ascii85(3)

ascii85(3tcl)        Text encoding & decoding binary data        ascii85(3tcl)

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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

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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  Trackers  [http://core.tcl.tk/tcllib/reportlist].   Please
       also report any ideas for enhancements you may have for either  package
       and/or documentation.

       When proposing code changes, please provide unified diffs, i.e the out-
       put of diff -u.

       Note further that  attachments  are  strongly  preferred  over  inlined
       patches.  Attachments  can  be  made  by  going to the Edit form of the
       ticket immediately after its creation, and  then  using  the  left-most
       button in the secondary navigation bar.

KEYWORDS
       ascii85, encoding

CATEGORY
       Text processing

COPYRIGHT
       Copyright (c) 2010, Emiliano Gavilan

tcllib                                1.0                        ascii85(3tcl)