Support feature IDs for decoding

decode.cpp

@@ -102,6 +102,11 @@ void handle(std::string message, int z, unsigned x, unsigned y, int describe) {
 			within = 1;
 
 			printf("{ \"type\": \"Feature\"");
+
+			if (feat.has_id) {
+				printf(", \"id\": %llu", feat.id);
+			}
+
 			printf(", \"properties\": { ");
 
 			for (size_t t = 0; t + 1 < feat.tags.size(); t += 2) {

mvt.cpp

@@ -178,6 +178,11 @@ bool mvt_tile::decode(std::string &message) {
 
 					while (feature_reader.next()) {
 						switch (feature_reader.tag()) {
+						case 1: /* id */
+							feature.id = feature_reader.get_uint64();
+							feature.has_id = true;
+							break;
+
 						case 2: /* tag */
 						{
 							auto pi = feature_reader.get_packed_uint32();

mvt.hpp

@@ -25,6 +25,13 @@ struct mvt_feature {
 	std::vector<unsigned> tags;
 	std::vector<mvt_geometry> geometry;
 	int /* mvt_geometry_type */ type;
+	unsigned long long id;
+	bool has_id;
+
+	mvt_feature() {
+		has_id = false;
+		id = 0;
+	}
 };
 
 enum mvt_value_type {