Re: [xml] Testing help needed (was: The NaN dilemma)
- From: Bjorn Reese <breese mail1 stofanet dk>
- Cc: "xml gnome org" <xml gnome org>
- Subject: Re: [xml] Testing help needed (was: The NaN dilemma)
- Date: Sun, 05 Aug 2001 15:06:40 +0000
Daniel Veillard wrote:
Basically we control only a part of the framework, so my suggestion
is to try to cascade all possibilies in order to minimize the probablility
of getting to the problem.
The solution became more complex than what I had hoped for, so I ended up
factoring out the NaN/Inf code of trio to a self-contained unit (albeit it
still uses the trio namespace), and made my enhancements to this. This has
the side-effect that any other project can reuse the code.
Before I commit anything to libxml, I would like to test its cross-platform
portability. I have attached the code (together with two necessary header
files), which must be compiled with the -DSTANDALONE option.
Below is a list of combinations of OS, CPU, and compilers I have already
tested. If any of you people out there have access to other combinations,
then I would appreciate if you could send me (directly, to avoid flooding
the mailing-list with off-topic posts) the output of the program. It is
not necessary to test on the same OSes as listed below if only the minor
version number differs. Also, please tell me what CPU, OS, and compiler
you are using (you can use the config.guess script that comes with libxml).
The platforms I have tested are:
OS CPU Compiler
-------------------------------------------------
Linux 2.2 x86 gcc
Linux 2.2 Alpha gcc
Linux 2.4 StrongARM gcc
WinNT x86 MSVC 5.0 & 6.0
Solaris 2.5.1 x86 gcc
Solaris 2.5.1 Sparc gcc
Solaris 2.6 Sparc WorkShop 4.2
HP-UX 10.20 PA-RISC gcc
HP-UX 10.20 PA-RISC HP C++
AIX 4.1.4 PowerPC gcc
OSF/1 4.0D Alpha gcc
Tru64 5.1 Alpha gcc
NetBSD 1.5 Alpha gcc
FreeBSD 4.3 x86 gcc
FreeBSD 4.3 Alpha gcc
/*************************************************************************
*
* $Id: $
*
* Copyright (C) 2001 Bjorn Reese <breese users sourceforge net>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE AUTHORS AND
* CONTRIBUTORS ACCEPT NO RESPONSIBILITY IN ANY CONCEIVABLE MANNER.
*
************************************************************************/
#ifndef __TRIO_TRIODEF_H__
#define __TRIO_TRIODEF_H__
/*************************************************************************
* Platform and compiler support detection
*/
#if defined(__GNUC__)
# define TRIO_COMPILER_GCC
#elif defined(__SUNPRO_C)
# define TRIO_COMPILER_SUNPRO
#elif defined(__SUNPRO_CC)
# define TRIO_COMPILER_SUNPRO
# define __SUNPRO_C __SUNPRO_CC
#elif defined(__xlC__) || defined(__IBMC__) || defined(__IBMCPP__)
# define TRIO_COMPILER_XLC
#elif defined(_AIX) && !defined(__GNUC__)
# define TRIO_COMPILER_XLC /* Workaround for old xlc */
#elif defined(__DECC) || defined(__DECCXX)
# define TRIO_COMPILER_DECC
#elif defined(_MSC_VER)
# define TRIO_COMPILER_MSVC
#endif
#if defined(unix) || defined(__unix) || defined(__unix__)
# define TRIO_PLATFORM_UNIX
#elif defined(TRIO_COMPILER_XLC) || defined(_AIX)
# define TRIO_PLATFORM_UNIX
#elif defined(TRIO_COMPILER_DECC) || defined(__osf__)
# define TRIO_PLATFORM_UNIX
#elif defined(__NetBSD__)
# define TRIO_PLATFORM_UNIX
#elif defined(__QNX__)
# define TRIO_PLATFORM_UNIX
#elif defined(AMIGA) && defined(TRIO_COMPILER_GCC)
# define TRIO_PLATFORM_UNIX
#elif defined(TRIO_COMPILER_MSVC) || defined(WIN32) || defined(_WIN32)
# define TRIO_PLATFORM_WIN32
#endif
#if defined(__STDC__)
