trionan.c

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    : 0;
  
#elif defined(TRIO_COMPILER_MSVC) || defined(TRIO_COMPILER_BCB)
  /*
   * Microsoft Visual C++ and Borland C++ Builder have an _fpclass()
   * function that can be used to detect infinity.
   */
  return ((_fpclass(number) == _FPCLASS_PINF)
	  ? 1
	  : ((_fpclass(number) == _FPCLASS_NINF) ? -1 : 0));

#elif defined(USE_IEEE_754)
  /*
   * Examine IEEE 754 bit-pattern. Infinity must have a special exponent
   * pattern, and an empty mantissa.
   */
  int has_mantissa;
  int is_special_quantity;

  is_special_quantity = trio_is_special_quantity(number, &has_mantissa);
  
  return (is_special_quantity && !has_mantissa)
    ? ((number < 0.0) ? -1 : 1)
    : 0;

#else
  /*
   * Fallback solution.
   */
  int status;
  
# if defined(TRIO_PLATFORM_UNIX)
  void (*signal_handler)(int) = signal(SIGFPE, SIG_IGN);
# endif
  
  double infinity = trio_pinf();
  
  status = ((number == infinity)
	    ? 1
	    : ((number == -infinity) ? -1 : 0));
  
# if defined(TRIO_PLATFORM_UNIX)
  signal(SIGFPE, signal_handler);
# endif
  
  return status;
  
#endif
}

#if 0
	/* Temporary fix - this routine is not used anywhere */
/**
   Check for finity.

   @param number An arbitrary floating-point number.
   @return Boolean value indicating whether or not the number is a finite.
*/
TRIO_PUBLIC int
trio_isfinite
TRIO_ARGS1((number),
	   double number)
{
#if defined(TRIO_COMPILER_SUPPORTS_C99) && defined(isfinite)
  /*
   * C99 defines isfinite() as a macro.
   */
  return isfinite(number);
  
#elif defined(TRIO_COMPILER_MSVC) || defined(TRIO_COMPILER_BCB)
  /*
   * Microsoft Visual C++ and Borland C++ Builder use _finite().
   */
  return _finite(number);

#elif defined(USE_IEEE_754)
  /*
   * Examine IEEE 754 bit-pattern. For finity we do not care about the
   * mantissa.
   */
  int dummy;

  return (! trio_is_special_quantity(number, &dummy));

#else
  /*
   * Fallback solution.
   */
  return ((trio_isinf(number) == 0) && (trio_isnan(number) == 0));
  
#endif
}

#endif

/*
 * The sign of NaN is always false
 */
TRIO_PUBLIC int
trio_fpclassify_and_signbit
TRIO_ARGS2((number, is_negative),
	   double number,
	   int *is_negative)
{
#if defined(fpclassify) && defined(signbit)
  /*
   * C99 defines fpclassify() and signbit() as a macros
   */
  *is_negative = signbit(number);
  switch (fpclassify(number)) {
  case FP_NAN:
    return TRIO_FP_NAN;
  case FP_INFINITE:
    return TRIO_FP_INFINITE;
  case FP_SUBNORMAL:
    return TRIO_FP_SUBNORMAL;
  case FP_ZERO:
    return TRIO_FP_ZERO;
  default:
    return TRIO_FP_NORMAL;
  }

#else
# if defined(TRIO_COMPILER_DECC)
  /*
   * DECC has an fp_class() function.
   */
#  define TRIO_FPCLASSIFY(n) fp_class(n)
#  define TRIO_QUIET_NAN FP_QNAN
#  define TRIO_SIGNALLING_NAN FP_SNAN
#  define TRIO_POSITIVE_INFINITY FP_POS_INF
#  define TRIO_NEGATIVE_INFINITY FP_NEG_INF
#  define TRIO_POSITIVE_SUBNORMAL FP_POS_DENORM
#  define TRIO_NEGATIVE_SUBNORMAL FP_NEG_DENORM
#  define TRIO_POSITIVE_ZERO FP_POS_ZERO
#  define TRIO_NEGATIVE_ZERO FP_NEG_ZERO
#  define TRIO_POSITIVE_NORMAL FP_POS_NORM
#  define TRIO_NEGATIVE_NORMAL FP_NEG_NORM
  
