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89 lines
2.3 KiB
89 lines
2.3 KiB
# $Id: fortbin.py,v 1.1 2010-02-08 21:49:54 wirawan Exp $
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#
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# wpylib.iofmt.fortbin module
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# Created: 20100208
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# Wirawan Purwanto
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#
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"""
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Fortran binary format.
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"""
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import numpy
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import sys
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from wpylib.sugar import ifelse
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class fortran_bin_file(object):
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"""A tool for reading Fortran binary files."""
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def __init__(self, filename=None):
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self.record_marker_type = numpy.uint32
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self.debug = 100
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if filename:
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self.open(filename)
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def open(self, filename):
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self.F = open(filename, "rb")
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def read(self, *fields, **opts):
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"""Reads a Fortran record.
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The description of the fields are given as
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(name, dtype, length) tuples."""
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from numpy import fromfile as rd
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if self.debug:
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dbg = lambda msg : sys.stderr.write(msg)
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else:
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dbg = lambda msg : None
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def fld_count(f):
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if len(f) > 2:
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return f[2]
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else:
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return 1
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reclen = numpy.fromfile(self.F, self.record_marker_type, 1)
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dbg("Record length = %d\n" % reclen)
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expected_len = sum([ fld_count(f) * numpy.dtype(f[1]).itemsize
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for f in fields ])
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dbg("Expected length = %d\n" % expected_len)
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if expected_len > reclen:
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raise IOError, \
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"Attempting to read %d bytes from a record of length %d bytes" \
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% (expected_len, reclen)
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if "out" in opts:
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rslt = opts["out"]
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else:
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rslt = {}
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if (issubclass(rslt.__class__, dict) and issubclass(dict, rslt.__class__)) \
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or "__setitem__" in dir(rslt):
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def setval(d, k, v):
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d[k] = v
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else:
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# Assume we can use setattr method:
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setval = setattr
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for f in fields:
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if len(f) > 2:
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(name,Dtyp,Len) = f
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dtyp = numpy.dtype(Dtyp)
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setval(rslt, name, numpy.fromfile(self.F, dtyp, Len))
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else:
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# Special handling for scalars
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name = f[0]
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dtyp = numpy.dtype(f[1])
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setval(rslt, name, numpy.fromfile(self.F, dtyp, 1)[0])
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if expected_len < reclen:
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self.F.seek(reclen - expected_len, 1)
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reclen2 = numpy.fromfile(self.F, self.record_marker_type, 1)
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dbg("Record length tail = %d\n" % reclen2)
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if reclen2 != reclen:
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raise IOError, \
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"Inconsistency in record: end-marker length = %d; was expecting %d" \
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% (reclen2, reclen)
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return rslt
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