Merge in conversion to C++.

[awesomized/libmemcached] / libhashkit / one_at_a_time.cc

diff --git a/libhashkit/one_at_a_time.cc b/libhashkit/one_at_a_time.cc
new file mode 100644 (file)
index 0000000..aeb11b1
--- /dev/null
+++ b/libhashkit/one_at_a_time.cc
@@ -0,0 +1,34 @@
+/* HashKit
+ * Copyright (C) 2009 Brian Aker
+ * All rights reserved.
+ *
+ * Use and distribution licensed under the BSD license.  See
+ * the COPYING file in the parent directory for full text.
+ */
+
+/*
+  This has is Jenkin's "One at A time Hash".
+http://en.wikipedia.org/wiki/Jenkins_hash_function
+*/
+
+#include <libhashkit/common.h>
+
+uint32_t hashkit_one_at_a_time(const char *key, size_t key_length, void *context)
+{
+  const char *ptr= key;
+  uint32_t value= 0;
+  (void)context;
+
+  while (key_length--)
+  {
+    uint32_t val= (uint32_t) *ptr++;
+    value += val;
+    value += (value << 10);
+    value ^= (value >> 6);
+  }
+  value += (value << 3);
+  value ^= (value >> 11);
+  value += (value << 15);
+
+  return value;
+}