1 files changed, 59 insertions, 0 deletions
diff --git a/ouroboros/_timespec.py b/ouroboros/_timespec.py
new file mode 100644
index 0000000..1656eb2
--- /dev/null
+++ b/ouroboros/_timespec.py
@@ -0,0 +1,59 @@
+#
+# SPDX-FileCopyrightText: 2016 - 2026 Dimitri Staessens
+# SPDX-License-Identifier: LGPL-2.1-only
+#
+
+"""
+Shared float-seconds <-> ``struct timespec *`` conversions.
+
+The caller passes its own ``ffi`` instance so the returned CData is
+bound to the right CFFI extension module.
+"""
+
+from __future__ import annotations
+
+from math import modf
+from typing import TYPE_CHECKING, Any, Optional
+
+if TYPE_CHECKING:
+    from cffi import FFI
+
+BILLION = 1000 * 1000 * 1000
+
+
+def fl_to_timespec(ffi: FFI, timeo: Optional[float]) -> Any:
+    """
+    Convert *timeo* (seconds, or None) to a ``struct timespec *``.
+
+    *None* yields ``ffi.NULL`` (block forever). A non-positive *timeo*
+    yields a zeroed timespec (async / poll).
+    """
+
+    if timeo is None:
+        return ffi.NULL
+
+    if timeo <= 0:
+        return ffi.new("struct timespec *", [0, 0])
+
+    frac, whole = modf(timeo)
+    _timeo = ffi.new("struct timespec *")
+    _timeo.tv_sec = int(whole)
+    _timeo.tv_nsec = int(frac * BILLION)
+
+    return _timeo
+
+
+def timespec_to_fl(ffi: FFI, _timeo: Any) -> Optional[float]:
+    """
+    Convert a ``struct timespec *`` to seconds-as-float.
+
+    ``ffi.NULL`` yields *None* (block forever).
+    """
+
+    if _timeo == ffi.NULL:
+        return None
+
+    if _timeo.tv_sec <= 0 and _timeo.tv_nsec == 0:
+        return 0.0
+
+    return _timeo.tv_sec + _timeo.tv_nsec / BILLION