remove use of std::to_string in favor of boost::lexical_cast

std::to_string calls sprintf() internally, which is really slow

1 files changed, 18 insertions, 0 deletions

diff --git a/include/mbgl/util/string.hpp b/include/mbgl/util/string.hpp
index f17d55cec3..690a67d471 100644
--- a/include/mbgl/util/string.hpp
+++ b/include/mbgl/util/string.hpp
@@ -3,9 +3,27 @@
 
 #include <string>
 
+#pragma GCC diagnostic push
+#ifndef __clang__
+#pragma GCC diagnostic ignored "-Wunused-local-typedefs"
+#endif
+#include <boost/lexical_cast.hpp>
+#pragma GCC diagnostic pop
+
 namespace mbgl {
 namespace util {
 
+template <typename... Args>
+inline std::string toString(Args&&... args) {
+    return boost::lexical_cast<std::string>(::std::forward<Args>(args)...);
+}
+
+// boost::lexical_cast() treats this as a character, but we are using it as number types.
+inline std::string toString(int8_t num) {
+    return boost::lexical_cast<std::string>(int(num));
+}
+
+
 template<size_t max, typename... Args>
 inline std::string sprintf(const char *msg, Args... args) {
     char res[max];