From ebe0d849b57cc5893acf28b571e42b10aef382c5 Mon Sep 17 00:00:00 2001
From: Alexey Milovidov <milovidov@yandex-team.ru>
Date: Tue, 4 May 2021 18:18:51 +0300
Subject: [PATCH] Fix error in serialization of UInt256

---
 src/IO/WriteIntText.h | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/IO/WriteIntText.h b/src/IO/WriteIntText.h
index 93444e7df73..55b384220e4 100644
--- a/src/IO/WriteIntText.h
+++ b/src/IO/WriteIntText.h
@@ -4,8 +4,24 @@
 #include <IO/WriteBuffer.h>
 #include <common/itoa.h>
 
-/// 40 digits or 39 digits and a sign
-#define WRITE_HELPERS_MAX_INT_WIDTH 40U
+
+namespace
+{
+    template <typename T> constexpr size_t max_int_width = 0;
+    template <> constexpr size_t max_int_width<UInt8> = 3;    /// 255
+    template <> constexpr size_t max_int_width<Int8> = 4;     /// -128
+    template <> constexpr size_t max_int_width<UInt16> = 5;   /// 65535
+    template <> constexpr size_t max_int_width<Int16> = 6;    /// -32768
+    template <> constexpr size_t max_int_width<UInt32> = 10;  /// 4294967295
+    template <> constexpr size_t max_int_width<Int32> = 11;   /// -2147483648
+    template <> constexpr size_t max_int_width<UInt64> = 20;  /// 18446744073709551615
+    template <> constexpr size_t max_int_width<Int64> = 20;   /// -9223372036854775808
+    template <> constexpr size_t max_int_width<UInt128> = 39; /// 340282366920938463463374607431768211455
+    template <> constexpr size_t max_int_width<Int128> = 40;  /// -170141183460469231731687303715884105728
+    template <> constexpr size_t max_int_width<UInt256> = 78; /// 115792089237316195423570985008687907853269984665640564039457584007913129639935
+    template <> constexpr size_t max_int_width<Int256> = 78;  /// -57896044618658097711785492504343953926634992332820282019728792003956564819968
+}
+
 
 namespace DB
 {
@@ -15,7 +31,7 @@ namespace detail
     template <typename T>
     void NO_INLINE writeUIntTextFallback(T x, WriteBuffer & buf)
     {
-        char tmp[WRITE_HELPERS_MAX_INT_WIDTH];
+        char tmp[max_int_width<T>];
         int len = itoa(x, tmp) - tmp;
         buf.write(tmp, len);
     }
@@ -24,7 +40,7 @@ namespace detail
 template <typename T>
 void writeIntText(T x, WriteBuffer & buf)
 {
-    if (likely(reinterpret_cast<intptr_t>(buf.position()) + WRITE_HELPERS_MAX_INT_WIDTH < reinterpret_cast<intptr_t>(buf.buffer().end())))
+    if (likely(reinterpret_cast<uintptr_t>(buf.position()) + max_int_width<T> < reinterpret_cast<uintptr_t>(buf.buffer().end())))
         buf.position() = itoa(x, buf.position());
     else
         detail::writeUIntTextFallback(x, buf);