Pass tests (except one)

Author: balbasty

src/zarr/core/buffer/core.py

@@ -551,30 +551,44 @@ def __len__(self) -> int:
     def __getitem__(self, key: slice) -> Self:
         check_item_key_is_1d_contiguous(key)
         start, stop = key.start, key.stop
+        this_len = len(self)
         if start is None:
             start = 0
+        if start < 0:
+            start = this_len + start
         if stop is None:
-            stop = len(self)
+            stop = this_len
+        if stop < 0:
+            stop = this_len + stop
+        if stop > this_len:
+            stop = this_len
+        if stop <= start:
+            return Buffer.from_buffer(b'')
+
         new_list = []
         offset = 0
         found_last = False
         for chunk in self._data_list:
             chunk_size = len(chunk)
             skip = False
-            if offset <= start < offset + chunk_size:
+            if 0 <= start - offset < chunk_size:
                 # first chunk
-                if stop <= offset + chunk_size:
+                if stop - offset <= chunk_size:
                     # also last chunk
                     chunk = chunk[start-offset:stop-offset]
                     found_last = True
                 else:
                     chunk = chunk[start-offset:]
-            elif offset <= stop <= offset + chunk_size:
+            elif 0 <= stop - offset <= chunk_size:
                 # last chunk
                 chunk = chunk[:stop-offset]
                 found_last = True
-            elif offset + chunk_size <= start:
+            elif chunk_size <= start - offset:
+                # before first chunk
                 skip = True
+            else:
+                # middle chunk
+                pass
 
             if not skip:
                 new_list.append(chunk)
@@ -590,29 +604,39 @@ def __setitem__(self, key: slice, value: Any) -> None:
         start, stop = key.start, key.stop
         if start is None:
             start = 0
+        if start < 0:
+            start = len(self) + start
         if stop is None:
             stop = len(self)
-        new_list = []
+        if stop < 0:
+            stop = len(self) + stop
+        if stop <= start:
+            return
+
         offset = 0
         found_last = False
         value = memoryview(np.asanyarray(value))
         for chunk in self._data_list:
             chunk_size = len(chunk)
             skip = False
-            if offset <= start < offset + chunk_size:
+            if 0 <= start - offset < chunk_size:
                 # first chunk
-                if stop <= offset + chunk_size:
+                if stop - offset <= chunk_size:
                     # also last chunk
                     chunk = chunk[start-offset:stop-offset]
                     found_last = True
                 else:
                     chunk = chunk[start-offset:]
-            elif offset <= stop <= offset + chunk_size:
+            elif 0 <= stop - offset <= chunk_size:
                 # last chunk
                 chunk = chunk[:stop-offset]
                 found_last = True
-            elif offset + chunk_size <= start:
+            elif chunk_size <= start - offset:
+                # before first chunk
                 skip = True
+            else:
+                # middle chunk
+                pass
 
             if not skip:
                 chunk[:] = value[:len(chunk)]
@@ -623,7 +647,6 @@ def __setitem__(self, key: slice, value: Any) -> None:
             if found_last:
                 break
             offset += chunk_size
-        return self.__class__(new_list)
 
 
 # The default buffer prototype used throughout the Zarr codebase.

src/zarr/core/buffer/cpu.py

@@ -196,6 +196,24 @@ def __init__(self, array: NDArrayLike | list[NDArrayLike] | None) -> None:
         core.DelayedBuffer.__init__(self, array)
         self._data_list = list(map(np.asanyarray, self._data_list))
 
+    @classmethod
+    def create_zero_length(cls) -> Self:
+        return cls(np.array([], dtype="b"))
+
+    @classmethod
+    def from_buffer(cls, buffer: core.Buffer) -> Self:
+        if isinstance(buffer, cls):
+            return cls(buffer._data_list)
+        else:
+            return cls(buffer._data)
+
+    @classmethod
+    def from_bytes(cls, bytes_like: BytesLike) -> Self:
+        return cls(np.asarray(bytes_like, dtype="b"))
+
+    def as_numpy_array(self) -> npt.NDArray[Any]:
+        return np.asanyarray(self._data)
+
 
 Buffer.Delayed = DelayedBuffer
 

src/zarr/core/buffer/gpu.py

@@ -229,6 +229,24 @@ def __init__(self, array: NDArrayLike | list[NDArrayLike] | None) -> None:
         core.DelayedBuffer.__init__(self, array)
         self._data_list = list(map(cp.asarray, self._data_list))
 
+    @classmethod
+    def create_zero_length(cls) -> Self:
+        return cls(np.array([], dtype="b"))
+
+    @classmethod
+    def from_buffer(cls, buffer: core.Buffer) -> Self:
+        if isinstance(buffer, cls):
+            return cls(buffer._data_list)
+        else:
+            return cls(buffer._data)
+
+    @classmethod
+    def from_bytes(cls, bytes_like: BytesLike) -> Self:
+        return cls(np.asarray(bytes_like, dtype="b"))
+
+    def as_numpy_array(self) -> npt.NDArray[Any]:
+        return np.asanyarray(self._data)
+
 
 Buffer.Delayed = DelayedBuffer