Add m-esr52 at 52.6.0

1 files changed, 791 insertions, 0 deletions

diff --git a/mfbt/CheckedInt.h b/mfbt/CheckedInt.h
new file mode 100644
index 0000000000..02ef8d5b7e
--- /dev/null
+++ b/mfbt/CheckedInt.h
@@ -0,0 +1,791 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Provides checked integers, detecting integer overflow and divide-by-0. */
+
+#ifndef mozilla_CheckedInt_h
+#define mozilla_CheckedInt_h
+
+#include <stdint.h>
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/IntegerTypeTraits.h"
+
+namespace mozilla {
+
+template<typename T> class CheckedInt;
+
+namespace detail {
+
+/*
+ * Step 1: manually record supported types
+ *
+ * What's nontrivial here is that there are different families of integer
+ * types: basic integer types and stdint types. It is merrily undefined which
+ * types from one family may be just typedefs for a type from another family.
+ *
+ * For example, on GCC 4.6, aside from the basic integer types, the only other
+ * type that isn't just a typedef for some of them, is int8_t.
+ */
+
+struct UnsupportedType {};
+
+template<typename IntegerType>
+struct IsSupportedPass2
+{
+  static const bool value = false;
+};
+
+template<typename IntegerType>
+struct IsSupported
+{
+  static const bool value = IsSupportedPass2<IntegerType>::value;
+};
+
+template<>
+struct IsSupported<int8_t>
+{ static const bool value = true; };
+
+template<>
+struct IsSupported<uint8_t>
+{ static const bool value = true; };
+
+template<>
+struct IsSupported<int16_t>
+{ static const bool value = true; };
+
+template<>
+struct IsSupported<uint16_t>
+{ static const bool value = true; };
+
+template<>
+struct IsSupported<int32_t>
+{ static const bool value = true; };
+
+template<>
+struct IsSupported<uint32_t>
+{ static const bool value = true; };
+
+template<>
+struct IsSupported<int64_t>
+{ static const bool value = true; };
+
+template<>
+struct IsSupported<uint64_t>
+{ static const bool value = true; };
+
+
+template<>
+struct IsSupportedPass2<char>
+{ static const bool value = true; };
+
+template<>
+struct IsSupportedPass2<signed char>
+{ static const bool value = true; };
+
+template<>
+struct IsSupportedPass2<unsigned char>
+{ static const bool value = true; };
+
+template<>
+struct IsSupportedPass2<short>
+{ static const bool value = true; };
+
+template<>
+struct IsSupportedPass2<unsigned short>
+{ static const bool value = true; };
+
+template<>
+struct IsSupportedPass2<int>
+{ static const bool value = true; };
+
+template<>
+struct IsSupportedPass2<unsigned int>
+{ static const bool value = true; };
+
+template<>
+struct IsSupportedPass2<long>
+{ static const bool value = true; };
+
+template<>
+struct IsSupportedPass2<unsigned long>
+{ static const bool value = true; };
+
+template<>
+struct IsSupportedPass2<long long>
+{ static const bool value = true; };
+
+template<>
+struct IsSupportedPass2<unsigned long long>
+{ static const bool value = true; };
+
+/*
+ * Step 2: Implement the actual validity checks.
+ *
+ * Ideas taken from IntegerLib, code different.
+ */
+
+template<typename IntegerType, size_t Size = sizeof(IntegerType)>
+struct TwiceBiggerType
+{
+  typedef typename detail::StdintTypeForSizeAndSignedness<
+                     sizeof(IntegerType) * 2,
+                     IsSigned<IntegerType>::value
+                   >::Type Type;
+};
+
+template<typename IntegerType>
+struct TwiceBiggerType<IntegerType, 8>
+{
+  typedef UnsupportedType Type;
+};
+
+template<typename T>
+inline bool
+HasSignBit(T aX)
+{
+  // In C++, right bit shifts on negative values is undefined by the standard.
+  // Notice that signed-to-unsigned conversions are always well-defined in the
+  // standard, as the value congruent modulo 2**n as expected. By contrast,
+  // unsigned-to-signed is only well-defined if the value is representable.
+  return bool(typename MakeUnsigned<T>::Type(aX) >>
+              PositionOfSignBit<T>::value);
+}
+
+// Bitwise ops may return a larger type, so it's good to use this inline
+// helper guaranteeing that the result is really of type T.