# elif defined(TRIO_COMPILER_MSVC) || defined(TRIO_COMPILER_BCB)
  /*
   * Microsoft Visual C++ and Borland C++ Builder have an _fpclass()
   * function.
   */
#  define TRIO_FPCLASSIFY(n) _fpclass(n)
#  define TRIO_QUIET_NAN _FPCLASS_QNAN
#  define TRIO_SIGNALLING_NAN _FPCLASS_SNAN
#  define TRIO_POSITIVE_INFINITY _FPCLASS_PINF
#  define TRIO_NEGATIVE_INFINITY _FPCLASS_NINF
#  define TRIO_POSITIVE_SUBNORMAL _FPCLASS_PD
#  define TRIO_NEGATIVE_SUBNORMAL _FPCLASS_ND
#  define TRIO_POSITIVE_ZERO _FPCLASS_PZ
#  define TRIO_NEGATIVE_ZERO _FPCLASS_NZ
#  define TRIO_POSITIVE_NORMAL _FPCLASS_PN
#  define TRIO_NEGATIVE_NORMAL _FPCLASS_NN
  
# elif defined(FP_PLUS_NORM)
  /*
   * HP-UX 9.x and 10.x have an fpclassify() function, that is different
   * from the C99 fpclassify() macro supported on HP-UX 11.x.
   *
   * AIX has class() for C, and _class() for C++, which returns the
   * same values as the HP-UX fpclassify() function.
   */
#  if defined(TRIO_PLATFORM_AIX)
#   if defined(__cplusplus)
#    define TRIO_FPCLASSIFY(n) _class(n)
#   else
#    define TRIO_FPCLASSIFY(n) class(n)
#   endif
#  else
#   define TRIO_FPCLASSIFY(n) fpclassify(n)
#  endif
#  define TRIO_QUIET_NAN FP_QNAN
#  define TRIO_SIGNALLING_NAN FP_SNAN
#  define TRIO_POSITIVE_INFINITY FP_PLUS_INF
#  define TRIO_NEGATIVE_INFINITY FP_MINUS_INF
#  define TRIO_POSITIVE_SUBNORMAL FP_PLUS_DENORM
#  define TRIO_NEGATIVE_SUBNORMAL FP_MINUS_DENORM
#  define TRIO_POSITIVE_ZERO FP_PLUS_ZERO
#  define TRIO_NEGATIVE_ZERO FP_MINUS_ZERO
#  define TRIO_POSITIVE_NORMAL FP_PLUS_NORM
#  define TRIO_NEGATIVE_NORMAL FP_MINUS_NORM
# endif

# if defined(TRIO_FPCLASSIFY)
  switch (TRIO_FPCLASSIFY(number)) {
  case TRIO_QUIET_NAN:
  case TRIO_SIGNALLING_NAN:
    *is_negative = TRIO_FALSE; /* NaN has no sign */
    return TRIO_FP_NAN;
  case TRIO_POSITIVE_INFINITY:
    *is_negative = TRIO_FALSE;
    return TRIO_FP_INFINITE;
  case TRIO_NEGATIVE_INFINITY:
    *is_negative = TRIO_TRUE;
    return TRIO_FP_INFINITE;
  case TRIO_POSITIVE_SUBNORMAL:
    *is_negative = TRIO_FALSE;
    return TRIO_FP_SUBNORMAL;
  case TRIO_NEGATIVE_SUBNORMAL:
    *is_negative = TRIO_TRUE;
    return TRIO_FP_SUBNORMAL;
  case TRIO_POSITIVE_ZERO:
    *is_negative = TRIO_FALSE;
    return TRIO_FP_ZERO;
  case TRIO_NEGATIVE_ZERO:
    *is_negative = TRIO_TRUE;
    return TRIO_FP_ZERO;
  case TRIO_POSITIVE_NORMAL:
    *is_negative = TRIO_FALSE;
    return TRIO_FP_NORMAL;
  case TRIO_NEGATIVE_NORMAL:
    *is_negative = TRIO_TRUE;
    return TRIO_FP_NORMAL;
  default:
    /* Just in case... */
    *is_negative = (number < 0.0);
    return TRIO_FP_NORMAL;
  }
  
