SymbolRegistry

In-memory bijective mapping between human-readable (exchange, symbol) pairs (e.g. "bybit", "BTCUSDT") and compact SymbolId integers used throughout the engine.

class SymbolRegistry {
public:
  SymbolId registerSymbol(const std::string& exchange,
                          const std::string& symbol);

  std::optional<SymbolId>
  getSymbolId(const std::string& exchange,
              const std::string& symbol) const;

  std::pair<std::string, std::string>
  getSymbolName(SymbolId id) const;
};

Purpose

• Provide fast look-ups from textual symbols → numeric IDs for hot-path data structures.
• Allow reverse resolution for logging, UI, or persistence layers.

Responsibilities

Method	Behaviour
registerSymbol	If the (exchange,symbol) pair is new, assigns a fresh SymbolId and stores the mapping; returns existing ID otherwise.
getSymbolId	Thread-safe lookup; returns std::nullopt if pair is unknown.
getSymbolName	Reverse lookup; throws/asserts if id out of range.

Internal Data

Field	Type	Note
_mutex	std::mutex	Guards both maps for write/read concurrency.
_map	unordered_map<std::string, SymbolId>	Key is "exchange:symbol" concatenated.
_reverse	std::vector<std::pair<std::string,std::string>>	Index = SymbolId; value is original pair.

Notes

• SymbolId is uint32_t (from common.h) — small enough for array indexing.
• Registry is typically filled at startup from EngineConfig; reads dominate afterwards.