yencode(3tcl) Text encoding & decoding binary data yencode(3tcl)
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NAME
yencode - Y-encode/decode binary data
SYNOPSIS
package require Tcl 8.2
package require yencode ?1.1.2?
::yencode::encode string
::yencode::decode string
::yencode::yencode ?-name string? ?-line integer? ?-crc32 boolean? (-file filename | ?--? string)
::yencode::ydecode (-file filename | ?--? string)
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DESCRIPTION
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 http://www.yenc.org/ for details concerning the algorithm.
::yencode::encode string
returns the yEnc encoded data.
::yencode::decode string
Decodes the given yEnc encoded data.
::yencode::yencode ?-name string? ?-line integer? ?-crc32 boolean? (-file filename | ?--? string)
Encode a file or block of data.
::yencode::ydecode (-file filename | ?--? 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.
OPTIONS
-filename name
Cause the yencode or ydecode commands to read their data from the named file rather that taking a string parameter.
-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".
-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.
-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 true to false.
% 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
REFERENCES
[1] http://www.yenc.org/yenc-draft.1.3.txt
BUGS, IDEAS, FEEDBACK
This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category base64
of the Tcllib SF Trackers [http://sourceforge.net/tracker/?group_id=12883]. Please also report any ideas for enhancements you may have for
either package and/or documentation.
KEYWORDS
encoding, yEnc, ydecode, yencode
CATEGORY
Text processing
COPYRIGHT
Copyright (c) 2002, Pat Thoyts
base64 1.1.2 yencode(3tcl)