66 lines
5.0 KiB
Markdown
66 lines
5.0 KiB
Markdown
[stringbuf.general]
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# 31 Input/output library [[input.output]](./#input.output)
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## 31.8 String-based streams [[string.streams]](string.streams#stringbuf.general)
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### 31.8.2 Class template basic_stringbuf [[stringbuf]](stringbuf#general)
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#### 31.8.2.1 General [stringbuf.general]
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[ð](#lib:basic_stringbuf)
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namespace std {template<class charT, class traits = char_traits<charT>, class Allocator = allocator<charT>>class basic_stringbuf : public basic_streambuf<charT, traits> {public:using char_type = charT; using int_type = typename traits::int_type; using pos_type = typename traits::pos_type; using off_type = typename traits::off_type; using traits_type = traits; using allocator_type = Allocator; // [[stringbuf.cons]](stringbuf.cons "31.8.2.2 Constructors"), constructors basic_stringbuf() : basic_stringbuf(ios_base::in | ios_base::out) {}explicit basic_stringbuf(ios_base::openmode which); explicit basic_stringbuf(const basic_string<charT, traits, Allocator>& s,
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ios_base::openmode which = ios_base::in | ios_base::out); explicit basic_stringbuf(const Allocator& a): basic_stringbuf(ios_base::in | ios_base::out, a) {} basic_stringbuf(ios_base::openmode which, const Allocator& a); explicit basic_stringbuf( basic_string<charT, traits, Allocator>&& s,
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ios_base::openmode which = ios_base::in | ios_base::out); template<class SAlloc> basic_stringbuf(const basic_string<charT, traits, SAlloc>& s, const Allocator& a): basic_stringbuf(s, ios_base::in | ios_base::out, a) {}template<class SAlloc> basic_stringbuf(const basic_string<charT, traits, SAlloc>& s,
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ios_base::openmode which, const Allocator& a); template<class SAlloc>explicit basic_stringbuf(const basic_string<charT, traits, SAlloc>& s,
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ios_base::openmode which = ios_base::in | ios_base::out); template<class T>explicit basic_stringbuf(const T& t,
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ios_base::openmode which = ios_base::in | ios_base::out); template<class T> basic_stringbuf(const T& t, const Allocator& a); template<class T> basic_stringbuf(const T& t, ios_base::openmode which, const Allocator& a);
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basic_stringbuf(const basic_stringbuf&) = delete;
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basic_stringbuf(basic_stringbuf&& rhs);
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basic_stringbuf(basic_stringbuf&& rhs, const Allocator& a); // [[stringbuf.assign]](stringbuf.assign "31.8.2.3 Assignment and swap"), assignment and swap basic_stringbuf& operator=(const basic_stringbuf&) = delete;
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basic_stringbuf& operator=(basic_stringbuf&& rhs); void swap(basic_stringbuf& rhs) noexcept(*see below*); // [[stringbuf.members]](stringbuf.members "31.8.2.4 Member functions"), getters and setters allocator_type get_allocator() const noexcept;
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basic_string<charT, traits, Allocator> str() const &; template<class SAlloc> basic_string<charT,traits,SAlloc> str(const SAlloc& sa) const;
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basic_string<charT, traits, Allocator> str() &&;
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basic_string_view<charT, traits> view() const noexcept; void str(const basic_string<charT, traits, Allocator>& s); template<class SAlloc>void str(const basic_string<charT, traits, SAlloc>& s); void str(basic_string<charT, traits, Allocator>&& s); template<class T>void str(const T& t); protected:// [[stringbuf.virtuals]](stringbuf.virtuals "31.8.2.5 Overridden virtual functions"), overridden virtual functions int_type underflow() override;
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int_type pbackfail(int_type c = traits::eof()) override;
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int_type overflow (int_type c = traits::eof()) override;
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basic_streambuf<charT, traits>* setbuf(charT*, streamsize) override;
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pos_type seekoff(off_type off, ios_base::seekdir way,
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ios_base::openmode which = ios_base::in | ios_base::out) override;
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pos_type seekpos(pos_type sp,
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ios_base::openmode which = ios_base::in | ios_base::out) override; private: ios_base::openmode *mode*; // *exposition only* basic_string<charT, traits, Allocator> *buf*; // *exposition only*void *init-buf-ptrs*(); // *exposition only*};}
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[1](#1)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L8113)
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The classbasic_stringbuf is derived frombasic_streambuf to associate possibly the input sequence and possibly
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the output sequence with a sequence of arbitrary[*characters*](#def:characters)[.](#1.sentence-1)
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The sequence can be initialized from, or made available as, an object of classbasic_string[.](#1.sentence-2)
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[2](#2)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L8124)
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For the sake of exposition,
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the maintained data and internal pointer initialization is presented here as:
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- [(2.1)](#2.1)
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ios_base::openmode *mode*, has in set if the input sequence can be read, and out set if the output sequence can be written[.](#2.1.sentence-1)
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- [(2.2)](#2.2)
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basic_string<charT, traits, Allocator> *buf* contains the underlying character sequence[.](#2.2.sentence-1)
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- [(2.3)](#2.3)
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*init-buf-ptrs*() sets the base class'
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get area ([[streambuf.get.area]](streambuf.get.area "31.6.3.4.2 Get area access")) and
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put area ([[streambuf.put.area]](streambuf.put.area "31.6.3.4.3 Put area access")) pointers
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after initializing, moving from, or assigning to *buf* accordingly[.](#2.3.sentence-1)
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