diff --git a/numcodecs/astype.py b/numcodecs/astype.py
index 0d3a3160..f222860f 100644
--- a/numcodecs/astype.py
+++ b/numcodecs/astype.py
@@ -50,7 +50,8 @@ def __init__(self, encode_dtype, decode_dtype):
     def encode(self, buf):
 
         # view input data as 1D array
-        arr = ndarray_from_buffer(buf, self.decode_dtype)
+        arr = ndarray_from_buffer(buf)
+        arr = arr.view(self.decode_dtype).reshape(-1, order='A')
 
         # convert and copy
         enc = arr.astype(self.encode_dtype)
@@ -60,7 +61,8 @@ def encode(self, buf):
     def decode(self, buf, out=None):
 
         # view encoded data as 1D array
-        enc = ndarray_from_buffer(buf, self.encode_dtype)
+        enc = ndarray_from_buffer(buf)
+        enc = enc.view(self.encode_dtype).reshape(-1, order='A')
 
         # convert and copy
         dec = enc.astype(self.decode_dtype)
diff --git a/numcodecs/bz2.py b/numcodecs/bz2.py
index a74ba3d4..15500082 100644
--- a/numcodecs/bz2.py
+++ b/numcodecs/bz2.py
@@ -1,14 +1,10 @@
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, print_function, division
 import bz2 as _bz2
-import array
-
-
-import numpy as np
 
 
 from numcodecs.abc import Codec
-from numcodecs.compat import buffer_copy, handle_datetime
+from numcodecs.compat import buffer_copy, to_buffer
 
 
 class BZ2(Codec):
@@ -28,18 +24,7 @@ def __init__(self, level=1):
 
     def encode(self, buf):
 
-        # deal with lack of buffer support for datetime64 and timedelta64
-        buf = handle_datetime(buf)
-
-        if isinstance(buf, np.ndarray):
-
-            # cannot compress object array
-            if buf.dtype == object:
-                raise ValueError('cannot encode object array')
-
-            # if numpy array, can only handle C contiguous directly
-            if not buf.flags.c_contiguous:
-                buf = buf.tobytes(order='A')
+        buf = to_buffer(buf)
 
         # do compression
         return _bz2.compress(buf, self.level)
@@ -47,10 +32,7 @@ def encode(self, buf):
     # noinspection PyMethodMayBeStatic
     def decode(self, buf, out=None):
 
-        # BZ2 cannot handle ndarray directly at all, coerce everything to
-        # memoryview
-        if not isinstance(buf, array.array):
-            buf = memoryview(buf)
+        buf = memoryview(to_buffer(buf))
 
         # do decompression
         dec = _bz2.decompress(buf)
diff --git a/numcodecs/categorize.py b/numcodecs/categorize.py
index 49a899e7..adfd28cd 100644
--- a/numcodecs/categorize.py
+++ b/numcodecs/categorize.py
@@ -53,7 +53,8 @@ def __init__(self, labels, dtype, astype='u1'):
     def encode(self, buf):
 
         # view input as ndarray
-        arr = ndarray_from_buffer(buf, self.dtype)
+        arr = ndarray_from_buffer(buf)
+        arr = arr.view(self.dtype).reshape(-1, order='A')
 
         # setup output array
         enc = np.zeros_like(arr, dtype=self.astype)
@@ -67,7 +68,8 @@ def encode(self, buf):
     def decode(self, buf, out=None):
 
         # view encoded data as ndarray
-        enc = ndarray_from_buffer(buf, self.astype)
+        enc = ndarray_from_buffer(buf)
+        enc = enc.view(self.astype).reshape(-1, order='A')
 
