using fake modules to prevent sphinx from actually importing

docs/conf.py

@@ -61,3 +61,9 @@
    author, 'dsdtools', 'One line description of project.',
    'Miscellaneous'),
 ]
+
+# Fake imports to avoid actually loading NumPy and libsndfile
+import fake_numpy
+sys.modules['numpy'] = sys.modules['fake_numpy']
+import fake_cffi
+sys.modules['cffi'] = sys.modules['fake_cffi']

docs/fake_cffi.py

@@ -0,0 +1,18 @@
+"""Mock module for Sphinx autodoc."""
+
+
+class FFI(object):
+
+    def cdef(self, _):
+        pass
+
+    def dlopen(self, _):
+        return self
+
+    def string(self, _):
+        return b'not implemented'
+
+    def sf_version_string(self):
+        return NotImplemented
+
+    SFC_GET_FORMAT_INFO = NotImplemented

docs/fake_numpy.py

@@ -0,0 +1,5 @@
+"""Mock module for Sphinx autodoc."""
+
+
+def dtype(_):
+    return NotImplemented