make encoding detection code a bit faster if the first two source file lines...

make encoding detection code a bit faster if the first two source file lines are longer than 250 bytes

Cython/Utils.py

@@ -189,6 +189,7 @@ def decode_filename(filename):
 
 _match_file_encoding = re.compile(u"coding[:=]\s*([-\w.]+)").search
 
+
 def detect_file_encoding(source_filename):
     f = open_source_file(source_filename, encoding="UTF-8", error_handling='ignore')
     try:
@@ -196,18 +197,22 @@ def detect_file_encoding(source_filename):
     finally:
         f.close()
 
+
 def detect_opened_file_encoding(f):
     # PEPs 263 and 3120
     # Most of the time the first two lines fall in the first 250 chars,
     # and this bulk read/split is much faster.
-    lines = f.read(250).split("\n")
-    if len(lines) > 2:
-        m = _match_file_encoding(lines[0]) or _match_file_encoding(lines[1])
+    lines = f.read(250).split(u"\n")
+    if len(lines) > 1:
+        m = _match_file_encoding(lines[0])
+        if m:
+            return m.group(1)
+        elif len(lines) > 2:
+            m = _match_file_encoding(lines[1])
             if m:
                 return m.group(1)
             else:
                 return "UTF-8"
-    else:
     # Fallback to one-char-at-a-time detection.
     f.seek(0)
     chars = []