gtest-internal.h

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//   actual_expression:   "bar"
//   expected_value:      "5"
//   actual_value:        "6"
//
// The ignoring_case parameter is true iff the assertion is a
// *_STRCASEEQ*.  When it's true, the string " (ignoring case)" will
// be inserted into the message.
AssertionResult EqFailure(const char* expected_expression,
                          const char* actual_expression,
                          const String& expected_value,
                          const String& actual_value,
                          bool ignoring_case);


// This template class represents an IEEE floating-point number
// (either single-precision or double-precision, depending on the
// template parameters).
//
// The purpose of this class is to do more sophisticated number
// comparison.  (Due to round-off error, etc, it's very unlikely that
// two floating-points will be equal exactly.  Hence a naive
// comparison by the == operation often doesn't work.)
//
// Format of IEEE floating-point:
//
//   The most-significant bit being the leftmost, an IEEE
//   floating-point looks like
//
//     sign_bit exponent_bits fraction_bits
//
//   Here, sign_bit is a single bit that designates the sign of the
//   number.
//
//   For float, there are 8 exponent bits and 23 fraction bits.
//
//   For double, there are 11 exponent bits and 52 fraction bits.
//
//   More details can be found at
//   http://en.wikipedia.org/wiki/IEEE_floating-point_standard.
//
// Template parameter:
//
//   RawType: the raw floating-point type (either float or double)
template <typename RawType>
class FloatingPoint {
 public:
  // Defines the unsigned integer type that has the same size as the
  // floating point number.
  typedef typename TypeWithSize<sizeof(RawType)>::UInt Bits;

  // Constants.

  // # of bits in a number.
  static const size_t kBitCount = 8*sizeof(RawType);

  // # of fraction bits in a number.
  static const size_t kFractionBitCount =
    std::numeric_limits<RawType>::digits - 1;

  // # of exponent bits in a number.
  static const size_t kExponentBitCount = kBitCount - 1 - kFractionBitCount;

  // The mask for the sign bit.
  static const Bits kSignBitMask = static_cast<Bits>(1) << (kBitCount - 1);

  // The mask for the fraction bits.
  static const Bits kFractionBitMask =
    ~static_cast<Bits>(0) >> (kExponentBitCount + 1);

  // The mask for the exponent bits.
  static const Bits kExponentBitMask = ~(kSignBitMask | kFractionBitMask);

  // How many ULP's (Units in the Last Place) we want to tolerate when
  // comparing two numbers.  The larger the value, the more error we
  // allow.  A 0 value means that two numbers must be exactly the same
  // to be considered equal.
  //
  // The maximum error of a single floating-point operation is 0.5
  // units in the last place.  On Intel CPU's, all floating-point
  // calculations are done with 80-bit precision, while double has 64
  // bits.  Therefore, 4 should be enough for ordinary use.
  //
  // See the following article for more details on ULP:
  // http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm.
  static const size_t kMaxUlps = 4;

  // Constructs a FloatingPoint from a raw floating-point number.
  //
  // On an Intel CPU, passing a non-normalized NAN (Not a Number)
  // around may change its bits, although the new value is guaranteed
  // to be also a NAN.  Therefore, don't expect this constructor to
  // preserve the bits in x when x is a NAN.
  explicit FloatingPoint(const RawType& x) : value_(x) {}

  // Static methods

  // Reinterprets a bit pattern as a floating-point number.
  //
  // This function is needed to test the AlmostEquals() method.
  static RawType ReinterpretBits(const Bits bits) {
    FloatingPoint fp(0);
    fp.bits_ = bits;
    return fp.value_;
  }

  // Returns the floating-point number that represent positive infinity.
  static RawType Infinity() {
    return ReinterpretBits(kExponentBitMask);
  }

  // Non-static methods

  // Returns the bits that represents this number.
  const Bits &bits() const { return bits_; }

  // Returns the exponent bits of this number.
  Bits exponent_bits() const { return kExponentBitMask & bits_; }

  // Returns the fraction bits of this number.
  Bits fraction_bits() const { return kFractionBitMask & bits_; }

  // Returns the sign bit of this number.
  Bits sign_bit() const { return kSignBitMask & bits_; }

  // Returns true iff this is NAN (not a number).
  bool is_nan() const {
    // It's a NAN if the exponent bits are all ones and the fraction
    // bits are not entirely zeros.
    return (exponent_bits() == kExponentBitMask) && (fraction_bits() != 0);
  }

