source: tol/tolsh/tolsh.vfs/lib/tcllib1.10/textutil/repeat.tcl @ 8597867d

# repeat.tcl --
#
#       Emulation of string repeat for older
#       revisions of Tcl.
#
# Copyright (c) 2000      by Ajuba Solutions.
# Copyright (c) 2001-2006 by Andreas Kupries <andreas_kupries@users.sourceforge.net>
#
# See the file "license.terms" for information on usage and redistribution
# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#
# RCS: @(#) $Id: repeat.tcl,v 1.1 2006/04/21 04:42:28 andreas_kupries Exp $

# ### ### ### ######### ######### #########
## Requirements

package require Tcl 8.2

namespace eval ::textutil::repeat {}

# ### ### ### ######### ######### #########

namespace eval ::textutil::repeat {
    variable HaveBuiltin [expr {![catch {string repeat a 1}]}]
}

if {0} {
    # Problems with the deactivated code:
    # - Linear in 'num'.
    # - Tests for 'string repeat' in every call!
    #   (Ok, just the variable, still a test every call)
    # - Fails for 'num == 0' because of undefined 'str'.

    proc textutil::repeat::StrRepeat { char num } {
        variable HaveBuiltin
        if { $HaveBuiltin == 0 } then {
            for { set i 0 } { $i < $num } { incr i } {
                append str $char
            }
        } else {
            set str [ string repeat $char $num ]
        }
        return $str
    }
}

if {$::textutil::repeat::HaveBuiltin} {
    proc ::textutil::repeat::strRepeat {char num} {
        return [string repeat $char $num]
    }

    proc ::textutil::repeat::blank {n} {
        return [string repeat " " $n]
    }
} else {
    proc ::textutil::repeat::strRepeat {char num} {
        if {$num <= 0} {
            # No replication required
            return ""
        } elseif {$num == 1} {
            # Quick exit for recursion
            return $char
        } elseif {$num == 2} {
            # Another quick exit for recursion
            return $char$char
        } elseif {0 == ($num % 2)} {
            # Halving the problem results in O (log n) complexity.
            set result [strRepeat $char [expr {$num / 2}]]
            return "$result$result"
        } else {
            # Uneven length, reduce problem by one
            return "$char[strRepeat $char [incr num -1]]"
        }
    }

    proc ::textutil::repeat::blank {n} {
        return [strRepeat " " $n]
    }
}

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## Data structures

namespace eval ::textutil::repeat {
    namespace export strRepeat blank
}

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## Ready

package provide textutil::repeat 0.7