sim: IPC module (lacks str/int encoding)

diff --git a/migen/sim/__init__.py b/migen/sim/__init__.py
new file mode 100644 (file)
index 0000000..e69de29

diff --git a/migen/sim/ipc.py b/migen/sim/ipc.py
new file mode 100644 (file)
index 0000000..ad89ce1
--- /dev/null
+++ b/migen/sim/ipc.py
@@ -0,0 +1,127 @@
+import socket
+import os
+
+#
+# Message classes
+#
+
+class Message:
+       def __init__(self, *pvalues):
+               for parameter, value in zip(self.parameters, pvalues):
+                       assert(isinstance(value, parameter[0]))
+                       setattr(self, parameter[1], value)
+
+class MessageTick(Message):
+       code = 0
+       parameters = []
+
+class MessageGo(Message):
+       code = 1
+       parameters = []
+
+class MessageWrite(Message):
+       code = 2
+       parameters = [(str, "signal"), (int, "value")]
+
+class MessageRead(Message):
+       code = 3
+       parameters = [(str, "signal")]
+
+class MessageReadReply(Message):
+       code = 4
+       parameters = [(int, "value")]
+
+message_classes = [MessageTick, MessageGo, MessageWrite, MessageRead, MessageReadReply]
+
+#
+# Packing
+#
+
+def _pack_int(v):
+       # TODO
+       return []
+
+def _pack_str(v):
+       # TODO
+       return []
+
+def _pack(message):
+       r = [message.code]
+       for p, t in message.parameters:
+               value = getattr(message, p)
+               assert(isinstance(value, t))
+               if t == int:
+                       r += _pack_int(value)
+               elif t == str:
+                       r += _pack_str(value)
+               else:
+                       raise TypeError
+       return bytes(r)
+
+#
+# Unpacking
+#
+
+def _unpack_int(i):
+       # TODO
+       return 0
+
+def _unpack_str(i):
+       # TODO
+       return ""
+
+def _unpack(message):
+       i = iter(message)
+       code = next(i)
+       msgclass = next(filter(lambda x: x.code == code, message_classes))
+       pvalues = []
+       for p, t in msgclass.parameters:
+               if t == int:
+                       v = _unpack_int(i)
+               elif t == str:
+                       v = _unpack_str(i)
+               else:
+                       raise TypeError
+               pvalues.append(v)
+       return msgclass(*pvalues)
+
+#
+# I/O
+#
+
+class PacketTooLarge(Exception):
+       pass
+       
+class Initiator:
+       def __init__(self, sockaddr="simsocket"):
+               self.sockaddr = sockaddr
+               self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_SEQPACKET)
+               self._cleanup_file()
+               self.socket.bind(self.sockaddr)
+               self.socket.listen(1)
+       
+       def _cleanup_file(self):
+               try:
+                       os.remove(self.sockaddr)
+               except OSError:
+                       pass
+       
+       def accept(self):
+               self.conn, addr = self.socket.accept()
+       
+       def send(self, message):
+               self.conn.send(_pack(message))
+       
+       def recv(self):
+               maxlen = 4096
+               packet = self.conn.recv(maxlen)
+               if len(packet) >= maxlen:
+                       raise PacketTooLarge
+               return _unpack(packet)
+
+       def __del__(self):
+               if hasattr(self, "conn"):
+                       self.conn.close()
+               if hasattr(self, "socket"):
+                       self.socket.close()
+               self._cleanup_file()