NAME

       ascii85 - ascii85-encode/decode binary data

SYNOPSIS

       package require Tcl  8.4

       package require ascii85  ?1.0?

       ::ascii85::encode ?-maxlen maxlen? ?-wrapchar wrapchar? string

       ::ascii85::decode string

_________________________________________________________________

DESCRIPTION

       This package provides procedures to encode binary data into ascii85 and back.

       ::ascii85::encode ?-maxlen maxlen? ?-wrapchar wrapchar? string
              Ascii85  encodes  the  given  binary  string and returns the encoded result. Inserts the character
              wrapchar every maxlen characters of output. wrapchar defaults to newline. maxlen defaults to 76.

              Note well: If your string is not simple ascii you should fix  the  string  encoding  before  doing
              ascii85 encoding. See the examples.

              The  command  will  throw  an  error for negative values of maxlen, or if maxlen is not an integer
              number.

       ::ascii85::decode string
              Ascii85 decodes the given string and returns the binary data.  The decoder ignores  whitespace  in
              the string, as well as tabs and newlines.

EXAMPLES

              % ascii85::encode "Hello, world"
              87cURD_*#TDfTZ)
              % ascii85::encode [string repeat xyz 24]
              G^4U[H$X^\H?a^]G^4U[H$X^\H?a^]G^4U[H$X^\H?a^]G^4U[H$X^\H?a^]G^4U[H$X^\H?a^]G
              ^4U[H$X^\H?a^]
              % ascii85::encode -wrapchar "" [string repeat xyz 24]
              G^4U[H$X^\H?a^]G^4U[H$X^\H?a^]G^4U[H$X^\H?a^]G^4U[H$X^\H?a^]G^4U[H$X^\H?a^]G^4U[H$X^\H?a^]
              # NOTE: ascii85 encodes BINARY strings.
              % set chemical [encoding convertto utf-8 "C\u2088H\u2081\u2080N\u2084O\u2082"]
              % set encoded [ascii85::encode $chemical]
              6fN]R8E,5Pidu\UiduhZidua
              % set caffeine [encoding convertfrom utf-8 [ascii85::decode $encoded]]

REFERENCES

       [1]    http://en.wikipedia.org/wiki/Ascii85

       [2]    Postscript       Language       Reference       Manual,      3rd      Edition,      page      131.
              http://www.adobe.com/devnet/postscript/pdfs/PLRM.pdf

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

       ascii85, encoding

CATEGORY

       Text processing

COPYRIGHT

       Copyright (c) 2010, Emiliano Gavilán