Move hash.h/cc from net/disk_cache to base.

net/disk_cache/hash.cc

-// From http://www.azillionmonkeys.com/qed/hash.html
-
-#include "net/disk_cache/hash.h"
-
-typedef uint32 uint32_t;
-typedef uint16 uint16_t;
-
-namespace disk_cache {
-
-#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;
-}
-
-}  // namespace disk_cache