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From: Andreas Schwab <schwab@suse.de> To: nobody@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org, Subject: Re: libstdc++/7961: compare( char *) implemented incorrectly. Date: Wed, 18 Sep 2002 01:46:00 -0000 [thread overview] Message-ID: <20020918084604.8795.qmail@sources.redhat.com> (raw) [-- Warning: decoded text below may be mangled, UTF-8 assumed --] [-- Attachment #1: Type: text/plain, Size: 1316 bytes --] The following reply was made to PR libstdc++/7961; it has been noted by GNATS. From: Andreas Schwab <schwab@suse.de> To: john.carter@tait.co.nz Cc: gcc-gnats@gcc.gnu.org Subject: Re: libstdc++/7961: compare( char *) implemented incorrectly. Date: Wed, 18 Sep 2002 10:39:54 +0200 john.carter@tait.co.nz writes: |> A correct implementation would be... |> template<typename _CharT, typename _Traits, typename _Alloc> |> int |> basic_string<_CharT, _Traits, _Alloc>:: |> compare(const _CharT* __s) const |> { |> size_type __size = this->size(); |> size_type __s_size = traits_types::length(__s); |> size_type __min = __size; |> if ( __size > __s_size) |> __min = __s_size; |> |> int __r = traits_type::compare(_M_data(), __s, __min); |> if (!__r) |> __r = __size - _s_size; |> |> return __r; |> } This is not correct either, because __size - __s_size may overflow the range of int. Try this instead: if (!__r) __r = (__size > __s_size) - (__size < __s_size); Andreas. -- Andreas Schwab, SuSE Labs, schwab@suse.de SuSE Linux AG, Deutschherrnstr. 15-19, D-90429 Nürnberg Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different."
next reply other threads:[~2002-09-18 8:46 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-09-18 1:46 Andreas Schwab [this message] -- strict thread matches above, loose matches on Subject: below -- 2002-11-01 7:27 paolo 2002-11-01 2:55 paolo 2002-11-01 2:36 paolo 2002-11-01 2:23 paolo 2002-09-18 14:46 John Carter 2002-09-18 14:36 John Carter 2002-09-17 20:36 john.carter
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