filesystem::huge_file Class Reference

Supports reading and writing to very large files, > 4 gigabytes. More...

#include <huge_file.h>

Public Types
enum	outcomes { OKAY = basis::common::OKAY , FAILURE = basis::common::FAILURE , ACCESS_DENIED = basis::common::ACCESS_DENIED , BAD_INPUT = basis::common::BAD_INPUT }

Public Member Functions
	huge_file (const basis::astring &filename, const basis::astring &permissions)
	opens "filename" for access, where it presumably is a very large file. More...
virtual	~huge_file ()
	DEFINE_CLASS_NAME ("huge_file")
const basis::astring &	name () const
	returns the name of the file this operates on. More...
bool	good () const
	reports if the file was opened successfully. More...
bool	eof () const
	reports when the file pointer has reached the end of the file. More...
double	length ()
	expensive operation accesses the file to find length. More...
double	file_pointer () const
	returns where we currently are in the file. More...
basis::outcome	seek (double new_position, byte_filer::origins origin=byte_filer::FROM_CURRENT)
	move the file pointer to "new_position" if possible. More...
basis::outcome	move_to (double absolute_posn)
	simpler seek just goes from current location to "absolute_posn". More...
basis::outcome	read (basis::byte_array &to_fill, int desired_size, int &size_read)
	reads "desired_size" into "to_fill" if possible. More...
basis::outcome	write (const basis::byte_array &to_write, int &size_written)
	stores the array "to_write" into the file. More...
bool	truncate ()
	truncates the file after the current position. More...
basis::outcome	touch ()
void	flush ()
	forces any pending writes to actually be saved to the file. More...

Detailed Description

Supports reading and writing to very large files, > 4 gigabytes.

The standard file I/O functions only handle files up to 4 gigabytes. This class extends the range to essentially unlimited sizes, as long as the operating system can accurately do relative seeks and can read/write to files of the size needed.

Definition at line 35 of file huge_file.h.

Member Enumeration Documentation

outcomes

enum filesystem::huge_file::outcomes

Enumerator
OKAY
FAILURE
ACCESS_DENIED
BAD_INPUT

Definition at line 46 of file huge_file.h.

Constructor & Destructor Documentation

huge_file()

filesystem::huge_file::huge_file	(	const basis::astring &	filename,
		const basis::astring &	permissions
	)

opens "filename" for access, where it presumably is a very large file.

see byte filer for a description of the permissions.

Definition at line 40 of file huge_file.cpp.

~huge_file()

filesystem::huge_file::~huge_file ( )

virtual

Definition at line 46 of file huge_file.cpp.

References basis::WHACK().

Member Function Documentation

DEFINE_CLASS_NAME()

filesystem::huge_file::DEFINE_CLASS_NAME

(

"huge_file"

)

eof()

bool filesystem::huge_file::eof

(

)

const

reports when the file pointer has reached the end of the file.

Definition at line 183 of file huge_file.cpp.

References filesystem::byte_filer::eof().

Referenced by filesystem::heavy_file_operations::copy_file().

file_pointer()

double filesystem::huge_file::file_pointer ( ) const

inline

returns where we currently are in the file.

Definition at line 65 of file huge_file.h.

flush()

void filesystem::huge_file::flush

(

)

forces any pending writes to actually be saved to the file.

Definition at line 53 of file huge_file.cpp.

References filesystem::byte_filer::flush().

good()

bool filesystem::huge_file::good

(

)

const

reports if the file was opened successfully.

Definition at line 181 of file huge_file.cpp.

References filesystem::byte_filer::good().

Referenced by filesystem::heavy_file_operations::buffer_files(), filesystem::file_info::calculate(), filesystem::heavy_file_operations::copy_file(), and filesystem::heavy_file_operations::write_file_chunk().

length()

double filesystem::huge_file::length

(

)

expensive operation accesses the file to find length.

Definition at line 57 of file huge_file.cpp.

