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