Src/cppunit/TestAssert.

src/cppunit/TestAssert.cpp (assertDoubleEquals): Moved finite & NaN
tests to include/cppunit/portability/FloatingPoint.h. Changed
implementation assertDoubleEquals to explicitly test for NaN
in case of non-finite values to force equality failure in the
presence of NaN. Previous implementation failed on Microsoft
Visual Studio 6 (on this platform: NaN == NaN).
* examples/cppunittest/TestAssertTest.cpp: Add more unit tests to
test the portable floating-point primitive. Added missing
include <limits>.

* include/cppunit/portability/Makefile.am:
* include/cppunit/portability/FloatingPoint.h: Added file. Extracted
isfinite() from TestAssert.cpp.

* include/cppunit/config-evc4:
* include/cppunit/config-msvc6: Added support for _finite().

5 files changed, 75 insertions, 5 deletions

diff --git a/include/cppunit/TestAssert.h b/include/cppunit/TestAssert.h
index 07783a2..f74797b 100644
--- a/include/cppunit/TestAssert.h
+++ b/include/cppunit/TestAssert.h
@@ -109,6 +109,7 @@ void assertEquals( const T& expected,
 /*! \brief (Implementation) Asserts that two double are equals given a tolerance.
  * Use CPPUNIT_ASSERT_DOUBLES_EQUAL instead of this function.
  * \sa Asserter::failNotEqual().
+ * \sa CPPUNIT_ASSERT_DOUBLES_EQUAL for detailed semantic of the assertion.
  */
 void CPPUNIT_API assertDoubleEquals( double expected,
                                      double actual,
@@ -218,6 +219,13 @@ void CPPUNIT_API assertDoubleEquals( double expected,
 
 /*! \brief Macro for primitive double value comparisons. 
  * \ingroup Assertions
+ *
+ * The assertion pass if both expected and actual are finite and
+ * \c fabs( \c expected - \c actual ) <= \c delta.
+ * If either \c expected or actual are infinite (+/- inf), the 
+ * assertion pass if \c expected == \c actual.
+ * If either \c expected or \c actual is a NaN (not a number), then
+ * the assertion fails.
  */
 #define CPPUNIT_ASSERT_DOUBLES_EQUAL(expected,actual,delta)        \
   ( CPPUNIT_NS::assertDoubleEquals( (expected),            \
@@ -230,6 +238,7 @@ void CPPUNIT_API assertDoubleEquals( double expected,
 /*! \brief Macro for primitive double value comparisons, setting a 
  * user-supplied message in case of failure. 
  * \ingroup Assertions
+ * \sa CPPUNIT_ASSERT_DOUBLES_EQUAL for detailed semantic of the assertion.
  */
 #define CPPUNIT_ASSERT_DOUBLES_EQUAL_MESSAGE(message,expected,actual,delta)  \
   ( CPPUNIT_NS::assertDoubleEquals( (expected),            \
diff --git a/include/cppunit/config/config-evc4.h b/include/cppunit/config/config-evc4.h
index cb141b0..a791698 100644
--- a/include/cppunit/config/config-evc4.h
+++ b/include/cppunit/config/config-evc4.h
@@ -60,6 +60,11 @@
 # define CPPUNIT_COMPILER_LOCATION_FORMAT "%p(%l):"
 #endif
 
+/* define to 1 if the compiler has _finite() */
+#ifndef CPPUNIT_HAVE__FINITE
+#define CPPUNIT_HAVE__FINITE 1 
+#endif
+
 // Uncomment to turn on STL wrapping => use this to test compilation. 
 // This will make CppUnit subclass std::vector & co to provide default
 // parameter.
diff --git a/include/cppunit/config/config-msvc6.h b/include/cppunit/config/config-msvc6.h
index a1b0af2..d688171 100644
--- a/include/cppunit/config/config-msvc6.h
+++ b/include/cppunit/config/config-msvc6.h
@@ -64,6 +64,11 @@
 // Define to 1 if the compiler support C++ style cast.
 #define CPPUNIT_HAVE_CPP_CAST 1
 
