FILTERS(2)                                             FILTERS(2)

     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 inter-
          face. For details of the interface, see filter(2).

          deflate   Deflate implements gzip-compatible stream compres-
                    sion.  The param string argument to start can con-
                    tain one or more of the following option charac-
                    ters:

                    `d'  Enable debugging output. Each line of debug-
                         ging output is provided in an Rq.Info mes-
                         sage.

                    `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 trans-
                    mit 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 com-
                         pression.

                    mtime
                         The rest of msg (after a following space) is

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     FILTERS(2)                                             FILTERS(2)

                         the modification time of the original file
                         before compression.

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

     SEE ALSO
          gzip(1), filter(2)

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