Support per-feature minzoom and maxzoom in geobuf

mvt.cpp

@@ -11,6 +11,7 @@
 #include "protozero/varint.hpp"
 #include "protozero/pbf_reader.hpp"
 #include "protozero/pbf_writer.hpp"
+#include "milo/dtoa_milo.h"
 
 mvt_geometry::mvt_geometry(int nop, long long nx, long long ny) {
 	this->op = nop;
@@ -394,6 +395,57 @@ bool mvt_value::operator<(const mvt_value &o) const {
 	return false;
 }
 
+static std::string quote(std::string const &s) {
+	std::string buf;
+
+	for (size_t i = 0; i < s.size(); i++) {
+		unsigned char ch = s[i];
+
+		if (ch == '\\' || ch == '\"') {
+			buf.push_back('\\');
+			buf.push_back(ch);
+		} else if (ch < ' ') {
+			char tmp[7];
+			sprintf(tmp, "\\u%04x", ch);
+			buf.append(std::string(tmp));
+		} else {
+			buf.push_back(ch);
+		}
+	}
+
+	return buf;
+}
+
+std::string mvt_value::toString() {
+	if (type == mvt_string) {
+		return quote(string_value);
+	} else if (type == mvt_int) {
+		return std::to_string((long long) numeric_value.int_value);
+	} else if (type == mvt_double) {
+		double v = numeric_value.double_value;
+		if (v == (long long) v) {
+			return std::to_string((long long) v);
+		} else {
+			return milo::dtoa_milo(v);
+		}
+	} else if (type == mvt_float) {
+		double v = numeric_value.float_value;
+		if (v == (long long) v) {
+			return std::to_string((long long) v);
+		} else {
+			return milo::dtoa_milo(v);
+		}
+	} else if (type == mvt_sint) {
+		return std::to_string((long long) numeric_value.sint_value);
+	} else if (type == mvt_uint) {
+		return std::to_string((long long) numeric_value.uint_value);
+	} else if (type == mvt_bool) {
+		return numeric_value.bool_value ? "true" : "false";
+	} else {
+		return "unknown";
+	}
+}
+
 void mvt_layer::tag(mvt_feature &feature, std::string key, mvt_value value) {
 	size_t ko, vo;