         # setup output
         if isinstance(out, np.ndarray):
diff --git a/numcodecs/checksum32.py b/numcodecs/checksum32.py
index bd044621..574446c6 100644
--- a/numcodecs/checksum32.py
+++ b/numcodecs/checksum32.py
@@ -17,7 +17,8 @@ class Checksum32(Codec):
     def encode(self, buf):
         if isinstance(buf, np.ndarray) and buf.dtype == object:
             raise ValueError('cannot encode object array')
-        arr = ndarray_from_buffer(buf, dtype='u1')
+        arr = ndarray_from_buffer(buf)
+        arr = arr.view('u1').reshape(-1, order='A')
         checksum = self.checksum(arr) & 0xffffffff
         enc = np.empty(arr.nbytes + 4, dtype='u1')
         enc[:4].view('<u4')[0] = checksum
@@ -25,7 +26,8 @@ def encode(self, buf):
         return enc
 
     def decode(self, buf, out=None):
-        arr = ndarray_from_buffer(buf, dtype='u1')
+        arr = ndarray_from_buffer(buf)
+        arr = arr.view('u1').reshape(-1, order='A')
         expect = arr[:4].view('<u4')[0]
         checksum = self.checksum(arr[4:]) & 0xffffffff
         if expect != checksum:
diff --git a/numcodecs/compat.py b/numcodecs/compat.py
index cd749a32..0f4ae51d 100644
--- a/numcodecs/compat.py
+++ b/numcodecs/compat.py
@@ -27,16 +27,19 @@
     from functools import reduce
 
 
-def buffer_tobytes(v):
-    """Obtain a sequence of bytes for the memory buffer used by `v`."""
-    if isinstance(v, binary_type):
-        return v
-    elif isinstance(v, np.ndarray):
-        return v.tobytes(order='A')
-    elif PY2 and isinstance(v, array.array):  # pragma: py3 no cover
-        return v.tostring()
-    else:
-        return memoryview(v).tobytes()
+def to_buffer(v):
+    """Obtain a `buffer` or `memoryview` for `v`."""
+
+    b = ndarray_from_buffer(v)
+
+    if b.dtype.kind is 'O':
+        raise ValueError('cannot encode object array')
+    elif b.dtype.kind in 'Mm':
+        b = b.view(np.int64)
+
+    b = b.reshape(-1, order='A')
+
+    return b
 
 
 def buffer_copy(buf, out=None):
@@ -46,50 +49,50 @@ def buffer_copy(buf, out=None):
         # no-op
         return buf
 
-    # handle ndarray destination
-    if isinstance(out, np.ndarray):
-
-        # view source as destination dtype
-        if isinstance(buf, np.ndarray):
-            buf = buf.view(dtype=out.dtype).reshape(-1, order='A')
-        else:
-            buf = np.frombuffer(buf, dtype=out.dtype)
-
-        # ensure shapes are compatible
-        if buf.shape != out.shape:
-            if out.flags.f_contiguous:
-                order = 'F'
-            else:
-                order = 'C'
-            buf = buf.reshape(out.shape, order=order)
-
-        # copy via numpy
-        np.copyto(out, buf)
-
-    # handle generic buffer destination
-    else:
+    # coerce to ndarrays
+    buf = ndarray_from_buffer(buf)
+    out = ndarray_from_buffer(out)
 
-        # obtain memoryview of destination
-        dest = memoryview(out)
+    # view source as destination dtype
+    if out.dtype.kind is not 'O':
+        buf = buf.view(out.dtype)
 
-        # ensure source is 1D
-        if isinstance(buf, np.ndarray):
-            buf = buf.reshape(-1, order='A')
-            # try to match itemsize
-            dtype = 'u%s' % dest.itemsize
-            buf = buf.view(dtype=dtype)
+    # ensure shapes are compatible
+    buf = buf.reshape(-1, order='A')
+    if buf.shape != out.shape:
+        if out.flags.f_contiguous:
+            order = 'F'
+        else:
+            order = 'C'
+        buf = buf.reshape(out.shape, order=order)
 
-        # try to copy via memoryview
-        dest[:] = buf
+    # copy via numpy
+    np.copyto(out, buf)
 
     return out
 
 
-def ndarray_from_buffer(buf, dtype):
-    if isinstance(buf, np.ndarray):
-        arr = buf.reshape(-1, order='A').view(dtype)
-    else:
-        arr = np.frombuffer(buf, dtype=dtype)
+def ndarray_from_buffer(buf):
+    arr = buf
+    if not isinstance(arr, np.ndarray):
+        try:
+            arr = memoryview(arr)
+        except TypeError:
+            if PY2:  # pragma: py3 no cover
+                arr = np.getbuffer(arr)
+            else:
+                raise
+        else:  # pragma: py2 no cover
+            if isinstance(buf, array.array) and buf.typecode is 'u':
+                arr = arr.cast('B').cast(np.dtype('u%i' % buf.itemsize).char)
+
+        arr = np.array(arr, copy=False)
+        if PY2 and isinstance(buf, array.array):  # pragma: py3 no cover
+            if buf.typecode is 'u':
+                arr = arr.view('u%i' % buf.itemsize)
+            else:
+                arr = arr.view(buf.typecode)
+
     return arr
 
