[manpage_begin yencode n 1.0]
[moddesc   {encode/decoding a binary file}]
[titledesc {encode/decoding a binary file}]
[require Tcl 8]
[require yencode [opt 1.0]]
[description]
[para]

This package provides a Tcl-only implementation of the yEnc file
encoding. This is a recently introduced method of encoding binary
files for transmission through usenet. This encoding packs binary data
into a format that requires an 8-bit clean transmission layer but that
escapes characters special to the NNTP posting protocols. See 
[uri http://www.yenc.org/] for details concerning the algorithm.

[list_begin definitions]

[call [cmd ::yencode::encode] [arg string]]

returns the yEnc encoded data.

[call [cmd ::yencode::decode] [arg "string"]]

Decodes the given yEnc encoded data.

[call [cmd ::yencode::yencode] \
  [opt "-name [arg string]"] \
  [opt "-line [arg integer]"] \
  [opt "-crc32 [arg boolean]"] \
  "(-file [arg filename] | [opt --] [arg string])"]

Encode a file or block of data.

[call [cmd ::yencode::ydecode] \
  "(-file [arg filename] | [opt --] [arg string])"]

Decode a file or block of data. A file may contain more than one
embedded file so the result is a list where each element is a three
element list of filename, file size and data.

[list_end]

[section OPTIONS]

[list_begin definitions]

[lst_item "-filename name"]

Cause the yencode or ydecode commands to read their data from the
named file rather that taking a string parameter.

[lst_item "-name string"]

The encoded data header line contains the suggested file name to be
used when unpacking the data. Use this option to change this from the
default of "data.dat".

[lst_item "-line integer"]

The yencoded data header line contains records the line length used
during the encoding. Use this option to select a line length other
that the default of 128. Note that NNTP imposes a 1000 character line
length limit and some gateways may have trouble with more than 255
characters per line.

[lst_item "-crc32 boolean"]

The yEnc specification recommends the inclusion of a cyclic redundancy
check value in the footer. Use this option to change the default from
[arg true] to [arg false].

[list_end]

[para]
[example {
% set d [yencode::yencode -file testfile.txt]
=ybegin line=128 size=584 name=testfile.txt
 -o- data not shown -o-
=yend size=584 crc32=ded29f4f
}]

[keywords encoding uuencode yEnc yencode ydecode]
[manpage_end]