References filesystem::byte_filer::eof(), filesystem::byte_filer::file_size_limit(), filesystem::byte_filer::FROM_CURRENT, filesystem::byte_filer::FROM_START, FUNCDEF, filesystem::byte_filer::length(), LOG, filesystem::byte_filer::name(), OKAY, filesystem::byte_filer::read(), seek(), and filesystem::byte_filer::seek().

Referenced by filesystem::heavy_file_operations::buffer_files(), filesystem::file_info::calculate(), seek(), and filesystem::heavy_file_operations::write_file_chunk().

move_to()

outcome filesystem::huge_file::move_to

(

double

absolute_posn

)

simpler seek just goes from current location to "absolute_posn".

Definition at line 185 of file huge_file.cpp.

References basis::absolute_value(), FAILURE, filesystem::byte_filer::file_size_limit(), filesystem::byte_filer::FROM_CURRENT, FUNCDEF, LOG, basis::minimum(), OKAY, and filesystem::byte_filer::seek().

Referenced by seek().

name()

const astring & filesystem::huge_file::name

(

)

const

returns the name of the file this operates on.

Definition at line 51 of file huge_file.cpp.

References filesystem::byte_filer::name().

read()

outcome filesystem::huge_file::read	(	basis::byte_array &	to_fill,
		int	desired_size,
		int &	size_read
	)

reads "desired_size" into "to_fill" if possible.

"size_read" reports how many bytes were actually read.

Definition at line 263 of file huge_file.cpp.

References FAILURE, FUNCDEF, OKAY, and filesystem::byte_filer::read().

Referenced by filesystem::heavy_file_operations::buffer_files(), filesystem::file_info::calculate(), and filesystem::heavy_file_operations::copy_file().

seek()

outcome filesystem::huge_file::seek	(	double	new_position,
		byte_filer::origins	origin = byte_filer::FROM_CURRENT
	)

move the file pointer to "new_position" if possible.

the relative seek is the easiest type of seek to accomplish with a huge file. the other types are also supported, but take a bit more to implement.

Definition at line 231 of file huge_file.cpp.

References BAD_INPUT, FAILURE, filesystem::byte_filer::FROM_CURRENT, filesystem::byte_filer::FROM_END, filesystem::byte_filer::FROM_START, FUNCDEF, length(), LOG, move_to(), and filesystem::byte_filer::seek().

Referenced by filesystem::heavy_file_operations::buffer_files(), filesystem::file_info::calculate(), length(), and filesystem::heavy_file_operations::write_file_chunk().

touch()

basis::outcome filesystem::huge_file::touch

(

)

Definition at line 287 of file huge_file.cpp.

References filesystem::filename::exists(), eml_to_txt::f, FAILURE, FUNCDEF, LOG, filesystem::byte_filer::name(), NULL_POINTER, basis::astring::observe(), OKAY, truncate(), and write().

Referenced by filesystem::heavy_file_operations::write_file_chunk().

truncate()

bool filesystem::huge_file::truncate

(

)

truncates the file after the current position.

Definition at line 55 of file huge_file.cpp.

References filesystem::byte_filer::truncate().

Referenced by touch(), and filesystem::heavy_file_operations::write_file_chunk().

write()

outcome filesystem::huge_file::write	(	const basis::byte_array &	to_write,
		int &	size_written
	)

stores the array "to_write" into the file.

"size_written" reports how many bytes got written.

Definition at line 275 of file huge_file.cpp.

References FAILURE, FUNCDEF, OKAY, and filesystem::byte_filer::write().

Referenced by filesystem::heavy_file_operations::copy_file(), touch(), and filesystem::heavy_file_operations::write_file_chunk().

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

• /opt/feistymeow.org/feisty_meow/nucleus/library/filesystem/huge_file.h
• /opt/feistymeow.org/feisty_meow/nucleus/library/filesystem/huge_file.cpp