#!/bin/bash 
# copyright 2007 Gilbert Ashley <amigo@ibiblio.org>
# BashTrix sort is an implementation of the 'sort' command
# written in pure shell. Very few sort options are supported.
# It's based on the combsort algorithm and was originally
# written in BASH by Carl McNealy as a numerical sorter.
VERSION=0.1

ERROR=0
# show program usage
show_usage() {
echo "Usage: ${0##/*} [OPTION]... [FILE]..."
echo "Try '${0##/*} --help' for more information."
exit $ERROR
}

# show program help
show_help() {
echo
echo "Usage: ${0##/*} [OPTION]... [FILE]..."
echo "  or: (cat|echo) | ${0##/*} [OPTION]..."
echo "Sort lines of each FILE and print the result to standard output."
echo "With no FILE, read standard input."
echo "      --help     display this help and exit"
echo "      --version  output version information and exit"
exit $ERROR
}

show_version() {
echo ${0##/*}" (BashTrix) $VERSION"
echo "Copyright 2007 Gilbert Ashley <amigo@ibiblio.org>"
echo "This is free software written in pure shell."
exit $ERROR
}

# get the - options DUMMY
for WORD in "$@" ; do
	case $WORD in
		-*)  true ;
			case $WORD in
				-v) REVERSE_MATCH=1 ; shift ;;
				-n) PRINT_LINE_NUMBERS=1 ; shift ;;
				-H) PRINT_FILE_NAMES=1 ; shift ;;
				--help) show_help ;;
				--version) show_version ;;
				-) READ_STDIN=1 ; shift ;;
			esac
		;;
	esac
done


function  newGap 
{
    typeset -i newgap
    newgap=($1*10)
    newgap=$newgap/13
    if [[ $newgap -eq 9 || $newgap -eq 10 ]]
    then
	newgap=11
    elif [[ $newgap -lt 1 ]]
    then 
	newgap=1
    fi
    return $newgap
}

function swap 
{
    temp=${LINE[$1]}
    LINE[$1]=${LINE[$2]}
    LINE[$2]=$temp
}

ignoreme(){
# declare -a a=(1 6 5 7 8 9 3 2 4 0)
#declare -a a=("Gh" "GH" G N B D F O Z U 1 10 2 3)
declare -a a=("$@")

echo "${#a[@]} Original values are ${a[@]} "

let aSize=${#a[@]}
let gap=$aSize

while(true)
do    
    newGap $gap
    gap=$?
    let swapped=0
    let i=0
    let diff=$aSize-$gap
    while(true)
    do
	if [[ $i -ge $diff ]]
	then
	    break
	fi
	let j=$i+$gap
	if [[ "${a[$i]}" > "${a[$j]}" ]]
	then
	    swap $i $j
	    let swapped=1
	fi
	let i=i+1
    done
    echo "gap=$gap"
    if [[ $gap -eq 1 && $swapped -eq 0 ]] 
    then
	break 2
    fi

done
echo "New      values are ${a[@]} "

}

# from rev
if [[ $# -gt 0 ]] ; then
	while [[ $# -gt 0 ]] ; do
		FILE_NAME="$1"
		if [ ! -r "$1" ] ; then
			echo "Cannot find file $1" 1>&2
			exit 1
		else
			FILE_LINE_COUNT=0
			LINE=
			IFS=
			while read LINE ; do
				# add the curent line to the line counter
				(( FILE_LINE_COUNT++ ))
				declare -a LINE[$FILE_LINE_COUNT]=$LINE
				
			done <"$1"
			
		fi
		
		#let aSize=${#a[FILE_LINE_COUNT]}
		let aSize=$FILE_LINE_COUNT
		let gap=$aSize
		
		
		while(true)
		do    
			newGap $gap
			gap=$?
			let swapped=0
			let i=0
			let diff=$aSize-$gap
			while(true) ; do
				if [[ $i -ge $diff ]] ; then
				break
				fi
				let j=$i+$gap
				if [[ "${LINE[$i]}" > "${LINE[$j]}" ]] ; then
					swap $i $j
					let swapped=1
				fi
				let i=i+1
			done
			#echo "gap=$gap"
			if [[ $gap -eq 1 && $swapped -eq 0 ]] ; then
				break 2
			fi
		done
		
	# go to next FILE in $@
	shift
	done
	
	echo $FILE_LINE_COUNT
	# print the lines in reverse order
	while [[ ${FILE_LINE_COUNT} -gt 0 ]] ; do
		echo $FILE_LINE_COUNT:${LINE[$FILE_LINE_COUNT]}
		(( FILE_LINE_COUNT-- ))
	done
	
	# print the lines in foward order
	while [[ ${FILE_LINE_COUNT} -le ${aSize} ]] ; do
		echo $FILE_LINE_COUNT:${LINE[$FILE_LINE_COUNT]}
		(( FILE_LINE_COUNT++ ))
	done
else
	# piped input is presumed to be separated into lines already
	FILE_NAME="STDIN"
	# output the requested lines in the file
	FILE_LINE_COUNT=0
	LINE=
	IFS=
	while read LINE ; do
		# add the curent line to the line counter
		(( FILE_LINE_COUNT++ ))
		OUTPUT_STRING=
		STRING=$LINE
		while [[ "$STRING" != "" ]] ; do
			OUTPUT_STRING=${STRING:0:1}$OUTPUT_STRING
			STRING=${STRING:1}
		done
		echo $OUTPUT_STRING
		# go to next line in stdin
		shift
	done
fi