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uuencode(3trf) | uuencode(3trf) |
NAME¶
uuencode - Encoding "uuencode"SYNOPSIS¶
package require Tcl ?8.2?DESCRIPTION¶
The command uuencode is one of several data encodings provided by the package trf. See trf-intro for an overview of the whole package. This encoding transforms every block of three bytes into a block of four bytes, each of which is printable, i.e. 7bit ASCII. This implies that the result is valid UTF-8 too. The command uses essentially the same algorithm as for base64, except for a different mapping from 6-bit fragments to printable bytes.- uuencode ?options...? ?data?
- -mode encode|decode
- This option has to be present and is always understood by
the encoding.
- -attach channel
- The presence/absence of this option determines the main
operation mode of the transformation.
- -in channel
- This options is legal if and only if the transformation is
used in immediate mode. It provides the handle of the channel the
data to transform has to be read from.
- -out channel
- This options is legal if and only if the transformation is
used in immediate mode. It provides the handle of the channel the
generated transformation result is written to.
NOTES¶
- [1]
- The encoding buffers 2 bytes.
IMMEDIATE VERSUS ATTACHED¶
The transformation distinguishes between two main ways of using it. These are the immediate and attached operation modes. For the attached mode the option -attach is used to associate the transformation with an existing channel. During the execution of the command no transformation is performed, instead the channel is changed in such a way, that from then on all data written to or read from it passes through the transformation and is modified by it according to the definition above. This attachment can be revoked by executing the command unstack for the chosen channel. This is the only way to do this at the Tcl level. In the second mode, which can be detected by the absence of option -attach, the transformation immediately takes data from either its commandline or a channel, transforms it, and returns the result either as result of the command, or writes it into a channel. The mode is named after the immediate nature of its execution. Where the data is taken from, and delivered to, is governed by the presence and absence of the options -in and -out. It should be noted that this ability to immediately read from and/or write to a channel is an historic artifact which was introduced at the beginning of Trf's life when Tcl version 7.6 was current as this and earlier versions have trouble to deal with \0 characters embedded into either input or output.SEE ALSO¶
ascii85, base64, bin, hex, oct, otp_words, quoted-printable, trf-intro, uuencodeKEYWORDS¶
base64, encoding, uuencodeCOPYRIGHT¶
Copyright (c) 1996-2003, Andreas Kupries <andreas_kupries@users.sourceforge.net>
2.1.3 | Trf transformer commands |