# define TRIO_COMPILER_SUPPORTS_C90
# if defined(__STDC_VERSION__)
# if (__STDC_VERSION__ >= 199409L)
# define TRIO_COMPILER_SUPPORTS_C94
# endif
# if (__STDC_VERSION__ >= 199901L)
# define TRIO_COMPILER_SUPPORTS_C99
# endif
# elif defined(TRIO_COMPILER_SUNPRO)
# if (__SUNPRO_C >= 0x420)
# define TRIO_COMPILER_SUPPORTS_C94
# endif
# endif
#endif
#if defined(_XOPEN_SOURCE)
# if defined(_XOPEN_SOURCE_EXTENDED)
# define TRIO_COMPILER_SUPPORTS_UNIX95
# endif
# if (_XOPEN_VERSION >= 500)
# define TRIO_COMPILER_SUPPORTS_UNIX98
# endif
#endif
#endif /* __TRIO_TRIODEF_H__ */
/*************************************************************************
*
* $Id: trionan.h,v 1.1 2001/06/23 16:08:33 breese Exp $
*
* Copyright (C) 2001 Bjorn Reese <breese users sourceforge net>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE AUTHORS AND
* CONTRIBUTORS ACCEPT NO RESPONSIBILITY IN ANY CONCEIVABLE MANNER.
*
************************************************************************/
#ifndef __TRIO_NAN_H__
#define __TRIO_NAN_H__
#ifdef __cplusplus
extern "C" {
#endif
/*
* Return NaN (Not-a-Number).
*/
double trio_nan(void);
/*
* Return positive infinity.
*/
double trio_pinf(void);
/*
* Return negative infinity.
*/
double trio_ninf(void);
/*
* If number is a NaN return non-zero, otherwise return zero.
*/
int trio_isnan(double number);
/*
* If number is positive infinity return 1, if number is negative
* infinity return -1, otherwise return 0.
*/
int trio_isinf(double number);
#ifdef __cplusplus
}
#endif
#endif /* __TRIO_NAN_H__ */
/*************************************************************************
*
* $Id: trionan.c,v 1.4 2001/06/25 16:45:35 breese Exp $
*
* Copyright (C) 2001 Bjorn Reese <breese users sourceforge net>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE AUTHORS AND
* CONTRIBUTORS ACCEPT NO RESPONSIBILITY IN ANY CONCEIVABLE MANNER.
*
************************************************************************
*
* Functions to handle special quantities in floating-point numbers
* (that is, NaNs and infinity). They provide the capability to detect
* and fabricate special quantities.
*
* Although written to be as portable as possible, it can never be
* guaranteed to work on all platforms, as not all hardware supports
* special quantities.
*
* The approach used here (approximately) is to:
*
* 1. Use C99 functionality when available.
* 2. Use IEEE 754 bit-patterns if possible.
* 3. Use platform-specific techniques.
*
************************************************************************/
static const char rcsid[] = "@(#)$Id: trionan.c,v 1.4 2001/06/25 16:45:35 breese Exp $";
/*************************************************************************
* Include files
*/
#include "triodef.h"
#include "trionan.h"
#include <math.h>
#include <string.h>
#include <limits.h>
#include <float.h>
#if defined(TRIO_PLATFORM_UNIX)
# include <signal.h>
#endif
#include <assert.h>
#ifndef __STDC__
# define volatile
# define const
#endif
/*************************************************************************
* Definitions
*/
/* We must enable IEEE floating-point on Alpha */
#if defined(__alpha) && !defined(_IEEE_FP)
# if defined(TRIO_COMPILER_DECC)
# error "Must be compiled with option -ieee"
# elif defined(TRIO_COMPILER_GCC) && (defined(__osf__) || defined(__linux__))
# error "Must be compiled with option -mieee"
# endif
#endif /* __alpha && ! _IEEE_FP */
/*
* In ANSI/IEEE 754-1985 64-bits double format numbers have the
* following properties (amoungst others)
*
* o FLT_RADIX == 2: binary encoding
* o DBL_MAX_EXP == 1024: 11 bits exponent, where one bit is used
* to indicate special numbers (e.g. NaN and Infinity), so the
* maximum exponent is 10 bits wide (2^10 == 1024).
