std::basic_spanbuf
Defined in header <spanstream> |
||
---|---|---|
template< class CharT, class Traits = std::char_traits<CharT> > class basic_spanbuf : public std::basic_streambuf<CharT, Traits> |
(since C++23) |
std::basic_spanbuf
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::span<CharT>
.
std::basic_spanbuf
performs I/O on a fixed buffer, and therefore it does not attempt to obtain a new buffer when the underlying buffer is exhausted.
Typical implementations of std::basic_spanbuf
add two member subobjects: a std::ios_base::openmode
recording the open mode, and a std::span<CharT>
referencing the underlying buffer.
Two specializations for common character types are also defined:
Defined in header <spanstream> |
|
---|---|
Type | Definition |
spanbuf |
basic_spanbuf<char> |
wspanbuf |
basic_spanbuf<wchar_t> |
Member types
Member type | Definition |
---|---|
char_type |
CharT |
traits_type |
Traits ; the program is ill-formed if Traits::char_type is not CharT . |
int_type |
Traits::int_type |
pos_type |
Traits::pos_type |
off_type |
Traits::off_type |
Member functions
Public member functions |
|
(C++23)
|
constructs a basic_spanbuf object (public member function) |
(destructor)
[virtual] (C++23)
|
destroys the basic_spanbuf object (virtual public member function) |
(C++23)
|
assigns a basic_spanbuf object (public member function) |
(C++23)
|
swaps two basic_spanbuf objects (public member function) |
(C++23)
|
obtains or initializes an underlying buffer according to mode (public member function) |
Protected member functions |
|
[virtual] (C++23)
|
attempts to replace the controlled character sequence with an array (virtual protected member function) |
[virtual] (C++23)
|
repositions the next pointer in the input sequence, output sequence, or both, using relative addressing (virtual protected member function) |
[virtual] (C++23)
|
repositions the next pointer in the input sequence, output sequence, or both using absolute addressing (virtual protected member function) |
Non-member functions
(C++23)
|
specializes the std::swap algorithm (function template) |
Inherited from std::basic_streambuf
Member types
Member type | Definition |
---|---|
char_type |
CharT |
traits_type |
Traits ; the program is ill-formed if Traits::char_type is not CharT . |
int_type |
Traits::int_type |
pos_type |
Traits::pos_type |
off_type |
Traits::off_type |
Member functions
[virtual]
|
destructs the basic_streambuf object (virtual public member function of std::basic_streambuf<CharT,Traits> ) |
Locales |
|
invokes imbue() (public member function of std::basic_streambuf<CharT,Traits> ) |
|
obtains a copy of the associated locale (public member function of std::basic_streambuf<CharT,Traits> ) |
|
Positioning |
|
invokes setbuf() (public member function of std::basic_streambuf<CharT,Traits> ) |
|
invokes seekoff() (public member function of std::basic_streambuf<CharT,Traits> ) |
|
invokes seekpos() (public member function of std::basic_streambuf<CharT,Traits> ) |
|
invokes sync() (public member function of std::basic_streambuf<CharT,Traits> ) |
|
Get area |
|
obtains the number of characters immediately available in the get area (public member function of std::basic_streambuf<CharT,Traits> ) |
|
advances the input sequence, then reads one character without advancing again (public member function of std::basic_streambuf<CharT,Traits> ) |
|
(removed in C++17)
|
reads one character from the input sequence and advances the sequence (public member function of std::basic_streambuf<CharT,Traits> ) |
reads one character from the input sequence without advancing the sequence (public member function of std::basic_streambuf<CharT,Traits> ) |
|
invokes xsgetn() (public member function of std::basic_streambuf<CharT,Traits> ) |
|
Put area |
|
writes one character to the put area and advances the next pointer (public member function of std::basic_streambuf<CharT,Traits> ) |
|
invokes xsputn() (public member function of std::basic_streambuf<CharT,Traits> ) |
|
Putback |
|
puts one character back in the input sequence (public member function of std::basic_streambuf<CharT,Traits> ) |
|
moves the next pointer in the input sequence back by one (public member function of std::basic_streambuf<CharT,Traits> ) |
Protected member functions
constructs a basic_streambuf object (protected member function) |
|
(C++11)
|
replaces a basic_streambuf object (protected member function) |
(C++11)
|
swaps two basic_streambuf objects (protected member function) |
Locales |
|
[virtual]
|
changes the associated locale (virtual protected member function of std::basic_streambuf<CharT,Traits> ) |
Positioning |
|
[virtual]
|
replaces the buffer with user-defined array, if permitted (virtual protected member function of std::basic_streambuf<CharT,Traits> ) |
[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> ) |
[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> ) |
[virtual]
|
synchronizes the buffers with the associated character sequence (virtual protected member function of std::basic_streambuf<CharT,Traits> ) |
Get area |
|
[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> ) |
[virtual]
|
reads characters from the associated input sequence to the get area (virtual protected member function of std::basic_streambuf<CharT,Traits> ) |
[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> ) |
[virtual]
|
reads multiple characters from the input sequence (virtual protected member function of std::basic_streambuf<CharT,Traits> ) |
returns a pointer to the beginning, current character and the end of the get area (protected member function) |
|
advances the next pointer in the input sequence (protected member function) |
|
repositions the beginning, next, and end pointers of the input sequence (protected member function) |
|
Put area |
|
[virtual]
|
writes multiple characters to the output sequence (virtual protected member function of std::basic_streambuf<CharT,Traits> ) |
[virtual]
|
writes characters to the associated output sequence from the put area (virtual protected member function of std::basic_streambuf<CharT,Traits> ) |
returns a pointer to the beginning, current character and the end of the put area (protected member function) |
|
advances the next pointer of the output sequence (protected member function) |
|
repositions the beginning, next, and end pointers of the output sequence (protected member function) |
|
Putback |
|
[virtual]
|
puts a character back into the input sequence, possibly modifying the input sequence (virtual protected member function of std::basic_streambuf<CharT,Traits> ) |
Notes
std::basic_spanbuf
does not owns the underlying buffer.
It is the responsibility of programmers to ensure the underlying buffer is in its lifetime when used by a std::basic_spanbuf
object. Additional synchronization may be needed if more than one thread operates the same underlying buffer through different std::basic_spanbuf
objects.
Feature testing macro: __cpp_lib_spanstream
.
See also
implements raw string device (class template) |
|
(deprecated in C++98)
|
implements raw character array device (class) |
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