Initial revision

Demo/rpc/xdr.py

@@ -0,0 +1,141 @@
+# Implement (a subset of) Sun XDR -- RFC1014.
+
+
+import struct
+
+
+class Packer:
+
+	def init(self):
+		self.reset()
+		return self
+
+	def reset(self):
+		self.buf = ''
+
+	def get_buf(self):
+		return self.buf
+
+	def pack_uint(self, x):
+		self.buf = self.buf + \
+			(chr(int(x>>24 & 0xff)) + chr(int(x>>16 & 0xff)) + \
+			 chr(int(x>>8 & 0xff)) + chr(int(x & 0xff)))
+	if struct.pack('i', 1) == '\0\0\0\1':
+		def pack_uint(self, x):
+			self.buf = self.buf + struct.pack('i', x)
+
+	pack_int = pack_uint
+
+	pack_enum = pack_int
+
+	def pack_bool(self, x):
+		if x: self.buf = self.buf + '\0\0\0\1'
+		else: self.buf = self.buf + '\0\0\0\0'
+
+	def pack_uhyper(self, x):
+		self.pack_uint(x>>32 & 0xffffffff)
+		self.pack_uint(x & 0xffffffff)
+
+	pack_hyper = pack_uhyper
+
+	def pack_fstring(self, n, s):
+		if n < 0:
+			raise ValueError, 'fstring size must be nonnegative'
+		n = ((n+3)/4)*4
+		data = s[:n]
+		data = data + (n - len(data)) * '\0'
+		self.buf = self.buf + data
+
+	pack_fopaque = pack_fstring
+
+	def pack_string(self, s):
+		n = len(s)
+		self.pack_uint(n)
+		self.pack_fstring(n, s)
+
+	pack_opaque = pack_string
+
+	def pack_list(self, list, pack_item):
+		for item in list:
+			self.pack_uint(1)
+			pack_item(list)
+		self.pack_uint(0)
+
+
+class Unpacker:
+
+	def init(self, data):
+		self.reset(data)
+		return self
+
+	def reset(self, data):
+		self.buf = data
+		self.pos = 0
+
+	def done(self):
+		if self.pos < len(self.buf):
+			raise RuntimeError, 'unextracted data remains'
+
+	def unpack_uint(self):
+		i = self.pos
+		self.pos = j = i+4
+		data = self.buf[i:j]
+		x = long(ord(data[0]))<<24 | ord(data[1])<<16 | \
+			ord(data[2])<<8 | ord(data[3])
+		# Return a Python long only if the value is not representable
+		# as a nonnegative Python int
+		if x < 0x80000000L: x = int(x)
+		return x
+	if struct.unpack('i', '\0\0\0\1') == 1:
+		def unpack_uint(self):
+			i = self.pos
+			self.pos = j = i+4
+			return struct.unpack('i', self.buf[i:j])
+
+	def unpack_int(self):
+		x = self.unpack_uint()
+		if x >= 0x80000000L: x = x - 0x100000000L
+		return int(x)
+
+	unpack_enum = unpack_int
+
+	unpack_bool = unpack_int
+
+	def unpack_uhyper(self):
+		hi = self.unpack_uint()
+		lo = self.unpack_uint()
+		return long(hi)<<32 | lo
+
+	def unpack_hyper(self):
+		x = self.unpack_uhyper()
+		if x >= 0x8000000000000000L: x = x - 0x10000000000000000L
+		return x
+
+	def unpack_fstring(self, n):
+		if n < 0:
+			raise ValueError, 'fstring size must be nonnegative'
+		i = self.pos
+		j = i + (n+3)/4*4
+		if j > len(self.buf):
+			raise RuntimeError, 'buffer overrun'
+		self.pos = j
+		return self.buf[i:i+n]
+
+	unpack_fopaque = unpack_fstring
+
+	def unpack_string(self):
+		n = self.unpack_uint()
+		return self.unpack_fstring(n)
+
+	unpack_opaque = unpack_string
+
+	def unpack_list(self, unpack_item):
+		list = []
+		while 1:
+			x = self.unpack_uint()
+			if not x: break
+			if x <> 1:
+				raise RuntimeError, \
+					'0 or 1 expected, got ' + `x`
+			list.append(unpack_item())
+		return list