transfer::copy(3tcl)					     Data transfer facilities					      transfer::copy(3tcl)

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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 sim-
       pler 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 possi-
		     bility 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  chan-
		     nel  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(3tcl)