 
@@ -98,9 +101,3 @@ def ensure_text(l, encoding='utf-8'):
         return l
     else:  # pragma: py3 no cover
         return text_type(l, encoding=encoding)
-
-
-def handle_datetime(buf):
-    if hasattr(buf, 'dtype') and buf.dtype.kind in 'Mm':
-        return buf.view('i8')
-    return buf
diff --git a/numcodecs/delta.py b/numcodecs/delta.py
index 094fbf8a..144ec70c 100644
--- a/numcodecs/delta.py
+++ b/numcodecs/delta.py
@@ -57,7 +57,8 @@ def __init__(self, dtype, astype=None):
     def encode(self, buf):
 
         # view input data as 1D array
-        arr = ndarray_from_buffer(buf, self.dtype)
+        arr = ndarray_from_buffer(buf)
+        arr = arr.view(self.dtype).reshape(-1, order='A')
 
         # setup encoded output
         enc = np.empty_like(arr, dtype=self.astype)
@@ -73,7 +74,8 @@ def encode(self, buf):
     def decode(self, buf, out=None):
 
         # view encoded data as 1D array
-        enc = ndarray_from_buffer(buf, self.astype)
+        enc = ndarray_from_buffer(buf)
+        enc = enc.view(self.astype).reshape(-1, order='A')
 
         # setup decoded output
         if isinstance(out, np.ndarray):
diff --git a/numcodecs/fixedscaleoffset.py b/numcodecs/fixedscaleoffset.py
index a5f86aca..787b7858 100644
--- a/numcodecs/fixedscaleoffset.py
+++ b/numcodecs/fixedscaleoffset.py
@@ -88,7 +88,8 @@ def __init__(self, offset, scale, dtype, astype=None):
     def encode(self, buf):
 
         # interpret buffer as 1D array
-        arr = ndarray_from_buffer(buf, self.dtype)
+        arr = ndarray_from_buffer(buf)
+        arr = arr.view(self.dtype).reshape(-1, order='A')
 
         # compute scale offset
         enc = (arr - self.offset) * self.scale
@@ -104,7 +105,8 @@ def encode(self, buf):
     def decode(self, buf, out=None):
 
         # interpret buffer as 1D array
-        enc = ndarray_from_buffer(buf, self.astype)
+        enc = ndarray_from_buffer(buf)
+        enc = enc.view(self.astype).reshape(-1, order='A')
 
         # decode scale offset
         dec = (enc / self.scale) + self.offset
diff --git a/numcodecs/gzip.py b/numcodecs/gzip.py
index 802d9fcd..98efa8f6 100644
--- a/numcodecs/gzip.py
+++ b/numcodecs/gzip.py
@@ -4,11 +4,8 @@
 import io
 
 
-import numpy as np
-
-
 from .abc import Codec
-from .compat import buffer_copy, handle_datetime, buffer_tobytes, PY2
+from .compat import buffer_copy, to_buffer
 
 
 class GZip(Codec):
@@ -28,22 +25,7 @@ def __init__(self, level=1):
 
     def encode(self, buf):
 
-        # deal with lack of buffer support for datetime64 and timedelta64
-        buf = handle_datetime(buf)
-
-        if isinstance(buf, np.ndarray):
-
-            # cannot compress object array
-            if buf.dtype == object:
-                raise ValueError('cannot encode object array')
-
-            # if numpy array, can only handle C contiguous directly
-            if not buf.flags.c_contiguous:
-                buf = buf.tobytes(order='A')
-
-        if PY2:  # pragma: py3 no cover
-            # ensure bytes, PY2 cannot handle things like bytearray
-            buf = buffer_tobytes(buf)
+        buf = memoryview(to_buffer(buf))
 
