Move everything into a separate futatabi/ subdir, for the upcoming merge with Nageru.

[nageru] / futatabi / frame_on_disk.h

diff --git a/futatabi/frame_on_disk.h b/futatabi/frame_on_disk.h
new file mode 100644 (file)
index 0000000..1843857
--- /dev/null
+++ b/futatabi/frame_on_disk.h
@@ -0,0 +1,37 @@
+#ifndef _FRAME_ON_DISK_H
+#define _FRAME_ON_DISK_H 1
+
+#include <mutex>
+#include <string>
+#include <vector>
+
+#include <stdint.h>
+
+#include "defs.h"
+
+extern std::mutex frame_mu;
+struct FrameOnDisk {
+        int64_t pts = -1;  // -1 means empty.
+        off_t offset;
+        unsigned filename_idx;
+        uint32_t size;  // Not using size_t saves a few bytes; we can have so many frames.
+};
+extern std::vector<FrameOnDisk> frames[MAX_STREAMS];  // Under frame_mu.
+extern std::vector<std::string> frame_filenames;  // Under frame_mu.
+
+// A helper class to read frames from disk. It caches the file descriptor
+// so that the kernel has a better chance of doing readahead when it sees
+// the sequential reads. (For this reason, each display has a private
+// FrameReader. Thus, we can easily keep multiple open file descriptors around
+// for a single .frames file.)
+class FrameReader {
+public:
+       ~FrameReader();
+       std::string read_frame(FrameOnDisk frame);
+
+private:
+       int fd = -1;
+       int last_filename_idx = -1;
+};
+
+#endif  // !defined(_FRAME_ON_DISK_H)