Import first working version

[fuse-aexplorer.git] / AEpy / AEMultipart.py

diff --git a/AEpy/AEMultipart.py b/AEpy/AEMultipart.py
new file mode 100644 (file)
index 0000000..a542bfa
--- /dev/null
+++ b/AEpy/AEMultipart.py
@@ -0,0 +1,94 @@
+import struct
+
+
+
+def recvHeader(session):
+    (type, data) = session.recvMsg()
+    # TODO: Check for type 1, as that means an error.
+    #       For example, a directory can't be listed because it doesn't exist.
+    assert type == 3
+    assert len(data) == 8
+
+    (datalen, pktsize) = struct.unpack('!LL', data)
+
+    return (datalen, pktsize)
+
+
+def recvBlock(session):
+    # Send empty type 0 message to request next block
+    session.sendMsg(0, b'')
+
+    (type, data) = session.recvMsg()
+
+    if type == 1:
+        print('recvMultipartBlock: Host cancelled transfer.')
+        # Maybe TODO: Raise an exception
+        return (None, None)
+
+    if type == 4:
+        # Last block
+        assert len(data) == 0
+        return (None, None)
+
+    # Expect a data block
+    assert type == 5
+
+    # Any data block has the offset prepended,
+    # followed by up to PACKETSIZE-4 bytes of payload.
+    assert len(data) >= 4
+
+    (offset,) = struct.unpack('!L', data[0:4])
+
+    return (offset, data[4:])
+
+
+def recv(session):
+    fullData = b''
+
+    (datalen, pktsize) = recvHeader(session)
+
+    offset = 0
+    data = b''
+    while data != None:
+        assert offset == len(fullData)
+        fullData += data
+
+        (offset, data) = recvBlock(session)
+
+    return fullData
+
+
+def send(session, fullData):
+    # Wait for Amiga to request first block with type 0
+    (type, _) = session.recvMsg()
+
+    # TODO: Handle transfer abort (type 1)
+    # TODO: What happens when sending an ADF != 901120 bytes?
+    assert (type == 0) or (type == 8)
+
+    if type == 8:
+        # Does this confirm that we want to overwrite?
+        session.sendMsg(0, b'')
+
+    # Send length and block size
+    session.sendMsg(3, struct.pack('!LL', len(fullData), session.packetsize))
+
+    bytesSent = 0
+    while bytesSent < len(fullData):
+        # Wait for Amiga to request block with type 0
+        (type, _) = session.recvMsg()
+        assert type == 0
+
+        print("AEMultipart.send: " + str(bytesSent))
+
+        txlen = min(session.packetsize - 4, len(fullData) - bytesSent)
+        session.sendMsg(5, struct.pack('!L', bytesSent) + fullData[bytesSent : bytesSent+txlen])
+
+        bytesSent += txlen
+
+    # Wait for Amiga's type 0
+    (type, _) = session.recvMsg()
+    assert type == 0
+
+    # Finish transfer
+    session.sendMsg(4, b'')