oscopy/readers/spice2raw_reader.py

   1 from __future__ import with_statement
   2
   3 from oscopy import Signal
   4 from reader import Reader, ReadError
   5 import struct
   6
   7 class Spice2rawReader(Reader):
   8     """ Read Berkeley Spice2G6 'raw' output files
   9
  10     Currently support only one dataset per file
  11     Date and Time fields are not processed
  12
  13     see http://www.rvq.fr/linux/gawfmt.php for format description
  14     """
  15     _signature = 'rawfile1'
  16     _types_to_unit = {0: 'a.u.', 1: 's', 2: 'V', 3: 'A', 4: 'Hz', 5: 'a.u.'}
  17     def detect(self, fn):
  18         """ Look at the header if it contains the keyword self._signature
  19
  20         Parameter
  21         ---------
  22         fn: string
  23         Path to the file to test
  24
  25         Returns
  26         -------
  27         bool
  28         True if the file can be handled by this reader
  29         """
  30         self._check(fn)
  31         try:
  32             f = open(fn)
  33         except IOError, e:
  34             return False
  35         s = f.read(8)
  36         f.close()
  37         return s == self._signature
  38
  39     def _read_signals(self):
  40         """ Read the signals from the file
  41
  42         Supports only one dataset per file
  43
  44         Parameter
  45         ---------
  46         fn: string
  47         The filename
  48
  49         Returns
  50         -------
  51         Dict of Signals
  52         The list of Signals read from the file
  53
  54         Raises
  55         ------
  56         ReaderError
  57         In case of invalid path or unsupported file format
  58         """
  59         header_fields = ['signature', 'title', 'date', 'time',
  60                          'mode', 'nvars', 'const4']
  61         with open(self._fn) as f:
  62             # Header
  63             signature = f.read(8)
  64             title = f.read(80).strip('\x00')
  65             res = f.read(22)
  66             (date, t, mode, nvars, const4) = struct.unpack('<2d3h' ,res)
  67             self._info.update(dict(zip(header_fields, (signature, title, date, t, mode, nvars, const4))))
  68
  69             names = []
  70             for i in xrange(nvars):
  71                 names.append(f.read(8).strip('#').strip('\x00'))
  72             types = struct.unpack('<%dh' % nvars, f.read(2 * nvars))
  73             locs = struct.unpack('<%dh' % nvars, f.read(2 * nvars))
  74             self._info['plottitle'] = f.read(24).strip('\x00')
  75
  76             # Now we can create the signals
  77             signals = []
  78             for i in xrange(nvars):
  79                 signals.append(Signal(names[i],
  80                                       self._types_to_unit.get(types[i], 'a.u.')))
  81             # Data
  82             data = [[] for x in xrange(len(names))]
  83             # optimization: cache the append methods,
  84             # avoiding one dictionary lookup per line
  85             append = [x.append for x in data]
  86             while f:
  87                 tmp = f.read(8 * nvars)
  88                 if len(tmp) < 8 * nvars: break
  89                 values = struct.unpack('<%dd' % nvars, tmp)
  90                 for i, v in enumerate(values):
  91                     append[i](v)
  92
  93         ref = signals[0]
  94         ref.data = data[0]
  95         for i, s in enumerate(signals[1:]):
  96             s.ref = ref
  97             s.data = data[i + 1]
  98
  99         self._signals = dict(zip(names[1:], signals[1:]))
 100         print self._signals
 101         return self._signals
 102
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