Add wrappers for zarr v3

.github/workflows/ci.yaml

@@ -13,7 +13,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.11", "3.12", "3.13"]
-        # macos-12 is an intel runner, macos-14 is a arm64 runner
+        # macos-13 is an intel runner, macos-14 is a arm64 runner
         platform: [ubuntu-latest, windows-latest, macos-13, macos-14]
 
     steps:
@@ -70,10 +70,15 @@ jobs:
             conda activate env
             python -m pip install -v ".[pcodec]"
 
+      - name: Install zarr-python
+        shell: "bash -l {0}"
+        run: |
+          conda activate env
+          python -m pip install 'zarr==3.0.0b1'
 
       # This is used to test with zfpy, which does not yet support numpy 2.0
       - name: Install older numpy and zfpy
-        if: matrix.python-version == '3.11'
+        if: matrix.python-version == '3.11' && matrix.platform != 'macos-14'
         shell: "bash -l {0}"
         run: |
           conda activate env

docs/api.rst

@@ -10,3 +10,4 @@ API reference
     checksum32
     abc
     registry
+    zarr3

docs/zarr3.rst

@@ -0,0 +1,99 @@
+Zarr 3 codecs
+=============
+.. automodule:: numcodecs.zarr3
+
+
+Bytes-to-bytes codecs
+---------------------
+.. autoclass:: Blosc()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: LZ4()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: Zstd()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: Zlib()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: GZip()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: BZ2()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: LZMA()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: Shuffle()
+
+    .. autoattribute:: codec_name
+
+
+Array-to-array codecs
+---------------------
+.. autoclass:: Delta()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: BitRound()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: FixedScaleOffset()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: Quantize()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: PackBits()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: AsType()
+
+    .. autoattribute:: codec_name
+
+
+Bytes-to-bytes checksum codecs
+------------------------------
+.. autoclass:: CRC32()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: CRC32C()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: Adler32()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: Fletcher32()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: JenkinsLookup3()
+
+    .. autoattribute:: codec_name
+
+
+Array-to-bytes codecs
+---------------------
+.. autoclass:: PCodec()
+
+    .. autoattribute:: codec_name
+
+.. autoclass:: ZFPY()
+
+    .. autoattribute:: codec_name

