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 (defined(_MSC_VER) && _MSC_VER < 1800) || \
  86     (!defined(_MSC_VER) && __STDC_VERSION__ < 199901L && !defined(__cplusplus))
  87 static inline long int
  88 lrint(double d)
  89 {
  90    long int rounded = (long int)(d + 0.5);
  91
  92    if (d - floor(d) == 0.5) {
  93       if (rounded % 2 != 0)
  94          rounded += (d > 0) ? -1 : 1;
  95    }
  96
  97    return rounded;
  98 }
  99
 100 static inline long int
 101 lrintf(float f)
 102 {
 103    long int rounded = (long int)(f + 0.5f);
 104
 105    if (f - floorf(f) == 0.5f) {
 106       if (rounded % 2 != 0)
 107          rounded += (f > 0) ? -1 : 1;
 108    }
 109
 110    return rounded;
 111 }
 112
 113 static inline long long int
 114 llrint(double d)
 115 {
 116    long long int rounded = (long long int)(d + 0.5);
 117
 118    if (d - floor(d) == 0.5) {
 119       if (rounded % 2 != 0)
 120          rounded += (d > 0) ? -1 : 1;
 121    }
 122
 123    return rounded;
 124 }
 125
 126 static inline long long int
 127 llrintf(float f)
 128 {
 129    long long int rounded = (long long int)(f + 0.5f);
 130
 131    if (f - floorf(f) == 0.5f) {
 132       if (rounded % 2 != 0)
 133          rounded += (f > 0) ? -1 : 1;
 134    }
 135
 136    return rounded;
 137 }
 138 #endif /* C99 */
 139
 140
 141 /*
 142  * signbit() is a macro on Linux.  Not available on Windows.
 143  */
 144 #ifndef signbit
 145 #define signbit(x) ((x) < 0.0f)
 146 #endif
 147
 148
 149 #ifndef M_PI
 150 #define M_PI (3.14159265358979323846)
 151 #endif
 152
 153 #ifndef M_E
 154 #define M_E (2.7182818284590452354)
 155 #endif
 156
 157 #ifndef M_LOG2E
 158 #define M_LOG2E (1.4426950408889634074)
 159 #endif
 160
 161 #ifndef FLT_MAX_EXP
 162 #define FLT_MAX_EXP 128
 163 #endif
 164
 165
 166 #if defined(fpclassify)
 167 /* ISO C99 says that fpclassify is a macro.  Assume that any implementation
 168  * of fpclassify, whether it's in a C99 compiler or not, will be a macro.
 169  */
 170 #elif defined(__cplusplus)
 171 /* For C++, fpclassify() should be defined in <cmath> */
 172 #elif defined(_MSC_VER)
 173 /* Not required on VS2013 and above.  Oddly, the fpclassify() function
 174  * doesn't exist in such a form on MSVC.  This is an implementation using
 175  * slightly different lower-level Windows functions.
 176  */
 177 #include <float.h>
 178
 179 static inline enum {FP_NAN, FP_INFINITE, FP_ZERO, FP_SUBNORMAL, FP_NORMAL}
 180 fpclassify(double x)
 181 {
 182    switch(_fpclass(x)) {
 183    case _FPCLASS_SNAN: /* signaling NaN */
 184    case _FPCLASS_QNAN: /* quiet NaN */
 185       return FP_NAN;
 186    case _FPCLASS_NINF: /* negative infinity */
 187    case _FPCLASS_PINF: /* positive infinity */
 188       return FP_INFINITE;
 189    case _FPCLASS_NN:   /* negative normal */
 190    case _FPCLASS_PN:   /* positive normal */
 191       return FP_NORMAL;
 192    case _FPCLASS_ND:   /* negative denormalized */
 193    case _FPCLASS_PD:   /* positive denormalized */
 194       return FP_SUBNORMAL;
 195    case _FPCLASS_NZ:   /* negative zero */
 196    case _FPCLASS_PZ:   /* positive zero */
 197       return FP_ZERO;
 198    default:
 199       /* Should never get here; but if we do, this will guarantee
 200        * that the pattern is not treated like a number.
 201        */
 202       return FP_NAN;
 203    }
 204 }
 205 #else
 206 #error "Need to include or define an fpclassify function"
 207 #endif
 208
 209
 210 #endif /* #define _C99_MATH_H_ */