diff options
Diffstat (limited to 'numpy/lib/format.py')
| -rw-r--r-- | numpy/lib/format.py | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/numpy/lib/format.py b/numpy/lib/format.py index cfe0e62ac..e62677bd8 100644 --- a/numpy/lib/format.py +++ b/numpy/lib/format.py @@ -558,8 +558,11 @@ def write_array(fp, array, version=None, allow_pickle=True, pickle_kwargs=None): warnings.warn("Stored array in format 2.0. It can only be" "read by NumPy >= 1.9", UserWarning) - # Set buffer size to 16 MiB to hide the Python loop overhead. - buffersize = max(16 * 1024 ** 2 // array.itemsize, 1) + if array.itemsize == 0: + buffersize = 0 + else: + # Set buffer size to 16 MiB to hide the Python loop overhead. + buffersize = max(16 * 1024 ** 2 // array.itemsize, 1) if array.dtype.hasobject: # We contain Python objects so we cannot write out the data @@ -655,15 +658,21 @@ def read_array(fp, allow_pickle=True, pickle_kwargs=None): # of the read. In non-chunked case count < max_read_count, so # only one read is performed. - max_read_count = BUFFER_SIZE // min(BUFFER_SIZE, dtype.itemsize) - - array = numpy.empty(count, dtype=dtype) - for i in range(0, count, max_read_count): - read_count = min(max_read_count, count - i) - read_size = int(read_count * dtype.itemsize) - data = _read_bytes(fp, read_size, "array data") - array[i:i+read_count] = numpy.frombuffer(data, dtype=dtype, - count=read_count) + # Use np.ndarray instead of np.empty since the latter does + # not correctly instantiate zero-width string dtypes; see + # https://github.com/numpy/numpy/pull/6430 + array = numpy.ndarray(count, dtype=dtype) + + if dtype.itemsize > 0: + # If dtype.itemsize == 0 then there's nothing more to read + max_read_count = BUFFER_SIZE // min(BUFFER_SIZE, dtype.itemsize) + + for i in range(0, count, max_read_count): + read_count = min(max_read_count, count - i) + read_size = int(read_count * dtype.itemsize) + data = _read_bytes(fp, read_size, "array data") + array[i:i+read_count] = numpy.frombuffer(data, dtype=dtype, + count=read_count) if fortran_order: array.shape = shape[::-1] |