Adding support for polyline compression. Reduces file size, see http://open.mapquestapi.com/common/encodedecode.html

2011-06-27 22:08:53 +00:00
parent 676333ab5a
commit e3b648ea72
4 changed files with 97 additions and 24 deletions
@@ -0,0 +1,78 @@
+/*
+    open source routing machine
+    Copyright (C) Dennis Luxen, others 2010
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU AFFERO General Public License as published by
+the Free Software Foundation; either version 3 of the License, or
+any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+or see http://www.gnu.org/licenses/agpl.txt.
+ */
+
+#ifndef POLYLINECOMPRESSOR_H_
+#define POLYLINECOMPRESSOR_H_
+
+#include "ExtractorStructs.h"
+
+class PolylineCompressor {
+private:
+	inline string encodeSignedNumber(int number) const {
+	    int signedNumber = number << 1;
+	    if (number < 0) {
+	        signedNumber = ~(signedNumber);
+	    }
+	    return (encodeNumber(signedNumber));
+	}
+
+	inline string encodeNumber(int numberToEncode) const {
+	    ostringstream encodeString;
+
+	    while (numberToEncode >= 0x20) {
+	        int nextValue = (0x20 | (numberToEncode & 0x1f)) + 63;
+	        encodeString << (static_cast<char> (nextValue));
+	        numberToEncode >>= 5;
+	    }
+
+	    numberToEncode += 63;
+	    encodeString << (static_cast<char> (numberToEncode));
+
+	    return encodeString.str();
+	}
+public:
+	inline void printEncodedString(vector<_Coordinate>& polyline, string &output) {
+		output += encodeSignedNumber(polyline[0].lat);
+		output += encodeSignedNumber(polyline[0].lon);
+		for(unsigned i = 1; i < polyline.size(); i++) {
+			output += encodeSignedNumber(polyline[i].lat - polyline[i-1].lat);
+			output += encodeSignedNumber(polyline[i].lon - polyline[i-1].lon);
+		}
+	}
+
+	inline void printUnencodedString(vector<_Coordinate> & polyline, string & output) {
+		string tmp;
+		for(unsigned i = 0; i < polyline.size(); i++) {
+			convertLatLon(polyline[i].lat, tmp);
+			output += "[";
+			output += tmp;
+			convertLatLon(polyline[i].lon, tmp);
+			output += ", ";
+			output += tmp;
+			output += "]";
+			if( i < polyline.size()-1 ) {
+				output += ",";
+			}
+		}
+
+	}
+};
+
+#endif /* POLYLINECOMPRESSOR_H_ */