Closes

core/value_descriptions.h

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: MIT
+#ifndef VALUE_DESCRIPTIONS_H
+#define VALUE_DESCRIPTIONS_H
+
+#include <cstdint>
+#include <map>
+#include <string>
+#include <variant>
+
+using RawSignalValue = std::variant<std::int64_t, std::uint64_t>;
+
+/** Canonical keys: negative int64_t, nonnegative uint64_t. */
+inline RawSignalValue NormalizeValueKey(const RawSignalValue &value) {
+    if (const auto *number = std::get_if<std::int64_t>(&value)) {
+        if (*number >= 0)
+            return static_cast<std::uint64_t>(*number);
+    }
+    return value;
+}
+
+using ValueDescriptions = std::map<RawSignalValue, std::string>;
+
+/** Returns a borrowed string, or nullptr; never converts integers to double. */
+inline const std::string *FindValueDescription(const ValueDescriptions &descriptions,
+                                               const RawSignalValue &rawValue) {
+    const auto found = descriptions.find(NormalizeValueKey(rawValue));
+    return found == descriptions.end() ? nullptr : &found->second;
+}
+
+#endif