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Save values using extra dictionary instead of attributes #9

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AdamStrojek wants to merge 2 commits into from
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Save values using extra dictionary instead of attributes #9

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9e1fff6
Save values using extra dictionary instead of attributes
AdamStrojek May 6, 2019
2620afb
Fix missing declaration for metaclass
AdamStrojek May 7, 2019
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51 changes: 33 additions & 18 deletions cstruct/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -182,12 +182,13 @@ def __new__(mcs, name, bases, dict):
__struct__ = dict.get("__struct__", None)
if __struct__ is not None:
dict['__fmt__'], dict['__fields__'], dict['__fields_types__'] = mcs.parse_struct(__struct__)
dict['__values__'] = {}
if '__byte_order__' in dict:
dict['__fmt__'] = dict['__byte_order__'] + dict['__fmt__']
# Add the missing fields to the class
for field in dict['__fields__']:
if field not in dict:
dict[field] = None
if field not in dict['__values__']:
dict['__values__'][field] = None
# Calculate the structure size
dict['__size__'] = struct.calcsize(dict['__fmt__'])
new_class = type.__new__(mcs, name, bases, dict)
Expand Down Expand Up @@ -312,8 +313,9 @@ def __init__(self, string=None, **kargs):
self.unpack(string)
except:
pass
self.__values__ = {}
for key, value in kargs.items():
setattr(self, key, value)
self.__values__[key] = value

def unpack(self, string):
"""
Expand All @@ -326,29 +328,29 @@ def unpack(self, string):
for field in self.__fields__:
(vtype, vlen) = self.__fields_types__[field]
if vtype == 'char': # string
setattr(self, field, data[i])
i = i + 1
self.__values__[field] = data[i]
i += 1
elif isinstance(vtype, CStructMeta):
num = int(vlen / vtype.size)
if num == 1: # single struct
sub_struct = vtype()
sub_struct.unpack(EMPTY_BYTES_STRING.join(data[i:i+sub_struct.size]))
setattr(self, field, sub_struct)
i = i + sub_struct.size
self.__values__[field] = sub_struct
i += sub_struct.size
else: # multiple struct
sub_structs = []
for j in range(0, num):
sub_struct = vtype()
sub_struct.unpack(EMPTY_BYTES_STRING.join(data[i:i+sub_struct.size]))
i = i + sub_struct.size
i += sub_struct.size
sub_structs.append(sub_struct)
setattr(self, field, sub_structs)
self.__values__[field] = sub_structs
elif vlen == 1:
setattr(self, field, data[i])
i = i + vlen
self.__values__[field] = data[i]
i += vlen
else:
setattr(self, field, list(data[i:i+vlen]))
i = i + vlen
self.__values__[field] = list(data[i:i+vlen])
i += vlen

def pack(self):
"""
Expand All @@ -358,17 +360,17 @@ def pack(self):
for field in self.__fields__:
(vtype, vlen) = self.__fields_types__[field]
if vtype == 'char': # string
data.append(getattr(self, field))
data.append(self.__values__.get(field))
elif isinstance(vtype, CStructMeta):
num = int(vlen / vtype.size)
if num == 1: # single struct
v = getattr(self, field, vtype())
v = self.__values__.get(field, vtype())
v = v.pack()
if sys.version_info >= (3, 0):
v = ([bytes([x]) for x in v])
data.extend(v)
else: # multiple struct
values = getattr(self, field, [])
values = self.__values__.get(field, [])
for j in range(0, num):
try:
v = values[j]
Expand All @@ -379,13 +381,26 @@ def pack(self):
v = ([bytes([x]) for x in v])
data.extend(v)
elif vlen == 1:
data.append(getattr(self, field))
data.append(self.__values__.get(field))
else:
v = getattr(self, field)
v = self.__values__.get(field)
v = v[:vlen] + [0] * (vlen - len(v))
data.extend(v)
return struct.pack(self.__fmt__, *data)

def __getattr__(self, name):
if name in self.__fields__:
try:
return self.__values__[name]
except KeyError:
raise AttributeError("'{}' object has no attribute '{}'".format(self.__name__, name))
return super(CStruct, self).__getattr__(name)

def __setattr__(self, name, value):
if name in self.__fields__:
self.__values__[name] = value
super(CStruct, self).__setattr__(name, value)

def clear(self):
self.unpack(None)

Expand Down