1transfer::copy(n)          Data transfer facilities          transfer::copy(n)
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5______________________________________________________________________________
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NAME

8       transfer::copy - Data transfer foundation
9

SYNOPSIS

11       package require Tcl  8.4
12
13       package require transfer::copy  ?0.2?
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15       transfer::copy::do chan|string data outchannel ?options...?
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17       transfer::copy::chan channel outchannel ?options...?
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19       transfer::copy::string string outchannel ?options...?
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21       transfer::copy::doChan channel outchannel optvar
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23       transfer::copy::doString string outchannel optvar
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25       transfer::copy::options outchannel optionlist optvar
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27______________________________________________________________________________
28

DESCRIPTION

30       This  package  provides  a  number  of commands for the asynchronous of
31       information contained in either a string or channel. The main point  of
32       this  package  is  that  the commands here provide a nicer callback API
33       than the builtin command fcopy, making the use of these facilities sim‐
34       pler than the builtin.
35

API

37       transfer::copy::do chan|string data outchannel ?options...?
38              This  command  transfers the information in data to the outchan‐
39              nel, according to the options. The type of  the  information  in
40              data is determined by the first argument.
41
42              The options available to this command are the same as are avail‐
43              able  to  the  command  transfer::copy::options,  and  explained
44              there.
45
46              chan   The  argument  data  contains the handle of a channel and
47                     the actual infomration to  transfer  is  read  from  that
48                     channel.
49
50              string The  argument  data  contains  a  string  and this is the
51                     information to be transfered.
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53       transfer::copy::chan channel outchannel ?options...?
54              This command is a shorter and more direct form for  the  command
55              transfer::copy::do chan.
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57       transfer::copy::string string outchannel ?options...?
58              This  command  is a shorter and more direct form for the command
59              transfer::copy::do string.
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61       transfer::copy::doChan channel outchannel optvar
62              This command is an alternate form of transfer::copy::chan  which
63              reads  its  options  out  of  the array variable named by optvar
64              instead of from a variable length argument list.
65
66       transfer::copy::doString string outchannel optvar
67              This command is  an  alternate  form  of  transfer::copy::string
68              which  reads its options out of the array variable named by opt‐
69              var instead of from a variable length argument list.
70
71       transfer::copy::options outchannel optionlist optvar
72              This command is the option processor used by  all  the  commands
73              above  which  read their options from a variable length argument
74              list. It first reads default settings from  the  channel  handle
75              outchannel, then processes the list of options in optionlist, at
76              last stores the results in the array variable named  by  optvar.
77              The  contents of that variable are in a format which is directly
78              understood by all the commands above which  read  their  options
79              out of an array variable.
80
81              The recognized options are:
82
83              -blocksize int
84                     This  option specifies the size of the chunks to transfer
85                     in one operation. It is  optional  and  defaults  to  the
86                     value  of  -buffersize as configured for the output chan‐
87                     nel.
88
89                     If specified its  value  has  to  be  an  integer  number
90                     greater than zero.
91
92              -command commandprefix
93                     This  option  specifies  the  completion  callback of the
94                     operation. This option has to be specified. An error will
95                     be  thrown  if it is not, or if the empty list was speci‐
96                     fied as argument to it.
97
98                     Its value has to be a command prefix, i.e. a  list  whose
99                     first  word  is the command to execute, followed by words
100                     containing fixed arguments. When the callback is  invoked
101                     one  or two additional arguments are appended to the pre‐
102                     fix. The first argument is the number of bytes which were
103                     transfered. The optional second argument is an error mes‐
104                     sage and added if and only if an error occured during the
105                     the transfer.
106
107              -progress commandprefix
108                     This option specifies the progress callback of the opera‐
109                     tion. It is optional and defaults to the empty list. This
110                     last  possibility  signals that no feedback was asked for
111                     and disabled it.
112
113                     Its value has to be a command prefix, see above, -command
114                     for  a  more  detailed  explanation. When the callback is
115                     invoked a single additional arguments is appended to  the
116                     prefix.  This  argument is the number of bytes which were
117                     transfered so far.
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119              -size int
120                     This option specifies the number of bytes  to  read  from
121                     the  input data and transfer. It is optional and defaults
122                     to "Transfer everything".  Its value has to be an integer
123                     number and any value less than zero has the same meaning,
124                     i.e. to transfer all available data. Any other  value  is
125                     the amount of bytes to transfer.
126
127                     All transfer commands will throw error an when their user
128                     tries to transfer more data  than  is  available  in  the
129                     input.  This  happens immediately, before the transfer is
130                     actually started, should the input be a string. Otherwise
131                     the, i.e. for a channel as input, the error is thrown the
132                     moment the underflow condition is actually detected.
133
134              -encoding encodingname
135
136              -eofchar eofspec
137
138              -translation transspec
139                     These options are the  same  as  are  recognized  by  the
140                     builtin  command  fconfigure and provide the settings for
141                     the output channel which are  to  be  active  during  the
142                     transfer,  and only then. I.e. the settings of the output
143                     channel before the transfer are saved,  and  restored  at
144                     the end of a transfer, regardless of its success or fail‐
145                     ure. None of these options are required, and they default
146                     to the settings of the output channel if not specified.
147

BUGS, IDEAS, FEEDBACK

149       This  document,  and the package it describes, will undoubtedly contain
150       bugs and other problems.  Please report such in the  category  transfer
151       of  the Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist].  Please
152       also report any ideas for enhancements you may have for either  package
153       and/or documentation.
154
155       When proposing code changes, please provide unified diffs, i.e the out‐
156       put of diff -u.
157
158       Note further that  attachments  are  strongly  preferred  over  inlined
159       patches.  Attachments  can  be  made  by  going to the Edit form of the
160       ticket immediately after its creation, and  then  using  the  left-most
161       button in the secondary navigation bar.
162

KEYWORDS

164       channel, copy, transfer
165

CATEGORY

167       Transfer module
168
170       Copyright (c) 2006-2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>
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175tcllib                                0.2                    transfer::copy(n)
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