Writes to a file of unsigned integers using gamma compression. More...

Classes
class	compressed_file_writer_exception
	Basic exception for compressed_file_writer interactions. More...

Public Member Functions
	compressed_file_writer (const std::string &filename, std::function< uint64_t(uint64_t)> mapping)
	Constructor; Opens a compressed file for writing or creates a new file if it doesn't exist. More...

	~compressed_file_writer ()
	Destructor; closes the compressed file.

uint64_t	bit_location () const

void	write (uint64_t value)
	Writes a value to the end of the compressed file. More...

void	write (const std::string &str)
	Writes a binary string to the file. More...

void	close ()
	Closes this compressed file.

Private Member Functions
void	write_bit (bool bit)
	Writes a bit to the file and advances the current location in the file. More...

void	write_buffer () const
	Writes the buffer to the file.

Private Attributes
FILE *	outfile_
	Where to write the compressed data.

uint64_t	char_cursor_
	The current byte this reader is on.

uint64_t	bit_cursor_
	The current bit of the current byte this reader is on.

uint64_t	buffer_size_
	How large to make the internal writer buffer.

unsigned char *	buffer_
	Saved data that is not yet written to disk.

std::function< uint64_t(uint64_t)>	mapping_
	The mapping to use (actual -> compressed id)

uint64_t	bit_location_
	The number of total bits that have been written (for seeking)

bool	closed_
	Ensures the file isn't closed more than once.

Detailed Description

Writes to a file of unsigned integers using gamma compression.

Constructor & Destructor Documentation

meta::io::compressed_file_writer::compressed_file_writer	(	const std::string &	filename,
		std::function< uint64_t(uint64_t)>	mapping
	)

Constructor; Opens a compressed file for writing or creates a new file if it doesn't exist.

Parameters

filename	The path to the compressed file
mapping	A function to map the original numbers to their compressed id, usually to take advantage of a skewed distribution of towards many small numbers

uint64_t meta::io::compressed_file_writer::bit_location ( ) const

Returns: the character index and bit index of the current location in the compressed file

void meta::io::compressed_file_writer::write ( uint64_t value )

Writes a value to the end of the compressed file.

Parameters

value The number to write

void meta::io::compressed_file_writer::write ( const std::string & str )

Writes a binary string to the file.

Parameters

str	The string to write

void meta::io::compressed_file_writer::write_bit ( bool bit )

private

Writes a bit to the file and advances the current location in the file.

Parameters

bit

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