SF.net SVN: fclient:[689] trunk/fclient/src/fclient/lib/fcp2/lib/pmstruct. py

[<jU...@us...>]

Revision: 689
          http://fclient.svn.sourceforge.net/fclient/?rev=689&view=rev
Author:   jUrner
Date:     2008-07-20 10:34:07 +0000 (Sun, 20 Jul 2008)

Log Message:
-----------
support for persistent params handling

Added Paths:
-----------
    trunk/fclient/src/fclient/lib/fcp2/lib/pmstruct.py

Added: trunk/fclient/src/fclient/lib/fcp2/lib/pmstruct.py
===================================================================
--- trunk/fclient/src/fclient/lib/fcp2/lib/pmstruct.py	                        (rev 0)
+++ trunk/fclient/src/fclient/lib/fcp2/lib/pmstruct.py	2008-07-20 10:34:07 UTC (rev 689)
@@ -0,0 +1,215 @@
+"""poor mans struct
+
+simple structure with (safe) serializing support
+
+
+@requires: python >= 2.5 (L is never removed from str(nL) )
+"""
+
+import base64
+#*******************************************************************
+#
+#*******************************************************************
+class PMStructError(Exception): pass
+
+SEP = '|'
+HEADER = 'PMS'
+
+class BOOL(object):
+	_typecode_ = 'B'
+	@classmethod
+	def default(clss):
+		return False
+	@classmethod
+	def from_data(clss, data):
+		if data:
+			typecode, data = data[ :1], data [ 1: ]
+			if typecode == clss._typecode_:
+				try:
+					return data == '1'
+				except: pass
+		raise PMStructError('invalid bool')
+	@classmethod
+	def to_data(clss, value):
+		return clss._typecode_ + ('1' if value else '0')
+	@classmethod
+	def is_type(self, value):
+		return type(value) is bool
+
+
+class FLOAT(object):
+	_typecode_ = 'F'
+	@classmethod
+	def default(clss):
+		return 0.0
+	@classmethod
+	def from_data(clss, data):
+		if data:
+			typecode, data = data[ :1], data [ 1: ]
+			if typecode == clss._typecode_:
+				try:
+					return float(data)
+				except: pass
+		raise PMStructError('invalid int')
+	@classmethod
+	def to_data(clss, value):
+		return clss._typecode_ + str(value)
+	@classmethod
+	def is_type(self, value):
+		return type(value) is float
+
+
+class INT(object):
+	_typecode_ = 'I'
+	@classmethod
+	def default(clss):
+		return 0
+	@classmethod
+	def from_data(clss, data):
+		if data:
+			typecode, data = data[ :1], data [ 1: ]
+			if typecode == clss._typecode_:
+				try:
+					return int(data)
+				except: pass
+		raise PMStructError('invalid int')
+	@classmethod
+	def to_data(clss, value):
+		return clss._typecode_ + str(value)
+	@classmethod
+	def is_type(self, value):
+		return type(value) in (int, long)
+			
+
+class STRING(object):
+	_typecode_ = 'S'
+	@classmethod
+	def default(clss):
+		return ''
+	@classmethod
+	def from_data(clss, data):
+		if data:
+			typecode, data = data[ :1], data [ 1: ]
+			if typecode == clss._typecode_:
+				try:
+					return base64.b64decode(data)
+				except: pass
+		raise PMStructError('invalid string')
+	@classmethod
+	def to_data(clss, value):
+		return clss._typecode_ + base64.b64encode(value)
+	@classmethod
+	def is_type(self, value):
+		return type(value) in (str, unicode)
+			
+
+class PMStruct(object):
+	_fields_ = ()
+	
+	def __init__(self, **kws):
+		self._fielddict_ = dict(self._fields_)
+		self.values = {}
+		for name, fieldtype in self._fields_:
+			value = kws.get(name, None)
+			if value is None:
+				value = fieldtype.default()
+			else:
+				if not fieldtype.is_type(value):
+					raise TypeError('invalid type for field: %r' % name)
+				del kws[name]
+			self.values[name] = value
+		if kws:
+			raise ValueError('no such field: %r' % kws.keys()[0])
+		
+		
+	def __getitem__(self, name):
+		return self.values[name]
+	
+	def __setitem__(self, name, value):
+		fieldtype = self._fielddict_	[name]
+		if not fieldtype.is_type(value):
+			raise TypeError('invalid type for field: %r' % name)
+		self.values[name] = value
+		
+	
+	def __str__(self):
+		return self.__repr__()
+	
+	def __repr__(self):
+		return '<PMS' + repr(self.values) + '>'
+	
+	@classmethod
+	def load(clss, data):
+		data = data.split(SEP, 1)
+		if len(data) != 2:
+			raise PMStructError('invalid data')
+		header, data = data
+		if header	!= HEADER:
+			raise PMStructError('invalid data header')
+		#data = base64.b64decode(data)
+		data = data.split(SEP)
+		if len(data) != len(clss._fields_):
+			raise PMStructError('too few or too many fields')
+		kws = {}
+		for i, (name, fieldtype) in enumerate(clss._fields_):
+			kws[name] = fieldtype.from_data(data[i])
+		return clss(**kws)	
+			
+	def dump(self):
+		p = []
+		for name, fieldtype in self._fields_:
+			value = fieldtype.to_data(self.values[name])
+			p.append(value)
+		data = SEP.join(p)
+		#data = base64.b64encode(data)
+		return HEADER + SEP + data
+			
+			
+
+def foo():
+	class PersistentParamsGet(PMStruct):
+		_fields_ = (
+				('Version', INT),
+				('InitTime', FLOAT),
+				('PersistentUserData', STRING),
+				('HandleFilenameCollision', BOOL),
+				('FilenameCollisionHandled', BOOL),
+				('HandlePermanentRedirect', BOOL),
+				('PermanentRedirectHandled', BOOL),
+				)
+				
+				
+	p = PersistentParamsGet()
+	print p.dump()
+	print p
+
+#foo()
+#print {1: 1, 2: 2}
+#print repr({1: 1, 2: 2})
+
+def test():
+
+	class MyStruct(PMStruct):
+		_fields_ = (
+			('Foo', INT),
+			('Bar', BOOL),
+			('Baz', STRING),
+			('Muu', FLOAT)
+			)
+		
+
+
+	p = MyStruct(Foo=100000000000L, Bar=True, Baz=u'abcdefg', Muu=1.2345678)
+	x = p.dump()
+	print x
+	print p.load(x)
+	print p['Foo']
+	print p['Bar']
+	print p['Baz']
+	print p['Muu']
+
+	p['Muu'] = 123
+			
+		
+	
+	


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