1 files changed, 82 insertions, 0 deletions
diff --git a/contrib/byacc/warshall.c b/contrib/byacc/warshall.c
new file mode 100644
index 0000000..efb7cf4
--- /dev/null
+++ b/contrib/byacc/warshall.c
@@ -0,0 +1,82 @@
+/* $Id: warshall.c,v 1.7 2010/06/06 22:48:51 tom Exp $ */
+
+#include "defs.h"
+
+static void
+transitive_closure(unsigned *R, int n)
+{
+    int rowsize;
+    unsigned i;
+    unsigned *rowj;
+    unsigned *rp;
+    unsigned *rend;
+    unsigned *ccol;
+    unsigned *relend;
+    unsigned *cword;
+    unsigned *rowi;
+
+    rowsize = WORDSIZE(n);
+    relend = R + n * rowsize;
+
+    cword = R;
+    i = 0;
+    rowi = R;
+    while (rowi < relend)
+    {
+	ccol = cword;
+	rowj = R;
+
+	while (rowj < relend)
+	{
+	    if (*ccol & (unsigned)(1 << i))
+	    {
+		rp = rowi;
+		rend = rowj + rowsize;
+		while (rowj < rend)
+		    *rowj++ |= *rp++;
+	    }
+	    else
+	    {
+		rowj += rowsize;
+	    }
+
+	    ccol += rowsize;
+	}
+
+	if (++i >= BITS_PER_WORD)
+	{
+	    i = 0;
+	    cword++;
+	}
+
+	rowi += rowsize;
+    }
+}
+
+void
+reflexive_transitive_closure(unsigned *R, int n)
+{
+    int rowsize;
+    unsigned i;
+    unsigned *rp;
+    unsigned *relend;
+
+    transitive_closure(R, n);
+
+    rowsize = WORDSIZE(n);
+    relend = R + n * rowsize;
+
+    i = 0;
+    rp = R;
+    while (rp < relend)
+    {
+	*rp |= (unsigned)(1 << i);
+	if (++i >= BITS_PER_WORD)
+	{
+	    i = 0;
+	    rp++;
+	}
+
+	rp += rowsize;
+    }
+}