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) && \
  87      __STDC_VERSION__ < 199901L && \
  88      (!defined(_XOPEN_SOURCE) || _XOPEN_SOURCE < 600) && \
  89      !defined(__cplusplus))
  90
  91 static inline long int
  92 lrint(double d)
  93 {
  94    long int rounded = (long int)(d + 0.5);
  95
  96    if (d - floor(d) == 0.5) {
  97       if (rounded % 2 != 0)
  98          rounded += (d > 0) ? -1 : 1;
  99    }
 100
 101    return rounded;
 102 }
 103
 104 static inline long int
 105 lrintf(float f)
 106 {
 107    long int rounded = (long int)(f + 0.5f);
 108
 109    if (f - floorf(f) == 0.5f) {
 110       if (rounded % 2 != 0)
 111          rounded += (f > 0) ? -1 : 1;
 112    }
 113
 114    return rounded;
 115 }
 116
 117 static inline long long int
 118 llrint(double d)
 119 {
 120    long long int rounded = (long long int)(d + 0.5);
 121
 122    if (d - floor(d) == 0.5) {
 123       if (rounded % 2 != 0)
 124          rounded += (d > 0) ? -1 : 1;
 125    }
 126
 127    return rounded;
 128 }
 129
 130 static inline long long int
 131 llrintf(float f)
 132 {
 133    long long int rounded = (long long int)(f + 0.5f);
 134
 135    if (f - floorf(f) == 0.5f) {
 136       if (rounded % 2 != 0)
 137          rounded += (f > 0) ? -1 : 1;
 138    }
 139
 140    return rounded;
 141 }
 142
 143 #endif /* C99 */
 144
 145
 146 /*
 147  * signbit() is a macro on Linux.  Not available on Windows.
 148  */
 149 #ifndef signbit
 150 #define signbit(x) ((x) < 0.0f)
 151 #endif
 152
 153
 154 #ifndef M_PI
 155 #define M_PI (3.14159265358979323846)
 156 #endif
 157
 158 #ifndef M_E
 159 #define M_E (2.7182818284590452354)
 160 #endif
 161
 162 #ifndef M_LOG2E
 163 #define M_LOG2E (1.4426950408889634074)
 164 #endif
 165
 166 #ifndef FLT_MAX_EXP
 167 #define FLT_MAX_EXP 128
 168 #endif
 169
 170
 171 #if defined(fpclassify)
 172 /* ISO C99 says that fpclassify is a macro.  Assume that any implementation
 173  * of fpclassify, whether it's in a C99 compiler or not, will be a macro.
 174  */
 175 #elif defined(__cplusplus)
 176 /* For C++, fpclassify() should be defined in <cmath> */
 177 #elif defined(_MSC_VER)
 178 /* Not required on VS2013 and above.  Oddly, the fpclassify() function
 179  * doesn't exist in such a form on MSVC.  This is an implementation using
 180  * slightly different lower-level Windows functions.
 181  */
 182 #include <float.h>
 183
 184 static inline enum {FP_NAN, FP_INFINITE, FP_ZERO, FP_SUBNORMAL, FP_NORMAL}
 185 fpclassify(double x)
 186 {
 187    switch(_fpclass(x)) {
 188    case _FPCLASS_SNAN: /* signaling NaN */
 189    case _FPCLASS_QNAN: /* quiet NaN */
 190       return FP_NAN;
 191    case _FPCLASS_NINF: /* negative infinity */
 192    case _FPCLASS_PINF: /* positive infinity */
 193       return FP_INFINITE;
 194    case _FPCLASS_NN:   /* negative normal */
 195    case _FPCLASS_PN:   /* positive normal */
 196       return FP_NORMAL;
 197    case _FPCLASS_ND:   /* negative denormalized */
 198    case _FPCLASS_PD:   /* positive denormalized */
 199       return FP_SUBNORMAL;
 200    case _FPCLASS_NZ:   /* negative zero */
 201    case _FPCLASS_PZ:   /* positive zero */
 202       return FP_ZERO;
 203    default:
 204       /* Should never get here; but if we do, this will guarantee
 205        * that the pattern is not treated like a number.
 206        */
 207       return FP_NAN;
 208    }
 209 }
 210 #else
 211 #error "Need to include or define an fpclassify function"
 212 #endif
 213
 214
 215 #endif /* #define _C99_MATH_H_ */