#!perl 

=head1 NAME

GMapPolylineUtil - helper-functions for putting paths on Google Maps

=head1 AUTHOR

David Lee Lambert 

=cut



package GMapPolylineUtil;

use POSIX;




sub _enc_one ($) {
    local ($x, $xx, $j, $i, $_);
    $x = $_[0];
    $xx = int(floor($x * 1e5));
    $xx <<= 1;
    $xx = ~$xx if $x < 0.0;
    for ($j=6; $j>=0; $j--) {
	last if ((($xx >> (5*$j))&0x1F));
    }
    $j=0 if $j==-1;
    for ($i=0 ; $i<=$j ; $i++) {
	$_ .= chr( 63 +
		   (($xx >> (5*$i))&0x1F) +
		   (($i==$j) ? 0x0 : 0x20) );
    }
    return $_;    
}

sub _enc_seq(@) {
    return join('',map { _enc_one($_) } @_);
}

sub encode(@) {
    return _enc_seq( map { $_<2 
			       ? $_[$_]
			       : $_[$_] - $_[$_-2] } 0..$#_ );
}

sub encode_arrrefs {
    return encode( map { @$_ } @_ );
}

sub encode_hashrefs {
    local $_ = '';
    return encode( map { ( $_->{'latitude'} || $_->{'lat'} || $_->{'y'},
			   $_->{'longitude'}|| $_->{'lon'} || $_->{'x'} ) }
		   @_ );
}


return 1;