+template<typename T>
+inline T
+BinaryComplement(T aX)
+{
+  return ~aX;
+}
+
+template<typename T,
+         typename U,
+         bool IsTSigned = IsSigned<T>::value,
+         bool IsUSigned = IsSigned<U>::value>
+struct DoesRangeContainRange
+{
+};
+
+template<typename T, typename U, bool Signedness>
+struct DoesRangeContainRange<T, U, Signedness, Signedness>
+{
+  static const bool value = sizeof(T) >= sizeof(U);
+};
+
+template<typename T, typename U>
+struct DoesRangeContainRange<T, U, true, false>
+{
+  static const bool value = sizeof(T) > sizeof(U);
+};
+
+template<typename T, typename U>
+struct DoesRangeContainRange<T, U, false, true>
+{
+  static const bool value = false;
+};
+
+template<typename T,
+         typename U,
+         bool IsTSigned = IsSigned<T>::value,
+         bool IsUSigned = IsSigned<U>::value,
+         bool DoesTRangeContainURange = DoesRangeContainRange<T, U>::value>
+struct IsInRangeImpl {};
+
+template<typename T, typename U, bool IsTSigned, bool IsUSigned>
+struct IsInRangeImpl<T, U, IsTSigned, IsUSigned, true>
+{
+  static bool run(U)
+  {
+    return true;
+  }
+};
+
+template<typename T, typename U>
+struct IsInRangeImpl<T, U, true, true, false>
+{
+  static bool run(U aX)
+  {
+    return aX <= MaxValue<T>::value && aX >= MinValue<T>::value;
+  }
+};
+
+template<typename T, typename U>
+struct IsInRangeImpl<T, U, false, false, false>
+{
+  static bool run(U aX)
+  {
+    return aX <= MaxValue<T>::value;
+  }
+};
+
+template<typename T, typename U>
+struct IsInRangeImpl<T, U, true, false, false>
+{
+  static bool run(U aX)
+  {
+    return sizeof(T) > sizeof(U) || aX <= U(MaxValue<T>::value);
+  }
+};
+
+template<typename T, typename U>
+struct IsInRangeImpl<T, U, false, true, false>
+{
+  static bool run(U aX)
+  {
+    return sizeof(T) >= sizeof(U)
+           ? aX >= 0
+           : aX >= 0 && aX <= U(MaxValue<T>::value);
+  }
+};
+
+template<typename T, typename U>
+inline bool
+IsInRange(U aX)
+{
+  return IsInRangeImpl<T, U>::run(aX);
+}
+
+template<typename T>
+inline bool
+IsAddValid(T aX, T aY)
+{
+  // Addition is valid if the sign of aX+aY is equal to either that of aX or
+  // that of aY. Since the value of aX+aY is undefined if we have a signed
+  // type, we compute it using the unsigned type of the same size.  Beware!
+  // These bitwise operations can return a larger integer type, if T was a
+  // small type like int8_t, so we explicitly cast to T.
+
+  typename MakeUnsigned<T>::Type ux = aX;
+  typename MakeUnsigned<T>::Type uy = aY;
+  typename MakeUnsigned<T>::Type result = ux + uy;
+  return IsSigned<T>::value
+         ? HasSignBit(BinaryComplement(T((result ^ aX) & (result ^ aY))))
+         : BinaryComplement(aX) >= aY;
+}
+
+template<typename T>
+inline bool
+IsSubValid(T aX, T aY)
+{
+  // Subtraction is valid if either aX and aY have same sign, or aX-aY and aX
+  // have same sign. Since the value of aX-aY is undefined if we have a signed
+  // type, we compute it using the unsigned type of the same size.
