package Travel::Status::DE::HAFAS::Polyline; use strict; use warnings; use 5.014; # Adapted from code by Slaven Rezic # # Copyright (C) 2009,2010,2012,2017,2018 Slaven Rezic. All rights reserved. # This package is free software; you can redistribute it and/or # modify it under the same terms as Perl itself. # # Mail: slaven@rezic.de # WWW: http://www.rezic.de/eserte/ use parent 'Exporter'; our @EXPORT_OK = qw(decode_polyline); our $VERSION = '6.04'; # Translated this php script # # to perl sub decode_polyline { my ($encoded) = @_; my $length = length $encoded; my $index = 0; my @points; my $lat = 0; my $lng = 0; while ( $index < $length ) { # The encoded polyline consists of a latitude value followed # by a longitude value. They should always come in pairs. Read # the latitude value first. for my $val ( \$lat, \$lng ) { my $shift = 0; my $result = 0; # Temporary variable to hold each ASCII byte. my $b; do { # The `ord(substr($encoded, $index++))` statement returns # the ASCII code for the character at $index. Subtract 63 # to get the original value. (63 was added to ensure # proper ASCII characters are displayed in the encoded # polyline string, which is `human` readable) $b = ord( substr( $encoded, $index++, 1 ) ) - 63; # AND the bits of the byte with 0x1f to get the original # 5-bit `chunk. Then left shift the bits by the required # amount, which increases by 5 bits each time. OR the # value into $results, which sums up the individual 5-bit # chunks into the original value. Since the 5-bit chunks # were reversed in order during encoding, reading them in # this way ensures proper summation. $result |= ( $b & 0x1f ) << $shift; $shift += 5; } # Continue while the read byte is >= 0x20 since the last # `chunk` was not OR'd with 0x20 during the conversion # process. (Signals the end) while ( $b >= 0x20 ); # see last paragraph of "Integer Arithmetic" in perlop.pod use integer; # Check if negative, and convert. (All negative values have the last bit # set) my $dtmp = ( ( $result & 1 ) ? ~( $result >> 1 ) : ( $result >> 1 ) ); # Compute actual latitude (resp. longitude) since value is # offset from previous value. $$val += $dtmp; } # The actual latitude and longitude values were multiplied by # 1e5 before encoding so that they could be converted to a 32-bit # integer representation. (With a decimal accuracy of 5 places) # Convert back to original values. push( @points, { lat => $lat * 1e-5, lon => $lng * 1e-5 } ); } return @points; } 1;