BUG: Fix the error when reading the compressed UTF-16 file

Author: Licht-T

pandas/_libs/parsers.pyx

@@ -374,6 +374,17 @@ cdef class TextReader:
                   float_precision=None,
                   skip_blank_lines=True):
 
+        # encoding
+        if encoding is not None:
+            if not isinstance(encoding, bytes):
+                encoding = encoding.encode('utf-8')
+            encoding = encoding.lower()
+            self.c_encoding = <char*> encoding
+        else:
+            self.c_encoding = NULL
+
+        self.encoding = encoding
+
         self.parser = parser_new()
         self.parser.chunksize = tokenize_chunksize
 
@@ -495,17 +506,6 @@ cdef class TextReader:
             self.parser.double_converter_nogil = NULL
             self.parser.double_converter_withgil = round_trip
 
-        # encoding
-        if encoding is not None:
-            if not isinstance(encoding, bytes):
-                encoding = encoding.encode('utf-8')
-            encoding = encoding.lower()
-            self.c_encoding = <char*> encoding
-        else:
-            self.c_encoding = NULL
-
-        self.encoding = encoding
-
         if isinstance(dtype, dict):
             dtype = {k: pandas_dtype(dtype[k])
                      for k in dtype}
@@ -684,6 +684,12 @@ cdef class TextReader:
             else:
                 raise ValueError('Unrecognized compression type: %s' %
                                  self.compression)
+
+            if b'utf-16' in (self.encoding or b''):
+                source = com.UTF8Recoder(source, self.encoding.decode('utf-8'))
+                self.encoding = b'utf-8'
+                self.c_encoding = <char*> self.encoding
+
             self.handle = source
 
         if isinstance(source, basestring):

pandas/io/parsers.py

@@ -1671,7 +1671,8 @@ def __init__(self, src, **kwds):
 
         ParserBase.__init__(self, kwds)
 
-        if 'utf-16' in (kwds.get('encoding') or ''):
+        if kwds.get('compression') is None \
+           and 'utf-16' in (kwds.get('encoding') or ''):
             if isinstance(src, compat.string_types):
                 src = open(src, 'rb')
                 self.handles.append(src)