write attributions.txt crediting OSM contributors, mention OSM copyri…

…ght in README, closes #53

README.md

@@ -109,3 +109,7 @@ The following flags may be useful for debugging:
 # Configuration
 
 A default configuration file `pfaedle.cfg` can be found in this repo and will be installed with `make install`. Custom configuration files can be specified with the `-c` flag. If no `-c` flag is set, `pfaedle` will parse and merge the following cfg files in the given order (if present): `<install prefix>/etc/pfaedle/pfaedle.cfg`, `$HOME/.config/pfaedle/pfaedle.cfg`, `<CWD>/pfaedle.cfg`. Values given in later files will overwrite earlier defined values.
+
+# Attribution
+
+Note that the `shapes.txt` produced by `pfaedle` is based on OpenStreetMap data, which is licensed under OdBL 1.0 (see [here](https://osm.org/copyright)). If you copy, distribute, transmit and adapt the shapefied GTFS feed, please credit the contributors of OpenStreetMap.

src/pfaedle/gtfs/Writer.cpp

@@ -345,6 +345,22 @@ void Writer::write(gtfs::Feed* sourceFeed, const std::string& path) const {
           cannotWrite(curFileTg);
       }
     }
+
+    curFile = getTmpFName(gtfsPath, ".pfaedle-tmp", "attributions.txt");
+    curFileTg = gtfsPath + "/attributions.txt";
+    fs.open(curFile.c_str());
+    if (!fs.good()) cannotWrite(curFile, curFileTg);
+    writeAttribution(sourceFeed, &fs);
+    fs.close();
+
+    if (toZip) {
+#ifdef LIBZIP_FOUND
+      moveIntoZip(za, curFile, "attributions.txt");
+#endif
+    } else {
+      if (std::rename(curFile.c_str(), curFileTg.c_str()))
+        cannotWrite(curFileTg);
+    }
   } catch (...) {
 #ifdef LIBZIP_FOUND
     zip_discard(za);
@@ -363,6 +379,18 @@ void Writer::write(gtfs::Feed* sourceFeed, const std::string& path) const {
   }
 }
 
+// ____________________________________________________________________________
+void Writer::writeAttribution(gtfs::Feed*, std::ostream* os) const {
+  auto csvw = ad::cppgtfs::Writer::getAttributionCsvw(os);
+
+  csvw->flushLine();
+  csvw->writeString("OpenStreetMap contributors");
+  csvw->writeString("https://www.openstreetmap.org/copyright");
+  csvw->writeInt(1);
+
+  csvw->flushLine();
+}
+
 // ____________________________________________________________________________
 void Writer::writeFeedInfo(gtfs::Feed* f, std::ostream* os) const {
   auto csvw = ad::cppgtfs::Writer::getFeedInfoCsvw(os);

src/pfaedle/gtfs/Writer.h

@@ -40,6 +40,7 @@ class Writer {
   void writeStopTimes(Feed* f, std::ostream* os) const;
   void writeLevels(Feed* f, std::ostream* os) const;
   void writePathways(Feed* f, std::ostream* os) const;
+  void writeAttribution(Feed* f, std::ostream* os) const;
 
   static void cannotWrite(const std::string& file, const std::string& file2);
   static void cannotWrite(const std::string& file);