# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1290465944 -3600
# Node ID 8d35240236b2a411c31a389881b4176687b236f6
# Parent  d308dc25f5a2b0330d08bcb147e51eb328ee2139
Added integrity checks for appropriate term and position ordering.

diff -r d308dc25f5a2 -r 8d35240236b2 iixr/terms.py
--- a/iixr/terms.py	Sun Nov 21 20:44:43 2010 +0100
+++ b/iixr/terms.py	Mon Nov 22 23:45:44 2010 +0100
@@ -40,6 +40,9 @@
         term information file.
         """
 
+        if term <= self.last_term:
+            raise ValueError, "Term %r precedes the previous term %r." % (term, self.last_term)
+
         # Write the prefix length and term suffix.
 
         common = len(commonprefix([self.last_term, term]))
@@ -193,6 +196,10 @@
         """
 
         offset, frequency, doc_frequency = self.position_dict_writer.write_term_positions(doc_positions)
+
+        if not frequency or not doc_frequency:
+            raise ValueError, "Term %r has no occurrences recorded: %r" % (term, doc_positions)
+
         self._write_term(term, offset, frequency, doc_frequency)
 
     def close(self):