigit;
return (PyObject *)long_normalize(v);
}
int
_PyLong_AsByteArray(PyLongObject* v,
unsigned char* bytes, size_t n,
int little_endian, int is_signed)
{
Py_ssize_t i; /* index into v->ob_digit */
Py_ssize_t ndigits; /* |v->ob_size| */
twodigits accum; /* sliding register */
unsigned int accumbits; /* # bits in accum */
int do_twos_comp; /* store 2's-comp? is_signed and v < 0 */
digit carry; /* for computing 2's-comp */
size_t j; /* # bytes filled */
unsigned char* p; /* pointer to next byte in bytes */
int pincr; /* direction to move p */
assert(v != NULL && PyLong_Check(v));
if (Py_SIZE(v) < 0) {
ndigits = -(Py_SIZE(v));
if (!is_signed) {
PyErr_SetString(PyExc_TypeError,
"can't convert negative long to unsigned");
return -1;
}
do_twos_comp = 1;
}
else {
ndigits = Py_SIZE(v);
do_twos_comp = 0;
}
if (little_endian) {
p = bytes;
pincr = 1;
}
else {
p = bytes + n - 1;
pincr = -1;
}
/* Copy over all the Python digits.
It's crucial that every Python digit except for the MSD contribute
exactly PyLong_SHIFT bits to the total, so first assert that the long is
normalized. */
assert(ndigits == 0 || v->ob_digit[ndigits - 1] != 0);
j = 0;
accum = 0;
accumbits = 0;
carry = do_twos_comp ? 1 : 0;
for (i = 0; i < ndigits; ++i) {
digit thisdigit = v->ob_digit[i];
if (do_twos_comp) {
thisdigit = (thisdigit ^ PyLong_MASK) + carry;
carry = thisdigit >> PyLong_SHIFT;
thisdigit &= PyLong_MASK;
}
/* Because we're going LSB to MSB, thisdigit is more
significant than what's already in accum, so needs to be
prepended to accum. */
accum |= (twodigits)thisdigit << accumbits;
/* The most-significant digit may be (probably is) at least
partly empty. */
if (i == ndigits - 1) {
/* Count # of sign bits -- they needn't be stored,
* although for signed conversion we need later to
* make sure at least one sign bit gets stored. */
digit s = do_twos_comp ? thisdigit ^ PyLong_MASK :
thisdigit;
while (s != 0) {
s >>= 1;
accumbits++;
}
}
else
accumbits += PyLong_SHIFT;
/* Store as many bytes as possible. */
while (accumbits >= 8) {
if (j >= n)
goto Overflow;
++j;
*p = (unsigned char)(accum & 0xff);
p += pincr;
accumbits -= 8;
accum >>= 8;
}
}
/* Store the straggler (if any). */
assert(accumbits < 8);
assert(carry == 0); /* else do_twos_comp and *every* digit was 0 */
if (accumbits > 0) {
if (j >= n)
goto Overflow;
++j;
if (do_twos_comp) {
/* Fill leading bits of the byte with sign bits
(appropriately pretending that the long had an
infinite supply of sign bits). */
accum |= (~(twodigits)0) << accumbits;
}
*p = (unsigned char)(accum & 0xff);
p += pincr;
}
else if (j == n && n > 0 && is_signed) {
/* The main loop filled the byte array exactly, so the code
just above didn't get to ensure there's a sign bit, and the
loop below wouldn't add one either. Make sure a sign bit
exists. */
unsigned char msb = *(p - pincr);
int sign_bit_set = msb >= 0x80;
assert(accumbits == 0);
if (sign_bit_set == do_twos_comp)
return 0;
else
goto Overflow;
}
/* Fill remaining bytes with copies of the sign bit. */
{
unsigned char signbyte = do_twos_comp ? 0xffU : 0U;
for ( ; j < n; ++j, p += pincr)
*p = signbyte;
}
return 0;
Overflow:
PyErr_SetString(PyExc_OverflowError, "long too big to convert");
return -1;
}
double
_PyLong_AsScaledDouble(PyObject *vv, int *exponent)
{
/* NBITS_WANTED should be > the number of bits in a double's precision,
but small enough so that 2**NBITS_WANTED is within the normal double
range. nbitsneeded is set to 1 less than that because the most-significant
Python digit contains at least 1 significant bit, but we don't want to
bother counting them (catering to the worst case cheaply).
57 is one more than VAX-D double precision; I (Tim) don't know of a double
format with more precision than that; it's 1 larger so that we add in at
least one round bit to stand in for the ignored least-significant bits.
