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third/spdlog/stopwatch.h

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+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <chrono>
+#include <spdlog/fmt/fmt.h>
+
+// Stopwatch support for spdlog  (using std::chrono::steady_clock).
+// Displays elapsed seconds since construction as double.
+//
+// Usage:
+//
+// spdlog::stopwatch sw;
+// ...
+// spdlog::debug("Elapsed: {} seconds", sw);    =>  "Elapsed 0.005116733 seconds"
+// spdlog::info("Elapsed: {:.6} seconds", sw);  =>  "Elapsed 0.005163 seconds"
+//
+//
+// If other units are needed (e.g. millis instead of double), include "fmt/chrono.h" and use
+// "duration_cast<..>(sw.elapsed())":
+//
+// #include <spdlog/fmt/chrono.h>
+//..
+// using std::chrono::duration_cast;
+// using std::chrono::milliseconds;
+// spdlog::info("Elapsed {}", duration_cast<milliseconds>(sw.elapsed())); => "Elapsed 5ms"
+
+namespace spdlog {
+class stopwatch {
+    using clock = std::chrono::steady_clock;
+    std::chrono::time_point<clock> start_tp_;
+
+public:
+    stopwatch()
+        : start_tp_{clock::now()} {}
+
+    std::chrono::duration<double> elapsed() const {
+        return std::chrono::duration<double>(clock::now() - start_tp_);
+    }
+
+    std::chrono::milliseconds elapsed_ms() const {
+        return std::chrono::duration_cast<std::chrono::milliseconds>(clock::now() - start_tp_);
+    }
+
+    void reset() { start_tp_ = clock::now(); }
+};
+}  // namespace spdlog
+
+// Support for fmt formatting  (e.g. "{:012.9}" or just "{}")
+namespace
+#ifdef SPDLOG_USE_STD_FORMAT
+    std
+#else
+    fmt
+#endif
+{
+
+template <>
+struct formatter<spdlog::stopwatch> : formatter<double> {
+    template <typename FormatContext>
+    auto format(const spdlog::stopwatch &sw, FormatContext &ctx) const -> decltype(ctx.out()) {
+        return formatter<double>::format(sw.elapsed().count(), ctx);
+    }
+};
+}  // namespace std