import farmhash

Summary:
This diff imports farmhash.h and farmhash.cc from
https://github.com/google/farmhash and updates the public_tld license
file accordingly. Build integration and namespace changes will occur in
later diffs.

Reviewed By: yfeldblum

Differential Revision: D13436553

fbshipit-source-id: 7a081032cb35a1a3e1cd14e2edf2685906956396

LICENSE

@@ -175,3 +175,26 @@
       of your accepting any such warranty or additional liability.
 
    END OF TERMS AND CONDITIONS
+
+
+Files in folly/external/farmhash licensed as follows
+
+    Copyright (c) 2014 Google, Inc.
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.

folly/external/farmhash/farmhash.h

+// Copyright (c) 2014 Google, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+// FarmHash, by Geoff Pike
+
+//
+// http://code.google.com/p/farmhash/
+//
+// This file provides a few functions for hashing strings and other
+// data.  All of them are high-quality functions in the sense that
+// they do well on standard tests such as Austin Appleby's SMHasher.
+// They're also fast.  FarmHash is the successor to CityHash.
+//
+// Functions in the FarmHash family are not suitable for cryptography.
+//
+// WARNING: This code has been only lightly tested on big-endian platforms!
+// It is known to work well on little-endian platforms that have a small penalty
+// for unaligned reads, such as current Intel and AMD moderate-to-high-end CPUs.
+// It should work on all 32-bit and 64-bit platforms that allow unaligned reads;
+// bug reports are welcome.
+//
+// By the way, for some hash functions, given strings a and b, the hash
+// of a+b is easily derived from the hashes of a and b.  This property
+// doesn't hold for any hash functions in this file.
+
+#ifndef FARM_HASH_H_
+#define FARM_HASH_H_
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>   // for memcpy and memset
+#include <utility>
+
+#ifndef NAMESPACE_FOR_HASH_FUNCTIONS
+#define NAMESPACE_FOR_HASH_FUNCTIONS util
+#endif
+
+namespace NAMESPACE_FOR_HASH_FUNCTIONS {
+
+#if defined(FARMHASH_UINT128_T_DEFINED)
+inline uint64_t Uint128Low64(const uint128_t x) {
+  return static_cast<uint64_t>(x);
+}
+inline uint64_t Uint128High64(const uint128_t x) {
+  return static_cast<uint64_t>(x >> 64);
+}
+inline uint128_t Uint128(uint64_t lo, uint64_t hi) {
+  return lo + (((uint128_t)hi) << 64);
+}
+#else
+typedef std::pair<uint64_t, uint64_t> uint128_t;
+inline uint64_t Uint128Low64(const uint128_t x) { return x.first; }
+inline uint64_t Uint128High64(const uint128_t x) { return x.second; }
+inline uint128_t Uint128(uint64_t lo, uint64_t hi) { return uint128_t(lo, hi); }
+#endif
+
+
+// BASIC STRING HASHING
+
+// Hash function for a byte array.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+size_t Hash(const char* s, size_t len);
+
+// Hash function for a byte array.  Most useful in 32-bit binaries.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+uint32_t Hash32(const char* s, size_t len);
+
+// Hash function for a byte array.  For convenience, a 32-bit seed is also
+// hashed into the result.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+uint32_t Hash32WithSeed(const char* s, size_t len, uint32_t seed);
+
+// Hash 128 input bits down to 64 bits of output.
+// Hash function for a byte array.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+uint64_t Hash64(const char* s, size_t len);
+
+// Hash function for a byte array.  For convenience, a 64-bit seed is also
+// hashed into the result.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+uint64_t Hash64WithSeed(const char* s, size_t len, uint64_t seed);
+
+// Hash function for a byte array.  For convenience, two seeds are also
+// hashed into the result.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+uint64_t Hash64WithSeeds(const char* s, size_t len,
+                       uint64_t seed0, uint64_t seed1);
+
+// Hash function for a byte array.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+uint128_t Hash128(const char* s, size_t len);
+
+// Hash function for a byte array.  For convenience, a 128-bit seed is also
+// hashed into the result.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+uint128_t Hash128WithSeed(const char* s, size_t len, uint128_t seed);
+
+// BASIC NON-STRING HASHING
+
+// This is intended to be a reasonably good hash function.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+inline uint64_t Hash128to64(uint128_t x) {
+  // Murmur-inspired hashing.
+  const uint64_t kMul = 0x9ddfea08eb382d69ULL;
+  uint64_t a = (Uint128Low64(x) ^ Uint128High64(x)) * kMul;
+  a ^= (a >> 47);
+  uint64_t b = (Uint128High64(x) ^ a) * kMul;
+  b ^= (b >> 47);
+  b *= kMul;
