Add normalize_shape since it is not in Zarr's public API (#479)

cubed/array_api/creation_functions.py

@@ -1,8 +1,6 @@
 import math
 from typing import TYPE_CHECKING, Iterable, List
 
-from zarr.util import normalize_shape
-
 from cubed.backend_array_api import namespace as nxp
 from cubed.core import Plan, gensym
 from cubed.core.ops import map_blocks
@@ -12,7 +10,7 @@
     virtual_in_memory,
     virtual_offsets,
 )
-from cubed.utils import to_chunksize
+from cubed.utils import normalize_shape, to_chunksize
 from cubed.vendor.dask.array.core import normalize_chunks
 
 if TYPE_CHECKING:

cubed/random.py

@@ -1,12 +1,11 @@
 import random as pyrandom
 
 from numpy.random import Generator, Philox
-from zarr.util import normalize_shape
 
 from cubed.backend_array_api import namespace as nxp
 from cubed.backend_array_api import numpy_array_to_backend_array
 from cubed.core.ops import map_blocks
-from cubed.utils import block_id_to_offset
+from cubed.utils import block_id_to_offset, normalize_shape
 from cubed.vendor.dask.array.core import normalize_chunks
 
 

cubed/tests/test_utils.py

@@ -15,6 +15,7 @@
     join_path,
     map_nested,
     memory_repr,
+    normalize_shape,
     offset_to_block_id,
     peak_measured_mem,
     split_into,
@@ -170,3 +171,13 @@ def test_broadcast_trick():
     a = nxp.ones((), dtype=nxp.int8)
     b = broadcast_trick(nxp.ones)((), dtype=nxp.int8)
     assert_array_equal(a, b)
+
+
+def test_normalize_shape():
+    assert normalize_shape(2) == (2,)
+    assert normalize_shape((2,)) == (2,)
+    assert normalize_shape((2, 0)) == (2, 0)
+    assert normalize_shape((2, 3)) == (2, 3)
+
+    with pytest.raises(TypeError):
+        normalize_shape(None)

cubed/utils.py

@@ -1,5 +1,6 @@
 import collections
 import itertools
+import numbers
 import platform
 import sys
 import sysconfig
@@ -12,7 +13,7 @@
 from operator import add
 from pathlib import Path
 from posixpath import join
-from typing import Dict, Tuple, Union
+from typing import Dict, Tuple, Union, cast
 from urllib.parse import quote, unquote, urlsplit, urlunsplit
 
 import numpy as np
@@ -385,3 +386,17 @@ def _concatenate2(arrays, axes=None):
         return ret
     else:
         return concatenate(arrays, axis=axes[0])
+
+
+def normalize_shape(shape: Union[int, Tuple[int, ...], None]) -> Tuple[int, ...]:
+    """Normalize a `shape` argument to a tuple of ints."""
+
+    if shape is None:
+        raise TypeError("shape is None")
+
+    if isinstance(shape, numbers.Integral):
+        shape = (int(shape),)
+
+    shape = cast(Tuple[int, ...], shape)
+    shape = tuple(int(s) for s in shape)
+    return shape