# else
  /*
   * Fallback solution.
   */
  int rc;
  
  if (number == 0.0) {
    /*
     * In IEEE 754 the sign of zero is ignored in comparisons, so we
     * have to handle this as a special case by examining the sign bit
     * directly.
     */
#  if defined(USE_IEEE_754)
    *is_negative = trio_is_negative(number);
#  else
    *is_negative = TRIO_FALSE; /* FIXME */
#  endif
    return TRIO_FP_ZERO;
  }
  if (trio_isnan(number)) {
    *is_negative = TRIO_FALSE;
    return TRIO_FP_NAN;
  }
  if ((rc = trio_isinf(number))) {
    *is_negative = (rc == -1);
    return TRIO_FP_INFINITE;
  }
  if ((number > 0.0) && (number < DBL_MIN)) {
    *is_negative = TRIO_FALSE;
    return TRIO_FP_SUBNORMAL;
  }
  if ((number < 0.0) && (number > -DBL_MIN)) {
    *is_negative = TRIO_TRUE;
    return TRIO_FP_SUBNORMAL;
  }
  *is_negative = (number < 0.0);
  return TRIO_FP_NORMAL;
  
# endif
#endif
}

/**
   Examine the sign of a number.

   @param number An arbitrary floating-point number.
   @return Boolean value indicating whether or not the number has the
   sign bit set (i.e. is negative).
*/
TRIO_PUBLIC int
trio_signbit
TRIO_ARGS1((number),
	   double number)
{
  int is_negative;
  
  (void)trio_fpclassify_and_signbit(number, &is_negative);
  return is_negative;
}

#if 0
	/* Temporary fix - this routine is not used in libxml */
/**
   Examine the class of a number.

   @param number An arbitrary floating-point number.
   @return Enumerable value indicating the class of @p number
*/
TRIO_PUBLIC int
trio_fpclassify
TRIO_ARGS1((number),
	   double number)
{
  int dummy;
  
  return trio_fpclassify_and_signbit(number, &dummy);
}

#endif

/** @} SpecialQuantities */

/*************************************************************************
 * For test purposes.
 *
 * Add the following compiler option to include this test code.
 *
 *  Unix : -DSTANDALONE
 *  VMS  : /DEFINE=(STANDALONE)
 */
#if defined(STANDALONE)
# include <stdio.h>

static TRIO_CONST char *
getClassification
TRIO_ARGS1((type),
	   int type)
{
  switch (type) {
  case TRIO_FP_INFINITE:
    return "FP_INFINITE";
  case TRIO_FP_NAN:
    return "FP_NAN";
  case TRIO_FP_NORMAL:
    return "FP_NORMAL";
  case TRIO_FP_SUBNORMAL:
    return "FP_SUBNORMAL";
  case TRIO_FP_ZERO:
    return "FP_ZERO";
  default:
    return "FP_UNKNOWN";
  }
}

static void
print_class
TRIO_ARGS2((prefix, number),
	   TRIO_CONST char *prefix,
	   double number)
{
  printf("%-6s: %s %-15s %g\n",
	 prefix,
	 trio_signbit(number) ? "-" : "+",
	 getClassification(TRIO_FPCLASSIFY(number)),
	 number);
}

int main(TRIO_NOARGS)
{
  double my_nan;
  double my_pinf;
  double my_ninf;
# if defined(TRIO_PLATFORM_UNIX)
  void (*signal_handler) TRIO_PROTO((int));
# endif

  my_nan = trio_nan();
  my_pinf = trio_pinf();
  my_ninf = trio_ninf();

