Summary: [libcxx] Fix basic_stringbuf constructor The C++ Standard [stringbuf.cons]p1 defines the effects of the basic_stringbuf constructor that takes ios_base::openmode as follows: Effects: Constructs an object of class basic_stringbuf, initializing the base class with basic_streambuf(), and initializing mode with which. Postconditions: str() == "". The default constructor of basic_streambuf shall initialize all its pointer member objects to null pointers [streambuf.cons]p1. Currently libc++ calls "str(string_type());" in the aforementioned constructor setting basic_streambuf's pointers to a non-null value. This patch removes the call (note that the postcondition str() == "" remains valid because __str_ is default-initialized) and adds a test checking that the basic_streambuf's pointers are null after construction. Thanks Mikhail Maltsev for the patch. Reviewers: EricWF, mclow.lists Reviewed By: mclow.lists Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D40707 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@320604 91177308-0d34-0410-b5e6-96231b3b80d8
54 lines
1.2 KiB
C++
54 lines
1.2 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// <sstream>
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// template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
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// class basic_stringbuf
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// explicit basic_stringbuf(ios_base::openmode which = ios_base::in | ios_base::out);
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#include <sstream>
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#include <cassert>
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template<typename CharT>
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struct testbuf
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: std::basic_stringbuf<CharT>
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{
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void check()
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{
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assert(this->eback() == NULL);
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assert(this->gptr() == NULL);
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assert(this->egptr() == NULL);
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assert(this->pbase() == NULL);
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assert(this->pptr() == NULL);
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assert(this->epptr() == NULL);
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}
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};
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int main()
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{
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{
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std::stringbuf buf;
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assert(buf.str() == "");
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}
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{
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std::wstringbuf buf;
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assert(buf.str() == L"");
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}
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{
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testbuf<char> buf;
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buf.check();
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}
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{
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testbuf<wchar_t> buf;
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buf.check();
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}
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}
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