2011-12-27 21:18:07 +00:00
commit 9f98ea7e22
192 changed files with 77747 additions and 0 deletions
@@ -0,0 +1,68 @@
+// File: crn_hash.cpp
+// See Paul Hsieh's page at: http://www.azillionmonkeys.com/qed/hash.html
+// Also see http://www.concentric.net/~Ttwang/tech/inthash.htm,
+// http://burtleburtle.net/bob/hash/integer.html
+#include "crn_core.h"
+
+#undef get16bits
+#if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__) \
+   || defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__)
+#define get16bits(d) (*((const uint16 *) (d)))
+#endif
+
+#if !defined (get16bits)
+#define get16bits(d) ((((uint32)(((const uint8 *)(d))[1])) << 8)\
+   +(uint32)(((const uint8 *)(d))[0]) )
+#endif
+
+namespace crnlib
+{
+   uint32 fast_hash (const void* p, int len) 
+   {
+      const char * data = static_cast<const char *>(p);
+      
+      uint32 hash = len, 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);
+         hash  += hash >> 11;
+      }
+
+      /* Handle end cases */
+      switch (rem) {
+           case 3: hash += get16bits (data);
+              hash ^= hash << 16;
+              hash ^= data[sizeof (uint16)] << 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;
+   }
+
+}  // namespace crnlib