  // Returns true iff this number is at most kMaxUlps ULP's away from
  // rhs.  In particular, this function:
  //
  //   - returns false if either number is (or both are) NAN.
  //   - treats really large numbers as almost equal to infinity.
  //   - thinks +0.0 and -0.0 are 0 DLP's apart.
  bool AlmostEquals(const FloatingPoint& rhs) const {
    // The IEEE standard says that any comparison operation involving
    // a NAN must return false.
    if (is_nan() || rhs.is_nan()) return false;

    return DistanceBetweenSignAndMagnitudeNumbers(bits_, rhs.bits_) <= kMaxUlps;
  }

 private:
  // Converts an integer from the sign-and-magnitude representation to
  // the biased representation.  More precisely, let N be 2 to the
  // power of (kBitCount - 1), an integer x is represented by the
  // unsigned number x + N.
  //
  // For instance,
  //
  //   -N + 1 (the most negative number representable using
  //          sign-and-magnitude) is represented by 1;
  //   0      is represented by N; and
  //   N - 1  (the biggest number representable using
  //          sign-and-magnitude) is represented by 2N - 1.
  //
  // Read http://en.wikipedia.org/wiki/Signed_number_representations
  // for more details on signed number representations.
  static Bits SignAndMagnitudeToBiased(const Bits &sam) {
    if (kSignBitMask & sam) {
      // sam represents a negative number.
      return ~sam + 1;
    } else {
      // sam represents a positive number.
      return kSignBitMask | sam;
    }
  }

  // Given two numbers in the sign-and-magnitude representation,
  // returns the distance between them as an unsigned number.
  static Bits DistanceBetweenSignAndMagnitudeNumbers(const Bits &sam1,
                                                     const Bits &sam2) {
    const Bits biased1 = SignAndMagnitudeToBiased(sam1);
    const Bits biased2 = SignAndMagnitudeToBiased(sam2);
    return (biased1 >= biased2) ? (biased1 - biased2) : (biased2 - biased1);
  }

  union {
    RawType value_;  // The raw floating-point number.
    Bits bits_;      // The bits that represent the number.
  };
};

// Typedefs the instances of the FloatingPoint template class that we
// care to use.
typedef FloatingPoint<float> Float;
typedef FloatingPoint<double> Double;

// In order to catch the mistake of putting tests that use different
// test fixture classes in the same test case, we need to assign
// unique IDs to fixture classes and compare them.  The TypeId type is
// used to hold such IDs.  The user should treat TypeId as an opaque
// type: the only operation allowed on TypeId values is to compare
// them for equality using the == operator.
typedef const void* TypeId;

template <typename T>
class TypeIdHelper {
 public:
  // dummy_ must not have a const type.  Otherwise an overly eager
  // compiler (e.g. MSVC 7.1 & 8.0) may try to merge
  // TypeIdHelper<T>::dummy_ for different Ts as an "optimization".
  static bool dummy_;
};

template <typename T>
bool TypeIdHelper<T>::dummy_ = false;

// GetTypeId<T>() returns the ID of type T.  Different values will be
// returned for different types.  Calling the function twice with the
// same type argument is guaranteed to return the same ID.
template <typename T>
TypeId GetTypeId() {
  // The compiler is required to allocate a different
  // TypeIdHelper<T>::dummy_ variable for each T used to instantiate
  // the template.  Therefore, the address of dummy_ is guaranteed to
  // be unique.
  return &(TypeIdHelper<T>::dummy_);
}

// Returns the type ID of ::testing::Test.  Always call this instead
// of GetTypeId< ::testing::Test>() to get the type ID of
// ::testing::Test, as the latter may give the wrong result due to a
// suspected linker bug when compiling Google Test as a Mac OS X
// framework.
TypeId GetTestTypeId();

// Defines the abstract factory interface that creates instances
// of a Test object.
class TestFactoryBase {
 public:
  virtual ~TestFactoryBase() {}

  // Creates a test instance to run. The instance is both created and destroyed
  // within TestInfoImpl::Run()
  virtual Test* CreateTest() = 0;

 protected:
  TestFactoryBase() {}

 private:
  GTEST_DISALLOW_COPY_AND_ASSIGN_(TestFactoryBase);
};

// This class provides implementation of TeastFactoryBase interface.
// It is used in TEST and TEST_F macros.
template <class TestClass>
class TestFactoryImpl : public TestFactoryBase {
 public:
  virtual Test* CreateTest() { return new TestClass; }
};

#ifdef GTEST_OS_WINDOWS

// Predicate-formatters for implementing the HRESULT checking macros
// {ASSERT|EXPECT}_HRESULT_{SUCCEEDED|FAILED}
// We pass a long instead of HRESULT to avoid causing an
// include dependency for the HRESULT type.
AssertionResult IsHRESULTSuccess(const char* expr, long hr);  // NOLINT
AssertionResult IsHRESULTFailure(const char* expr, long hr);  // NOLINT

#endif  // GTEST_OS_WINDOWS

// Formats a source file path and a line number as they would appear
// in a compiler error message.
inline String FormatFileLocation(const char* file, int line) {
  const char* const file_name = file == NULL ? "unknown file" : file;
  if (line < 0) {
    return String::Format("%s:", file_name);
  }
#ifdef _MSC_VER
  return String::Format("%s(%d):", file_name, line);
#else
  return String::Format("%s:%d:", file_name, line);
#endif  // _MSC_VER
}

// Types of SetUpTestCase() and TearDownTestCase() functions.
typedef void (*SetUpTestCaseFunc)();
typedef void (*TearDownTestCaseFunc)();

// Creates a new TestInfo object and registers it with Google Test;
// returns the created object.
//
// Arguments:
//
//   test_case_name:   name of the test case
//   name:             name of the test
//   test_case_comment: a comment on the test case that will be included in
//                      the test output