include/c99_math.h

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  27
  28 /**
  29  * Wrapper for math.h which makes sure we have definitions of all the c99
  30  * functions.
  31  */
  32
  33
  34 #ifndef _C99_MATH_H_
  35 #define _C99_MATH_H_
  36
  37 #include <math.h>
  38 #include "c99_compat.h"
  39
  40
  41 #if defined(_MSC_VER)
  42
  43 /* This is to ensure that we get M_PI, etc. definitions */
  44 #if !defined(_USE_MATH_DEFINES)
  45 #error _USE_MATH_DEFINES define required when building with MSVC
  46 #endif
  47
  48 #if _MSC_VER < 1800
  49 #define isfinite(x) _finite((double)(x))
  50 #define isnan(x) _isnan((double)(x))
  51 #endif /* _MSC_VER < 1800 */
  52
  53 #if _MSC_VER < 1800
  54 static inline double log2( double x )
  55 {
  56    const double invln2 = 1.442695041;
  57    return log( x ) * invln2;
  58 }
  59
  60 static inline double
  61 round(double x)
  62 {
  63    return x >= 0.0 ? floor(x + 0.5) : ceil(x - 0.5);
  64 }
  65
  66 static inline float
  67 roundf(float x)
  68 {
  69    return x >= 0.0f ? floorf(x + 0.5f) : ceilf(x - 0.5f);
  70 }
  71 #endif
  72
  73 #ifndef INFINITY
  74 #include <float.h> // DBL_MAX
  75 #define INFINITY (DBL_MAX + DBL_MAX)
  76 #endif
  77
  78 #ifndef NAN
  79 #define NAN (INFINITY - INFINITY)
  80 #endif
  81
  82 #endif /* _MSC_VER */
  83
  84
  85 #if __STDC_VERSION__ < 199901L && (!defined(__cplusplus) || defined(_MSC_VER))
  86 static inline long int
  87 lrint(double d)
  88 {
  89    long int rounded = (long int)(d + 0.5);
  90
  91    if (d - floor(d) == 0.5) {
  92       if (rounded % 2 != 0)
  93          rounded += (d > 0) ? -1 : 1;
  94    }
  95
  96    return rounded;
  97 }
  98
  99 static inline long int
 100 lrintf(float f)
 101 {
 102    long int rounded = (long int)(f + 0.5f);
 103
 104    if (f - floorf(f) == 0.5f) {
 105       if (rounded % 2 != 0)
 106          rounded += (f > 0) ? -1 : 1;
 107    }
 108
 109    return rounded;
 110 }
 111
 112 static inline long long int
 113 llrint(double d)
 114 {
 115    long long int rounded = (long long int)(d + 0.5);
 116
 117    if (d - floor(d) == 0.5) {
 118       if (rounded % 2 != 0)
 119          rounded += (d > 0) ? -1 : 1;
 120    }
 121
 122    return rounded;
 123 }
 124
 125 static inline long long int
 126 llrintf(float f)
 127 {
 128    long long int rounded = (long long int)(f + 0.5f);
 129
 130    if (f - floorf(f) == 0.5f) {
 131       if (rounded % 2 != 0)
 132          rounded += (f > 0) ? -1 : 1;
 133    }
 134
 135    return rounded;
 136 }
 137 #endif /* C99 */
 138
 139
 140 /*
 141  * signbit() is a macro on Linux.  Not available on Windows.
 142  */
 143 #ifndef signbit
 144 #define signbit(x) ((x) < 0.0f)
 145 #endif
 146
 147
 148 #ifndef M_PI
 149 #define M_PI (3.14159265358979323846)
 150 #endif
 151
 152 #ifndef M_E
 153 #define M_E (2.7182818284590452354)
 154 #endif
 155
 156 #ifndef M_LOG2E
 157 #define M_LOG2E (1.4426950408889634074)
 158 #endif
 159
 160 #ifndef FLT_MAX_EXP
 161 #define FLT_MAX_EXP 128
 162 #endif
 163
 164
 165 #if defined(fpclassify)
 166 /* ISO C99 says that fpclassify is a macro.  Assume that any implementation
 167  * of fpclassify, whether it's in a C99 compiler or not, will be a macro.
 168  */
 169 #elif defined(__cplusplus)
 170 /* For C++, fpclassify() should be defined in <cmath> */
 171 #elif defined(_MSC_VER)
 172 /* Not required on VS2013 and above.  Oddly, the fpclassify() function
 173  * doesn't exist in such a form on MSVC.  This is an implementation using
 174  * slightly different lower-level Windows functions.
 175  */
 176 #include <float.h>
 177
 178 static inline enum {FP_NAN, FP_INFINITE, FP_ZERO, FP_SUBNORMAL, FP_NORMAL}
 179 fpclassify(double x)
 180 {
 181    switch(_fpclass(x)) {
 182    case _FPCLASS_SNAN: /* signaling NaN */
 183    case _FPCLASS_QNAN: /* quiet NaN */
 184       return FP_NAN;
 185    case _FPCLASS_NINF: /* negative infinity */
 186    case _FPCLASS_PINF: /* positive infinity */
 187       return FP_INFINITE;
 188    case _FPCLASS_NN:   /* negative normal */
 189    case _FPCLASS_PN:   /* positive normal */
 190       return FP_NORMAL;
 191    case _FPCLASS_ND:   /* negative denormalized */
 192    case _FPCLASS_PD:   /* positive denormalized */
 193       return FP_SUBNORMAL;
 194    case _FPCLASS_NZ:   /* negative zero */
 195    case _FPCLASS_PZ:   /* positive zero */
 196       return FP_ZERO;
 197    default:
 198       /* Should never get here; but if we do, this will guarantee
 199        * that the pattern is not treated like a number.
 200        */
 201       return FP_NAN;
 202    }
 203 }
 204 #else
 205 #error "Need to include or define an fpclassify function"
 206 #endif
 207
 208
 209 #endif /* #define _C99_MATH_H_ */