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().

2 files changed, 56 insertions, 5 deletions

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