+  return b;
+}
+
+// FINGERPRINTING (i.e., good, portable, forever-fixed hash functions)
+
+// Fingerprint function for a byte array.  Most useful in 32-bit binaries.
+uint32_t Fingerprint32(const char* s, size_t len);
+
+// Fingerprint function for a byte array.
+uint64_t Fingerprint64(const char* s, size_t len);
+
+// Fingerprint function for a byte array.
+uint128_t Fingerprint128(const char* s, size_t len);
+
+// This is intended to be a good fingerprinting primitive.
+// See below for more overloads.
+inline uint64_t Fingerprint(uint128_t x) {
+  // Murmur-inspired hashing.
+  const uint64_t kMul = 0x9ddfea08eb382d69ULL;
+  uint64_t a = (Uint128Low64(x) ^ Uint128High64(x)) * kMul;
+  a ^= (a >> 47);
+  uint64_t b = (Uint128High64(x) ^ a) * kMul;
+  b ^= (b >> 44);
+  b *= kMul;
+  b ^= (b >> 41);
+  b *= kMul;
+  return b;
+}
+
+// This is intended to be a good fingerprinting primitive.
+inline uint64_t Fingerprint(uint64_t x) {
+  // Murmur-inspired hashing.
+  const uint64_t kMul = 0x9ddfea08eb382d69ULL;
+  uint64_t b = x * kMul;
+  b ^= (b >> 44);
+  b *= kMul;
+  b ^= (b >> 41);
+  b *= kMul;
+  return b;
+}
+
+#ifndef FARMHASH_NO_CXX_STRING
+
+// Convenience functions to hash or fingerprint C++ strings.
+// These require that Str::data() return a pointer to the first char
+// (as a const char*) and that Str::length() return the string's length;
+// they work with std::string, for example.
+
+// Hash function for a byte array.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+template <typename Str>
+inline size_t Hash(const Str& s) {
+  assert(sizeof(s[0]) == 1);
+  return Hash(s.data(), s.length());
+}
+
+// Hash function for a byte array.  Most useful in 32-bit binaries.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+template <typename Str>
+inline uint32_t Hash32(const Str& s) {
+  assert(sizeof(s[0]) == 1);
+  return Hash32(s.data(), s.length());
+}
+
+// Hash function for a byte array.  For convenience, a 32-bit seed is also
+// hashed into the result.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+template <typename Str>
+inline uint32_t Hash32WithSeed(const Str& s, uint32_t seed) {
+  assert(sizeof(s[0]) == 1);
+  return Hash32WithSeed(s.data(), s.length(), seed);
+}
+
+// Hash 128 input bits down to 64 bits of output.
+// Hash function for a byte array.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+template <typename Str>
+inline uint64_t Hash64(const Str& s) {
+  assert(sizeof(s[0]) == 1);
+  return Hash64(s.data(), s.length());
+}
+
+// Hash function for a byte array.  For convenience, a 64-bit seed is also
+// hashed into the result.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+template <typename Str>
+inline uint64_t Hash64WithSeed(const Str& s, uint64_t seed) {
+  assert(sizeof(s[0]) == 1);
+  return Hash64WithSeed(s.data(), s.length(), seed);
+}
+
+// Hash function for a byte array.  For convenience, two seeds are also
+// hashed into the result.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+template <typename Str>
+inline uint64_t Hash64WithSeeds(const Str& s, uint64_t seed0, uint64_t seed1) {
+  assert(sizeof(s[0]) == 1);
+  return Hash64WithSeeds(s.data(), s.length(), seed0, seed1);
+}
+
+// Hash function for a byte array.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+template <typename Str>
+inline uint128_t Hash128(const Str& s) {
+  assert(sizeof(s[0]) == 1);
+  return Hash128(s.data(), s.length());
+}
+
+// Hash function for a byte array.  For convenience, a 128-bit seed is also
+// hashed into the result.
+// May change from time to time, may differ on different platforms, may differ
+// depending on NDEBUG.
+template <typename Str>
+inline uint128_t Hash128WithSeed(const Str& s, uint128_t seed) {
+  assert(sizeof(s[0]) == 1);
+  return Hash128(s.data(), s.length(), seed);
+}
+
+// FINGERPRINTING (i.e., good, portable, forever-fixed hash functions)
+
+// Fingerprint function for a byte array.  Most useful in 32-bit binaries.
+template <typename Str>
+inline uint32_t Fingerprint32(const Str& s) {
+  assert(sizeof(s[0]) == 1);
+  return Fingerprint32(s.data(), s.length());
+}
+
+// Fingerprint 128 input bits down to 64 bits of output.
+// Fingerprint function for a byte array.
+template <typename Str>
+inline uint64_t Fingerprint64(const Str& s) {
+  assert(sizeof(s[0]) == 1);
+  return Fingerprint64(s.data(), s.length());
+}
+
+// Fingerprint function for a byte array.
+template <typename Str>
+inline uint128_t Fingerprint128(const Str& s) {
+  assert(sizeof(s[0]) == 1);
+  return Fingerprint128(s.data(), s.length());
+}
+
+#endif
+
+}  // namespace NAMESPACE_FOR_HASH_FUNCTIONS
+
+#endif  // FARM_HASH_H_