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authorDaniel Friesel <derf@finalrewind.org>2022-10-10 21:50:09 +0200
committerDaniel Friesel <derf@finalrewind.org>2022-10-10 21:50:09 +0200
commit239820ffbaf2eab648bd278508db02440e2ff1f4 (patch)
tree304b1835908d9571f7aadcb5ffd3515f508ef0f1 /lib/Travel/Status/DE/HAFAS/Polyline.pm
parent2a4e84102440154d0320778bad870046b226d703 (diff)
HAFAS->new: support 'journey' requests. polylines and route still WiP
Diffstat (limited to 'lib/Travel/Status/DE/HAFAS/Polyline.pm')
-rw-r--r--lib/Travel/Status/DE/HAFAS/Polyline.pm96
1 files changed, 96 insertions, 0 deletions
diff --git a/lib/Travel/Status/DE/HAFAS/Polyline.pm b/lib/Travel/Status/DE/HAFAS/Polyline.pm
new file mode 100644
index 0000000..2d82912
--- /dev/null
+++ b/lib/Travel/Status/DE/HAFAS/Polyline.pm
@@ -0,0 +1,96 @@
+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 $VERSION = '0.06';
+
+# Translated this php script
+# <http://unitstep.net/blog/2008/08/02/decoding-google-maps-encoded-polylines-using-php/>
+# to perl
+sub decode_polyline {
+ my ($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;