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transfer::copy(n)                         Data transfer facilities                         transfer::copy(n)



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NAME
       transfer::copy - Data transfer foundation

SYNOPSIS
       package require Tcl  8.4

       package require transfer::copy  ?0.2?

       transfer::copy::do chan|string data outchannel ?options...?

       transfer::copy::chan channel outchannel ?options...?

       transfer::copy::string string outchannel ?options...?

       transfer::copy::doChan channel outchannel optvar

       transfer::copy::doString string outchannel optvar

       transfer::copy::options outchannel optionlist optvar

____________________________________________________________________________________________________________

DESCRIPTION
       This  package provides a number of commands for the asynchronous of information contained in either a
       string or channel. The main point of this package is that the commands here provide a nicer  callback
       API than the builtin command fcopy, making the use of these facilities simpler than the builtin.

API
       transfer::copy::do chan|string data outchannel ?options...?
              This  command  transfers  the information in data to the outchannel, according to the options.
              The type of the information in data is determined by the first argument.

              The options available to this command are the same as are  available  to  the  command  trans-fer::copy::options, transfer::copy::options,
              fer::copy::options, and explained there.

              chan   The argument data contains the handle of a channel and the actual infomration to trans-fer transfer
                     fer is read from that channel.

              string The argument data contains a string and this is the information to be transfered.

       transfer::copy::chan channel outchannel ?options...?
              This command is a shorter and more direct form for the command transfer::copy::do chan.

       transfer::copy::string string outchannel ?options...?
              This command is a shorter and more direct form for the command transfer::copy::do string.

       transfer::copy::doChan channel outchannel optvar
              This command is an alternate form of transfer::copy::chan which reads its options out  of  the
              array variable named by optvar instead of from a variable length argument list.

       transfer::copy::doString string outchannel optvar
              This command is an alternate form of transfer::copy::string which reads its options out of the
              array variable named by optvar instead of from a variable length argument list.

       transfer::copy::options outchannel optionlist optvar
              This command is the option processor used by all the commands above which read  their  options
              from  a variable length argument list. It first reads default settings from the channel handle
              outchannel, then processes the list of options in optionlist, at last stores  the  results  in
              the  array  variable  named  by optvar. The contents of that variable are in a format which is
              directly understood by all the commands above which read their options out of an  array  vari-able. variable.
              able.

              The recognized options are:

              -blocksize int
                     This  option  specifies  the  size  of  the  chunks to transfer in one operation. It is
                     optional and defaults to the value of -buffersize as configured for the output channel.

                     If specified its value has to be an integer number greater than zero.

              -command commandprefix
                     This  option  specifies the completion callback of the operation. This option has to be
                     specified. An error will be thrown if it is not, or if the empty list was specified  as
                     argument to it.

                     Its  value  has  to be a command prefix, i.e. a list whose first word is the command to
                     execute, followed by words containing fixed arguments. When the callback is invoked one
                     or  two additional arguments are appended to the prefix. The first argument is the num-ber number
                     ber of bytes which were transfered. The optional second argument is  an  error  message
                     and added if and only if an error occured during the the transfer.

              -progress commandprefix
                     This  option  specifies  the  progress  callback  of  the operation. It is optional and
                     defaults to the empty list. This last possibility signals that no  feedback  was  asked
                     for and disabled it.

                     Its  value has to be a command prefix, see above, -command for a more detailed explana-tion. explanation.
                     tion. When the callback is invoked a single additional arguments  is  appended  to  the
                     prefix. This argument is the number of bytes which were transfered so far.

              -size int
                     This  option specifies the number of bytes to read from the input data and transfer. It
                     is optional and defaults to "Transfer everything".  Its value has to be an integer num-ber number
                     ber  and  any value less than zero has the same meaning, i.e. to transfer all available
                     data. Any other value is the amount of bytes to transfer.

                     All transfer commands will throw error an when their user tries to transfer  more  data
                     than  is available in the input. This happens immediately, before the transfer is actu-ally actually
                     ally started, should the input be a string. Otherwise the, i.e. for a channel as input,
                     the error is thrown the moment the underflow condition is actually detected.

              -encoding encodingname

              -eofchar eofspec

              -translation transspec
                     These options are the same as are recognized by the builtin command fconfigure and pro-vide provide
                     vide the settings for the output channel which are to be active  during  the  transfer,
                     and  only  then. I.e. the settings of the output channel before the transfer are saved,
                     and restored at the end of a transfer, regardless of its success or  failure.  None  of
                     these  options  are required, and they default to the settings of the output channel if
                     not specified.


BUGS, IDEAS, FEEDBACK
       This document, and the package it describes,  will  undoubtedly  contain  bugs  and  other  problems.
       Please   report   such   in   the  category  transfer  of  the  Tcllib  SF  Trackers  [http://source -
       forge.net/tracker/? group_id=12883].  Please also report any ideas for enhancements you may  have  for
       either package and/or documentation.

KEYWORDS
       channel, copy, transfer

CATEGORY
       Transfer module

COPYRIGHT
       Copyright (c) 2006-2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>




transfer                                             0.2                                   transfer::copy(n)