         # do compression
         compressed = io.BytesIO()
@@ -58,9 +40,7 @@ def encode(self, buf):
     # noinspection PyMethodMayBeStatic
     def decode(self, buf, out=None):
 
-        if PY2:  # pragma: py3 no cover
-            # ensure bytes, PY2 cannot handle things like bytearray
-            buf = buffer_tobytes(buf)
+        buf = to_buffer(buf)
 
         # do decompression
         buf = io.BytesIO(buf)
diff --git a/numcodecs/json.py b/numcodecs/json.py
index 3d8d9f13..bb9a99ba 100644
--- a/numcodecs/json.py
+++ b/numcodecs/json.py
@@ -8,7 +8,7 @@
 
 
 from .abc import Codec
-from .compat import buffer_tobytes
+from .compat import to_buffer
 
 
 class JSON(Codec):
@@ -63,7 +63,7 @@ def encode(self, buf):
         return self._encoder.encode(items).encode(self._text_encoding)
 
     def decode(self, buf, out=None):
-        buf = buffer_tobytes(buf)
+        buf = to_buffer(buf).tobytes()
         items = self._decoder.decode(buf.decode(self._text_encoding))
         dec = np.empty(items[-1], dtype=items[-2])
         dec[:] = items[:-2]
@@ -125,7 +125,7 @@ def encode(self, buf):
         return self._encoder.encode(items).encode(self._text_encoding)
 
     def decode(self, buf, out=None):
-        buf = buffer_tobytes(buf)
+        buf = to_buffer(buf).tobytes()
         items = self._decoder.decode(buf.decode(self._text_encoding))
         dec = np.array(items[:-1], dtype=items[-1])
         if out is not None:
diff --git a/numcodecs/lzma.py b/numcodecs/lzma.py
index 5f7521b6..20521593 100644
--- a/numcodecs/lzma.py
+++ b/numcodecs/lzma.py
@@ -14,9 +14,8 @@
 
 if _lzma:
 
-    import numpy as np
     from .abc import Codec
-    from .compat import buffer_copy, handle_datetime
+    from .compat import buffer_copy, to_buffer
 
     # noinspection PyShadowingBuiltins
     class LZMA(Codec):
@@ -48,18 +47,7 @@ def __init__(self, format=1, check=-1, preset=None, filters=None):
 
         def encode(self, buf):
 
-            # deal with lack of buffer support for datetime64 and timedelta64
-            buf = handle_datetime(buf)
-
-            if isinstance(buf, np.ndarray):
-
-                # cannot compress object array
-                if buf.dtype == object:
-                    raise ValueError('cannot encode object array')
-
-                # if numpy array, can only handle C contiguous directly
-                if not buf.flags.c_contiguous:
-                    buf = buf.tobytes(order='A')
+            buf = to_buffer(buf)
 
             # do compression
             return _lzma.compress(buf, format=self.format, check=self.check,
@@ -67,6 +55,8 @@ def encode(self, buf):
 
         def decode(self, buf, out=None):
 
+            buf = to_buffer(buf)
+
             # do decompression
             dec = _lzma.decompress(buf, format=self.format,
                                    filters=self.filters)
diff --git a/numcodecs/msgpacks.py b/numcodecs/msgpacks.py
index 198b98e7..f3d47a64 100644
--- a/numcodecs/msgpacks.py
+++ b/numcodecs/msgpacks.py
@@ -7,7 +7,7 @@
 
 
 from .abc import Codec
-from .compat import buffer_tobytes
+from .compat import to_buffer
 
 
 class MsgPack(Codec):
@@ -64,7 +64,7 @@ def encode(self, buf):
                              use_single_float=self.use_single_float)
 
     def decode(self, buf, out=None):
-        buf = buffer_tobytes(buf)
+        buf = to_buffer(buf).tobytes()
         items = msgpack.unpackb(buf, raw=self.raw)
         dec = np.empty(items[-1], dtype=items[-2])
         dec[:] = items[:-2]
@@ -111,7 +111,7 @@ def encode(self, buf):
         return msgpack.packb(items, encoding=self.encoding)
 
     def decode(self, buf, out=None):
-        buf = buffer_tobytes(buf)
+        buf = to_buffer(buf).tobytes()
         items = msgpack.unpackb(buf, encoding=self.encoding)
         dec = np.array(items[:-1], dtype=items[-1])
         if out is not None:
diff --git a/numcodecs/packbits.py b/numcodecs/packbits.py
index 2161dd2a..95c71fc5 100644
--- a/numcodecs/packbits.py
+++ b/numcodecs/packbits.py
@@ -40,7 +40,8 @@ def __init__(self):
     def encode(self, buf):
 
