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

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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 transfer::copy::options, and explained
              there.

              chan   The argument data contains the handle of a channel and
                     the actual infomration to transfer 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 variable.

              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 number 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 explanation. 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
                     number 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
                     actually 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 provide 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://sourceforge.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)
