# Extractor¶

class Extractor

This class automatically extracts the contents of a Multifile to the current directory (or to a specified directory) in the background.

It is designed to limit its use of system resources and run unobtrusively in the background. After specifying the files you wish to extract via repeated calls to request_subfile(), begin the process by calling run() repeatedly. Each call to run() extracts another small portion of the Multifile. Call run() whenever you have spare cycles until run() returns EU_success.

Inheritance diagram

Extractor(void)
PN_stdfloat get_progress(void) const

Returns the fraction of the Multifile extracted so far.

int request_all_subfiles(void)

Requests all subfiles in the Multifile to be extracted. Returns the number requested.

bool request_subfile(Filename const &subfile_name)

Requests a particular subfile to be extracted when step() or run() is called. Returns true if the subfile exists, false otherwise.

void reset(void)

Interrupts the Extractor in the middle of its business and makes it ready to accept a new list of subfiles to extract.

bool run(void)

A convenience function to extract the Multifile all at once, when you don’t care about doing it in the background.

First, call request_file() or request_all_files() to specify the files you would like to extract, then call run() to do the extraction. Also see step() for when you would like the extraction to happen as a background task.

void set_extract_dir(Filename const &extract_dir)

Specifies the directory into which all extracted subfiles will be written. Relative paths of subfiles within the Multifile will be written as relative paths to this directory.

bool set_multifile(Filename const &multifile_name)

Specifies the filename of the Multifile that the Extractor will read. Returns true on success, false if the mulifile name is invalid.

int step(void)

After all of the requests have been made via request_file() or request_all_subfiles(), call step() repeatedly until it stops returning EU_ok.

step() extracts the next small unit of data from the Multifile. Returns EU_ok if progress is continuing, EU_error_abort if there is a problem, or EU_success when the last piece has been extracted.

Also see run().