*/
#define NBITS_WANTED 57
PyLongObject *v;
double x;
const double multiplier = (double)(1L << PyLong_SHIFT);
Py_ssize_t i;
int sign;
int nbitsneeded;
if (vv == NULL || !PyLong_Check(vv)) {
PyErr_BadInternalCall();
return -1;
}
v = (PyLongObject *)vv;
i = Py_SIZE(v);
sign = 1;
if (i < 0) {
sign = -1;
i = -(i);
}
else if (i == 0) {
*exponent = 0;
return 0.0;
}
--i;
x = (double)v->ob_digit[i];
nbitsneeded = NBITS_WANTED - 1;
/* Invariant: i Python digits remain unaccounted for. */
while (i > 0 && nbitsneeded > 0) {
--i;
x = x * multiplier + (double)v->ob_digit[i];
nbitsneeded -= PyLong_SHIFT;
}
/* There are i digits we didn't shift in. Pretending they're all
zeroes, the true value is x * 2**(i*PyLong_SHIFT). */
*exponent = i;
assert(x > 0.0);
return x * sign;
#undef NBITS_WANTED
}
/* Get a C double from a long int object. */
double
PyLong_AsDouble(PyObject *vv)
{
int e = -1;
double x;
if (vv == NULL || !PyLong_Check(vv)) {
PyErr_BadInternalCall();
return -1;
}
x = _PyLong_AsScaledDouble(vv, &e);
if (x == -1.0 && PyErr_Occurred())
return -1.0;
/* 'e' initialized to -1 to silence gcc-4.0.x, but it should be
set correctly after a successful _PyLong_AsScaledDouble() call */
assert(e >= 0);
if (e > INT_MAX / PyLong_SHIFT)
goto overflow;
errno = 0;
x = ldexp(x, e * PyLong_SHIFT);
if (Py_OVERFLOWED(x))
goto overflow;
return x;
overflow:
PyErr_SetString(PyExc_OverflowError,
"long int too large to convert to float");
return -1.0;
}
/* Create a new long (or int) object from a C pointer */
PyObject *
PyLong_FromVoidPtr(void *p)
{
#if SIZEOF_VOID_P <= SIZEOF_LONG
if ((long)p < 0)
return PyLong_FromUnsignedLong((unsigned long)p);
return PyInt_FromLong((long)p);
#else
#ifndef HAVE_LONG_LONG
# error "PyLong_FromVoidPtr: sizeof(void*) > sizeof(long), but no long long"
#endif
#if SIZEOF_LONG_LONG < SIZEOF_VOID_P
# error "PyLong_FromVoidPtr: sizeof(PY_LONG_LONG) < sizeof(void*)"
#endif
/* optimize null pointers */
if (p == NULL)
return PyInt_FromLong(0);
return PyLong_FromUnsignedLongLong((unsigned PY_LONG_LONG)p);
#endif /* SIZEOF_VOID_P <= SIZEOF_LONG */
}
/* Get a C pointer from a long object (or an int object in some cases) */
void *
PyLong_AsVoidPtr(PyObject *vv)
{
/* This function will allow int or long objects. If vv is neither,
then the PyLong_AsLong*() functions will raise the exception:
PyExc_SystemError, "bad argument to internal function"
*/
#if SIZEOF_VOID_P <= SIZEOF_LONG
long x;
if (PyInt_Check(vv))
x = PyInt_AS_LONG(vv);
else if (PyLong_Check(vv) && _PyLong_Sign(vv) < 0)
x = PyLong_AsLong(vv);
else
x = PyLong_AsUnsignedLong(vv);
#else
#ifndef HAVE_LONG_LONG
# error "PyLong_AsVoidPtr: sizeof(void*) > sizeof(long), but no long long"
#endif
#if SIZEOF_LONG_LONG < SIZEOF_VOID_P
# error "PyLong_AsVoidPtr: sizeof(PY_LONG_LONG) < sizeof(void*)"
#endif
PY_LONG_LONG x;
if (PyInt_Check(vv))
x = PyInt_AS_LONG(vv);
else if (PyLong_Check(vv) && _PyLong_Sign(vv) < 0)
x = PyLong_AsLongLong(vv);
else
x = PyLong_AsUnsignedLongLong(vv);
#endif /* SIZEOF_VOID_P <= SIZEOF_LONG */
if (x == -1 && PyErr_Occurred())
return NULL;
return (void *)x;
}
#ifdef HAVE_LONG_LONG
/* Initial PY_LONG_LONG support by Chris Herborth (chrish@qnx.com), later
* rewritten to use the newer PyLong_{As,From}ByteArray API.