+/* define to 1 if the compiler has _finite() */
+#ifndef CPPUNIT_HAVE__FINITE
+#define CPPUNIT_HAVE__FINITE 1 
+#endif
+
 
 // Uncomment to turn on STL wrapping => use this to test compilation. 
 // This will make CppUnit subclass std::vector & co to provide default
diff --git a/include/cppunit/portability/FloatingPoint.h b/include/cppunit/portability/FloatingPoint.h
new file mode 100644
index 0000000..fa3095e
--- /dev/null
+++ b/include/cppunit/portability/FloatingPoint.h
@@ -0,0 +1,50 @@
+#ifndef CPPUNIT_PORTABILITY_FLOATINGPOINT_H_INCLUDED
+#define CPPUNIT_PORTABILITY_FLOATINGPOINT_H_INCLUDED
+
+#include <math.h>
+
+CPPUNIT_NS_BEGIN
+
+/// \brief Tests if a floating-point is a NaN.
+// According to IEEE-754 floating point standard, NaN comparison should always
+// be 'false'. 
+// At least Microsoft Visual Studio 6 is known not to implement this test correctly.
+// It emits the following code to test equality:
+//  fcomp       qword ptr [nan]
+//  fnstsw      ax                        // copie fp (floating-point) status register to ax
+//  test        ah,40h                    // test bit 14 of ax (0x4000) => C3 of fp status register
+// According to the following documentation on the x86 floating point status register,
+// the C2 bit should be tested to test for NaN value. 
+// http://webster.cs.ucr.edu/AoA/Windows/HTML/RealArithmetic.html#1000117
+// In Microsoft Visual Studio 2003 & 2005, the test is implemented with:
+//  test        ah,44h         // Visual Studio 2005 test both C2 & C3...
+//
+// To work around this, a NaN is assumed to be detected if no strict ordering is found.
+inline bool floatingPointIsUnordered( double x )
+{
+   // x != x will detect a NaN on conformant platform
+   // (2.0 < x  &&  x < 1.0) will detect a NaN on non conformant platform:
+   // => no ordering can be found for x.
+   return  (x != x) ||  (2.0 < x  &&  x < 1.0);
+}
+
+
+/// \brief Tests if a floating-point is finite.
+/// @return \c true if x is neither a NaN, nor +inf, nor -inf, \c false otherwise.
+inline bool floatingPointIsFinite( double x )
+{
+#if defined(CPPUNIT_HAVE_ISFINITE)
+   return (bool)isfinite( x );
+#elif defined(CPPUNIT_HAVE_FINITE)
+   return (bool)finite( x );
+#elif defined(CPPUNIT_HAVE__FINITE)
+   return _finite(x);
+#else
+   double testInf = x * 0.0;  // Produce 0.0 if x is finite, a NaN otherwise.
+   return testInf == 0.0  &&  !floatingPointIsUnordered(testInf);
+#endif
+}
+
+CPPUNIT_NS_END
+
+#endif // CPPUNIT_PORTABILITY_FLOATINGPOINT_H_INCLUDED
diff --git a/include/cppunit/portability/Makefile.am b/include/cppunit/portability/Makefile.am
index 3c578e3..2caeb32 100644
--- a/include/cppunit/portability/Makefile.am
+++ b/include/cppunit/portability/Makefile.am
@@ -1,9 +1,10 @@
 libcppunitincludedir = $(includedir)/cppunit/portability
 
 libcppunitinclude_HEADERS = \
-	CppUnitDeque.h \
-	CppUnitMap.h \
-	CppUnitSet.h \
-	CppUnitStack.h \
+	CppUnitDeque.h  \
+	CppUnitMap.h    \
+	CppUnitSet.h    \
+	CppUnitStack.h  \
 	CppUnitVector.h \
-  Stream.h
+   FloatingPoint.h \
+   Stream.h