.

wcfs/internal/.gitignore

+/io.c
 /mm.c
 /wcfs_test.c

wcfs/internal/io.pyx

+# Copyright (C) 2019  Nexedi SA and Contributors.
+#                     Kirill Smelkov <kirr@nexedi.com>
+#
+# This program is free software: you can Use, Study, Modify and Redistribute
+# it under the terms of the GNU General Public License version 3, or (at your
+# option) any later version, as published by the Free Software Foundation.
+#
+# You can also Link and Combine this program with other software covered by
+# the terms of any of the Free Software licenses or any of the Open Source
+# Initiative approved licenses and Convey the resulting work. Corresponding
+# source of such a combination shall include the source code for all other
+# software used.
+#
+# This program is distributed WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#
+# See COPYING file for full licensing terms.
+# See https://www.nexedi.com/licensing for rationale and options.
+
+# cython: language_level=2
+
+"""Package io complements IO facility provided by Python."""
+
+from posix.unistd cimport pread
+from cpython.exc cimport PyErr_SetFromErrno
+
+# readat calls pread to read from fd@off into buf.
+def readat(int fd, size_t off, unsigned char[::1] buf not None):    # -> n
+    cdef void   *dest = &buf[0]
+    cdef size_t  size = buf.shape[0]
+    cdef ssize_t n
+
+    with nogil:
+        n = pread(fd, dest, size, off)
+
+    if n < 0:
+        PyErr_SetFromErrno(OSError)
+
+    return n

wcfs/internal/mm.pyx

@@ -19,7 +19,7 @@
 
 # cython: language_level=2
 
-"""Module mm provides access to OS memory management interfaces like mlock and mincore."""
+"""Package mm provides access to OS memory management interfaces like mlock and mincore."""
 
 from posix cimport mman
 from cpython.exc cimport PyErr_SetFromErrno