1 files changed, 76 insertions, 0 deletions
diff --git a/SuperFastHash.cpp b/SuperFastHash.cpp
new file mode 100644
index 0000000..1f6d39a
--- /dev/null
+++ b/SuperFastHash.cpp
@@ -0,0 +1,76 @@
+#include "Platform.h"
+#include <stdio.h> // for NULL
+
+/* By Paul Hsieh (C) 2004, 2005.  Covered under the Paul Hsieh derivative 
+   license. See: 
+   http://www.azillionmonkeys.com/qed/weblicense.html for license details.
+
+   http://www.azillionmonkeys.com/qed/hash.html */
+
+/*
+#undef get16bits
+#if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__) \
+  || defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__)
+#define get16bits(d) (*((const uint16_t *) (d)))
+#endif
+
+#if !defined (get16bits)
+#define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)\
+                       +(uint32_t)(((const uint8_t *)(d))[0]) )
+#endif
+*/
+
+FORCE_INLINE uint16_t get16bits ( const void * p )
+{
+  return *(const uint16_t*)p;
+}
+
+uint32_t SuperFastHash (const signed char * data, int len) {
+uint32_t hash = 0, tmp;
+int rem;
+
+  if (len <= 0 || data == NULL) return 0;
+
+  rem = len & 3;
+  len >>= 2;
+
+  /* Main loop */
+  for (;len > 0; len--) {
+    hash  += get16bits (data);
+    tmp    = (get16bits (data+2) << 11) ^ hash;
+    hash   = (hash << 16) ^ tmp;
+    data  += 2*sizeof (uint16_t);
+    hash  += hash >> 11;
+  }
+
+  /* Handle end cases */
+  switch (rem) {
+    case 3:	hash += get16bits (data);
+        hash ^= hash << 16;
+        hash ^= data[sizeof (uint16_t)] << 18;
+        hash += hash >> 11;
+        break;
+    case 2:	hash += get16bits (data);
+        hash ^= hash << 11;
+        hash += hash >> 17;
+        break;
+    case 1: hash += *data;
+        hash ^= hash << 10;
+        hash += hash >> 1;
+  }
+
+  /* Force "avalanching" of final 127 bits */
+  hash ^= hash << 3;
+  hash += hash >> 5;
+  hash ^= hash << 4;
+  hash += hash >> 17;
+  hash ^= hash << 25;
+  hash += hash >> 6;
+
+  return hash;
+}
+
+void SuperFastHash     ( const void * key, int len, uint32_t /*seed*/, void * out )
+{
+  *(uint32_t*)out = SuperFastHash((const signed char*)key,len);
+}