def __init__(self, filename, chunk_size=0.1, version='1.1'):
"""Initialize an HDF5 file for writing h5features.
Parameters
----------
filename : str --- The name of the HDF5 file to write on. For
clarity you should use a *.h5 extension but this is not
required.
chunk_size : float, optional --- The size in Mo of a chunk in
the file. Default is 0.1 Mo. A chunk size below 8 Ko is
not allowed as it results in poor performances.
Raise
-----
IOError if the file exists but is not HDF5.
IOError if the chunk size is below 8 Ko.
"""
if not is_supported_version(version):
raise IOError('version {} is not supported'.format(version))
self.version = version
# Raise if the file exists but is not HDF5
if os.path.isfile(filename) and not h5py.is_hdf5(filename):
raise IOError('{} is not a HDF5 file.'.format(filename))
self.filename = filename
if chunk_size < 0.008:
raise IOError('chunk size is below 8 Ko')
self.chunk_size = chunk_size
def _read_version(self):
"""Return the h5features version of the readed file.
This method raise IOError if version is not either 0.1, 1.0 or 1.1
"""
version = ('0.1' if not 'version' in self.group.attrs
else self.group.attrs['version'])
# decode from bytes to str
if type(version) == bytes:
version = version.decode()
if not is_supported_version(version):
raise IOError('version {} is not supported'.format(version))
return version
