NAME

deflate, inflate − data processing modules

SYNOPSIS

include "filter.m";
 deflate := load Filter "/dis/lib/deflate.dis";
inflate := load Filter "/dis/lib/inflate.dis";

DESCRIPTION

This page describes the currently implemented data-processing filters conforming to the ­Filter module interface. For details of the interface, see filter(2).

­deflate ­Deflate implements gzip-compatible stream compression.  The ­param string argument to ­start can contain one or more of the following option characters:

‘d’ Enable debugging output. Each line of debugging output is provided in an ­Rq.Info message. 

‘v’ Enable verbose mode. Each line of verbose output is provided in an ­Rq.Info message. 

‘h’ Add a gzip header and footer to the data. With this flag, the data after filtering will be in exactly the same format as a gzip file, with accompanying checksum. 

‘0’ to ‘9’
Specifies the level of compression to be used (9 highest). See gzip(1).

­inflate ­Inflate performs the inverse operation to deflate.  If the ­param argument to ­start begins with the character ‘h’ then the input to the filter is assumed to be in the standard gzip file format; the output will be checked for integrity. While processing, the ­Rq.Info message is used to transmit some information; the type of information is determined by the first word of msg, as follows:

­file The rest of ­msg (after a following space) is the name of the original filename before compression. 

­mtime
The rest of ­msg (after a following space) is the modification time of the original file before compression. 

SOURCE

­/appl/lib/deflate.b
­/appl/lib/inflate.b

SEE ALSO

gzip(1), filter(2)

Plan 9  —  June 29, 2000