vlink::FastStream Class Reference

Logger-friendly std::ostream with a custom growable string buffer. More...

#include <fast_stream.h>

Inheritance diagram for vlink::FastStream:

Collaboration diagram for vlink::FastStream:

Public Member Functions
	FastStream () noexcept
	Constructs the stream with the default initial backing capacity. More...
	~FastStream () noexcept override
	Destructor; releases the underlying string buffer. More...
void	reset () noexcept
	Empties the buffer and clears the stream's error state. More...
void	append_to (std::string &target) const noexcept
	Appends the current buffer contents to target without resetting the stream. More...
std::string_view	take_view ()
	Returns a non-owning view of the current buffer contents. More...
size_t	size () const noexcept
	Returns the number of bytes currently held in the buffer. More...
size_t	capacity () const noexcept
	Returns the current allocated capacity of the backing buffer. More...
void	shrink_to_fit () noexcept
	Trims the underlying buffer to its current backing size. More...
FastStream &	write_raw (const char *data, size_t len)
	Writes raw bytes into the buffer without going through std::ostream formatting. More...

Detailed Description

Logger-friendly std::ostream with a custom growable string buffer.

Routes every write through an embedded StringBuf that owns a std::string. The buffer grows by doubling up to 8 KiB and by linear 8 KiB increments thereafter. take_view yields a non-owning view into the buffer, so a single log line incurs at most one allocation when the buffer must grow and zero allocations on the steady-state path.

Constructor & Destructor Documentation

FastStream()

vlink::FastStream::FastStream ( )

noexcept

Constructs the stream with the default initial backing capacity.

Initial capacity is kDefaultCapacity (256 bytes); the buffer grows on demand.

~FastStream()

vlink::FastStream::~FastStream ( )

overridenoexcept

Destructor; releases the underlying string buffer.

Member Function Documentation

append_to()

void vlink::FastStream::append_to ( std::string &  target ) const

noexcept

Appends the current buffer contents to target without resetting the stream.

Parameters

target

Destination string; contents are appended in place.

capacity()

size_t vlink::FastStream::capacity ( ) const

noexcept

Returns the current allocated capacity of the backing buffer.

Returns

Capacity in bytes.

reset()

void vlink::FastStream::reset ( )

noexcept

Empties the buffer and clears the stream's error state.

Retains the allocated capacity so subsequent messages avoid reallocation.

shrink_to_fit()

void vlink::FastStream::shrink_to_fit ( )

noexcept

Trims the underlying buffer to its current backing size.

Does not shrink to the formatted message length; the put pointer is reset to the start.

size()

size_t vlink::FastStream::size ( ) const

noexcept

Returns the number of bytes currently held in the buffer.

Returns

Buffer length in bytes.

take_view()

std::string_view vlink::FastStream::take_view

(

)

Returns a non-owning view of the current buffer contents.

Primary zero-copy hand-off used by the logger. The view remains valid until the next write to this stream or an explicit reset.

Warning

Do not retain the view beyond the next stream operation; doing so dereferences freed or moved storage.

Returns

View covering the current buffer.

write_raw()

FastStream& vlink::FastStream::write_raw	(	const char *	data,
		size_t	len
	)

Writes raw bytes into the buffer without going through std::ostream formatting.

Faster than std::ostream::write for pre-formatted C strings because it skips the locale and format-flag plumbing.

Parameters

data	Source pointer; non-null when len is non-zero.
len	Number of bytes to write.

Returns

Reference to *this for chaining.

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The documentation for this class was generated from the following file:

• include/vlink/base/fast_stream.h