FFmpeg/libavutil/libm.h
Ganesh Ajjanagadde 14ea4151d7 avutil/libm: correct isnan, isinf compat hacks
isnan and isinf are actually macros as per the standard. In particular,
the existing implementation has incorrect signature. Furthermore, this
results in undefined behavior for e.g double values outside float range
as per the standard.

This patch corrects the undefined behavior for all usage within FFmpeg.

Note that long double is not handled as it is not used in FFmpeg.
Furthermore, even if at some point long double gets used, it is likely
not needed to modify the macro in practice for usage in FFmpeg. See
below for analysis.

Getting long double to work strictly per the spec is significantly harder
since a long double may be an IEEE 128 bit quad (very rare), 80 bit
extended precision value (on GCC/Clang), or simply double (on recent Microsoft).
On the other hand, any potential future usage of long double is likely
for precision (when a platform offers extra precision) and not for range, since
the range anyway varies and is not as portable as IEEE 754 single/double
precision. In such cases, the implicit cast to a double is well defined
and isinf and isnan should work as intended.

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
2015-11-21 08:51:49 -05:00

220 lines
4.8 KiB
C

/*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Replacements for frequently missing libm functions
*/
#ifndef AVUTIL_LIBM_H
#define AVUTIL_LIBM_H
#include <math.h>
#include "config.h"
#include "attributes.h"
#include "intfloat.h"
#if HAVE_MIPSFPU && HAVE_INLINE_ASM
#include "libavutil/mips/libm_mips.h"
#endif /* HAVE_MIPSFPU && HAVE_INLINE_ASM*/
#if !HAVE_ATANF
#undef atanf
#define atanf(x) ((float)atan(x))
#endif
#if !HAVE_ATAN2F
#undef atan2f
#define atan2f(y, x) ((float)atan2(y, x))
#endif
#if !HAVE_POWF
#undef powf
#define powf(x, y) ((float)pow(x, y))
#endif
#if !HAVE_CBRT
static av_always_inline double cbrt(double x)
{
return x < 0 ? -pow(-x, 1.0 / 3.0) : pow(x, 1.0 / 3.0);
}
#endif
#if !HAVE_CBRTF
static av_always_inline float cbrtf(float x)
{
return x < 0 ? -powf(-x, 1.0 / 3.0) : powf(x, 1.0 / 3.0);
}
#endif
#if !HAVE_COSF
#undef cosf
#define cosf(x) ((float)cos(x))
#endif
#if !HAVE_EXPF
#undef expf
#define expf(x) ((float)exp(x))
#endif
#if !HAVE_EXP2
#undef exp2
#define exp2(x) exp((x) * 0.693147180559945)
#endif /* HAVE_EXP2 */
#if !HAVE_EXP2F
#undef exp2f
#define exp2f(x) ((float)exp2(x))
#endif /* HAVE_EXP2F */
#if !HAVE_ISINF
#undef isinf
/* Note: these do not follow the BSD/Apple/GNU convention of returning -1 for
-Inf, +1 for Inf, 0 otherwise, but merely follow the POSIX/ISO mandated spec of
returning a non-zero value for +/-Inf, 0 otherwise. */
static av_always_inline av_const int avpriv_isinff(float x)
{
uint32_t v = av_float2int(x);
if ((v & 0x7f800000) != 0x7f800000)
return 0;
return !(v & 0x007fffff);
}
static av_always_inline av_const int avpriv_isinf(double x)
{
uint64_t v = av_double2int(x);
if ((v & 0x7ff0000000000000) != 0x7ff0000000000000)
return 0;
return !(v & 0x000fffffffffffff);
}
#define isinf(x) \
(sizeof(x) == sizeof(float) \
? avpriv_isinff(x) \
: avpriv_isinf(x))
#endif /* HAVE_ISINF */
#if !HAVE_ISNAN
static av_always_inline av_const int avpriv_isnanf(float x)
{
uint32_t v = av_float2int(x);
if ((v & 0x7f800000) != 0x7f800000)
return 0;
return v & 0x007fffff;
}
static av_always_inline av_const int avpriv_isnan(double x)
{
uint64_t v = av_double2int(x);
if ((v & 0x7ff0000000000000) != 0x7ff0000000000000)
return 0;
return v & 0x000fffffffffffff;
}
#define isnan(x) \
(sizeof(x) == sizeof(float) \
? avpriv_isnanf(x) \
: avpriv_isnan(x))
#endif /* HAVE_ISNAN */
#if !HAVE_LDEXPF
#undef ldexpf
#define ldexpf(x, exp) ((float)ldexp(x, exp))
#endif
#if !HAVE_LLRINT
#undef llrint
#define llrint(x) ((long long)rint(x))
#endif /* HAVE_LLRINT */
#if !HAVE_LLRINTF
#undef llrintf
#define llrintf(x) ((long long)rint(x))
#endif /* HAVE_LLRINT */
#if !HAVE_LOG2
#undef log2
#define log2(x) (log(x) * 1.44269504088896340736)
#endif /* HAVE_LOG2 */
#if !HAVE_LOG2F
#undef log2f
#define log2f(x) ((float)log2(x))
#endif /* HAVE_LOG2F */
#if !HAVE_LOG10F
#undef log10f
#define log10f(x) ((float)log10(x))
#endif
#if !HAVE_SINF
#undef sinf
#define sinf(x) ((float)sin(x))
#endif
#if !HAVE_RINT
static inline double rint(double x)
{
return x >= 0 ? floor(x + 0.5) : ceil(x - 0.5);
}
#endif /* HAVE_RINT */
#if !HAVE_LRINT
static av_always_inline av_const long int lrint(double x)
{
return rint(x);
}
#endif /* HAVE_LRINT */
#if !HAVE_LRINTF
static av_always_inline av_const long int lrintf(float x)
{
return (int)(rint(x));
}
#endif /* HAVE_LRINTF */
#if !HAVE_ROUND
static av_always_inline av_const double round(double x)
{
return (x > 0) ? floor(x + 0.5) : ceil(x - 0.5);
}
#endif /* HAVE_ROUND */
#if !HAVE_ROUNDF
static av_always_inline av_const float roundf(float x)
{
return (x > 0) ? floor(x + 0.5) : ceil(x - 0.5);
}
#endif /* HAVE_ROUNDF */
#if !HAVE_TRUNC
static av_always_inline av_const double trunc(double x)
{
return (x > 0) ? floor(x) : ceil(x);
}
#endif /* HAVE_TRUNC */
#if !HAVE_TRUNCF
static av_always_inline av_const float truncf(float x)
{
return (x > 0) ? floor(x) : ceil(x);
}
#endif /* HAVE_TRUNCF */
#endif /* AVUTIL_LIBM_H */