--- a/liboctave/sparse-util.cc	Wed Jul 29 07:22:05 2009 -0400
+++ b/liboctave/sparse-util.cc	Wed Jul 29 12:15:27 2009 -0400
@@ -1,6 +1,6 @@
 /*
 
-Copyright (C) 2005, 2007, 2008 David Bateman
+Copyright (C) 2005, 2007, 2008, 2009 David Bateman
 Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Andy Adler
 
 This file is part of Octave.
@@ -58,6 +58,66 @@
 }
 
 
+bool
+sparse_indices_ok (octave_idx_type *r, octave_idx_type *c,
+		   octave_idx_type nrows, octave_idx_type ncols,
+		   octave_idx_type nnz)
+{
+  if (nnz > 0)
+    {
+      if (c[0] != 0)
+	{
+	  (*current_liboctave_error_handler)
+	    ("invalid sparse matrix: cidx[0] must be zero");
+	  return false;
+	}
+
+      octave_idx_type jold = 0;
+
+      for (octave_idx_type j = 1; j < ncols+1; j++)
+	{
+	  if (c[j] < c[j-1])
+	    {
+	      (*current_liboctave_error_handler)
+		("invalid sparse matrix: cidx elements must appear in ascending order");
+	      return false;
+	    }
+
+	  if (c[j] > nnz)
+	    {
+	      (*current_liboctave_error_handler)
+		("invalid sparse matrix: cidx[%d] = %d exceeds number of nonzero elements", j, c[j]+1);
+	      return false;
+	    }
+
+	  if (c[j] != jold)
+	    {
+	      for (octave_idx_type i = jold+1; i < c[j]; i++)
+		{
+		  if (r[i] < r[i-1])
+		    {
+		      (*current_liboctave_error_handler)
+			("invalid sparse matrix: ridx elements must appear in ascending order for each column");
+		      return false;
+		    }
+
+		  if (r[i] >= nrows)
+		    {
+		      (*current_liboctave_error_handler)
+			("invalid sparse matrix: ridx[%d] = %d out of range",
+			 i, r[i]+1);
+		      return false;
+		    }
+		}
+
+	      jold = c[j];
+	    }
+	}
+    }
+
+  return true;
+}
+
 /*
 ;;; Local Variables: ***
 ;;; mode: C++ ***