1 files changed, 56 insertions, 0 deletions
diff --git a/src/backend/access/gin/ginpostinglist.c b/src/backend/access/gin/ginpostinglist.c
new file mode 100644
index 00000000000..e5a15bf2a9f
--- /dev/null
+++ b/src/backend/access/gin/ginpostinglist.c
@@ -0,0 +1,56 @@
+/*-------------------------------------------------------------------------
+ *
+ * ginpostinglist.c
+ *	  routines for dealing with posting lists.
+ *
+ *
+ * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *			src/backend/access/gin/ginpostinglist.c
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/gin_private.h"
+
+/*
+ * Merge two ordered arrays of itempointers, eliminating any duplicates.
+ * Returns the number of items in the result.
+ * Caller is responsible that there is enough space at *dst.
+ */
+uint32
+ginMergeItemPointers(ItemPointerData *dst,
+					 ItemPointerData *a, uint32 na,
+					 ItemPointerData *b, uint32 nb)
+{
+	ItemPointerData *dptr = dst;
+	ItemPointerData *aptr = a,
+			   *bptr = b;
+
+	while (aptr - a < na && bptr - b < nb)
+	{
+		int			cmp = ginCompareItemPointers(aptr, bptr);
+
+		if (cmp > 0)
+			*dptr++ = *bptr++;
+		else if (cmp == 0)
+		{
+			/* we want only one copy of the identical items */
+			*dptr++ = *bptr++;
+			aptr++;
+		}
+		else
+			*dptr++ = *aptr++;
+	}
+
+	while (aptr - a < na)
+		*dptr++ = *aptr++;
+
+	while (bptr - b < nb)
+		*dptr++ = *bptr++;
+
+	return dptr - dst;
+}