*/
#define IS_LITTLE_ENDIAN (int)*(unsigned char*)&one
/* Create a new long int object from a C PY_LONG_LONG int. */
PyObject *
PyLong_FromLongLong(PY_LONG_LONG ival)
{
PyLongObject *v;
unsigned PY_LONG_LONG abs_ival;
unsigned PY_LONG_LONG t; /* unsigned so >> doesn't propagate sign bit */
int ndigits = 0;
int negative = 0;
if (ival < 0) {
/* avoid signed overflow on negation; see comments
in PyLong_FromLong above. */
abs_ival = (unsigned PY_LONG_LONG)(-1-ival) + 1;
negative = 1;
}
else {
abs_ival = (unsigned PY_LONG_LONG)ival;
}
/* Count the number of Python digits.
We used to pick 5 ("big enough for anything"), but that's a
waste of time and space given that 5*15 = 75 bits are rarely
needed. */
t = abs_ival;
while (t) {
++ndigits;
t >>= PyLong_SHIFT;
}
v = _PyLong_New(ndigits);
if (v != NULL) {
digit *p = v->ob_digit;
Py_SIZE(v) = negative ? -ndigits : ndigits;
t = abs_ival;
while (t) {
*p++ = (digit)(t & PyLong_MASK);
t >>= PyLong_SHIFT;
}
}
return (PyObject *)v;
}
/* Create a new long int object from a C unsigned PY_LONG_LONG int. */
PyObject *
PyLong_FromUnsignedLongLong(unsigned PY_LONG_LONG ival)
{
PyLongObject *v;
unsigned PY_LONG_LONG t;
int ndigits = 0;
/* Count the number of Python digits. */
t = (unsigned PY_LONG_LONG)ival;
while (t) {
++ndigits;
t >>= PyLong_SHIFT;
}
v = _PyLong_New(ndigits);
if (v != NULL) {
digit *p = v->ob_digit;
Py_SIZE(v) = ndigits;
while (ival) {
*p++ = (digit)(ival & PyLong_MASK);
ival >>= PyLong_SHIFT;
}
}
return (PyObject *)v;
}
/* Create a new long int object from a C Py_ssize_t. */
PyObject *
PyLong_FromSsize_t(Py_ssize_t ival)
{
Py_ssize_t bytes = ival;
int one = 1;
return _PyLong_FromByteArray(
(unsigned char *)&bytes,
SIZEOF_SIZE_T, IS_LITTLE_ENDIAN, 1);
}
/* Create a new long int object from a C size_t. */
PyObject *
PyLong_FromSize_t(size_t ival)
{
size_t bytes = ival;
int one = 1;
return _PyLong_FromByteArray(
(unsigned char *)&bytes,
SIZEOF_SIZE_T, IS_LITTLE_ENDIAN, 0);
}
/* Get a C PY_LONG_LONG int from a long int object.
Return -1 and set an error if overflow occurs. */
PY_LONG_LONG
PyLong_AsLongLong(PyObject *vv)
{
PY_LONG_LONG bytes;
int one = 1;
int res;
if (vv == NULL) {
PyErr_BadInternalCall();
return -1;
}
if (!PyLong_Check(vv)) {
PyNumberMethods *nb;
PyObject *io;
if (PyInt_Check(vv))
return (PY_LONG_LONG)PyInt_AsLong(vv);
if ((nb = vv->ob_type->tp_as_number) == NULL ||
nb->nb_int == NULL) {
PyErr_SetString(PyExc_TypeError, "an integer is required");
return -1;
}
io = (*nb->nb_int) (vv);
if (io == NULL)
return -1;
if (PyInt_Check(io)) {
bytes = PyInt_AsLong(io);
Py_DECREF(io);
return bytes;
}
if (PyLong_Check(io)) {
bytes = PyLong_AsLongLong(io);
Py_DECREF(io);
return bytes;
}
Py_DECREF(io);
PyErr_SetString(PyExc_TypeError, "integer conversion failed");
return -1;
}
res = _PyLong_AsByteArray(
(PyLongObject *)vv, (unsigned char *)&bytes,
SIZEOF_LONG_LONG, IS_LITTLE_ENDIAN, 1);
/* Plan 9 can't handle PY_LONG_LONG in ? : expressions */
if (res < 0)
return (PY_LONG_LONG)-1;
else
return bytes;
}
/* Get a C unsigned PY_LONG_LONG int from a long int object.
Return -1 and set an error if overflow occurs. */
unsigned PY_LONG_LONG
PyLong_AsUnsignedLongLong(PyObject *vv)
{
unsigned PY_LONG_LONG bytes;
int one = 1;
int res;
if (vv == NULL || !PyLong_Check(vv)) {
PyErr_BadInternalCall();
return (unsigned PY_LONG_LONG)-1;
}
res = _PyLong_AsByteArray(
(PyLongObject *)vv, (unsigned char *)&bytes,
SIZEOF_LONG_LONG, IS_LITTLE_ENDIAN, 0);
/* Plan 9 can't handle PY_LONG_LONG in ? : expressions */