chore: update README.rst

README.rst

@@ -58,9 +58,12 @@ Features
   whitespace. Such trailing whitespace is visually indistinguishable
   and some editors (or more recently, reindent.py) will trim them.
 
-See the the full documentation at `read-the-docs`_.
+See the the full documentation at `read-the-docs`_, especially the
+`requirements`_ section for a more detailed discussion of PEP 257 and other
+requirements.
 
 .. _read-the-docs: https://docformatter.readthedocs.io
+.. _requirements: https://docformatter.readthedocs.io/en/latest/requirements.html
 
 Installation
 ============

docformatter.py

@@ -410,7 +410,7 @@ def do_format_standard_in(self, parser: argparse.ArgumentParser):
         encoding = None
         source = self.stdin.read()
         if not isinstance(source, unicode):
-            encoding = self.stdin.encoding or _get_encoding()
+            encoding = self.stdin.encoding or self.encodor.system_encoding
             source = source.decode(encoding)
 
         formatted_source = self._do_format_code(source)
@@ -728,6 +728,9 @@ class Encodor:
     def __init__(self):
         """Initialize an Encodor instance."""
         self.encoding = "latin-1"
+        self.system_encoding = (
+            locale.getpreferredencoding() or sys.getdefaultencoding()
+        )
 
     def do_detect_encoding(self, filename: str) -> None:
         """Return the detected file encoding.
@@ -1153,11 +1156,6 @@ def _main(argv, standard_out, standard_error, standard_in):
         return formator.do_format_files()
 
 
-def _get_encoding():
-    """Return preferred encoding."""
-    return locale.getpreferredencoding() or sys.getdefaultencoding()
-
-
 def find_py_files(sources, recursive, exclude=None):
     """Find Python source files.