Fix Hintergrund extractionHEADmaster

The script added a bogus/empty page at offset 0x600, since only three
instead of four entries of the first page table were skipped.

To make sure offsets are correct, add the first page (not stored on
Hintergrund) to the output as well. FILE dataspace conversion can skip
this page with `--skip 1`.

1 files changed, 5 insertions, 2 deletions

diff --git a/convertFileDs.py b/convertFileDs.py
index 89e0cab..d5c234b 100755
--- a/convertFileDs.py
+++ b/convertFileDs.py
@@ -9,7 +9,7 @@ datastructure here. See EUMEL packet “file handling”.
 
 import struct, copy
 from collections import namedtuple
-from eumel import Dataspace, DataspaceTypeMismatch, HeapReferenceUnresolved
+from eumel import Dataspace, DataspaceTypeMismatch, HeapReferenceUnresolved, pagesize
 
 Segment = namedtuple ('Segment', ['succ', 'pred', 'end'])
 Sequence = namedtuple ('Sequence', ['index', 'segmentbegin', 'segmentend', 'lineno', 'lines'])
@@ -77,12 +77,13 @@ class FileDataspace (Dataspace):
         Dataspace.__init__ (self, fd)
 
         # header of the BOUND LIST (aka TYPE FILE)
+        start = fd.tell ()
         self.used = self.parseSequence ()
         self.parseInt (2)
         self.parseSequence ()
         self.parseSequence ()
         self.parseInt (7)
-        assert self.fd.tell () == 0x38
+        assert self.fd.tell ()-start == 0x30
 
         rows = self.parseRows ()
 
@@ -150,6 +151,7 @@ if __name__ == '__main__':
     
     parser = argparse.ArgumentParser(description='Convert EUMEL FILE dataspace into plain text file.')
     parser.add_argument ('-v', '--verbose', help='Enable debugging messages', action='store_true')
+    parser.add_argument ('-s', '--skip', metavar='PAGES', type=int, default=0, help='Skip pages at the beginning of the file')
     parser.add_argument ('file', help='Input file')
     args = parser.parse_args ()
 
@@ -160,6 +162,7 @@ if __name__ == '__main__':
 
     with open (args.file, 'rb') as fd:
         try:
+            fd.seek (args.skip*pagesize)
             ds = FileDataspace (fd)
             linecount = len (ds.text.splitlines ())
             if linecount != ds.used.lines: