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att
GitHub Repository: att/ast
 Path: blob/master/src/cmd/std/seq.sh
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########################################################################

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#                                                                      #

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#               This software is part of the ast package               #

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#          Copyright (c) 1989-2012 AT&T Intellectual Property          #

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#                      and is licensed under the                       #

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#                 Eclipse Public License, Version 1.0                  #

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#                    by AT&T Intellectual Property                     #

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#                                                                      #

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#                A copy of the License is available at                 #

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#          http://www.eclipse.org/org/documents/epl-v10.html           #

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#         (with md5 checksum b35adb5213ca9657e911e9befb180842)         #

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#                                                                      #

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#              Information and Software Systems Research               #

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#                            AT&T Research                             #

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#                           Florham Park NJ                            #

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#                                                                      #

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#                 Glenn Fowler <[email protected]>                  #

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#                                                                      #

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

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#

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# seq.sh

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# Written by David Korn

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# AT&T Labs

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# Sat May  5 00:32:40 EDT 2007

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#

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case $(getopts '[-]' opt "--???man" 2>&1) in

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version=[0-9]*)

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	usage=$'\n[-?\n@(#)$Id: seq (AT&T Labs Research) 2012-04-14 $\n]

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	'$USAGE_LICENSE$'

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	[+NAME?seq - print a sequence of numbers]

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	[+DESCRIPTION?\bseq\b writes the numbers from \afirst\a to \alast\a

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		in steps of increments.  If \afirst\a or \aincr\a is omitted,

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		it defaults to 1.  An omitted \aincr\a defaults to 1 even

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		when \alast\a is smaller than \afirst\a.]

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	[+?\afirst\a \aincr\a,  and \alast\a are interpreted as floating

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		point values.  \aincr\a is usually positive if \afirst\a  is

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		smaller than \alast\a, and \aincr\a is usually negative

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		if \afirst\a is greater than \alast\a.  When given, the

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		\aformat\a argument must contain exactly one of the

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		printf-style, floating point output formats \b%e\b, \b%f\b,

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		\b%g\b.]

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	[f:format]:[format:=%g?use printf style floating point \aformat\a.]

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	[s:separator]:[string:=\\n?use \astring\a to separate numbers.]

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	[w:equal-width?equalize width by padding with leading zeroes.]

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	[ first  [ incr ] ] last

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	[+EXIT STATUS?]{

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       		 [+0?Success.]

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       		 [+>0?An error occurred.]

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	}

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	[+SEE ALSO?\bksh\b(1), \bprintf\b(3)]

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	'

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	;;

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*)

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	usage=''

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	;;

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esac

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function err_exit

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{

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	print -ru2 -- "$command: $@"

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	exit 1

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}

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function format # first second next_to_last last

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{

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	typeset i

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	integer width=0 precision=0 n

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	for i

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	do	n=${#i}

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		(( n > width )) && width=$n

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		[[ $i != *.* ]] && continue

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		i=${i##*.}

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		n=${#i}

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		(( n > precision )) && precision=$n

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	done

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	print -r -- "%0$width.${precision}f"

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}

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command=${0##*/}

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width= sep=$'\n' fmt= end=

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float first=1 incr=1 last n sign=1 epsilon

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while getopts "$usage" var

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do	case $var in

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	f)

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		fmt=$OPTARG

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		[[ $fmt == *%*([^[:space:][:alpha:]])[efg]* ]] || err_exit "$fmt: invalid format string"

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		;;

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	s)

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		sep=$OPTARG;;

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	w)

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		width=1;;

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	esac

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done

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shift $((OPTIND-1))

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case $# in

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1)	last=$1;;

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2)	first=$1 last=$2;;

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3)	first=$1 incr=$2 last=$3;;

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0)	err_exit "too few arguments";;

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*)	err_exit "too many arguments";;

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esac

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if	[[ $width ]]

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then	[[ $fmt ]] && err_exit "format string may not be specified when printing equal width strings"

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	(( n = (last - first) / incr ))

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	if	(( abs(floor(n) - n) <= 1e-12 ))

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	then	end=$last

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	fi

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	fmt=$(format $first $((first+incr)) $((last-incr)) $end)

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elif	[[ ! $fmt ]]

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then	fmt=%g

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fi

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(( incr<0)) && sign=-1

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(( epsilon = sign*incr*1e-12 ))

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(( last += sign*epsilon ))

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(( last *= sign ))

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s=

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for ((n=first; (sign*n) <= last; n+= incr ))

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do	printf "%s$fmt" "$s" $(( abs(n) > epsilon ? n : 0 ))

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	s=$sep

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done

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[[ $s ]] && print

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exit 0

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