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# -*- tcl -*-
# # ## ### ##### ######## #############
# (C) 2009 Andreas Kupries
# @@ Meta Begin
# Package tcl::transform::counter 1
# Meta as::author {Andreas Kupries}
# Meta as::copyright 2009
# Meta as::license BSD
# Meta as::notes For other observers see adler32, crc32,
# Meta as::notes identity, and observer (stream copy).
# Meta as::notes Possibilities for extension: Separate
# Meta as::notes counters per byte value. Count over
# Meta as::notes fixed time-intervals = channel speed.
# Meta as::notes Use callbacks or traces to save changes
# Meta as::notes in the counters, etc. as time-series.
# Meta as::notes Compute statistics over the time-series.
# Meta description Implementation of a counter
# Meta description transformation. Based on Tcl 8.6's
# Meta description transformation reflection support (TIP
# Meta description 230). An observer instead of a
# Meta description transformation, it counts the number of
# Meta description bytes read and written. The observer
# Meta description saves the counts into two external
# Meta description namespaced variables specified at
# Meta description construction time. Exports a single
# Meta description command adding a new transformation of
# Meta description this type to a channel. One argument,
# Meta description the channel to extend, plus options to
# Meta description specify the variables for the counters.
# Meta description No result.
# Meta platform tcl
# Meta require tcl::transform::core
# Meta require {Tcl 8.6}
# @@ Meta End
# # ## ### ##### ######## #############
package require Tcl 8.6
package require tcl::transform::core
# # ## ### ##### ######## #############
namespace eval ::tcl::transform {}
proc ::tcl::transform::counter {chan args} {
::chan push $chan [counter::implementation new {*}$args]
}
oo::class create ::tcl::transform::counter::implementation {
superclass tcl::transform::core ;# -> initialize, finalize, destructor
method write {c data} {
my Count -write-variable $data
return $data
}
method read {c data} {
my Count -read-variable $data
return $data
}
# No partial data, nor state => no flush, drain, nor clear needed.
# # ## ### ##### ######## #############
constructor {args} {
array set options {
-read-variable {}
-write-variable {}
}
# todo: validity checking of options (legal names, legal
# values, etc.)
array set options $args
return
}
# # ## ### ##### ######## #############
variable options
# # ## ### ##### ######## #############
method Count {o data} {
if {$options($o) eq ""} return
upvar #0 $options($o) counter
incr counter [string length $data]
return
}
}
# # ## ### ##### ######## #############
package provide tcl::transform::counter 1
return
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