#!/usr/bin/perl
#
# Written by Marc Liyanage (http://www.entropy.ch)
#

print utf82iso(join("", <>));

sub utf82iso {

        my ($string) = @_;
        my %cache = ();

		# Match 2-byte sequences with the first byte having
		# the high bits set to 110xxxxx (0xc0 - 0xdf) and the second byte having
		# the high bits set to 10xxxxxx (0x80 - 0xbf). Send these sequences to the
		# decode function and replace them with the result of the function.
		#
        $string =~ s/([\xc0-\xdf][\x80-\xbf])/$cache{$1} ||= decode_2byte_utf8($1)/eg;
        return $string;

}

sub decode_2byte_utf8 {

	# Split the incoming 2-character string into two separate
	# strings each containing only one character
	#
	my ($a, $b) = split(//, $_[0]);

	# Get the integer values of the two characters using the ord() function.
	# Then mask their UTF-8 high bit patterns (3 bits / 0x1f for the first byte,
	# 2 bits / 0x3f for the second) to get the 11-bit character number which
	# is now still spread over two bytes.
	# Shift the first byte to the left by 6 positions
	# and OR the two bytes together. Then take the rightmost
	# 8 bits (& 0xff), interpret them as character with the chr() 
	# function and return that.
	#
	return chr((((ord($a) & 0x1f) << 6) | (ord($b) & 0x3f) & 0xff));

}