#!/bin/bash

# Text rotation
# $Id: unix2-rotate.sh 191 2006-03-29 11:07:00Z cactus $
#
# (C) 2005 Dr. ERDI Gergo <cactus@cactus.rulez.org>
#
# See http://cactus.rulez.org/elte/2005-1-unix/#2 for a description of what it does
#
# Licensed under the GNU General Public License, version 2


function help () {
    self=`basename $0`

    cat << EOF
Usage: $self [-c] [FILE]
Rotates the contents of FILE (or the standard input) by 90 degrees.

Options:
    -c      Replace certain graphical characters with their rotated counterparts
    -help   Display this help message

(C) 2005 Dr. ERDI Gergo <cactus@cactus.rulez.org>

Version: \$Id: unix2-rotate.sh 191 2006-03-29 11:07:00Z cactus $
EOF
    exit 0
}

function error () {
    echo ERROR: $@! >&2
    exit 1
}

function options () {
    [ -z "$1" ] && return
    case "$1" in
	-help)
	    help
	    ;;
	-c)
	    do_rotate_chars=1
	    shift
	    options "$@"
	    ;;
	*)
	    [ $# -gt 1 ] && error "Too many arguments"
	    [ -f "$1" -a -r "$1" ] || error "$1: Unable to open file"
	    exec <"$1"
	    ;;
    esac
}


# Mivel a feladat lenyegebol kovetkezik, hogy ismernunk kell a leghosszabb
# sort, nem tudjuk "azonnal" feldolgozni, hanem ideiglenesen el kell eloszor
# tarolnunk az osszes sort.
# Ez biztositja, hogy programunk lassu es nagy memoriaigenyu is lesz.
#
# Eredetileg pure Bash-ben irtam meg, de az borzaszto lassu lett (2
# perces teszt-futasidok, ugyhogy Awk lett belole.

function rotate ()
{
AWKPROG='
BEGIN {
    width = 0;
}

{
    lines[size++] = $0;
    
    if (length () > width)
	width = length ();
}

END {
    for (i = width; i != 0; i--) {
	empty_line = 1;
	lastline = "";
	
	for (j = 0; j < size; j++) {
	    if (length (lines[j]) < i)
		c = " ";
	    else
	        c = substr (lines[j], i, 1);

	    lastline = lastline c;
	    if (c != " ")
		empty_line = 0;
	}

	if (empty_line) {
	    empty_lines[e++] = lastline
        } else {
	    if (seen_nonempty_line)
		for (j = 0; j < e; j++)
		    print empty_lines[j];
	    delete empty_lines;
	    e = 0;

	    seen_nonempty_line = 1;
	    print lastline;
	}
    }
}'

    awk "$AWKPROG" 2>/dev/null
}

function rotate_chars ()
{
    [ -z $do_rotate_chars ] && (cat; return)

    # Hogy en mit szenvedtem, mire megfelelo " es ' vedelmeket
    # talaltam ezekhez...

    local class1='\\/`,'"'"'_\-|'
    local class2='/\\,'"'"',||_'

    tr "$class1" "$class2" 2>/dev/null
}

options "$@"
rotate | rotate_chars