TCLLIB - Tcl Standard Library: yencode

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)

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

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 http://sourceforge.net/tracker/?group_id=12883. Please also report any ideas for enhancements you may have for either package and/or documentation.

KEYWORDS