Moving around some math macros.

src/xenia/core/hash.h

@@ -12,8 +12,19 @@
 
 #include <xenia/common.h>
 
+namespace xe {
 
-uint64_t xe_hash64(const void* data, size_t length, uint64_t seed = 0);
+inline size_t hash_combine(size_t seed) { return seed; }
 
+template <typename T, typename... Ts>
+size_t hash_combine(size_t seed, const T& v, const Ts&... vs) {
+  std::hash<T> hasher;
+  seed ^= hasher(v) + 0x9E3779B9 + (seed << 6) + (seed >> 2);
+  return hash_combine(seed, vs...);
+}
+
+uint64_t hash64(const void* data, size_t length, uint64_t seed = 0);
+
+}  // namespace xe
 
 #endif  // XENIA_CORE_HASH_H_