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Fix potential signed-overflow bug in _PyLong_Format; also fix

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a couple of whitespace issues.
This commit is contained in:
Mark Dickinson 2009-09-13 11:56:13 +00:00
parent 3d85454bca
commit 1f4fc097f6
1 changed files with 11 additions and 9 deletions
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20
Objects/longobject.c
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@ -1371,7 +1371,7 @@ _PyLong_Format(PyObject *aa, int base, int addL, int newstyle)
{
register PyLongObject *a = (PyLongObject *)aa;
PyStringObject *str;
Py_ssize_t i, j, sz;
Py_ssize_t i, sz;
Py_ssize_t size_a;
char *p;
int bits;
@ -1392,20 +1392,21 @@ _PyLong_Format(PyObject *aa, int base, int addL, int newstyle)
i >>= 1;
}
i = 5 + (addL ? 1 : 0);
j = size_a*PyLong_SHIFT + bits-1;
sz = i + j / bits;
if (j / PyLong_SHIFT < size_a || sz < i) {
/* ensure we don't get signed overflow in sz calculation */
if (size_a > (PY_SSIZE_T_MAX - i) / PyLong_SHIFT) {
PyErr_SetString(PyExc_OverflowError,
"long is too large to format");
return NULL;
}
sz = i + 1 + (size_a * PyLong_SHIFT - 1) / bits;
assert(sz >= 0);
str = (PyStringObject *) PyString_FromStringAndSize((char *)0, sz);
if (str == NULL)
return NULL;
p = PyString_AS_STRING(str) + sz;
*p = '\0';
if (addL)
*--p = 'L';
if (addL)
*--p = 'L';
if (a->ob_size < 0)
sign = '-';
@ -1433,7 +1434,7 @@ _PyLong_Format(PyObject *aa, int base, int addL, int newstyle)
accumbits -= basebits;
accum >>= basebits;
} while (i < size_a-1 ? accumbits >= basebits :
accum > 0);
accum > 0);
}
}
else {
@ -1448,7 +1449,8 @@ _PyLong_Format(PyObject *aa, int base, int addL, int newstyle)
int power = 1;
for (;;) {
twodigits newpow = powbase * (twodigits)base;
if (newpow >> PyLong_SHIFT) /* doesn't fit in a digit */
if (newpow >> PyLong_SHIFT)
/* doesn't fit in a digit */
break;
powbase = (digit)newpow;
++power;
@ -1498,7 +1500,7 @@ _PyLong_Format(PyObject *aa, int base, int addL, int newstyle)
*--p = '0';
}
else if (base == 8) {
if (newstyle) {
if (newstyle) {
*--p = 'o';
*--p = '0';
}