cfloat.c

   1 /*
   2  * Floating point functions that are difficult or impossible to implement
   3  * in pure Haskell.
   4  *
   5  * Copyright (C) 2009-2010 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, const char *fmt, double val)
  19 {
  20         if (buf == NULL)
  21                 return snprintf(NULL, 0, fmt, val);
  22         return sprintf(buf, fmt, val);
  23 }
  24
  25 double double_signum(double val)
  26 {
  27         if (signbit(val))
  28                 return -1;
  29         return 1;
  30 }
  31
  32 int double_classify(double val)
  33 {
  34         switch (fpclassify(val)) {
  35         case FP_INFINITE:
  36                 return 0;
  37         case FP_NAN:
  38                 return 1;
  39         case FP_NORMAL:
  40                 return 2;
  41         case FP_SUBNORMAL:
  42                 return 3;
  43         case FP_ZERO:
  44                 return 4;
  45         }
  46
  47         return -1;
  48 }
  49
  50 int double_compare(double a, double b)
  51 {
  52         if (isless(a, b))
  53                 return 0;
  54         if (a == b)
  55                 return 1;
  56         if (isgreater(a, b))
  57                 return 2;
  58         if (isunordered(a, b))
  59                 return 3;
  60         return -1;
  61 }