std::basic_stringbuf - cppreference.com (original) (raw)
std::basic_stringbuf is a std::basic_streambuf whose associated character sequence is a memory-resident sequence of arbitrary characters, which can be initialized from or made available as an instance of std::basic_string.
Typical implementations of std::basic_stringbuf hold an object of type std::basic_string or equivalent resizable sequence container directly as a data member and use it as both the controlled character sequence (the array where the six pointers of std::basic_streambuf are pointing to) and as the associated character sequence (the source of characters for all input operations and the target for the output).
In addition, a typical implementation holds a data member of type std::ios_base::openmode to indicate the I/O mode of the associated stream (input-only, output-only, input/output, at-end, etc).
| If over-allocation strategy is used by overflow(), an additional high-watermark pointer may be stored to track the last initialized character. | (since C++11) |
|---|
Several typedefs for common character types are provided:
| Type | Definition |
| std::stringbuf | std::basic_stringbuf<char> |
| std::wstringbuf | std::basic_stringbuf<wchar_t> |
Contents
- 1 Member types
- 2 Exposition-only members
- 3 Public member functions
- 4 Protected member functions
- 5 Non-member functions
- 6 Inherited from std::basic_streambuf
[edit] Member types
| Member type | Definition |
|---|---|
| char_type | CharT[edit] |
| traits_type | Traits; the program is ill-formed if Traits::char_type is not CharT.[edit] |
| int_type | Traits::int_type[edit] |
| pos_type | Traits::pos_type[edit] |
| off_type | Traits::off_type[edit] |
| allocator_type | Allocator[edit] |
[edit] Exposition-only members
| buf | the std::basic_string<CharT, Traits, Allocator> used as the underlying buffer(exposition-only member object*) |
|---|---|
| mode | the std::ios_base::openmode of the associated stream(exposition-only member object*) |
| initializes the input and output sequences(exposition-only member function*) |
[edit] Public member functions
| (constructor) | constructs a basic_stringbuf object (public member function) [edit] |
|---|---|
| operator=(C++11) | assigns a basic_stringbuf object (public member function) [edit] |
| swap(C++11) | swaps two basic_stringbuf objects (public member function) [edit] |
| (destructor)[virtual] (implicitly declared) | destructs a basic_stringbuf object and the string it holds (virtual public member function) [edit] |
| str | replaces or obtains a copy of the associated character string (public member function) [edit] |
| get_allocator(C++20) | obtains a copy of the allocator associated with the internal sequence container (public member function) [edit] |
| view(C++20) | obtains a view over the underlying character sequence (public member function) [edit] |
[edit] Protected member functions
| underflow[virtual] | returns the next character available in the input sequence (virtual protected member function) [edit] |
|---|---|
| pbackfail[virtual] | puts a character back into the input sequence (virtual protected member function) [edit] |
| overflow[virtual] | appends a character to the output sequence (virtual protected member function) [edit] |
| setbuf[virtual] | attempts to replace the controlled character sequence with an array (virtual protected member function) [edit] |
| seekoff[virtual] | repositions the next pointer in the input sequence, output sequence, or both, using relative addressing (virtual protected member function) [edit] |
| seekpos[virtual] | repositions the next pointer in the input sequence, output sequence, or both using absolute addressing (virtual protected member function) [edit] |
[edit] Non-member functions
Inherited from std::basic_streambuf
Member types
| Member type | Definition |
|---|---|
| char_type | CharT[edit] |
| traits_type | Traits; the program is ill-formed if Traits::char_type is not CharT.[edit] |
| int_type | Traits::int_type[edit] |
| pos_type | Traits::pos_type[edit] |
| off_type | Traits::off_type[edit] |
Member functions
| (destructor)[virtual] | destructs the basic_streambuf object (virtual public member function of std::basic_streambuf<CharT,Traits>) [edit] |
|---|---|
| Locales | |
| pubimbue | changes the associated locale and invokes imbue() (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| getloc | obtains a copy of the associated locale (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| Positioning | |
| pubsetbuf | invokes setbuf() (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| pubseekoff | invokes seekoff() (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| pubseekpos | invokes seekpos() (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| pubsync | invokes sync() (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| Get area | |
| in_avail | obtains the number of characters immediately available in the get area (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| snextc | advances the input sequence, then reads one character without advancing again (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| sbumpcstossc(removed in C++17) | reads one character from the input sequence and advances the sequence (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| sgetc | reads one character from the input sequence without advancing the sequence (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| sgetn | invokes xsgetn() (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| Put area | |
| sputc | writes one character to the put area and advances the next pointer (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| sputn | invokes xsputn() (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| Putback | |
| sputbackc | puts one character back in the input sequence (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
| sungetc | moves the next pointer in the input sequence back by one (public member function of std::basic_streambuf<CharT,Traits>) [edit] |
Protected member functions
| (constructor) | constructs a basic_streambuf object (protected member function) [edit] |
|---|---|
| operator=(C++11) | replaces a basic_streambuf object (protected member function) [edit] |
| swap(C++11) | swaps two basic_streambuf objects (protected member function) [edit] |
| Locales | |
| imbue[virtual] | reacts to a change of the associated locale (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |
| Positioning | |
| setbuf[virtual] | replaces the buffer with user-defined array, if permitted (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |
| seekoff[virtual] | repositions the next pointer in the input sequence, output sequence, or both, using relative addressing (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |
| seekpos[virtual] | repositions the next pointer in the input sequence, output sequence, or both using absolute addressing (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |
| sync[virtual] | synchronizes the buffers with the associated character sequence (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |
| Get area | |
| showmanyc[virtual] | obtains the number of characters available for input in the associated input sequence, if known (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |
| underflow[virtual] | reads characters from the associated input sequence to the get area (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |
| uflow[virtual] | reads characters from the associated input sequence to the get area and advances the next pointer (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |
| xsgetn[virtual] | reads multiple characters from the input sequence (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |
| ebackgptregptr | returns a pointer to the beginning, current character and the end of the get area (protected member function) [edit] |
| gbump | advances the next pointer in the input sequence (protected member function) [edit] |
| setg | repositions the beginning, next, and end pointers of the input sequence (protected member function) [edit] |
| Put area | |
| xsputn[virtual] | writes multiple characters to the output sequence (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |
| overflow[virtual] | writes characters to the associated output sequence from the put area (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |
| pbasepptrepptr | returns a pointer to the beginning, current character and the end of the put area (protected member function) [edit] |
| pbump | advances the next pointer of the output sequence (protected member function) [edit] |
| setp | repositions the beginning, next, and end pointers of the output sequence (protected member function) [edit] |
| Putback | |
| pbackfail[virtual] | puts a character back into the input sequence, possibly modifying the input sequence (virtual protected member function of std::basic_streambuf<CharT,Traits>) [edit] |