Avoid an int->string->int conversion

clip.cpp

@@ -904,7 +904,7 @@ std::string overzoom(mvt_tile tile, int oz, int ox, int oy, int nz, int nx, int
 
 					if (layer.keys[feature.tags[i]] == "tippecanoe:retain_points_multiplier_sequence") {
 						mvt_value v = layer.values[feature.tags[i + 1]];
-						feature.seq = atoll(mvt_value_to_serial_val(v).s.c_str());
+						feature.seq = mvt_value_to_long_long(v);
 						feature.tags.erase(feature.tags.begin() + i, feature.tags.begin() + i + 2);
 					}
 				}

mvt.cpp

@@ -800,3 +800,28 @@ serial_val mvt_value_to_serial_val(mvt_value const &v) {
 
 	return sv;
 }
+
+// This extracts an integer value from an mvt_value
+long long mvt_value_to_long_long(mvt_value const &v) {
+	switch (v.type) {
+	case mvt_string:
+		return atoll(v.string_value.c_str());
+	case mvt_float:
+		return v.numeric_value.float_value;
+	case mvt_double:
+		return v.numeric_value.double_value;
+	case mvt_int:
+		return v.numeric_value.int_value;
+	case mvt_uint:
+		return v.numeric_value.uint_value;
+	case mvt_sint:
+		return v.numeric_value.sint_value;
+	case mvt_bool:
+		return v.numeric_value.bool_value;
+	case mvt_null:
+		return 0;
+	default:
+		fprintf(stderr, "unhandled mvt_type %d\n", v.type);
+		exit(EXIT_IMPOSSIBLE);
+	}
+}

mvt.hpp

@@ -162,6 +162,7 @@ int compress(std::string const &input, std::string &output, bool gz);
 int dezig(unsigned n);
 
 mvt_value stringified_to_mvt_value(int type, const char *s);
+long long mvt_value_to_long_long(mvt_value const &v);
 
 bool is_integer(const char *s, long long *v);
 bool is_unsigned_integer(const char *s, unsigned long long *v);