+  typename MakeUnsigned<T>::Type ux = aX;
+  typename MakeUnsigned<T>::Type uy = aY;
+  typename MakeUnsigned<T>::Type result = ux - uy;
+
+  return IsSigned<T>::value
+         ? HasSignBit(BinaryComplement(T((result ^ aX) & (aX ^ aY))))
+         : aX >= aY;
+}
+
+template<typename T,
+         bool IsTSigned = IsSigned<T>::value,
+         bool TwiceBiggerTypeIsSupported =
+           IsSupported<typename TwiceBiggerType<T>::Type>::value>
+struct IsMulValidImpl {};
+
+template<typename T, bool IsTSigned>
+struct IsMulValidImpl<T, IsTSigned, true>
+{
+  static bool run(T aX, T aY)
+  {
+    typedef typename TwiceBiggerType<T>::Type TwiceBiggerType;
+    TwiceBiggerType product = TwiceBiggerType(aX) * TwiceBiggerType(aY);
+    return IsInRange<T>(product);
+  }
+};
+
+template<typename T>
+struct IsMulValidImpl<T, true, false>
+{
+  static bool run(T aX, T aY)
+  {
+    const T max = MaxValue<T>::value;
+    const T min = MinValue<T>::value;
+
+    if (aX == 0 || aY == 0) {
+      return true;
+    }
+    if (aX > 0) {
+      return aY > 0
+             ? aX <= max / aY
+             : aY >= min / aX;
+    }
+
+    // If we reach this point, we know that aX < 0.
+    return aY > 0
+           ? aX >= min / aY
+           : aY >= max / aX;
+  }
+};
+
+template<typename T>
+struct IsMulValidImpl<T, false, false>
+{
+  static bool run(T aX, T aY)
+  {
+    return aY == 0 ||  aX <= MaxValue<T>::value / aY;
+  }
+};
+
+template<typename T>
+inline bool
+IsMulValid(T aX, T aY)
+{
+  return IsMulValidImpl<T>::run(aX, aY);
+}
+
+template<typename T>
+inline bool
+IsDivValid(T aX, T aY)
+{
+  // Keep in mind that in the signed case, min/-1 is invalid because
+  // abs(min)>max.
+  return aY != 0 &&
+         !(IsSigned<T>::value && aX == MinValue<T>::value && aY == T(-1));
+}
+
+template<typename T, bool IsTSigned = IsSigned<T>::value>
+struct IsModValidImpl;
+
+template<typename T>
+inline bool
+IsModValid(T aX, T aY)
+{
+  return IsModValidImpl<T>::run(aX, aY);
+}
+
+/*
+ * Mod is pretty simple.
+ * For now, let's just use the ANSI C definition:
+ * If aX or aY are negative, the results are implementation defined.
+ *   Consider these invalid.
+ * Undefined for aY=0.
+ * The result will never exceed either aX or aY.
+ *
+ * Checking that aX>=0 is a warning when T is unsigned.
+ */
+
+template<typename T>
+struct IsModValidImpl<T, false>
+{
+  static inline bool run(T aX, T aY)
+  {
+    return aY >= 1;
+  }
+};
+
+template<typename T>
+struct IsModValidImpl<T, true>
+{
+  static inline bool run(T aX, T aY)
+  {
+    if (aX < 0) {
+      return false;
+    }
+    return aY >= 1;
+  }
+};
+
+template<typename T, bool IsSigned = IsSigned<T>::value>
+struct NegateImpl;
+
+template<typename T>
+struct NegateImpl<T, false>
+{
+  static CheckedInt<T> negate(const CheckedInt<T>& aVal)
+  {
+    // Handle negation separately for signed/unsigned, for simpler code and to
+    // avoid an MSVC warning negating an unsigned value.
+    return CheckedInt<T>(0, aVal.isValid() && aVal.mValue == 0);
+  }
+};
+
+template<typename T>
+struct NegateImpl<T, true>
+{
+  static CheckedInt<T> negate(const CheckedInt<T>& aVal)
+  {
+    // Watch out for the min-value, which (with twos-complement) can't be
+    // negated as -min-value is then (max-value + 1).
+    if (!aVal.isValid() || aVal.mValue == MinValue<T>::value) {
+      return CheckedInt<T>(aVal.mValue, false);
+    }
+    return CheckedInt<T>(-aVal.mValue, true);
+  }
+};
+
+} // namespace detail
+
+
+/*
+ * Step 3: Now define the CheckedInt class.
+ */
+
+/**
+ * @class CheckedInt
+ * @brief Integer wrapper class checking for integer overflow and other errors
+ * @param T the integer type to wrap. Can be any type among the following:
+ *            - any basic integer type such as |int|
+ *            - any stdint type such as |int8_t|
+ *
+ * This class implements guarded integer arithmetic. Do a computation, check
+ * that isValid() returns true, you then have a guarantee that no problem, such
+ * as integer overflow, happened during this computation, and you can call
+ * value() to get the plain integer value.
