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PyLong_FromSsize_t was incorrect when sizeof(size_t) > sizeof(long);

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rewrite it so that it doesn't care about relative sizes of size_t,
long and long long.

The rewrite is modeled on PyLong_FromLong, instead of using
PyLong_FromByteArray;  this makes the algorithm simpler and
more direct, and possibly also slightly faster.
This commit is contained in:
Mark Dickinson 2008-04-15 21:42:42 +00:00
parent 32dde22186
commit 7ab6be216a
2 changed files with 56 additions and 12 deletions
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65
Objects/longobject.c
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@ -1099,13 +1099,39 @@ PyLong_FromUnsignedLongLong(unsigned PY_LONG_LONG ival)
PyObject *
PyLong_FromSsize_t(Py_ssize_t ival)
{
Py_ssize_t bytes = ival;
int one = 1;
if (ival < PyLong_BASE)
return PyLong_FromLong(ival);
return _PyLong_FromByteArray(
(unsigned char *)&bytes,
SIZEOF_SIZE_T, IS_LITTLE_ENDIAN, 1);
PyLongObject *v;
size_t abs_ival;
size_t t; /* unsigned so >> doesn't propagate sign bit */
int ndigits = 0;
int negative = 0;
CHECK_SMALL_INT(ival);
if (ival < 0) {
/* avoid signed overflow when ival = SIZE_T_MIN */
abs_ival = (size_t)(-1-ival)+1;
negative = 1;
}
else {
abs_ival = (size_t)ival;
}
/* Count the number of Python digits. */
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 size_t. */
@ -1113,13 +1139,28 @@ PyLong_FromSsize_t(Py_ssize_t ival)
PyObject *
PyLong_FromSize_t(size_t ival)
{
size_t bytes = ival;
int one = 1;
PyLongObject *v;
size_t t;
int ndigits = 0;
if (ival < PyLong_BASE)
return PyLong_FromLong(ival);
return _PyLong_FromByteArray(
(unsigned char *)&bytes,
SIZEOF_SIZE_T, IS_LITTLE_ENDIAN, 0);
/* Count the number of Python digits. */
t = 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;
}
/* Get a C PY_LONG_LONG int from a long int object.