Can't roundtrip compression/decompression with empty numpy array

[pfackeldey]

Hi numcodecs devs,

I found that you can't roundtrip compression & decompression with an empty numpy array:

import numpy as np
import numcodecs

print(numcodecs.__version__)
# '0.16.5'

arr = np.array([])

codec = numcodecs.Blosc(cname="zstd", clevel=1, shuffle=numcodecs.Blosc.BITSHUFFLE)

# roundtrip
codec.decode(codec.encode(arr.tobytes()))
# ---------------------------------------------------------------------------
# RuntimeError                              Traceback (most recent call last)
# Cell In[14], line 1
# ----> 1 codec.decode(codec.encode(arr.tobytes()))
# 
# File numcodecs/blosc.pyx:500, in numcodecs.blosc.Blosc.decode()
# 
# File numcodecs/blosc.pyx:399, in numcodecs.blosc.decompress()
# 
# RuntimeError: error during blosc decompression: 0

I didn't find anything in the docs if this is expected behavior or not?

Best, Peter