  print_class("Nan", my_nan);
  print_class("PInf", my_pinf);
  print_class("NInf", my_ninf);
  print_class("PZero", 0.0);
  print_class("NZero", -0.0);
  print_class("PNorm", 1.0);
  print_class("NNorm", -1.0);
  print_class("PSub", 1.01e-307 - 1.00e-307);
  print_class("NSub", 1.00e-307 - 1.01e-307);
  
  printf("NaN : %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
	 my_nan,
	 ((unsigned char *)&my_nan)[0],
	 ((unsigned char *)&my_nan)[1],
	 ((unsigned char *)&my_nan)[2],
	 ((unsigned char *)&my_nan)[3],
	 ((unsigned char *)&my_nan)[4],
	 ((unsigned char *)&my_nan)[5],
	 ((unsigned char *)&my_nan)[6],
	 ((unsigned char *)&my_nan)[7],
	 trio_isnan(my_nan), trio_isinf(my_nan));
  printf("PInf: %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
	 my_pinf,
	 ((unsigned char *)&my_pinf)[0],
	 ((unsigned char *)&my_pinf)[1],
	 ((unsigned char *)&my_pinf)[2],
	 ((unsigned char *)&my_pinf)[3],
	 ((unsigned char *)&my_pinf)[4],
	 ((unsigned char *)&my_pinf)[5],
	 ((unsigned char *)&my_pinf)[6],
	 ((unsigned char *)&my_pinf)[7],
	 trio_isnan(my_pinf), trio_isinf(my_pinf));
  printf("NInf: %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
	 my_ninf,
	 ((unsigned char *)&my_ninf)[0],
	 ((unsigned char *)&my_ninf)[1],
	 ((unsigned char *)&my_ninf)[2],
	 ((unsigned char *)&my_ninf)[3],
	 ((unsigned char *)&my_ninf)[4],
	 ((unsigned char *)&my_ninf)[5],
	 ((unsigned char *)&my_ninf)[6],
	 ((unsigned char *)&my_ninf)[7],
	 trio_isnan(my_ninf), trio_isinf(my_ninf));
  
# if defined(TRIO_PLATFORM_UNIX)
  signal_handler = signal(SIGFPE, SIG_IGN);
# endif
  
  my_pinf = DBL_MAX + DBL_MAX;
  my_ninf = -my_pinf;
  my_nan = my_pinf / my_pinf;

# if defined(TRIO_PLATFORM_UNIX)
  signal(SIGFPE, signal_handler);
# endif
  
  printf("NaN : %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
	 my_nan,
	 ((unsigned char *)&my_nan)[0],
	 ((unsigned char *)&my_nan)[1],
	 ((unsigned char *)&my_nan)[2],
	 ((unsigned char *)&my_nan)[3],
	 ((unsigned char *)&my_nan)[4],
	 ((unsigned char *)&my_nan)[5],
	 ((unsigned char *)&my_nan)[6],
	 ((unsigned char *)&my_nan)[7],
	 trio_isnan(my_nan), trio_isinf(my_nan));
  printf("PInf: %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
	 my_pinf,
	 ((unsigned char *)&my_pinf)[0],
	 ((unsigned char *)&my_pinf)[1],
	 ((unsigned char *)&my_pinf)[2],
	 ((unsigned char *)&my_pinf)[3],
	 ((unsigned char *)&my_pinf)[4],
	 ((unsigned char *)&my_pinf)[5],
	 ((unsigned char *)&my_pinf)[6],
	 ((unsigned char *)&my_pinf)[7],
	 trio_isnan(my_pinf), trio_isinf(my_pinf));
  printf("NInf: %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
	 my_ninf,
	 ((unsigned char *)&my_ninf)[0],
	 ((unsigned char *)&my_ninf)[1],
	 ((unsigned char *)&my_ninf)[2],
	 ((unsigned char *)&my_ninf)[3],
	 ((unsigned char *)&my_ninf)[4],
	 ((unsigned char *)&my_ninf)[5],
	 ((unsigned char *)&my_ninf)[6],
	 ((unsigned char *)&my_ninf)[7],
	 trio_isnan(my_ninf), trio_isinf(my_ninf));
  
  return 0;
}
#endif