cfloat.c

   1 /*
   2  * Floating point functions that are difficult or impossible to implement
   3  * in pure Haskell.
   4  *
   5  * Copyright (C) 2009 Nick Bowler.
   6  *
   7  * License BSD2:  2-clause BSD license.  See LICENSE for full terms.
   8  * This is free software: you are free to change and redistribute it.
   9  * There is NO WARRANTY, to the extent permitted by law.
  10  */
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <errno.h>
  14 #include <math.h>
  15
  16 #include "cfloat.h"
  17
  18 int double_format(char *buf, char spec, int precision, double val)
  19 {
  20         char fmt[] = "%.*f";
  21         fmt[3] = spec;
  22
  23         if (buf == NULL)
  24                 return snprintf(NULL, 0, fmt, precision, val);
  25         return sprintf(buf, fmt, precision, val);
  26 }
  27
  28 double double_signum(double val)
  29 {
  30         if (signbit(val))
  31                 return -1;
  32         return 1;
  33 }
  34
  35 float float_signum(float val)
  36 {
  37         if (signbit(val))
  38                 return -1;
  39         return 1;
  40 }
  41
  42 int double_classify(double val)
  43 {
  44         switch (fpclassify(val)) {
  45         case FP_INFINITE:
  46                 return 0;
  47         case FP_NAN:
  48                 return 1;
  49         case FP_NORMAL:
  50                 return 2;
  51         case FP_SUBNORMAL:
  52                 return 3;
  53         case FP_ZERO:
  54                 return 4;
  55         }
  56
  57         return -1;
  58 }
  59
  60 int float_classify(float val)
  61 {
  62         switch (fpclassify(val)) {
  63         case FP_INFINITE:
  64                 return 0;
  65         case FP_NAN:
  66                 return 1;
  67         case FP_NORMAL:
  68                 return 2;
  69         case FP_SUBNORMAL:
  70                 return 3;
  71         case FP_ZERO:
  72                 return 4;
  73         }
  74
  75         return -1;
  76 }
  77
  78 int double_compare(double a, double b)
  79 {
  80         if (isless(a, b))
  81                 return 0;
  82         if (a == b)
  83                 return 1;
  84         if (isgreater(a, b))
  85                 return 2;
  86         if (isunordered(a, b))
  87                 return 3;
  88         return -1;
  89 }
  90
  91 int float_compare(float a, float b)
  92 {
  93         if (isless(a, b))
  94                 return 0;
  95         if (a == b)
  96                 return 1;
  97         if (isgreater(a, b))
  98                 return 2;
  99         if (isunordered(a, b))
 100                 return 3;
 101         return -1;
 102 }