Merge pull request #164 from mkitti/zstd_clevel

Add clevel argument for Zstd

src/hdf5plugin/__init__.py

@@ -390,9 +390,25 @@ class Zstd(_FilterRefClass):
             data=numpy.arange(100),
             **hdf5plugin.Zstd())
         f.close()
+
+    :param int clevel: Compression level from 1 (lowest compression) to 22 (maximum compression).
+        Ultra compression extends from 20 through 22. Default: 3.
+
+    .. code-block:: python
+
+        f = h5py.File('test.h5', 'w')
+        f.create_dataset(
+            'zstd',
+            data=numpy.arange(100),
+            **hdf5plugin.Zstd(clevel=22))
+        f.close()
     """
     filter_id = ZSTD_ID
 
+    def __init__(self, clevel=3):
+        assert 1 <= clevel <= 22
+        self.filter_options = (clevel,)
+
 
 def _init_filters():
     """Initialise and register HDF5 filters with h5py

src/hdf5plugin/test.py

@@ -177,6 +177,16 @@ def testZfp(self):
     def testZstd(self):
         """Write/read test with Zstd filter plugin"""
         self._test('zstd')
+        tests = [
+            {'clevel': 3},
+            {'clevel': 22}
+        ]
+        for options in tests:
+            for dtype in (numpy.float32, numpy.float64):
+                with self.subTest(options=options, dtype=dtype):
+                    self._test('zstd', dtype=dtype, **options)
+
+
 
 
 class TestPackage(unittest.TestCase):