dxl::MappedFile Class Reference

Description:

Todox: ai-generated. RAII file-to-memory loader with optional mmap backend.

This class loads a file into memory and provides a stable pointer + length.

Backend options:

• Portable "read-all" into an internal buffer (always available).
• Optional mmap mapping on non-Windows builds

Warning

Performance note: This class is designed for sequential processing of the returned data. For best results (especially with mmap + MADV_SEQUENTIAL), treat data() as a forward-only byte stream: read from begin to end without repeated random jumps backwards/forwards.

todos:

• move to alib::files
• change exceptions to ALib or don't throw even.
• use with classes TextFile and TextFileLineReader. Those are using std::basic_istream<CharT,Traits>::getline and that's quite slow
• add option to switch between MADV_SEQUENTIAL and MADV_WILLNEED

Definition at line 46 of file mappedfile.hpp.

#include <mappedfile.hpp>

Inner Type Index:
class	Data

Public Method Index:
	MappedFile ()=default
	Default constructor. Creates an empty view.
	MappedFile (const char *path, std::size_t knownSize=std::numeric_limits< std::size_t >::max(), bool preferMmap=true)
	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).
bool	IsEmpty () const noexcept
bool	IsMMap () const noexcept
Data	Open (const char *path, std::size_t knownSize=std::numeric_limits< std::size_t >::max(), bool disableMMap=false)
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::byte >	noMMapBuf
	Internal buffer used for fallback read mode.
std::size_t	size = 0
	Size of the loaded data.

Field Details:

noMMapBuf

std::vector<std::byte> dxl::MappedFile::noMMapBuf

protected

Internal buffer used for fallback read mode.

Definition at line 127 of file mappedfile.hpp.

size

std::size_t dxl::MappedFile::size = 0

protected

Size of the loaded data.

Definition at line 126 of file mappedfile.hpp.

Constructor(s) / Destructor Details:

MappedFile()

dxl::MappedFile::MappedFile ( const char * path, std::size_t knownSize = std::numeric_limits<std::size_t>::max(), bool preferMmap = true )

inline

Construct and load a file.

Parameters

path	File path.
knownSize	File size in bytes if known. Defaults to max(), which triggers size detection.
preferMmap	If true, tries mmap first (when supported), else uses ReadAll.

Exceptions

std::runtime_error

on failure to open/read/map the file.

Definition at line 143 of file mappedfile.hpp.

~MappedFile()

dxl::MappedFile::~MappedFile ( )

inline

Destructor. Calls Close.

Definition at line 152 of file mappedfile.hpp.

Method Details:

Close()

void dxl::MappedFile::Close ( )

noexcept

Release resources (unmap / free buffer).

Definition at line 110 of file mappedfile.cpp.

IsEmpty()

bool dxl::MappedFile::IsEmpty ( ) const

inlinenoexcept

Returns

true if the view is empty.

Definition at line 176 of file mappedfile.hpp.

IsMMap()

bool dxl::MappedFile::IsMMap ( ) const

inlinenoexcept

Returns

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

Definition at line 170 of file mappedfile.hpp.

Open()

MappedFile::Data dxl::MappedFile::Open	(	const char *	path,
		std::size_t	knownSize = std::numeric_limits<std::size_t>::max(),
		bool	disableMMap = false )

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.

Exceptions

std::runtime_error

on failure to open/read/map the file.

Returns

A Data object.

Definition at line 22 of file mappedfile.cpp.

operator=()

MappedFile & dxl::MappedFile::operator= ( MappedFile && )

delete

Deleted assignment operator.

Returns

Void (deleted).

Size()

std::size_t dxl::MappedFile::Size ( ) const

inlinenoexcept

Returns

File size in bytes.

Definition at line 173 of file mappedfile.hpp.

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

• mappedfile.hpp
• mappedfile.cpp