alib::system::MappedFile Class Reference

Description:

File-to-memory loader with optional mmap backend. This class loads a file into memory and provides a stable pointer + length, which is only allowed to be read sequentially.

Backend options:

• mmap-mapping where supported.
• Portable "read-all" into an internal buffer (always available, i.e on WindowsOS).

Definition at line 17 of file mappedfile.hpp.

#include <mappedfile.hpp>

Collaboration diagram for alib::system::MappedFile:

Inner Type Index:
class	Data

Public Method Index:
	MappedFile ()=default
	Default constructor. Creates an empty view.
	MappedFile (const MappedFile &)=delete
	Deleted copy constructor.
	MappedFile (MappedFile &&)=delete
	Deleted move constructor.
	~MappedFile ()
	Destructor. Calls Close.
void	Close () noexcept
	Release resources (unmap / free buffer).
template<typename T>
Data< T >	GetData () const noexcept
bool	IsEmpty () const noexcept
bool	IsMMap () const noexcept
std::errc	Open (const CPathString &path, std::size_t knownSize=(std::numeric_limits< std::size_t >::max)(), bool disableMMap=false, bool willNeed=true)
MappedFile &	operator= (const MappedFile &)=delete
	Deleted copy assignment operator.
MappedFile &	operator= (MappedFile &&)=delete
std::size_t	Size () const noexcept

Protected Field Index:
std::vector< std::max_align_t >	noMMapBuf
	Internal buffer used for fallback read mode.
std::size_t	size = 0
	Size of the loaded data.

Field Details:

noMMapBuf

std::vector<std::max_align_t> alib::system::MappedFile::noMMapBuf

protected

Internal buffer used for fallback read mode.

Definition at line 103 of file mappedfile.hpp.

size

std::size_t alib::system::MappedFile::size = 0

protected

Size of the loaded data.

Definition at line 102 of file mappedfile.hpp.

Constructor(s) / Destructor Details:

~MappedFile()

alib::system::MappedFile::~MappedFile ( )

inline

Destructor. Calls Close.

Definition at line 117 of file mappedfile.hpp.

Here is the call graph for this function:

Method Details:

Close()

void alib::system::MappedFile::Close ( )

noexcept

Release resources (unmap / free buffer).

Definition at line 123 of file mappedfile.cpp.

Here is the call graph for this function:

GetData()

template<typename T>

Data< T > alib::system::MappedFile::GetData ( ) const

inlinenoexcept

Returns a data-cursor for sequential read operations of the buffer.

Template Parameters

T	The data type to sequentially load from this cursor.

Returns

The data-cursor.

Definition at line 150 of file mappedfile.hpp.

IsEmpty()

bool alib::system::MappedFile::IsEmpty ( ) const

inlinenoexcept

Returns

true if the view is empty.

Definition at line 164 of file mappedfile.hpp.

IsMMap()

bool alib::system::MappedFile::IsMMap ( ) const

inlinenoexcept

Returns

true if the file was read with mmap mode, false otherwise.

Definition at line 138 of file mappedfile.hpp.

Here is the call graph for this function:

Open()

std::errc alib::system::MappedFile::Open	(	const CPathString &	path,
		std::size_t	knownSize = (std::numeric_limits<std::size_t>::max)(),
		bool	disableMMap = false,
		bool	willNeed = true )

Load a file (replaces previous contents).

Parameters

path	The file's path.
knownSize	File size in bytes if known. Defaults to max() , which triggers size detection.
disableMMap	If true, skips mmap mode and uses standard read methods. Defaults to false.
willNeed	If true (the default), MADV_WILLNEED is passed to the function madvise. Otherwise MADV_SEQUENTIAL is passed.

Exceptions

std::runtime_error

on failure to open/read/map the file.

Returns

The error code of the operation.

Definition at line 9 of file mappedfile.cpp.

Here is the call graph for this function:

operator=()

MappedFile & alib::system::MappedFile::operator= ( MappedFile && )

delete

Deleted assignment operator.

Returns

Void (deleted).

Here is the call graph for this function:

Size()

std::size_t alib::system::MappedFile::Size ( ) const

inlinenoexcept

Returns

File size in bytes.

Definition at line 161 of file mappedfile.hpp.

---

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

• mappedfile.hpp
• mappedfile.cpp