1 files changed, 50 insertions, 0 deletions
diff --git a/src/mbgl/util/token.hpp b/src/mbgl/util/token.hpp
new file mode 100644
index 0000000000..64192a99f9
--- /dev/null
+++ b/src/mbgl/util/token.hpp
@@ -0,0 +1,50 @@
+#ifndef MBGL_UTIL_TOKEN
+#define MBGL_UTIL_TOKEN
+
+#include <map>
+#include <string>
+#include <algorithm>
+
+namespace mbgl {
+namespace util {
+
+// Replaces {tokens} in a string by calling the lookup function.
+template <typename Lookup>
+std::string replaceTokens(const std::string &source, const Lookup &lookup) {
+    std::string result;
+    result.reserve(source.size());
+
+    auto pos = source.begin();
+    const auto end = source.end();
+
+    while (pos != end) {
+        auto brace = std::find(pos, end, '{');
+        result.append(pos, brace);
+        pos = brace;
+        if (pos != end) {
+            for (brace++; brace != end && (std::isalnum(*brace) || *brace == '_'); brace++);
+            if (brace != end && *brace == '}') {
+                result.append(lookup({ pos + 1, brace }));
+                pos = brace + 1;
+            } else {
+                result.append(pos, brace);
+                pos = brace;
+            }
+        }
+    }
+
+    return result;
+}
+
+template <typename T>
+inline std::string replaceTokens(const std::string &source, const std::map<std::string, T> &properties) {
+    return replaceTokens(source, [&properties](const std::string &token) -> std::string {
+        const auto it_prop = properties.find(token);
+        return it_prop != properties.end() ? toString(it_prop->second) : "";
+    });
+}
+
+} // end namespace util
+} // end namespace mbgl
+
+#endif