def read_template(line_stream):
"""
Read SAFNWC message template into a :class:`.Template`
SAFNWC template lines look as follows:
``1 001033 0 0 8 Code table Identification of originating/generating centre``
:param line_stream: Lines of SAFNWC template file
:return: the template as Template
:rtype: Template
:raises ValueError: if the template contains a desccriptor outside range [0,3]
"""
descriptors = []
metadata = {}
for l in line_stream:
if l.startswith("#") or l.startswith("/*"):
# Ignore comments, does not support multiline comments properly
continue
elif l.startswith("NUM"):
name, num = l.split(" ")
metadata[name] = int(num)
else:
# Input lines look like this:
# 1 001033 0 0 8 Code table Identification of originating/generating centre
num = int(l[:8])
raw_descriptor = l[8:14]
descriptor_code = fxy2int(raw_descriptor)
scale = int(l[14:23])
reference = int(l[23:33])
bits = int(l[33:47])
unit = l[47:65].strip()[:24]
significance = l[65:].strip()[:64]
descr_class = raw_descriptor[0]
if descr_class == '0':
descriptors.append(
ElementDescriptor(descriptor_code, bits, scale, reference,
significance, unit))
elif descr_class == '1':
f, x, y = fxy(raw_descriptor)
descriptors.append(
ReplicationDescriptor(descriptor_code, 0, x, y,
significance))
elif descr_class == '2':
f, x, y = fxy(raw_descriptor)
descriptors.append(
OperatorDescriptor(descriptor_code, 0, x, y, significance))
elif descr_class == '3':
# Ignore sequence descriptors, they are followed by constituent elements in the SAFNWC template format
continue
else:
raise ValueError("Encountered unknown descriptor class: %s" %
descr_class)
name = "B0000000000%(NUM_ORIGINATING_CENTRE)03d%(NUM_BUFR_MAIN_TABLE)03d%(NUM_BUFR_LOCAL_TABLES)03d.TXT" % metadata
return Template(name, descriptors)
def read_template(line_stream):
"""
Read SAFNWC message template into a :class:`.Template`
SAFNWC template lines look as follows:
``1 001033 0 0 8 Code table Identification of originating/generating centre``
:param line_stream: Lines of SAFNWC template file
:return: the template as Template
:rtype: Template
:raises ValueError: if the template contains a desccriptor outside range [0,3]
"""
descriptors = []
metadata = {}
for l in line_stream:
if l.startswith("#") or l.startswith("/*"):
# Ignore comments, does not support multiline comments properly
continue
elif l.startswith("NUM"):
name, num = l.split(" ")
metadata[name] = int(num)
else:
# Input lines look like this:
# 1 001033 0 0 8 Code table Identification of originating/generating centre
num = int(l[:8])
raw_descriptor = l[8:14]
descriptor_code = fxy2int(raw_descriptor)
scale = int(l[14:23])
reference = int(l[23:33])
bits = int(l[33:47])
unit = l[47:65].strip()[:24]
significance = l[65:].strip()[:64]
descr_class = raw_descriptor[0]
if descr_class == "0":
descriptors.append(ElementDescriptor(descriptor_code, bits, scale, reference, significance, unit))
elif descr_class == "1":
f, x, y = fxy(raw_descriptor)
descriptors.append(ReplicationDescriptor(descriptor_code, 0, x, y, significance))
elif descr_class == "2":
f, x, y = fxy(raw_descriptor)
descriptors.append(OperatorDescriptor(descriptor_code, 0, x, y, significance))
elif descr_class == "3":
# Ignore sequence descriptors, they are followed by constituent elements in the SAFNWC template format
continue
else:
raise ValueError("Encountered unknown descriptor class: %s" % descr_class)
name = "B0000000000%(NUM_ORIGINATING_CENTRE)03d%(NUM_BUFR_MAIN_TABLE)03d%(NUM_BUFR_LOCAL_TABLES)03d.TXT" % metadata
return Template(name, descriptors)
def read_tables(b_line_stream, d_line_stream=None):
"""
Read BUFR table(s) in from libbufr text file(s).
The return value is a dict that combines the tables read.
:param b_line_stream: Iterable of lines, contents of the B-table file
:param d_line_stream: Iterable of lines, contents of the D-table file
:return: Mapping from FXY integers to descriptors
:rtype: dict
:raises NotImplementedError: if the table contains sequence descriptors
:raises ValueError: if the table contains descriptors with illegal class (outside range [0,3])
"""
descriptors = {}
for line in b_line_stream:
# Format from btable.F:146 in libbufr version 000400
parts = slices(line, [1, 6, 1, 64, 1, 24, 1, 3, 1, 12, 1, 3])
if not parts[11]:
# Geo::BUFR skips lines without bit width definition,
# libbufr defaults bit width to 0
# choosing to skip here
continue
raw_descriptor = parts[1]
descriptor_code = fxy2int(raw_descriptor)
significance = parts[3].strip()
unit = parts[5].strip()
scale = int(parts[7])
reference = int(parts[9])
bits = int(parts[11])
descr_class = raw_descriptor[0]
if descr_class == '0':
descriptors[descriptor_code] = ElementDescriptor(
descriptor_code, bits, scale, reference, significance, unit)
elif descr_class == '1':
f, x, y = fxy(raw_descriptor)
descriptors[descriptor_code] = ReplicationDescriptor(
descriptor_code, 0, x, y, significance)
elif descr_class == '2':
f, x, y = fxy(raw_descriptor)
descriptors[descriptor_code] = OperatorDescriptor(
descriptor_code, 0, x, y, significance)
elif descr_class == '3':
raise ValueError(
"B-table file should not contain descriptors of class 3: %s" %
descr_class)
else:
raise ValueError("Encountered unknown descriptor class: %s" %
descr_class)
def group_d_lines(ls):
buf = None
for line in ls:
if line.startswith(' 3'):
if buf:
yield buf
buf = [line]
else:
buf.append(line)
yield buf
table = DescriptorTable(
descriptors) # descriptors is not copied, just referenced
if d_line_stream:
for lines in group_d_lines(d_line_stream):
# Format inferred
parts = slices(lines[0], [1, 6, 1, 2, 1, 6])
raw_d_descriptor = parts[1]
d_descriptor_code = fxy2int(raw_d_descriptor)
n_elements = int(parts[3])
actual_elements = len(lines)
if n_elements != actual_elements:
raise ValueError("Expected %d elements, found %d" %
(n_elements, actual_elements))
constituent_codes = []
for line in lines:
l_parts = slices(line, [1, 6, 1, 2, 1, 6])
constituent_codes.append(fxy2int(l_parts[5]))
descriptors[d_descriptor_code] = LazySequenceDescriptor(
d_descriptor_code, constituent_codes, '', table)
return table