         # view input as ndarray
-        arr = ndarray_from_buffer(buf, bool)
+        arr = ndarray_from_buffer(buf)
+        arr = arr.view(bool).reshape(-1, order='A')
 
         # determine size of packed data
         n = arr.size
@@ -67,7 +68,8 @@ def encode(self, buf):
     def decode(self, buf, out=None):
 
         # view encoded data as ndarray
-        enc = ndarray_from_buffer(buf, 'u1')
+        enc = ndarray_from_buffer(buf)
+        enc = enc.view('u1').reshape(-1, order='A')
 
         # find out how many bits were padded
         n_bits_padded = int(enc[0])
diff --git a/numcodecs/quantize.py b/numcodecs/quantize.py
index b1e2565b..cb930b76 100644
--- a/numcodecs/quantize.py
+++ b/numcodecs/quantize.py
@@ -64,7 +64,8 @@ def __init__(self, digits, dtype, astype=None):
     def encode(self, buf):
 
         # interpret buffer as 1D array
-        arr = ndarray_from_buffer(buf, self.dtype)
+        arr = ndarray_from_buffer(buf)
+        arr = arr.view(self.dtype).reshape(-1, order='A')
 
         # apply scaling
         precision = 10. ** -self.digits
@@ -84,7 +85,8 @@ def encode(self, buf):
 
     def decode(self, buf, out=None):
         # filter is lossy, decoding is no-op
-        dec = ndarray_from_buffer(buf, self.astype)
+        dec = ndarray_from_buffer(buf)
+        dec = dec.view(self.astype).reshape(-1, order='A')
         dec = dec.astype(self.dtype, copy=False)
         return buffer_copy(dec, out)
 
diff --git a/numcodecs/tests/common.py b/numcodecs/tests/common.py
index 6e6a20d1..042209c1 100644
--- a/numcodecs/tests/common.py
+++ b/numcodecs/tests/common.py
@@ -11,7 +11,7 @@
 import pytest
 
 
-from numcodecs.compat import buffer_tobytes, ndarray_from_buffer
+from numcodecs.compat import to_buffer, ndarray_from_buffer
 from numcodecs.registry import get_codec
 # star import needed for repr tests so eval finds names
 from numcodecs import *  # noqa
@@ -27,7 +27,8 @@ def compare_arrays(arr, res, precision=None):
 
     # ensure numpy array
     if not isinstance(res, np.ndarray):
-        res = ndarray_from_buffer(res, dtype=arr.dtype)
+        res = ndarray_from_buffer(res)
+        res = res.view(arr.dtype).reshape(-1, order='A')
     elif res.dtype != arr.dtype:
         res = res.view(arr.dtype)
 
@@ -86,7 +87,7 @@ def check_encode_decode(arr, codec, precision=None):
     # as well as array.array in PY2
 
     # setup
-    enc_bytes = buffer_tobytes(enc)
+    enc_bytes = to_buffer(enc).tobytes()
 
     # test decoding of raw bytes
     dec = codec.decode(enc_bytes)
@@ -224,7 +225,8 @@ def check_backwards_compatibility(codec_id, arrays, codecs, precision=None, pref
             with open(enc_fn, mode='rb') as ef:
                 enc = ef.read()
                 dec = codec.decode(enc)
-                dec_arr = ndarray_from_buffer(dec, dtype=arr.dtype)
+                dec_arr = ndarray_from_buffer(dec)
+                dec_arr = dec_arr.view(arr.dtype).reshape(-1, order='A')
                 dec_arr = dec_arr.reshape(arr.shape, order=order)
                 if precision and precision[j] is not None:
                     assert_array_almost_equal(arr, dec_arr, decimal=precision[j])
@@ -232,7 +234,7 @@ def check_backwards_compatibility(codec_id, arrays, codecs, precision=None, pref
                     assert_array_items_equal(arr, dec_arr)
                 else:
                     assert_array_equal(arr, dec_arr)
-                    assert buffer_tobytes(arr) == buffer_tobytes(dec)
+                    assert to_buffer(arr).tobytes() == to_buffer(dec).tobytes()
 
