Moved SuperFastHash function from base/hash.cc to base/third_party.

base/hash.cc

Index: base/hash.cc
diff --git a/base/hash.cc b/base/hash.cc
index 2c87065045bed70a1c2851ed4646bd4f6426393b..9088dbd42a7cf70405f42c8e200cdf3bfcba9c8f 100644
--- a/base/hash.cc
+++ b/base/hash.cc
@@ -1,73 +1,17 @@
-// From http://www.azillionmonkeys.com/qed/hash.html
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
 
 #include "base/hash.h"
 
-typedef uint32 uint32_t;
-typedef uint16 uint16_t;
+// Definition in base/third_party/superfasthash/superfasthash.c. (Third-party
+// code did not come with its own header file, so declaring the function here.)
+extern "C" uint32_t SuperFastHash(const char* data, int len);
 
 namespace base {
 
-#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
-
-uint32 SuperFastHash(const char * data, int len) {
-  uint32_t 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_t);
-    hash  += hash >> 11;
-  }
-
-  /* Handle end cases */
-  switch (rem) {
-    case 3:
-      hash += get16bits(data);
-      hash ^= hash << 16;
-
-      // Treat the final character as signed. This ensures all platforms behave
-      // consistently with the original x86 code.
-      hash ^= static_cast<signed char>(data[sizeof(uint16_t)]) << 18;
-      hash += hash >> 11;
-      break;
-    case 2:
-      hash += get16bits(data);
-      hash ^= hash << 11;
-      hash += hash >> 17;
-      break;
-    case 1:
-      hash += static_cast<signed char>(*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;
+uint32 SuperFastHash(const char* data, int len) {
+  return ::SuperFastHash(data, len);
 }
 
 }  // namespace base