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 /* This is to ensure that we get M_PI, etc. definitions */
  42 #if defined(_MSC_VER) && !defined(_USE_MATH_DEFINES)
  43 #error _USE_MATH_DEFINES define required when building with MSVC
  44 #endif
  45
  46
  47 #if !defined(_MSC_VER) && \
  48     __STDC_VERSION__ < 199901L && \
  49     (!defined(_XOPEN_SOURCE) || _XOPEN_SOURCE < 600) && \
  50     !defined(__cplusplus)
  51
  52 static inline long int
  53 lrint(double d)
  54 {
  55    long int rounded = (long int)(d + 0.5);
  56
  57    if (d - floor(d) == 0.5) {
  58       if (rounded % 2 != 0)
  59          rounded += (d > 0) ? -1 : 1;
  60    }
  61
  62    return rounded;
  63 }
  64
  65 static inline long int
  66 lrintf(float f)
  67 {
  68    long int rounded = (long int)(f + 0.5f);
  69
  70    if (f - floorf(f) == 0.5f) {
  71       if (rounded % 2 != 0)
  72          rounded += (f > 0) ? -1 : 1;
  73    }
  74
  75    return rounded;
  76 }
  77
  78 static inline long long int
  79 llrint(double d)
  80 {
  81    long long int rounded = (long long int)(d + 0.5);
  82
  83    if (d - floor(d) == 0.5) {
  84       if (rounded % 2 != 0)
  85          rounded += (d > 0) ? -1 : 1;
  86    }
  87
  88    return rounded;
  89 }
  90
  91 static inline long long int
  92 llrintf(float f)
  93 {
  94    long long int rounded = (long long int)(f + 0.5f);
  95
  96    if (f - floorf(f) == 0.5f) {
  97       if (rounded % 2 != 0)
  98          rounded += (f > 0) ? -1 : 1;
  99    }
 100
 101    return rounded;
 102 }
 103
 104 static inline float
 105 exp2f(float f)
 106 {
 107    return powf(2.0f, f);
 108 }
 109
 110 static inline double
 111 exp2(double d)
 112 {
 113    return pow(2.0, d);
 114 }
 115
 116 #endif /* C99 */
 117
 118
 119 /*
 120  * signbit() is a macro on Linux.  Not available on Windows.
 121  */
 122 #ifndef signbit
 123 #define signbit(x) ((x) < 0.0f)
 124 #endif
 125
 126
 127 #ifndef M_PI
 128 #define M_PI (3.14159265358979323846)
 129 #endif
 130
 131 #ifndef M_E
 132 #define M_E (2.7182818284590452354)
 133 #endif
 134
 135 #ifndef M_LOG2E
 136 #define M_LOG2E (1.4426950408889634074)
 137 #endif
 138
 139 #ifndef FLT_MAX_EXP
 140 #define FLT_MAX_EXP 128
 141 #endif
 142
 143
 144 #if defined(fpclassify)
 145 /* ISO C99 says that fpclassify is a macro.  Assume that any implementation
 146  * of fpclassify, whether it's in a C99 compiler or not, will be a macro.
 147  */
 148 #elif defined(__cplusplus)
 149 /* For C++, fpclassify() should be defined in <cmath> */
 150 #elif defined(_MSC_VER)
 151 /* Not required on VS2013 and above.  Oddly, the fpclassify() function
 152  * doesn't exist in such a form on MSVC.  This is an implementation using
 153  * slightly different lower-level Windows functions.
 154  */
 155 #include <float.h>
 156
 157 static inline enum {FP_NAN, FP_INFINITE, FP_ZERO, FP_SUBNORMAL, FP_NORMAL}
 158 fpclassify(double x)
 159 {
 160    switch(_fpclass(x)) {
 161    case _FPCLASS_SNAN: /* signaling NaN */
 162    case _FPCLASS_QNAN: /* quiet NaN */
 163       return FP_NAN;
 164    case _FPCLASS_NINF: /* negative infinity */
 165    case _FPCLASS_PINF: /* positive infinity */
 166       return FP_INFINITE;
 167    case _FPCLASS_NN:   /* negative normal */
 168    case _FPCLASS_PN:   /* positive normal */
 169       return FP_NORMAL;
 170    case _FPCLASS_ND:   /* negative denormalized */
 171    case _FPCLASS_PD:   /* positive denormalized */
 172       return FP_SUBNORMAL;
 173    case _FPCLASS_NZ:   /* negative zero */
 174    case _FPCLASS_PZ:   /* positive zero */
 175       return FP_ZERO;
 176    default:
 177       /* Should never get here; but if we do, this will guarantee
 178        * that the pattern is not treated like a number.
 179        */
 180       return FP_NAN;
 181    }
 182 }
 183 #else
 184 #error "Need to include or define an fpclassify function"
 185 #endif
 186
 187
 188 /* Since C++11, the following functions are part of the std namespace. Their C
 189  * counteparts should still exist in the global namespace, however cmath
 190  * undefines those functions, which in glibc 2.23, are defined as macros rather
 191  * than functions as in glibc 2.22.
 192  */
 193 #if __cplusplus >= 201103L && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 23))
 194 #include <cmath>
 195
 196 using std::fpclassify;
 197 using std::isfinite;
 198 using std::isinf;
 199 using std::isnan;
 200 using std::isnormal;
 201 using std::signbit;
 202 using std::isgreater;
 203 using std::isgreaterequal;
 204 using std::isless;
 205 using std::islessequal;
 206 using std::islessgreater;
 207 using std::isunordered;
 208 #endif
 209
 210
 211 #endif /* #define _C99_MATH_H_ */