1 files changed, 47 insertions, 0 deletions
diff --git a/ext/dbm/sdbm/hash.c b/ext/dbm/sdbm/hash.c
new file mode 100644
index 0000000000..9b55a7f571
--- /dev/null
+++ b/ext/dbm/sdbm/hash.c
@@ -0,0 +1,47 @@
+/*
+ * sdbm - ndbm work-alike hashed database library
+ * based on Per-Aake Larson's Dynamic Hashing algorithms. BIT 18 (1978).
+ * author: oz@nexus.yorku.ca
+ * status: public domain. keep it that way.
+ *
+ * hashing routine
+ */
+
+#include "sdbm.h"
+/*
+ * polynomial conversion ignoring overflows
+ * [this seems to work remarkably well, in fact better
+ * then the ndbm hash function. Replace at your own risk]
+ * use: 65599	nice.
+ *      65587   even better. 
+ */
+long
+sdbm_hash(str, len)
+register char *str;
+register int len;
+{
+	register unsigned long n = 0;
+
+#ifdef DUFF
+
+#define HASHC	n = *str++ + 65599 * n
+
+	if (len > 0) {
+		register int loop = (len + 8 - 1) >> 3;
+
+		switch(len & (8 - 1)) {
+		case 0:	do {
+			HASHC;	case 7:	HASHC;
+		case 6:	HASHC;	case 5:	HASHC;
+		case 4:	HASHC;	case 3:	HASHC;
+		case 2:	HASHC;	case 1:	HASHC;
+			} while (--loop);
+		}
+
+	}
+#else
+	while (len--)
+		n = *str++ + 65599 * n;
+#endif
+	return n;
+}