+ *
+ * The arithmetic operators in this class are guaranteed not to raise a signal
+ * (e.g. in case of a division by zero).
+ *
+ * For example, suppose that you want to implement a function that computes
+ * (aX+aY)/aZ, that doesn't crash if aZ==0, and that reports on error (divide by
+ * zero or integer overflow). You could code it as follows:
+   @code
+   bool computeXPlusYOverZ(int aX, int aY, int aZ, int* aResult)
+   {
+     CheckedInt<int> checkedResult = (CheckedInt<int>(aX) + aY) / aZ;
+     if (checkedResult.isValid()) {
+       *aResult = checkedResult.value();
+       return true;
+     } else {
+       return false;
+     }
+   }
+   @endcode
+ *
+ * Implicit conversion from plain integers to checked integers is allowed. The
+ * plain integer is checked to be in range before being casted to the
+ * destination type. This means that the following lines all compile, and the
+ * resulting CheckedInts are correctly detected as valid or invalid:
+ * @code
+   // 1 is of type int, is found to be in range for uint8_t, x is valid
+   CheckedInt<uint8_t> x(1);
+   // -1 is of type int, is found not to be in range for uint8_t, x is invalid
+   CheckedInt<uint8_t> x(-1);
+   // -1 is of type int, is found to be in range for int8_t, x is valid
+   CheckedInt<int8_t> x(-1);
+   // 1000 is of type int16_t, is found not to be in range for int8_t,
+   // x is invalid
+   CheckedInt<int8_t> x(int16_t(1000));
+   // 3123456789 is of type uint32_t, is found not to be in range for int32_t,
+   // x is invalid
+   CheckedInt<int32_t> x(uint32_t(3123456789));
+ * @endcode
+ * Implicit conversion from
+ * checked integers to plain integers is not allowed. As shown in the
+ * above example, to get the value of a checked integer as a normal integer,
+ * call value().
+ *
+ * Arithmetic operations between checked and plain integers is allowed; the
+ * result type is the type of the checked integer.
+ *
+ * Checked integers of different types cannot be used in the same arithmetic
+ * expression.
+ *
+ * There are convenience typedefs for all stdint types, of the following form
+ * (these are just 2 examples):
+   @code
+   typedef CheckedInt<int32_t> CheckedInt32;
+   typedef CheckedInt<uint16_t> CheckedUint16;
+   @endcode
+ */
+template<typename T>
+class CheckedInt
+{
+protected:
+  T mValue;
+  bool mIsValid;
+
+  template<typename U>
+  CheckedInt(U aValue, bool aIsValid) : mValue(aValue), mIsValid(aIsValid)
+  {
+    static_assert(detail::IsSupported<T>::value &&
+                  detail::IsSupported<U>::value,
+                  "This type is not supported by CheckedInt");
+  }
+
+  friend struct detail::NegateImpl<T>;
+
+public:
+  /**
+   * Constructs a checked integer with given @a value. The checked integer is
+   * initialized as valid or invalid depending on whether the @a value
+   * is in range.
+   *
+   * This constructor is not explicit. Instead, the type of its argument is a
+   * separate template parameter, ensuring that no conversion is performed
+   * before this constructor is actually called. As explained in the above
+   * documentation for class CheckedInt, this constructor checks that its
+   * argument is valid.
