[core] Add support for data-driven styling

1 files changed, 42 insertions, 0 deletions

diff --git a/include/mbgl/style/function/categorical_stops.hpp b/include/mbgl/style/function/categorical_stops.hpp
new file mode 100644
index 0000000000..11ec2a0e5a
--- /dev/null
+++ b/include/mbgl/style/function/categorical_stops.hpp
@@ -0,0 +1,42 @@
+#pragma once
+
+#include <mbgl/util/feature.hpp>
+#include <mbgl/util/variant.hpp>
+
+#include <cassert>
+#include <utility>
+#include <map>
+
+namespace mbgl {
+namespace style {
+
+class CategoricalValue : public variant<bool, int64_t, std::string> {
+public:
+    using variant<bool, int64_t, std::string>::variant;
+};
+
+template <class T>
+class CategoricalStops {
+public:
+    using Stops = std::map<CategoricalValue, T>;
+
+    Stops stops;
+    T defaultValue;
+
+    CategoricalStops() = default;
+    CategoricalStops(Stops stops_, T defaultValue_ = T())
+        : stops(std::move(stops_)),
+          defaultValue(std::move(defaultValue_)) {
+        assert(stops.size() > 0);
+    }
+
+    T evaluate(const Value&) const;
+
+    friend bool operator==(const CategoricalStops& lhs,
+                           const CategoricalStops& rhs) {
+        return lhs.stops == rhs.stops && lhs.defaultValue == rhs.defaultValue;
+    }
+};
+
+} // namespace style
+} // namespace mbgl