comparison scpi.py @ 15:37d6ceb4850f

Add helper functions for SCPI.
author Daniel O'Connor <darius@dons.net.au>
date Wed, 10 Aug 2011 12:50:37 +0930
parents
children 20df02be818a
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14:55c8dae6d1db 15:37d6ceb4850f
1 #!/usr/bin/env python
2
3 # Copyright (c) 2011
4 # Daniel O'Connor <darius@dons.net.au>. All rights reserved.
5 #
6 # Redistribution and use in source and binary forms, with or without
7 # modification, are permitted provided that the following conditions
8 # are met:
9 # 1. Redistributions of source code must retain the above copyright
10 # notice, this list of conditions and the following disclaimer.
11 # 2. Redistributions in binary form must reproduce the above copyright
12 # notice, this list of conditions and the following disclaimer in the
13 # documentation and/or other materials provided with the distribution.
14 #
15 # THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 # ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
19 # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 # SUCH DAMAGE.
26 #
27
28 import exceptions
29 import numpy
30
31 def bindecode(data, header = '', dtype = numpy.float32):
32 '''Decode binary data, returns numpy array'''
33 if data[0:len(header)] != header:
34 raise exceptions.ValueError('data header incorrect')
35 ofs = len(header)
36 if data[ofs] != '#':
37 raise exceptions.ValueError('data length header incorrect')
38 dlenlen = int(data[ofs + 1])
39 dlen = int(data[ofs + 2:ofs + dlenlen + 2])
40 if len(data) != len(header) + dlen + 2 + dlenlen:
41 raise exceptions.ValueError('length mismatch, header says %d, actually got %d bytes' % (len(header) + dlen + 2 + dlenlen, len(data)))
42 return numpy.frombuffer(data[len(header) + 2 + dlenlen:], dtype = dtype)
43
44 def ascdecode(data, dtype = numpy.float32):
45 '''Decode ASCII data, returns numpy array'''
46 return numpy.fromstring(data, dtype = dtype, sep = ',')
47