Revert ndarray coercion of encode returned data (#155)

* Preserve `decode` data type where reasonable

* Preserve `encode` data type where reasonable

* Regenerate Cython files

* Note reversion of ndarray coercion in changelog

* Always return `bytes` from `GZip.encode`

In order to make the user experience more consistent across Python 2/3,
always return a `bytes` object from `GZip.encode`. This will add a copy
to Python 3 before returning the result, but it will be no more copies
than already occur on Python 2.

Author: jakirkham

docs/release.rst

@@ -21,6 +21,9 @@ Release notes
 * Avoid copying into data in ``GZip``'s `decode()` method on Python 2.
   By :user:`John Kirkham <jakirkham>`, :issue:`152`.
 
+* Revert ndarray coercion of encode returned data.
+  By :user:`John Kirkham <jakirkham>`, :issue:`155`.
+
 
 .. _release_0.6.1:
 

numcodecs/blosc.c

@@ -16,7 +16,7 @@ from cpython.bytes cimport PyBytes_FromStringAndSize, PyBytes_AS_STRING
 
 from .compat_ext cimport Buffer
 from .compat_ext import Buffer
-from .compat import PY2, text_type, ensure_ndarray, ensure_contiguous_ndarray
+from .compat import PY2, text_type, ensure_contiguous_ndarray
 from .abc import Codec
 
 
@@ -488,13 +488,11 @@ class Blosc(Codec):
 
     def encode(self, buf):
         buf = ensure_contiguous_ndarray(buf, self.max_buffer_size)
-        out = compress(buf, self._cname_bytes, self.clevel, self.shuffle, self.blocksize)
-        return  ensure_ndarray(out)
+        return compress(buf, self._cname_bytes, self.clevel, self.shuffle, self.blocksize)
 
     def decode(self, buf, out=None):
         buf = ensure_contiguous_ndarray(buf, self.max_buffer_size)
-        out = decompress(buf, out)
-        return ensure_ndarray(out)
+        return decompress(buf, out)
 
     def __repr__(self):
         r = '%s(cname=%r, clevel=%r, shuffle=%s, blocksize=%s)' % \

numcodecs/blosc.pyx

@@ -4,7 +4,7 @@
 
 
 from numcodecs.abc import Codec
-from numcodecs.compat import ndarray_copy, ensure_ndarray, ensure_contiguous_ndarray
+from numcodecs.compat import ndarray_copy, ensure_contiguous_ndarray
 
 
 class BZ2(Codec):
@@ -28,7 +28,7 @@ def encode(self, buf):
         buf = ensure_contiguous_ndarray(buf)
 
         # do compression
-        return ensure_ndarray(_bz2.compress(buf, self.level))
+        return _bz2.compress(buf, self.level)
 
     # noinspection PyMethodMayBeStatic
     def decode(self, buf, out=None):

numcodecs/bz2.py

@@ -5,7 +5,7 @@
 
 
 from .abc import Codec
-from .compat import ensure_bytes, ensure_ndarray, ensure_contiguous_ndarray, PY2
+from .compat import ensure_bytes, ensure_contiguous_ndarray, PY2
 
 
 if PY2:  # pragma: py3 no cover
@@ -42,13 +42,9 @@ def encode(self, buf):
                             mode='wb',
                             compresslevel=self.level) as compressor:
             compressor.write(buf)
+        compressed = compressed.getvalue()
 
-        try:
-            compressed = compressed.getbuffer()
-        except AttributeError:  # pragma: py3 no cover
-            compressed = compressed.getvalue()
-
-        return ensure_ndarray(compressed)
+        return compressed
 
     # noinspection PyMethodMayBeStatic
     def decode(self, buf, out=None):
@@ -70,6 +66,6 @@ def decode(self, buf, out=None):
                 if decompressor.read(1) != b'':
                     raise ValueError("Unable to fit data into `out`")
             else:
-                out = ensure_ndarray(decompressor.read())
+                out = decompressor.read()
 
         return out