numcodecs/tests/test_zarr3.py

@@ -0,0 +1,233 @@
+from __future__ import annotations
+
+import numpy as np
+import pytest
+
+import numcodecs.zarr3
+
+zarr = pytest.importorskip("zarr")
+
+pytestmark = pytest.mark.skipif(
+    zarr.__version__ < "3.0.0", reason="zarr 3.0.0 or later is required"
+)
+
+get_codec_class = zarr.registry.get_codec_class
+Array = zarr.Array
+JSON = zarr.core.common.JSON
+BytesCodec = zarr.codecs.BytesCodec
+Store = zarr.abc.store.Store
+MemoryStore = zarr.storage.MemoryStore
+StorePath = zarr.storage.StorePath
+
+
+EXPECTED_WARNING_STR = "Numcodecs codecs are not in the Zarr version 3.*"
+
+
+@pytest.fixture
+def store() -> Store:
+    return StorePath(MemoryStore(mode="w"))
+
+
+ALL_CODECS = [getattr(numcodecs.zarr3, cls_name) for cls_name in numcodecs.zarr3.__all__]
+
+
+@pytest.mark.parametrize("codec_class", ALL_CODECS)
+def test_entry_points(codec_class: type[numcodecs.zarr3._NumcodecsCodec]):
+    codec_name = codec_class.codec_name
+    assert get_codec_class(codec_name) == codec_class
+
+
+@pytest.mark.parametrize("codec_class", ALL_CODECS)
+def test_docstring(codec_class: type[numcodecs.zarr3._NumcodecsCodec]):
+    assert "See :class:`numcodecs." in codec_class.__doc__
+
+
+@pytest.mark.parametrize(
+    "codec_class",
+    [
+        numcodecs.zarr3.Blosc,
+        numcodecs.zarr3.LZ4,
+        numcodecs.zarr3.Zstd,
+        numcodecs.zarr3.Zlib,
+        numcodecs.zarr3.GZip,
+        numcodecs.zarr3.BZ2,
+        numcodecs.zarr3.LZMA,
+        numcodecs.zarr3.Shuffle,
+    ],
+)
+def test_generic_codec_class(store: Store, codec_class: type[numcodecs.zarr3._NumcodecsCodec]):
+    data = np.arange(0, 256, dtype="uint16").reshape((16, 16))
+
+    with pytest.warns(UserWarning, match=EXPECTED_WARNING_STR):
+        a = Array.create(
+            store / "generic",
+            shape=data.shape,
+            chunk_shape=(16, 16),
+            dtype=data.dtype,
+            fill_value=0,
+            codecs=[BytesCodec(), codec_class()],
+        )
+
+    a[:, :] = data.copy()
+    np.testing.assert_array_equal(data, a[:, :])
+
+
+@pytest.mark.parametrize(
+    ("codec_class", "codec_config"),
+    [
+        (numcodecs.zarr3.Delta, {"dtype": "float32"}),
+        (numcodecs.zarr3.FixedScaleOffset, {"offset": 0, "scale": 25.5}),
+        (numcodecs.zarr3.FixedScaleOffset, {"offset": 0, "scale": 51, "astype": "uint16"}),
+        (numcodecs.zarr3.AsType, {"encode_dtype": "float32", "decode_dtype": "float64"}),
+    ],
+    ids=[
+        "delta",
+        "fixedscaleoffset",
+        "fixedscaleoffset2",
+        "astype",
+    ],
+)
+def test_generic_filter(
+    store: Store, codec_class: type[numcodecs.zarr3._NumcodecsCodec], codec_config: dict[str, JSON]
+):
+    data = np.linspace(0, 10, 256, dtype="float32").reshape((16, 16))
+
+    with pytest.warns(UserWarning, match=EXPECTED_WARNING_STR):
+        a = Array.create(
+            store / "generic",
+            shape=data.shape,
+            chunk_shape=(16, 16),
+            dtype=data.dtype,
+            fill_value=0,
+            codecs=[
+                codec_class(**codec_config),
+                BytesCodec(),
+            ],
+        )
+
+        a[:, :] = data.copy()
+        a = Array.open(store / "generic")
+    np.testing.assert_array_equal(data, a[:, :])
+
+
+def test_generic_filter_bitround(store: Store):
+    data = np.linspace(0, 1, 256, dtype="float32").reshape((16, 16))
+
+    with pytest.warns(UserWarning, match=EXPECTED_WARNING_STR):
+        a = Array.create(
+            store / "generic_bitround",
+            shape=data.shape,
+            chunk_shape=(16, 16),
+            dtype=data.dtype,
+            fill_value=0,
+            codecs=[numcodecs.zarr3.BitRound(keepbits=3), BytesCodec()],
+        )
+
+        a[:, :] = data.copy()
+        a = Array.open(store / "generic_bitround")
+    assert np.allclose(data, a[:, :], atol=0.1)
+
+
+def test_generic_filter_quantize(store: Store):
+    data = np.linspace(0, 10, 256, dtype="float32").reshape((16, 16))
+
+    with pytest.warns(UserWarning, match=EXPECTED_WARNING_STR):
+        a = Array.create(
+            store / "generic_quantize",
+            shape=data.shape,
+            chunk_shape=(16, 16),
+            dtype=data.dtype,
+            fill_value=0,
+            codecs=[numcodecs.zarr3.Quantize(digits=3), BytesCodec()],
+        )
+
+        a[:, :] = data.copy()
+        a = Array.open(store / "generic_quantize")
+    assert np.allclose(data, a[:, :], atol=0.001)
+
+
+def test_generic_filter_packbits(store: Store):
+    data = np.zeros((16, 16), dtype="bool")
+    data[0:4, :] = True
+
+    with pytest.warns(UserWarning, match=EXPECTED_WARNING_STR):
+        a = Array.create(
+            store / "generic_packbits",
+            shape=data.shape,
+            chunk_shape=(16, 16),
+            dtype=data.dtype,
+            fill_value=0,
+            codecs=[numcodecs.zarr3.PackBits(), BytesCodec()],
+        )
+
+        a[:, :] = data.copy()
+        a = Array.open(store / "generic_packbits")
+    np.testing.assert_array_equal(data, a[:, :])
+
+    with pytest.raises(ValueError, match=".*requires bool dtype.*"):
+        Array.create(
+            store / "generic_packbits_err",
+            shape=data.shape,
+            chunk_shape=(16, 16),
+            dtype="uint32",
+            fill_value=0,
+            codecs=[numcodecs.zarr3.PackBits(), BytesCodec()],
+        )
+
+
+@pytest.mark.parametrize(
+    "codec_class",
+    [
+        numcodecs.zarr3.CRC32,
+        numcodecs.zarr3.CRC32C,
+        numcodecs.zarr3.Adler32,
+        numcodecs.zarr3.Fletcher32,
+        numcodecs.zarr3.JenkinsLookup3,
+    ],
+)
+def test_generic_checksum(store: Store, codec_class: type[numcodecs.zarr3._NumcodecsCodec]):
+    data = np.linspace(0, 10, 256, dtype="float32").reshape((16, 16))
+
+    with pytest.warns(UserWarning, match=EXPECTED_WARNING_STR):
+        a = Array.create(
+            store / "generic_checksum",
+            shape=data.shape,
+            chunk_shape=(16, 16),
+            dtype=data.dtype,
+            fill_value=0,
+            codecs=[BytesCodec(), codec_class()],
+        )
+
+        a[:, :] = data.copy()
+        a = Array.open(store / "generic_checksum")
+    np.testing.assert_array_equal(data, a[:, :])
+
+
+@pytest.mark.parametrize("codec_class", [numcodecs.zarr3.PCodec, numcodecs.zarr3.ZFPY])
+def test_generic_bytes_codec(store: Store, codec_class: type[numcodecs.zarr3._NumcodecsCodec]):
+    try:
+        codec_class()._codec  # noqa: B018
+    except ValueError as e:
+        if "codec not available" in str(e):
+            pytest.xfail(f"{codec_class.codec_name} is not available: {e}")
+        else:
+            raise  # pragma: no cover
+    except ImportError as e:
+        pytest.xfail(f"{codec_class.codec_name} is not available: {e}")
+
+    data = np.arange(0, 256, dtype="float32").reshape((16, 16))
+
+    with pytest.warns(UserWarning, match=EXPECTED_WARNING_STR):
+        a = Array.create(
+            store / "generic",
+            shape=data.shape,
+            chunk_shape=(16, 16),
+            dtype=data.dtype,
+            fill_value=0,
+            codecs=[
+                codec_class(),
+            ],
+        )
+
+    a[:, :] = data.copy()
+    np.testing.assert_array_equal(data, a[:, :])

numcodecs/tests/test_zarr3_import.py

@@ -0,0 +1,13 @@
+from __future__ import annotations
+
+import pytest
+
+
+def test_zarr3_import():
+    ERROR_MESSAGE_MATCH = "zarr 3.0.0 or later.*"
+
+    try:
+        import zarr  # noqa: F401
+    except ImportError:  # pragma: no cover
+        with pytest.raises(ImportError, match=ERROR_MESSAGE_MATCH):
+            import numcodecs.zarr3  # noqa: F401