sort: Add support for combining cases with identical sort criteria.

[pspp] / src / math / merge.h

diff --git a/src/math/merge.h b/src/math/merge.h
index 5fdb6fc062d24d692b1d3b95552690d00e9fd793..45c84937832d12f7f36e18986a115b17a0777018 100644 (file)
--- a/src/math/merge.h
+++ b/src/math/merge.h
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2007, 2009 Free Software Foundation, Inc.
+   Copyright (C) 2007, 2009, 2010 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -21,7 +21,12 @@ struct caseproto;
 struct casereader;
 struct subcase;
 
-struct merge *merge_create (const struct subcase *, const struct caseproto *);
+typedef struct ccase *merge_distinct_combine_func (struct ccase *first,
+                                                   struct ccase *second,
+                                                   void *aux);
+
+struct merge *merge_create (const struct subcase *, const struct caseproto *,
+                            merge_distinct_combine_func *, void *aux);
 void merge_destroy (struct merge *);
 void merge_append (struct merge *, struct casereader *);
 struct casereader *merge_make_reader (struct merge *);