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hex(n) hex(n) NAME hex - Encoding "hex" SYNOPSIS package require Tcl ?8.2? package require Trf ?2.1.3? hex ?options...? ?data? DESCRIPTION The command hex is one of several data encodings provided by the pack- age trf. See trf-intro for an overview of the whole package. This encoding transforms every byte in the input into a sequence of 2 characters containing the hexadecimal representation of the byte. For example % hex -mode encode Z 5A hex ?options...? ?data? -mode encode|decode This option has to be present and is always understood by the encoding. For immediate mode the argument value specifies the oper- ation to use. For an attached encoding it specifies the operation to use for writing. Reading will automatically use the reverse operation. See section IMMEDIATE versus ATTACHED for explanations of these two terms. Beyond the argument values listed above all unique abbre- viations are recognized too. Encode converts from arbitrary (most likely binary) data into the described representation, decode does the re- verse . -attach channel The presence/absence of this option determines the main operation mode of the transformation. If present the transformation will be stacked onto the channel whose handle was given to the option and run in attached mode. More about this in section IMMEDIATE ver- sus ATTACHED. If the option is absent the transformation is used in im- mediate mode and the options listed below are recognized. More about this in section IMMEDIATE versus ATTACHED. -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. If the transformation is in immediate mode and this op- tion is absent the data to transform is expected as the last argument to the transformation. -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. If the transformation is in immediate mode and this op- tion is absent the generated data is returned as the re- sult of the command itself. 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 -at- tach, the transformation immediately takes data from either its comman- dline or a channel, transforms it, and returns the result either as re- sult 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 out- put. SEE ALSO ascii85, base64, bin, hex, oct, otp_words, quoted-printable, trf-intro, uuencode KEYWORDS bin, encoding, hex, oct COPYRIGHT Copyright (c) 1996-2003, Andreas Kupries <andreas_kupries@users.sourceforge.net> Trf transformer commands 2.1.3 hex(n)
NAME | SYNOPSIS | DESCRIPTION | IMMEDIATE VERSUS ATTACHED | SEE ALSO | KEYWORDS | COPYRIGHT
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