1 files changed, 109 insertions, 0 deletions
diff --git a/include/mbgl/style/value_comparison.hpp b/include/mbgl/style/value_comparison.hpp
new file mode 100644
index 0000000000..41c1d44123
--- /dev/null
+++ b/include/mbgl/style/value_comparison.hpp
@@ -0,0 +1,109 @@
+#ifndef MBGL_STYLE_VALUE_COMPARISON
+#define MBGL_STYLE_VALUE_COMPARISON
+
+#include "value.hpp"
+#include <cstdlib>
+#include <cerrno>
+
+namespace mbgl {
+
+namespace util {
+
+namespace detail {
+
+template <typename Operator>
+struct relaxed_operator_visitor {
+    typedef bool result_type;
+
+    inline bool operator()(bool lhs, bool rhs) const { return Operator()(lhs, rhs); }
+
+    template <typename T, class = typename std::enable_if<std::is_arithmetic<T>::value>::type>
+    inline bool operator()(bool lhs, T rhs) const { return Operator()(T(lhs), rhs); }
+
+    template <typename T, class = typename std::enable_if<std::is_arithmetic<T>::value>::type>
+    inline bool operator()(T lhs, bool rhs) const { return Operator()(lhs, T(rhs)); }
+
+    inline bool operator()(int64_t lhs, uint64_t rhs) const {
+        return lhs < 0 ? false : Operator()(uint64_t(lhs), rhs);
+    }
+    inline bool operator()(uint64_t lhs, int64_t rhs) const {
+        return rhs < 0 ? false : Operator()(lhs, uint64_t(rhs));
+    }
+
+    template <typename T, class = typename std::enable_if<std::is_arithmetic<T>::value>::type>
+    inline bool operator()(const std::string &lhs, T rhs) const {
+        double value;
+        return parseNumericString(lhs, value) ? Operator()(value, double(rhs)) : false;
+    }
+
+    template <typename T, class = typename std::enable_if<std::is_arithmetic<T>::value>::type>
+    inline bool operator()(T lhs, const std::string &rhs) const {
+        double value;
+        return parseNumericString(rhs, value) ? Operator()(double(lhs), value) : false;
+    }
+
+    template <typename T0, typename T1>
+    inline bool operator()(T0 lhs, T1 rhs) const { return Operator()(lhs, rhs); }
+};
+
+struct relaxed_equal_operator {
+    template <typename T0, typename T1>
+    inline bool operator()(T0 lhs, T1 rhs) const { return lhs == rhs; }
+};
+
+struct relaxed_not_equal_operator {
+    template <typename T0, typename T1>
+    inline bool operator()(T0 lhs, T1 rhs) const { return lhs != rhs; }
+};
+
+struct relaxed_greater_operator {
+    template <typename T0, typename T1>
+    inline bool operator()(T0 lhs, T1 rhs) const { return lhs > rhs; }
+};
+
+struct relaxed_greater_equal_operator {
+    template <typename T0, typename T1>
+    inline bool operator()(T0 lhs, T1 rhs) const { return lhs >= rhs; }
+};
+
+struct relaxed_less_operator {
+    template <typename T0, typename T1>
+    inline bool operator()(T0 lhs, T1 rhs) const { return lhs < rhs; }
+};
+
+struct relaxed_less_equal_operator {
+    template <typename T0, typename T1>
+    inline bool operator()(T0 lhs, T1 rhs) const { return lhs <= rhs; }
+};
+
+} // end namespace detail
+
+inline bool relaxed_equal(Value const &lhs, Value const &rhs) {
+    return apply_visitor(detail::relaxed_operator_visitor<detail::relaxed_equal_operator>(), lhs, rhs);
+}
+
+inline bool relaxed_not_equal(Value const &lhs, Value const &rhs) {
+    return apply_visitor(detail::relaxed_operator_visitor<detail::relaxed_not_equal_operator>(), lhs, rhs);
+}
+
+inline bool relaxed_greater(Value const &lhs, Value const &rhs) {
+    return apply_visitor(detail::relaxed_operator_visitor<detail::relaxed_greater_operator>(), lhs, rhs);
+}
+
+inline bool relaxed_greater_equal(Value const &lhs, Value const &rhs) {
+    return apply_visitor(detail::relaxed_operator_visitor<detail::relaxed_greater_equal_operator>(), lhs, rhs);
+}
+
+inline bool relaxed_less(Value const &lhs, Value const &rhs) {
+    return apply_visitor(detail::relaxed_operator_visitor<detail::relaxed_less_operator>(), lhs, rhs);
+}
+
+inline bool relaxed_less_equal(Value const &lhs, Value const &rhs) {
+    return apply_visitor(detail::relaxed_operator_visitor<detail::relaxed_less_equal_operator>(), lhs, rhs);
+}
+
+}
+
+}
+
+#endif