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, 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 float float_signum(float val)
  33 {
  34         if (signbit(val))
  35                 return -1;
  36         return 1;
  37 }
  38
  39 int double_classify(double val)
  40 {
  41         switch (fpclassify(val)) {
  42         case FP_INFINITE:
  43                 return 0;
  44         case FP_NAN:
  45                 return 1;
  46         case FP_NORMAL:
  47                 return 2;
  48         case FP_SUBNORMAL:
  49                 return 3;
  50         case FP_ZERO:
  51                 return 4;
  52         }
  53
  54         return -1;
  55 }
  56
  57 int float_classify(float val)
  58 {
  59         switch (fpclassify(val)) {
  60         case FP_INFINITE:
  61                 return 0;
  62         case FP_NAN:
  63                 return 1;
  64         case FP_NORMAL:
  65                 return 2;
  66         case FP_SUBNORMAL:
  67                 return 3;
  68         case FP_ZERO:
  69                 return 4;
  70         }
  71
  72         return -1;
  73 }
  74
  75 int double_compare(double a, double b)
  76 {
  77         if (isless(a, b))
  78                 return 0;
  79         if (a == b)
  80                 return 1;
  81         if (isgreater(a, b))
  82                 return 2;
  83         if (isunordered(a, b))
  84                 return 3;
  85         return -1;
  86 }
  87
  88 int float_compare(float a, float b)
  89 {
  90         if (isless(a, b))
  91                 return 0;
  92         if (a == b)
  93                 return 1;
  94         if (isgreater(a, b))
  95                 return 2;
  96         if (isunordered(a, b))
  97                 return 3;
  98         return -1;
  99 }