 
 def check_err_decode_object_buffer(compressor):
diff --git a/numcodecs/tests/test_compat.py b/numcodecs/tests/test_compat.py
index f4935401..d391f865 100644
--- a/numcodecs/tests/test_compat.py
+++ b/numcodecs/tests/test_compat.py
@@ -1,21 +1,50 @@
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, print_function, division
 import array
+import mmap
 
+import pytest
 
 import numpy as np
 
 
-from numcodecs.compat import buffer_tobytes
+from numcodecs.compat import PY2, to_buffer
 
 
-def test_buffer_tobytes():
-    bufs = [
-        b'adsdasdas',
-        bytes(20),
-        np.arange(100),
-        array.array('l', b'qwertyuiqwertyui')
+def test_buffer_coercion_raises():
+    a = np.array([u'Xin chào thế giới'], dtype=object)
+    for e in [a, memoryview(a)]:
+        with pytest.raises(ValueError):
+            to_buffer(e)
+    with pytest.raises(TypeError):
+        to_buffer(a.tolist())
+
+
+def test_buffer_writable():
+    for writable in [False, True]:
+        a = np.arange(100)
+        a.setflags(write=writable)
+
+        b = to_buffer(a)
+        m = memoryview(b)
+
+        assert m.readonly != writable
+
+
+def test_buffer_coercion():
+    typed_bufs = [
+        ('u', b'adsdasdas'),
+        ('u', bytes(20)),
+        ('i', np.arange(100, dtype=np.int64)),
+        ('i', array.array('l', b'qwertyuiqwertyui')),
+        ('u', array.array('u', u'qwertyuiqwertyui')),
+        ('u', mmap.mmap(-1, 10))
     ]
-    for buf in bufs:
-        b = buffer_tobytes(buf)
-        assert isinstance(b, bytes)
+    for typ, buf in typed_bufs:
+        b1 = to_buffer(buf)
+        assert isinstance(b1, np.ndarray)
+        assert b1.dtype.kind is typ
+        if PY2:  # pragma: py3 no cover
+            assert np.shares_memory(b1, np.getbuffer(buf))
+        else:  # pragma: py2 no cover
+            assert np.shares_memory(b1, memoryview(buf).cast('B'))
diff --git a/numcodecs/zlib.py b/numcodecs/zlib.py
index 0ab68d98..e56ee3a2 100644
--- a/numcodecs/zlib.py
+++ b/numcodecs/zlib.py
@@ -3,11 +3,8 @@
 import zlib as _zlib
 
 
-import numpy as np
-
-
 from .abc import Codec
-from .compat import buffer_copy, handle_datetime, buffer_tobytes, PY2
+from .compat import buffer_copy, to_buffer
 
 
 class Zlib(Codec):
@@ -27,22 +24,7 @@ def __init__(self, level=1):
 
     def encode(self, buf):
 
-        # deal with lack of buffer support for datetime64 and timedelta64
-        buf = handle_datetime(buf)
-
-        if isinstance(buf, np.ndarray):
-
-            # cannot compress object array
-            if buf.dtype == object:
-                raise ValueError('cannot encode object array')
-
-            # if numpy array, can only handle C contiguous directly
-            if not buf.flags.c_contiguous:
-                buf = buf.tobytes(order='A')
-
-        if PY2:  # pragma: py3 no cover
-            # ensure bytes, PY2 cannot handle things like bytearray
-            buf = buffer_tobytes(buf)
+        buf = to_buffer(buf)
 
         # do compression
         return _zlib.compress(buf, self.level)
@@ -50,9 +32,7 @@ def encode(self, buf):
     # noinspection PyMethodMayBeStatic
     def decode(self, buf, out=None):
 
-        if PY2:  # pragma: py3 no cover
-            # ensure bytes, PY2 cannot handle things like bytearray
-            buf = buffer_tobytes(buf)
+        buf = to_buffer(buf)
 
         # do decompression
         dec = _zlib.decompress(buf)