initial commit

1 files changed, 136 insertions, 0 deletions

diff --git a/scope.py b/scope.py
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+++ b/scope.py
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+#!/usr/bin/env python
+# LeCrunch
+# Copyright (C) 2010 Anthony LaTorre 
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import struct
+import socket
+import os
+
+headerformat = '>BBBBL'
+
+errors = { 1 : 'unrecognized command/query header',
+           2 : 'illegal header path',
+           3 : 'illegal number',
+           4 : 'illegal number suffix',
+           5 : 'unrecognized keyword',
+           6 : 'string error',
+           7 : 'GET embedded in another message',
+           10 : 'arbitrary data block expected',
+           11 : 'non-digit character in byte count field of ' \
+                'arbitrary data block',
+           12 : 'EOI detected during definite length data block transfer',
+           13 : 'extra bytes detected during definite length data block ' \
+                'transfer' }
+
+class Scope(object):
+    """
+    A class for low level communication with the oscilliscope over a socket
+    connection.
+    """
+    def __init__(self, host, port=1861, timeout=2.0):
+        """Create a socket object to *host* over *port*"""
+        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.sock.settimeout(timeout)
+        self.host = host
+        self.port = port
+        self.timeout = timeout
+
+    def settimeout(self, timeout):
+        """Set the *timeout* for the socket connection in seconds."""
+        self.sock.settimeout(timeout)
+        self.timeout = timeout
+        
+    def connect(self):
+        """Make the socket connection."""
+        self.sock.connect((self.host, self.port))
+
+    def clear(self):
+        """Clear the oscilloscope's output queue."""
+        self.sock.settimeout(2.0)
+        try:
+            while True:
+                self.sock.recv(100)
+        except socket.timeout:
+            pass
+        self.sock.settimeout(self.timeout)
+
+    def close(self):
+        """Close the socket connection."""
+        self.sock.close()
+
+    def send(self, str):
+        """Format and send the string *str*."""
+        if not str.endswith('\n'):
+            str += '\n'
+        header = struct.pack(headerformat, 129, 1, 1, 0, len(str))
+        self.sock.sendall(header + str)
+
+    def check_last_command(self):
+        """
+        Check that the last command sent was received okay; if not, then
+        raise an exception with details about the error.
+        """
+        self.send('cmr?')
+        err = int(self.recv().split(' ')[-1].rstrip('\n'))
+
+        if err in errors:
+            self.close()
+            raise Exception(errors[err])
+
+    def getheader(self):
+        """
+        Unpacks a header string from the oscilloscope into the tuple
+        (operation, header version, sequence number, spare, total bytes).
+        """
+        return struct.unpack(headerformat, self.sock.recv(8))
+
+    def recv(self):
+        """
+        Receive, concatenate, and return a 'logical series' of blocks from
+        the oscilloscope. A 'logical series' consists of one or more blocks
+        in which the final block is terminated by an EOI terminator
+        (i.e. the EOI bit in the header block is set to '1').
+        """
+        reply = ''
+        while True:
+            operation, headerver, seqnum, spare, totalbytes  = self.getheader()
+
+            buffer = ''
+
+            while len(buffer) < totalbytes:
+                buffer += self.sock.recv(totalbytes - len(buffer))
+
+            reply += buffer
+
+            if operation % 2:
+                break
+            
+        return reply
+
+if __name__ == '__main__':
+    import sys
+    scope = Scope('scope01.hep.upenn.edu')
+    scope.connect()
+    scope.clear()
+
+    for msg in sys.argv[1:]:
+        scope.send(msg)
+        if '?' in msg:
+            print repr(scope.recv())
+
+        scope.check_last_command()
+
+    scope.close()