diff --git a/src/tl/tl/tlString.cc b/src/tl/tl/tlString.cc
index 52d7f6715..aaf8ab3a0 100644
--- a/src/tl/tl/tlString.cc
+++ b/src/tl/tl/tlString.cc
@@ -831,186 +831,160 @@ tl::Extractor::read_quoted (std::string &value)
   return *this;
 }
 
-bool 
+namespace
+{
+  template <class T> struct overflow_msg_func;
+
+  template <> struct overflow_msg_func<long long>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on long long integer"));
+    }
+  };
+
+  template <> struct overflow_msg_func<unsigned long long>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on unsigned long long integer"));
+    }
+  };
+
+  template <> struct overflow_msg_func<long>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on long integer"));
+    }
+  };
+
+  template <> struct overflow_msg_func<unsigned long>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on unsigned long integer"));
+    }
+  };
+
+  template <> struct overflow_msg_func<int>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on integer"));
+    }
+  };
+
+  template <> struct overflow_msg_func<unsigned int>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on unsigned integer"));
+    }
+  };
+}
+
+template <class T> bool
+tl::Extractor::try_read_signed_int (T &value)
+{
+  if (! *skip ()) {
+    return false;
+  }
+
+  bool minus = false;
+  if (*m_cp == '-') {
+    minus = true;
+    ++m_cp;
+  } else if (*m_cp == '+') {
+    ++m_cp;
+  }
+
+  if (! isdigit (*m_cp)) {
+    return false;
+  }
+
+  value = 0;
+  while (isdigit (*m_cp)) {
+    if (value > std::numeric_limits<T>::max () / 10) {
+      throw tl::Exception (overflow_msg_func<T> () ());
+    }
+    value *= 10;
+    if (value > std::numeric_limits<T>::max () - (*m_cp - '0')) {
+      throw tl::Exception (overflow_msg_func<T> () ());
+    }
+    value += (*m_cp - '0');
+    ++m_cp;
+  }
+
+  if (minus) {
+    value = -value;
+  }
+
+  return true;
+}
+
+template <class T> bool
+tl::Extractor::try_read_unsigned_int (T &value)
+{
+  if (! *skip ()) {
+    return false;
+  }
+
+  if (! isdigit (*m_cp)) {
+    return false;
+  }
+
+  value = 0;
+  while (isdigit (*m_cp)) {
+    if (value > std::numeric_limits<T>::max () / 10) {
+      throw tl::Exception (overflow_msg_func<T> () ());
+    }
+    value *= 10;
+    if (value > std::numeric_limits<T>::max () - (*m_cp - '0')) {
+      throw tl::Exception (overflow_msg_func<T> () ());
+    }
+    value += (*m_cp - '0');
+    ++m_cp;
+  }
+
+  return true;
+}
+
+bool
 tl::Extractor::try_read (unsigned int &value)
 {
-  if (! *skip ()) {
-    return false;
-  } 
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on unsigned integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  return true;
+  return try_read_unsigned_int (value);
 }
 
-bool 
-tl::Extractor::try_read (int &value)
-{
-  if (! *skip ()) {
-    return false;
-  } 
-
-  bool minus = false;
-  if (*m_cp == '-') {
-    minus = true;
-    ++m_cp;
-  } else if (*m_cp == '+') {
-    ++m_cp;
-  }
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  if (minus) {
-    value = -value;
-  }
-
-  return true;
-}
-
-bool 
+bool
 tl::Extractor::try_read (unsigned long &value)
 {
-  if (! *skip ()) {
-    return false;
-  } 
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on unsigned long integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  return true;
+  return try_read_unsigned_int (value);
 }
 
-bool 
+bool
 tl::Extractor::try_read (unsigned long long &value)
 {
-  if (! *skip ()) {
-    return false;
-  } 
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on unsigned long long integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  return true;
+  return try_read_unsigned_int (value);
 }
 
