From a2ef0f6cba515e47e2c443baff82a5554efb6884 Mon Sep 17 00:00:00 2001
From: Alexey Milovidov <milovidov@yandex-team.ru>
Date: Sat, 10 Oct 2020 18:46:41 +0300
Subject: [PATCH] Minor changes in BigInt hash

---
 src/Common/HashTable/Hash.h | 29 ++---------------------------
 src/Core/BigInt.h           | 20 ++++----------------
 2 files changed, 6 insertions(+), 43 deletions(-)

diff --git a/src/Common/HashTable/Hash.h b/src/Common/HashTable/Hash.h
index abd1a69545..3d9cec1bb2 100644
--- a/src/Common/HashTable/Hash.h
+++ b/src/Common/HashTable/Hash.h
@@ -73,7 +73,7 @@ inline DB::UInt64 intHashCRC32(DB::UInt64 x, DB::UInt64 updated_value)
 }
 
 template <typename T>
-inline typename std::enable_if<(sizeof(T) > sizeof(DB::UInt64)) && !is_big_int_v<T>, DB::UInt64>::type
+inline typename std::enable_if<(sizeof(T) > sizeof(DB::UInt64)), DB::UInt64>::type
 intHashCRC32(const T & x, DB::UInt64 updated_value)
 {
     auto * begin = reinterpret_cast<const char *>(&x);
@@ -86,16 +86,6 @@ intHashCRC32(const T & x, DB::UInt64 updated_value)
     return updated_value;
 }
 
-template <typename T>
-inline typename std::enable_if<is_big_int_v<T>, DB::UInt64>::type
-intHashCRC32(const T & x, DB::UInt64 updated_value)
-{
-    std::vector<UInt64> parts = DB::BigInt<T>::toIntArray(x);
-    for (const auto & part : parts)
-        updated_value = intHashCRC32(part, updated_value);
-
-    return updated_value;
-}
 
 inline UInt32 updateWeakHash32(const DB::UInt8 * pos, size_t size, DB::UInt32 updated_value)
 {
@@ -248,22 +238,7 @@ inline size_t hashCRC32(std::enable_if_t<(sizeof(T) <= sizeof(UInt64)), T> key)
 template <typename T>
 inline size_t hashCRC32(std::enable_if_t<(sizeof(T) > sizeof(UInt64)), T> key)
 {
-    if constexpr (std::is_same_v<T, DB::Int128>)
-    {
-        return intHashCRC32(static_cast<UInt64>(key) ^ static_cast<UInt64>(key >> 64));
-    }
-    else if constexpr (std::is_same_v<T, DB::UInt128>)
-    {
-        return intHashCRC32(key.low ^ key.high);
-    }
-    else if constexpr (is_big_int_v<T> && sizeof(T) == 32)
-    {
-        return intHashCRC32(static_cast<UInt64>(key) ^
-            static_cast<UInt64>(key >> 64) ^
-            static_cast<UInt64>(key >> 128) ^
-            static_cast<UInt64>(key >> 256));
-    }
-    __builtin_unreachable();
+    return intHashCRC32(key, -1);
 }
 
 #define DEFINE_HASH(T) \
diff --git a/src/Core/BigInt.h b/src/Core/BigInt.h
index 5abd711006..8ce765fbc2 100644
--- a/src/Core/BigInt.h
+++ b/src/Core/BigInt.h
@@ -1,8 +1,10 @@
 #pragma once
 
 #include <common/StringRef.h>
+#include <common/unaligned.h>
 #include <Core/Types.h>
 
+
 namespace DB
 {
 
@@ -14,8 +16,7 @@ struct BigInt
 
     static StringRef serialize(const T & x, char * pos)
     {
-        //unalignedStore<T>(pos, x);
-        memcpy(pos, &x, size);
+        unalignedStore<T>(pos, x);
         return StringRef(pos, size);
     }
 
@@ -28,20 +29,7 @@ struct BigInt
 
     static T deserialize(const char * pos)
     {
-        //return unalignedLoad<T>(pos);
-        T res;
-        memcpy(&res, pos, size);
-        return res;
-    }
-
-    static std::vector<UInt64> toIntArray(const T & x)
-    {
-        std::vector<UInt64> parts(4, 0);
-        parts[0] = UInt64(x);
-        parts[1] = UInt64(x >> 64);
-        parts[2] = UInt64(x >> 128);
-        parts[4] = UInt64(x >> 192);
-        return parts;
+        return unalignedLoad<T>(pos);
     }
 };
 
-- 
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