factor out MyBuffer

Author: alimanfoo

docs/release.rst

@@ -1,6 +1,17 @@
 Release notes
 =============
 
+.. _release_0.1.0:
+
+0.1.0
+-----
+
+* Two new compressor codecs :class:`numcodecs.zstd.Zstd` and :class:`numcodecs.lz4.LZ4`
+  have been added (`#3 <https://github.com/alimanfoo/numcodecs/issues/3>`_,
+  `#22 <https://github.com/alimanfoo/numcodecs/issues/22>`_). These provide direct support for
+  compression/decompression using `Zstandard <https://github.com/facebook/zstd>`_ and
+  `LZ4 <https://github.com/lz4/lz4>`_ respectively.
+
 .. _release_0.0.1:
 
 0.0.1
@@ -19,7 +30,7 @@ the original Zarr module:
 
 * Codec classes have been re-organized into separate modules, mostly one per
   codec class, for ease of maintenance.
-* Two new codec classes have been added based on 32-bit checksums: CRC32 and
-  Adler32.
+* Two new codec classes have been added based on 32-bit checksums:
+  :class:`numcodecs.checksum32.CRC32` and :class:`numcodecs.checksum32.Adler32`.
 * The Blosc extension has been refactored to remove code duplications related
   to handling of buffer compatibility.

numcodecs/blosc.c

@@ -8,14 +8,12 @@ import threading
 import os
 
 
-# noinspection PyUnresolvedReferences
-from cpython cimport array, PyObject
-import array
-from cpython.buffer cimport PyObject_GetBuffer, PyBuffer_Release, PyBUF_ANY_CONTIGUOUS, \
-    PyBUF_WRITEABLE
+from cpython.buffer cimport PyBUF_ANY_CONTIGUOUS, PyBUF_WRITEABLE
 from cpython.bytes cimport PyBytes_FromStringAndSize, PyBytes_AS_STRING
 
 
+from numcodecs.compat_ext cimport MyBuffer
+from numcodecs.compat_ext import MyBuffer
 from numcodecs.compat import PY2, text_type
 from numcodecs.abc import Codec
 
@@ -98,37 +96,6 @@ def set_nthreads(int nthreads):
     return blosc_set_nthreads(nthreads)
 
 
-cdef class MyBuffer:
-    """Compatibility class to work around fact that array.array does not support new-style buffer
-    interface in PY2."""
-
-    cdef:
-        char *ptr
-        Py_buffer buffer
-        size_t nbytes
-        size_t itemsize
-        array.array arr
-        bint new_buffer
-
-    def __cinit__(self, obj, flags):
-        if PY2 and isinstance(obj, array.array):
-            self.new_buffer = False
-            self.arr = obj
-            self.ptr = <char *> self.arr.data.as_voidptr
-            self.itemsize = self.arr.itemsize
-            self.nbytes = self.arr.buffer_info()[1] * self.itemsize
-        else:
-            self.new_buffer = True
-            PyObject_GetBuffer(obj, &(self.buffer), flags)
-            self.ptr = <char *> self.buffer.buf
-            self.itemsize = self.buffer.itemsize
-            self.nbytes = self.buffer.len
-
-    def release(self):
-        if self.new_buffer:
-            PyBuffer_Release(&(self.buffer))
-
-
 def cbuffer_sizes(source):
     """Return information about a compressed buffer, namely the number of uncompressed bytes (
     `nbytes`) and compressed (`cbytes`).  It also returns the `blocksize` (which is used
@@ -358,6 +325,10 @@ class Blosc(Codec):
         The requested size of the compressed blocks.  If 0 (default), an automatic blocksize will
         be used.
 
+    See Also
+    --------
+    numcodecs.zstd.Zstd, numcodecs.lz4.LZ4
+
     """
 
     codec_id = 'blosc'