'compute the index content of the given filename, or binary data.
This is a python implementation of the unix command \'strings\'.
:param bin_data : datas in binary form
:return index_content : string containing all the printable character of the binary data'

@api.model
def _index(self, bin_data, datas_fname, file_type):

    index_content = False
    if file_type:
        index_content = file_type.split('/')[0]
        if (index_content == 'text'):
            words = re.findall('[^\x00-\x1f\x7f-\xff]{4,}', bin_data)
            index_content = ustr('\n'.join(words))
    return index_content
