Add support for CheckedNumeric bitshift operators

base/numerics/safe_math.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_NUMERICS_SAFE_MATH_H_
 #define BASE_NUMERICS_SAFE_MATH_H_
 
 #include <stddef.h>
 
 #include <limits>
@@ skipping 94 matching lines @@
     return CheckedNumeric<T>::cast(*this).ValueUnsafe();
   }
 
   // ValueUnsafe() - DO NOT USE THIS IN EXTERNAL CODE - It is public right now
   // for tests and to avoid a big matrix of friend operator overloads. But the
   // values it returns are unintuitive and likely to change in the future.
   // Returns: the raw numeric value, regardless of the current state.
   T ValueUnsafe() const { return state_.value(); }
 
   // Prototypes for the supported arithmetic operator overloads.
-  template <typename Src> CheckedNumeric& operator+=(Src rhs);
-  template <typename Src> CheckedNumeric& operator-=(Src rhs);
-  template <typename Src> CheckedNumeric& operator*=(Src rhs);
-  template <typename Src> CheckedNumeric& operator/=(Src rhs);
-  template <typename Src> CheckedNumeric& operator%=(Src rhs);
+  template <typename Src>
+  CheckedNumeric& operator+=(Src rhs);
+  template <typename Src>
+  CheckedNumeric& operator-=(Src rhs);
+  template <typename Src>
+  CheckedNumeric& operator*=(Src rhs);
+  template <typename Src>
+  CheckedNumeric& operator/=(Src rhs);
+  template <typename Src>
+  CheckedNumeric& operator%=(Src rhs);
+  template <typename Src>
+  CheckedNumeric& operator<<=(Src rhs);
+  template <typename Src>
+  CheckedNumeric& operator>>=(Src rhs);
 
   CheckedNumeric operator-() const {
     // Negation is always valid for floating point.
     T value = 0;
     bool is_valid = (std::numeric_limits<T>::is_iec559 || IsValid()) &&
                     CheckedNeg(state_.value(), &value);
     return CheckedNumeric<T>(value, is_valid);
   }
 
   CheckedNumeric Abs() const {
@@ skipping 103 matching lines @@
   CheckedNumeric<typename ArithmeticPromotion<PROMOTION, L, R>::type>         \
   operator OP(L lhs, const CheckedNumeric<R>& rhs) {                          \
     return CheckedNumeric<L>(lhs) OP rhs;                                     \
   }
 
 BASE_NUMERIC_ARITHMETIC_OPERATORS(Add, +, +=, MAX_EXPONENT_PROMOTION)
 BASE_NUMERIC_ARITHMETIC_OPERATORS(Sub, -, -=, MAX_EXPONENT_PROMOTION)
 BASE_NUMERIC_ARITHMETIC_OPERATORS(Mul, *, *=, MAX_EXPONENT_PROMOTION)
 BASE_NUMERIC_ARITHMETIC_OPERATORS(Div, /, /=, MAX_EXPONENT_PROMOTION)
 BASE_NUMERIC_ARITHMETIC_OPERATORS(Mod, %, %=, MAX_EXPONENT_PROMOTION)
+BASE_NUMERIC_ARITHMETIC_OPERATORS(LeftShift, <<, <<=, LEFT_PROMOTION)
+BASE_NUMERIC_ARITHMETIC_OPERATORS(RightShift, >>, >>=, LEFT_PROMOTION)
 
 #undef BASE_NUMERIC_ARITHMETIC_OPERATORS
 
 }  // namespace internal
 
 using internal::CheckedNumeric;
 
 }  // namespace base
 
 #endif  // BASE_NUMERICS_SAFE_MATH_H_