* o DBL_MANT_DIG == 53: The mantissa is 52 bits wide, but because
* numbers are normalized the initial binary 1 is represented
* implictly (the so-called "hidden bit"), which leaves us with
* the ability to represent 53 bits wide mantissa.
*/
#if (FLT_RADIX == 2) && (DBL_MAX_EXP == 1024) && (DBL_MANT_DIG == 53)
# define USE_IEEE_754
#endif
/*************************************************************************
* Data
*/
#if defined(USE_IEEE_754)
/*
* Endian-agnostic indexing macro.
*
* The value of internalEndianMagic, when converted into a 64-bit
* integer, becomes 0x0001020304050607 (we could have used a 64-bit
* integer value instead of a double, but not all platforms supports
* that type). The value is automatically encoded with the correct
* endianess by the compiler, which means that we can support any
* kind of endianess. The individual bytes are then used as an index
* for the IEEE 754 bit-patterns and masks.
*/
#define TRIO_DOUBLE_INDEX(x) ((unsigned char *)&internalEndianMagic)[(x)]
static const double internalEndianMagic = 1.4015997730788920e-309;
/* Mask for the exponent */
static const unsigned char ieee_754_exponent_mask[] = {
0x7F, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
/* Mask for the mantissa */
static const unsigned char ieee_754_mantissa_mask[] = {
0x00, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
};
/* Bit-pattern for infinity */
static const unsigned char ieee_754_infinity_array[] = {
0x7F, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
/* Bit-pattern for quiet NaN */
static const unsigned char ieee_754_qnan_array[] = {
0x7F, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
/*************************************************************************
* trio_make_double
*/
static double
trio_make_double(const unsigned char *values)
{
volatile double result;
int i;
for (i = 0; i < (int)sizeof(double); i++) {
((volatile unsigned char *)&result)[TRIO_DOUBLE_INDEX(i)] = values[i];
}
return result;
}
/*************************************************************************
* trio_examine_double
*/
static int
trio_is_special_quantity(double number,
int *has_mantissa)
{
unsigned int i;
unsigned char current;
int is_special_quantity = (1 == 1);
*has_mantissa = 0;
for (i = 0; i < (unsigned int)sizeof(double); i++) {
current = ((unsigned char *)&number)[TRIO_DOUBLE_INDEX(i)];
is_special_quantity
&= ((current & ieee_754_exponent_mask[i]) == ieee_754_exponent_mask[i]);
*has_mantissa |= (current & ieee_754_mantissa_mask[i]);
}
return is_special_quantity;
}
#endif /* USE_IEEE_754 */
/*************************************************************************
* trio_pinf
*/
double
trio_pinf(void)
{
/* Cache the result */
static double result = 0.0;
if (result == 0.0) {
#if defined(INFINITY) && defined(__STDC_IEC_559__)
result = (double)INFINITY;
#elif defined(USE_IEEE_754)
result = trio_make_double(ieee_754_infinity_array);
#else
/*
* If HUGE_VAL is different from DBL_MAX, then HUGE_VAL is used
* as infinity. Otherwise we have to resort to an overflow
* operation to generate infinity.