+   */
+  template<typename U>
+  MOZ_IMPLICIT CheckedInt(U aValue) MOZ_NO_ARITHMETIC_EXPR_IN_ARGUMENT
+    : mValue(T(aValue)),
+      mIsValid(detail::IsInRange<T>(aValue))
+  {
+    static_assert(detail::IsSupported<T>::value &&
+                  detail::IsSupported<U>::value,
+                  "This type is not supported by CheckedInt");
+  }
+
+  template<typename U>
+  friend class CheckedInt;
+
+  template<typename U>
+  CheckedInt<U> toChecked() const
+  {
+    CheckedInt<U> ret(mValue);
+    ret.mIsValid = ret.mIsValid && mIsValid;
+    return ret;
+  }
+
+  /** Constructs a valid checked integer with initial value 0 */
+  CheckedInt() : mValue(0), mIsValid(true)
+  {
+    static_assert(detail::IsSupported<T>::value,
+                  "This type is not supported by CheckedInt");
+  }
+
+  /** @returns the actual value */
+  T value() const
+  {
+    MOZ_ASSERT(mIsValid, "Invalid checked integer (division by zero or integer overflow)");
+    return mValue;
+  }
+
+  /**
+   * @returns true if the checked integer is valid, i.e. is not the result
+   * of an invalid operation or of an operation involving an invalid checked
+   * integer
+   */
+  bool isValid() const
+  {
+    return mIsValid;
+  }
+
+  template<typename U>
+  friend CheckedInt<U> operator +(const CheckedInt<U>& aLhs,
+                                  const CheckedInt<U>& aRhs);
+  template<typename U>
+  CheckedInt& operator +=(U aRhs);
+  CheckedInt& operator +=(const CheckedInt<T>& aRhs);
+
+  template<typename U>
+  friend CheckedInt<U> operator -(const CheckedInt<U>& aLhs,
+                                  const CheckedInt<U>& aRhs);
+  template<typename U>
+  CheckedInt& operator -=(U aRhs);
+  CheckedInt& operator -=(const CheckedInt<T>& aRhs);
+
+  template<typename U>
+  friend CheckedInt<U> operator *(const CheckedInt<U>& aLhs,
+                                  const CheckedInt<U>& aRhs);
+  template<typename U>
+  CheckedInt& operator *=(U aRhs);
+  CheckedInt& operator *=(const CheckedInt<T>& aRhs);
+
+  template<typename U>
+  friend CheckedInt<U> operator /(const CheckedInt<U>& aLhs,
+                                  const CheckedInt<U>& aRhs);
+  template<typename U>
+  CheckedInt& operator /=(U aRhs);
+  CheckedInt& operator /=(const CheckedInt<T>& aRhs);
+
+  template<typename U>
+  friend CheckedInt<U> operator %(const CheckedInt<U>& aLhs,
+                                  const CheckedInt<U>& aRhs);
+  template<typename U>
+  CheckedInt& operator %=(U aRhs);
+  CheckedInt& operator %=(const CheckedInt<T>& aRhs);
+
+  CheckedInt operator -() const
+  {
+    return detail::NegateImpl<T>::negate(*this);
+  }
+
+  /**
+   * @returns true if the left and right hand sides are valid
+   * and have the same value.
+   *
+   * Note that these semantics are the reason why we don't offer
+   * a operator!=. Indeed, we'd want to have a!=b be equivalent to !(a==b)
+   * but that would mean that whenever a or b is invalid, a!=b
+   * is always true, which would be very confusing.
+   *
+   * For similar reasons, operators <, >, <=, >= would be very tricky to
+   * specify, so we just avoid offering them.
+   *
+   * Notice that these == semantics are made more reasonable by these facts:
+   *  1. a==b implies equality at the raw data level
+   *     (the converse is false, as a==b is never true among invalids)
+   *  2. This is similar to the behavior of IEEE floats, where a==b
+   *     means that a and b have the same value *and* neither is NaN.
+   */
+  bool operator ==(const CheckedInt& aOther) const
+  {
+    return mIsValid && aOther.mIsValid && mValue == aOther.mValue;
+  }
+
+  /** prefix ++ */
+  CheckedInt& operator++()
+  {
+    *this += 1;
+    return *this;
+  }
+
+  /** postfix ++ */
+  CheckedInt operator++(int)
+  {
+    CheckedInt tmp = *this;
+    *this += 1;
+    return tmp;
+  }
+
+  /** prefix -- */
+  CheckedInt& operator--()
+  {
+    *this -= 1;
+    return *this;
+  }
+
+  /** postfix -- */
+  CheckedInt operator--(int)
+  {
+    CheckedInt tmp = *this;
+    *this -= 1;
+    return tmp;
+  }
+
+private:
+  /**
+   * The !=, <, <=, >, >= operators are disabled:
+   * see the comment on operator==.
