This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
libstdc++/4533: mistaken assumption in find_first_not_of and find_last_not_of
- To: gcc-gnats at gcc dot gnu dot org
- Subject: libstdc++/4533: mistaken assumption in find_first_not_of and find_last_not_of
- From: brendan at zen dot org
- Date: 11 Oct 2001 12:19:46 -0000
- Reply-To: brendan at zen dot org
>Number: 4533
>Category: libstdc++
>Synopsis: mistaken assumption in find_first_not_of and find_last_not_of
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: unassigned
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Thu Oct 11 05:26:24 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator: Brendan Kehoe
>Release: CVS tree
>Organization:
>Environment:
>Description:
In bits/basic_string.tcc, the function find_first_not_of includes a check in its for loop making sure the size specified in the third argument is non-zero. The standard doesn't actually say it's invalid to have a zero-width size. Thus we should be getting __pos back, not npos.
Similarly, the same goes with find_last_not_of.
>How-To-Repeat:
>Fix:
Take out `__n &&' from find_first_not_of.
Take out `&& __n' from find_last_not_of.
>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: text/plain; name="diffs-basic_string-1.txt"
Content-Disposition: inline; filename="diffs-basic_string-1.txt"
2001-10-10 Brendan Kehoe <brendan@zen.org>
* bits/basic_string.tcc (find_first_not_of): Take out check for
__n being non-zero, since the standard does not mandate that.
e.g., a search for "" in "" should yield position 0, not npos.
(find_last_not_of): Likewise.
Index: include/bits/basic_string.tcc
===================================================================
RCS file: /cvs/gcc/egcs/libstdc++-v3/include/bits/basic_string.tcc,v
retrieving revision 1.6
diff -u -p -r1.6 basic_string.tcc
--- basic_string.tcc 2001/07/20 00:09:31 1.6
+++ basic_string.tcc 2001/10/10 11:44:12
@@ -698,7 +698,7 @@ namespace std
find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const
{
size_t __xpos = __pos;
- for (; __n && __xpos < this->size(); ++__xpos)
+ for (; __xpos < this->size(); ++__xpos)
if (!traits_type::find(__s, __n, _M_data()[__xpos]))
return __xpos;
return npos;
@@ -722,7 +722,7 @@ namespace std
find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const
{
size_type __size = this->size();
- if (__size && __n)
+ if (__size)
{
if (--__size > __pos)
__size = __pos;