diff --git a/lib/hash-pjw.c b/lib/hash-pjw.c
index 0966598..8ee7c27 100644
--- a/lib/hash-pjw.c
+++ b/lib/hash-pjw.c
@@ -38,3 +38,15 @@ hash_pjw (const void *x, size_t tablesize)
 
   return h % tablesize;
 }
+
+size_t
+hash_pjw_s (const void *x, size_t x_size, size_t tablesize)
+{
+  const unsigned char *s;
+  size_t i, h = 0;
+
+  for (i=0; i<x_size; i++)
+    h = s[i] + ((h << 9) | (h >> (SIZE_BITS - 9)));
+
+  return h % tablesize;
+}
diff --git a/lib/hash-pjw.h b/lib/hash-pjw.h
index 6404916..5d39877 100644
--- a/lib/hash-pjw.h
+++ b/lib/hash-pjw.h
@@ -21,3 +21,4 @@
    The result is platform dependent: it depends on the size of the 'size_t'
    type and on the signedness of the 'char' type.  */
 extern size_t hash_pjw (void const *x, size_t tablesize) _GL_ATTRIBUTE_PURE;
+extern size_t hash_pjw_s (void const *x, size_t x_size, size_t tablesize) _GL_ATTRIBUTE_PURE;