+   */
+  template<typename U> bool operator !=(U aOther) const = delete;
+  template<typename U> bool operator < (U aOther) const = delete;
+  template<typename U> bool operator <=(U aOther) const = delete;
+  template<typename U> bool operator > (U aOther) const = delete;
+  template<typename U> bool operator >=(U aOther) const = delete;
+};
+
+#define MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(NAME, OP)                        \
+  template<typename T>                                                        \
+  inline CheckedInt<T>                                                        \
+  operator OP(const CheckedInt<T>& aLhs, const CheckedInt<T>& aRhs)           \
+  {                                                                           \
+    if (!detail::Is##NAME##Valid(aLhs.mValue, aRhs.mValue)) {                 \
+      return CheckedInt<T>(0, false);                                         \
+    }                                                                         \
+    return CheckedInt<T>(aLhs.mValue OP aRhs.mValue,                          \
+                         aLhs.mIsValid && aRhs.mIsValid);                     \
+  }
+
+MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(Add, +)
+MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(Sub, -)
+MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(Mul, *)
+MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(Div, /)
+MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR(Mod, %)
+
+#undef MOZ_CHECKEDINT_BASIC_BINARY_OPERATOR
+
+// Implement castToCheckedInt<T>(x), making sure that
+//  - it allows x to be either a CheckedInt<T> or any integer type
+//    that can be casted to T
+//  - if x is already a CheckedInt<T>, we just return a reference to it,
+//    instead of copying it (optimization)
+
+namespace detail {
+
+template<typename T, typename U>
+struct CastToCheckedIntImpl
+{
+  typedef CheckedInt<T> ReturnType;
+  static CheckedInt<T> run(U aU) { return aU; }
+};
+
+template<typename T>
+struct CastToCheckedIntImpl<T, CheckedInt<T> >
+{
+  typedef const CheckedInt<T>& ReturnType;
+  static const CheckedInt<T>& run(const CheckedInt<T>& aU) { return aU; }
+};
+
+} // namespace detail
+
+template<typename T, typename U>
+inline typename detail::CastToCheckedIntImpl<T, U>::ReturnType
+castToCheckedInt(U aU)
+{
+  static_assert(detail::IsSupported<T>::value &&
+                detail::IsSupported<U>::value,
+                "This type is not supported by CheckedInt");
+  return detail::CastToCheckedIntImpl<T, U>::run(aU);
+}
+
+#define MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(OP, COMPOUND_OP)            \
+  template<typename T>                                                          \
+  template<typename U>                                                          \
+  CheckedInt<T>& CheckedInt<T>::operator COMPOUND_OP(U aRhs)                    \
+  {                                                                             \
+    *this = *this OP castToCheckedInt<T>(aRhs);                                 \
+    return *this;                                                               \
+  }                                                                             \
+  template<typename T>                                                          \
+  CheckedInt<T>& CheckedInt<T>::operator COMPOUND_OP(const CheckedInt<T>& aRhs) \
+  {                                                                             \
+    *this = *this OP aRhs;                                                      \
+    return *this;                                                               \
+  }                                                                             \
+  template<typename T, typename U>                                              \
+  inline CheckedInt<T> operator OP(const CheckedInt<T>& aLhs, U aRhs)           \
+  {                                                                             \
+    return aLhs OP castToCheckedInt<T>(aRhs);                                   \
+  }                                                                             \
+  template<typename T, typename U>                                              \
+  inline CheckedInt<T> operator OP(U aLhs, const CheckedInt<T>& aRhs)           \
+  {                                                                             \
+    return castToCheckedInt<T>(aLhs) OP aRhs;                                   \
+  }
+
+MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(+, +=)
+MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(*, *=)
+MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(-, -=)
+MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(/, /=)
+MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS(%, %=)
+
+#undef MOZ_CHECKEDINT_CONVENIENCE_BINARY_OPERATORS
+
+template<typename T, typename U>
+inline bool
+operator ==(const CheckedInt<T>& aLhs, U aRhs)
+{
+  return aLhs == castToCheckedInt<T>(aRhs);
+}
+
+template<typename T, typename U>
+inline bool
+operator ==(U aLhs, const CheckedInt<T>& aRhs)
+{
+  return castToCheckedInt<T>(aLhs) == aRhs;
+}
+
+// Convenience typedefs.
+typedef CheckedInt<int8_t>   CheckedInt8;
+typedef CheckedInt<uint8_t>  CheckedUint8;
+typedef CheckedInt<int16_t>  CheckedInt16;
+typedef CheckedInt<uint16_t> CheckedUint16;
+typedef CheckedInt<int32_t>  CheckedInt32;
+typedef CheckedInt<uint32_t> CheckedUint32;
+typedef CheckedInt<int64_t>  CheckedInt64;
+typedef CheckedInt<uint64_t> CheckedUint64;
+
+} // namespace mozilla
+
+#endif /* mozilla_CheckedInt_h */