* Initial version of Fortran binary file reader.

Later a writing facility can be added as well.
* Note that this module is intended only for reading/writing
  Fortran-generated files.
  It is not recommended for any other purpose because of its terrible feature:
  no metadata, no description whatsoever.

iofmt/__init__.py

@@ -0,0 +1,11 @@
+# $Id: __init__.py,v 1.1 2010-02-08 21:49:54 wirawan Exp $
+#
+# wpylib.iofmt module
+# Created: 20100208
+# Wirawan Purwanto
+#
+# I/O format-related stuff.
+
+"""I/O format-related stuff."""
+
+pass

iofmt/fortbin.py

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