-bool 
+bool
+tl::Extractor::try_read (int &value)
+{
+  return try_read_signed_int (value);
+}
+
+bool
 tl::Extractor::try_read (long &value)
 {
-  if (! *skip ()) {
-    return false;
-  } 
-
-  bool minus = false;
-  if (*m_cp == '-') {
-    minus = true;
-    ++m_cp;
-  } else if (*m_cp == '+') {
-    ++m_cp;
-  }
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on long integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  if (minus) {
-    value = -value;
-  }
-
-  return true;
+  return try_read_signed_int (value);
 }
 
-bool 
+bool
 tl::Extractor::try_read (long long &value)
 {
-  if (! *skip ()) {
-    return false;
-  } 
-
-  bool minus = false;
-  if (*m_cp == '-') {
-    minus = true;
-    ++m_cp;
-  } else if (*m_cp == '+') {
-    ++m_cp;
-  }
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on long long integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  if (minus) {
-    value = -value;
-  }
-
-  return true;
+  return try_read_signed_int (value);
 }
-
 bool 
 tl::Extractor::try_read (double &value)
 {
diff --git a/src/tl/tl/tlString.h b/src/tl/tl/tlString.h
index 718b2c169..11c8b05a4 100644
--- a/src/tl/tl/tlString.h
+++ b/src/tl/tl/tlString.h
@@ -732,6 +732,9 @@ public:
   }
 
 private:
+  template <class T> bool try_read_signed_int (T &value);
+  template <class T> bool try_read_unsigned_int (T &value);
+
   const char *m_cp;
   std::string m_str;
 };
diff --git a/src/tl/tl/tlVariant.h b/src/tl/tl/tlVariant.h
index 967c753de..df9fda803 100644
--- a/src/tl/tl/tlVariant.h
+++ b/src/tl/tl/tlVariant.h
@@ -1268,7 +1268,7 @@ public:
    */
   bool is_longlong () const
   {
-    return m_type == t_longlong || is_long ();
+    return m_type == t_longlong;
   }
 
   /**
@@ -1276,7 +1276,7 @@ public:
    */
   bool is_ulonglong () const
   {
-    return m_type == t_ulonglong || is_ulong ();
+    return m_type == t_ulonglong;
   }
 
 #if defined(HAVE_64BIT_COORD)
diff --git a/src/tl/unit_tests/tlVariant.cc b/src/tl/unit_tests/tlVariant.cc
index d3a25748c..5a8b688d7 100644
--- a/src/tl/unit_tests/tlVariant.cc
+++ b/src/tl/unit_tests/tlVariant.cc
@@ -137,7 +137,7 @@ TEST(1)
   EXPECT_EQ (v.is_cstring (), false);
   EXPECT_EQ (v.is_id (), false);
   EXPECT_EQ (v.is_ulong (), true);
-  EXPECT_EQ (v.is_ulonglong (), true);
+  EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is_long (), false);
   EXPECT_EQ (v.is_longlong (), false);
   EXPECT_EQ (v.is_double (), false);
@@ -172,7 +172,7 @@ TEST(1)
   EXPECT_EQ (v.is<unsigned long> (), false);
   EXPECT_EQ (v.is<long> (), false);
   EXPECT_EQ (v.is_ulong (), true);
-  EXPECT_EQ (v.is_ulonglong (), true);
+  EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is_long (), false);
   EXPECT_EQ (v.is_longlong (), false);
   EXPECT_EQ (v.is_id (), false);
@@ -202,7 +202,7 @@ TEST(1)
   EXPECT_EQ (v.is_list (), false);
   EXPECT_EQ (v.is_cstring (), false);
   EXPECT_EQ (v.is_long (), true);
-  EXPECT_EQ (v.is_longlong (), true);
+  EXPECT_EQ (v.is_longlong (), false);
   EXPECT_EQ (v.is_ulong (), false);
   EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is<long> (), false);
@@ -389,7 +389,7 @@ TEST(1)
   EXPECT_EQ (v.is_char (), false);
   EXPECT_EQ (v.is_long (), true);
   EXPECT_EQ (v.is_ulong (), false);
-  EXPECT_EQ (v.is_longlong (), true);
+  EXPECT_EQ (v.is_longlong (), false);
   EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is_double (), false);
   EXPECT_EQ (v.to_parsable_string (), "#2");