From 0a339b6680d807d3dab854bd9f5484e7f2ccda87 Mon Sep 17 00:00:00 2001
From: Eric Fischer <enf@pobox.com>
Date: Mon, 17 Sep 2018 16:57:08 -0700
Subject: [PATCH] Read and write spline knots, but don't try to interpret them
 yet

---
 mvt.cpp | 10 ++++++++++
 mvt.hpp |  4 +++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/mvt.cpp b/mvt.cpp
index 0b7a73a..473ac0d 100644
--- a/mvt.cpp
+++ b/mvt.cpp
@@ -399,6 +399,15 @@ bool mvt_tile::decode(std::string &message, bool &was_compressed) {
 							break;
 						}
 
+						case 11: /* knots */
+						{
+							auto pi = feature_reader.get_packed_double();
+							for (auto it = pi.first; it != pi.second; ++it) {
+								feature.knots.push_back(*it);
+							}
+							break;
+						}
+
 						default:
 							feature_reader.skip();
 							break;
@@ -707,6 +716,7 @@ std::string mvt_tile::encode() {
 
 			feature_writer.add_packed_uint32(4, std::begin(geometry), std::end(geometry));
 			feature_writer.add_packed_uint64(6, std::begin(elevations), std::end(elevations));
+			feature_writer.add_packed_double(11, std::begin(layers[i].features[f].knots), std::end(layers[i].features[f].knots));
 
 			if (has_attributes > 0) {
 				std::vector<unsigned long> attributes;
diff --git a/mvt.hpp b/mvt.hpp
index d947b17..0567fd3 100644
--- a/mvt.hpp
+++ b/mvt.hpp
@@ -53,13 +53,15 @@ struct mvt_geometry {
 enum mvt_geometry_type {
 	mvt_point = 1,
 	mvt_linestring = 2,
-	mvt_polygon = 3
+	mvt_polygon = 3,
+	mvt_curve = 4,
 };
 
 struct mvt_feature {
 	std::vector<unsigned> tags{};
 	std::vector<unsigned long> properties{};
 	std::vector<mvt_geometry> geometry{};
+	std::vector<double> knots{};
 	int /* mvt_geometry_type */ type = 0;
 	unsigned long long id = 0;
 	bool has_id = false;