*/
# if defined(TRIO_PLATFORM_UNIX)
void (*signal_handler)(int) = signal(SIGFPE, SIG_IGN);
# endif
result = HUGE_VAL;
if (HUGE_VAL == DBL_MAX) {
/* Force overflow */
result += HUGE_VAL;
}
# if defined(TRIO_PLATFORM_UNIX)
signal(SIGFPE, signal_handler);
# endif
#endif
}
return result;
}
/*************************************************************************
* trio_ninf
*/
double
trio_ninf(void)
{
static double result = 0.0;
if (result == 0.0) {
/*
* Negative infinity is calculated by negating positive infinity,
* which can be done because it is legal to do calculations on
* infinity (for example, 1 / infinity == 0).
*/
result = -trio_pinf();
}
return result;
}
/*************************************************************************
* trio_nan
*/
double
trio_nan(void)
{
/* Cache the result */
static double result = 0.0;
if (result == 0.0) {
#if defined(TRIO_COMPILER_SUPPORTS_C99)
result = nan(NULL);
#elif defined(NAN) && defined(__STDC_IEC_559__)
result = (double)NAN;
#elif defined(USE_IEEE_754)
result = trio_make_double(ieee_754_qnan_array);
#else
/*
* There are several ways to generate NaN. The one used here is
* to divide infinity by infinity. I would have preferred to add
* negative infinity to positive infinity, but that yields wrong
* result (infinity) on FreeBSD.
*
* This may fail if the hardware does not support NaN, or if
* the Invalid Operation floating-point exception is unmasked.
*/
# if defined(TRIO_PLATFORM_UNIX)
void (*signal_handler)(int) = signal(SIGFPE, SIG_IGN);
# endif
result = trio_pinf() / trio_pinf();
# if defined(TRIO_PLATFORM_UNIX)
signal(SIGFPE, signal_handler);
# endif
#endif
}
return result;
}
/*************************************************************************
* trio_isnan
*/
int
trio_isnan(volatile double number)
{
#if defined(isnan) || defined(TRIO_COMPILER_SUPPORTS_UNIX95)
/*
* C99 defines isnan() as a macro. UNIX95 defines isnan() as a
* function. This function was already present in XPG4, but this
* is a bit tricky to detect with compiler defines, so we choose
* the conservative approach and only use it for UNIX95.
*/
return isnan(number);
#elif defined(TRIO_COMPILER_MSVC)
/*
* MSC has an _isnan() function
*/
return _isnan(number);
#elif defined(USE_IEEE_754)
/*
* Examine IEEE 754 bit-pattern. A NaN must have a special exponent
* pattern, and a non-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);
#else
/*
* Fallback solution
*/
int status;
double integral, fraction;
# if defined(TRIO_PLATFORM_UNIX)
void (*signal_handler)(int) = signal(SIGFPE, SIG_IGN);
# endif
status = (/*
* NaN is the only number which does not compare to itself
*/
(number != number) ||
/*
* Fallback solution if NaN compares to NaN
*/
((number != 0.0) &&
(fraction = modf(number, &integral),
integral == fraction)));
# if defined(TRIO_PLATFORM_UNIX)
signal(SIGFPE, signal_handler);
# endif
return status;
#endif
}
/*************************************************************************
* trio_isinf
*/
int
trio_isinf(volatile double number)
{
#if defined(TRIO_COMPILER_DECC)
/*
* DECC has an isinf() macro, but it works differently than that
* of C99, so we use the fp_class() function instead.
*/
return ((fp_class(number) == FP_POS_INF)
? 1
: ((fp_class(number) == FP_NEG_INF) ? -1 : 0));
#elif defined(isinf)
/*
* C99 defines isinf() as a macro.
*/
return isinf(number);
#elif defined(TRIO_COMPILER_MSVC)
/*
* MSVC has 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 defined(STANDALONE)
# include <stdio.h>
int main(void)
{
double my_nan;
double my_pinf;
double my_ninf;
# if defined(TRIO_PLATFORM_UNIX)
void (*signal_handler)(int);
# endif
my_nan = trio_nan();
my_pinf = trio_pinf();
my_ninf = trio_ninf();
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
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