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_range_error(): Speed and simplify (there's no real need for

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loops here).  Assert that size_t is actually big enough, and
that f->size is at least one.  Wrap a long line.
This commit is contained in:
Tim Peters 2006-05-31 15:33:22 +00:00
parent c2b550e16e
commit d6a6f023c8
1 changed files with 20 additions and 18 deletions
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38
Modules/_struct.c
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@ -308,26 +308,27 @@ unpack_double(const char *p, /* start of 8-byte string */
static int
_range_error(const formatdef *f, int is_unsigned)
{
if (is_unsigned == 0) {
Py_ssize_t smallest, largest = 0;
Py_ssize_t i = f->size * 8;
while (--i > 0) {
largest = (largest * 2) + 1;
}
smallest = -largest - 1;
PyErr_Format(StructError,
"'%c' format requires %zd <= number <= %zd",
f->format,
smallest,
largest);
} else {
size_t largest = 0;
Py_ssize_t i = f->size * 8;
while (--i >= 0)
largest = (largest * 2) + 1;
/* ulargest is the largest unsigned value with f->size bytes.
* Note that the simpler:
* ((size_t)1 << (f->size * 8)) - 1
* doesn't work when f->size == size_t because C doesn't define what
* happens when a left shift count is >= the number of bits in the
* integer being shifted; e.g., on some boxes it doesn't shift at
* all when they're equal.
*/
const size_t ulargest = (size_t)-1 >> ((SIZEOF_SIZE_T - f->size)*8);
assert(f->size >= 1 && f->size <= SIZEOF_SIZE_T);
if (is_unsigned)
PyErr_Format(StructError,
"'%c' format requires 0 <= number <= %zu",
f->format,
ulargest);
else {
const Py_ssize_t largest = (Py_ssize_t)(ulargest >> 1);
PyErr_Format(StructError,
"'%c' format requires %zd <= number <= %zd",
f->format,
~ largest,
largest);
}
#ifdef PY_STRUCT_OVERFLOW_MASKING
@ -343,7 +344,8 @@ _range_error(const formatdef *f, int is_unsigned)
Py_XDECREF(ptraceback);
if (msg == NULL)
return -1;
rval = PyErr_Warn(PyExc_DeprecationWarning, PyString_AS_STRING(msg));
rval = PyErr_Warn(PyExc_DeprecationWarning,
PyString_AS_STRING(msg));
Py_DECREF(msg);
if (rval == 0)
return 0;