Feature/iouring unchunked

cpp/mcap/include/mcap/writer.hpp

@@ -7,6 +7,11 @@
 #include <string>
 #include <unordered_set>
 #include <vector>
+#include <liburing.h>
+#include <mutex>
+#include <condition_variable>
+#include <thread>
+#include <atomic>
 
 // Forward declaration
 #ifndef MCAP_COMPRESSION_NO_ZSTD
@@ -104,6 +109,8 @@ struct MCAP_PUBLIC McapWriterOptions {
   bool noStatistics = false;
   bool noSummaryOffsets = false;
 
+  bool noIoUring = false;
+
   McapWriterOptions(const std::string_view profile)
       : profile(profile) {}
 };
@@ -167,16 +174,45 @@ class MCAP_PUBLIC FileWriter final : public IWritable {
 public:
   ~FileWriter() override;
 
-  Status open(std::string_view filename);
+  Status openStd(std::string_view filename);
+  Status openUring(std::string_view filename);
 
   void handleWrite(const std::byte* data, uint64_t size) override;
   void end() override;
   void flush() override;
   uint64_t size() const override;
 
 private:
+  bool isUring_ = false;
   std::FILE* file_ = nullptr;
   uint64_t size_ = 0;
+
+  int fd_=-1;
+  struct io_uring ring_;
+  bool ringInited_ = false;
+  void* buf_ = nullptr;
+  void* bufpong_ = nullptr;
+  uint64_t writeOffset_ = 0;
+  static constexpr int QUEUE_DEPTH = 128;
+  static constexpr size_t BUFFER_SIZE = 140 * 1024 * 1024;
+  static constexpr size_t IORING_BUFF_SIZE = 100 * 1024 * 1024;
+  static constexpr size_t ALIGNMENT = 512;
+  std::mutex mtx;
+  std::condition_variable cv;
+  bool ready= false;
+  std::atomic<bool> running{true};
+  int final_footer_count= 0;
+  bool final_footer= false;
+  bool ping_buffer_used = true;
+  std::thread workerThread_;
+  uint64_t aligned_blocks= 0;
+  void uringClose();
+  void handleWriteStd(const std::byte* data, uint64_t size);
+  void handleWriteUring(const std::byte* data, uint64_t size);
+  void worker_thread();
+  void* getActiveBuffer();
+  void switchBuffer();
+  void* getInactiveBuffer();
 };
 
 /**