#!/bin/sh

# version 1.1
# Usage: rotate < <input_file> > <output_file>
#  <input file> - a text file containing the subjects to be rotated
#  <output file> - name for the new file with the rotated subjects

# This program assumes that there are no line breaks inside a single 'line'
# in the input file


awk '

# every line of the input file must be printed to the output file
{
# this rountine makes sure that no output line is longer than 79 characters
	if (length ($0) < 80)
		print $0
	else {
		string = $0
		while (length(string) > 79) {
			for (i = 79; i > 0; i--)
				if (substr($0,i,1) == " ")
					break
			printf "%s\n",substr($0,0,i-1)
			string = substr($0,i,length($0)-(i-1))
			printf "%s", string
		}
		printf "\n"
	}
}

# if the current record is a subject to be rotated:
$1 == "SUBJECT" || $1 == ";" {
# count stores how many items are in the subject - must be at least 1
	count = 1
	for (i = 2; i <= NF; i++) {
# '-' delimits each item in the subject
		if ($i == "-")
			count++
		else
# the words in each item are concatonated together so they appear as in the
#  original, and each item is stored in the array 'subject'
			subject[count] = subject[count] " " $i
	}
	if (count > 1)
# if there is more than one item in the subject:
		for (i = 1; i < count; i++) {
# move each item in the array 'back' one space
			for (j = 1; j <= count - 1; j++)
				rotated[j] = subject[j+1]
# move the first item in the array to the end of the array
			rotated [count] = subject[1]
# concatonate each item into a single string
			string = ";"
			for (k = 1; k < count; k++)
				string = string rotated[k] " -"
			string = string rotated[k]
# print out the string, which is a rotation of the original subject
# this rountine makes sure that no output line is longer than 79 characters
        		if (length (string) < 80)
                		print string
        		else {
               			while (length(string) > 79) {
                       			for (m = 79; m > 0; m--)
                                		if (substr(string,m,1) == " ")
                                        		break
                        		printf "%s\n",substr(string,0,m-1)
                        		string = substr(string,m,length(string)-(m-1))
                        		printf "%s", string
                		}
                		printf "\n"
        		}
# the new array becomes the array to be rotated
			for (k = 1; k <= count; k++)
				subject[k] = rotated[k]
		}
# clear out the array
	for (i = 1; i <= count; i++)
		subject[i] = ""
}

'