shotgun/lib/float.c

   1 #include <string.h>
   2 #include <math.h>
   3
   4 /* Begin borrowing from MRI 1.8.6 stable */
   5 #if defined(__FreeBSD__) && __FreeBSD__ < 4
   6 #include <floatingpoint.h>
   7 #endif
   8
   9 #ifdef HAVE_FLOAT_H
  10 #include <float.h>
  11 #endif
  12
  13 #ifdef HAVE_IEEEFP_H
  14 #include <ieeefp.h>
  15 #endif
  16
  17 #ifdef WORDS_BIGENDIAN
  18 #define word0(x) ((unsigned int *)&x)[0]
  19 #define word1(x) ((unsigned int *)&x)[1]
  20 #else
  21 #define word0(x) ((unsigned int *)&x)[1]
  22 #define word1(x) ((unsigned int *)&x)[0]
  23 #endif
  24
  25 #include "shotgun/lib/shotgun.h"
  26 #include "shotgun/lib/string.h"
  27 #include "shotgun/lib/array.h"
  28 #include "shotgun/lib/bignum.h"
  29 #include "shotgun/lib/float.h"
  30
  31 int float_radix()      { return FLT_RADIX; }
  32 int float_rounds()     { return FLT_ROUNDS; }
  33 double float_min()     { return DBL_MIN; }
  34 double float_max()     { return DBL_MAX; }
  35 int float_min_exp()    { return DBL_MIN_EXP; }
  36 int float_max_exp()    { return DBL_MAX_EXP; }
  37 int float_min_10_exp() { return DBL_MIN_10_EXP; }
  38 int float_max_10_exp() { return DBL_MAX_10_EXP; }
  39 int float_dig()        { return DBL_DIG; }
  40 int float_mant_dig()   { return DBL_MANT_DIG; }
  41 double float_epsilon() { return DBL_EPSILON; }
  42
  43 OBJECT float_new(STATE, double dbl) {
  44   double *value;
  45   OBJECT o;
  46   o = object_memory_new_opaque(state, BASIC_CLASS(floatpoint), sizeof(double));
  47   value = (double *)BYTES_OF(o);
  48   *value = dbl;
  49   return o;
  50 }
  51
  52 /* This functions is only used when unmarshalling.
  53  * The assumptions made here are therefore safe.
  54  * String#to_f uses string_to_double
  55  */
  56 OBJECT float_from_string(STATE, char *str) {
  57   char *endp;
  58   double d;
  59   d = strtod(str, &endp);
  60   if (str != endp && *endp == '\0') {
  61     return float_new(state, d);
  62   }
  63   /* When we get here, we might have a system that doesn't conform to
  64      C99 (OpenBSD is at least one) that can't handle Infinity / NaN.
  65      We test the strings here manually and fix it if needed. */
  66
  67   int sign = 0;
  68
  69   if (*str == '-') {
  70     sign = 1;
  71     str++;
  72   } else if (*str == '+') {
  73     str++;
  74   }
  75
  76   if (*str == 'I' || *str == 'i') {
  77     return float_new(state, sign ? -HUGE_VAL : HUGE_VAL);
  78   }
  79   if (*str == 'N' || *str == 'n') {
  80     word0(d) = 0x7ff80000;
  81     word1(d) = 0;
  82     return float_new(state, d);
  83   }
  84
  85   return Qnil;
  86 }
  87
  88 void float_into_string(STATE, OBJECT self, char *buf, int sz) {
  89   snprintf(buf, sz, "%+.17e", FLOAT_TO_DOUBLE(self));
  90 }
  91
  92 OBJECT float_compare(STATE, double a, double b) {
  93   if(a < b) {
  94     return I2N(-1);
  95   } else if(a > b) {
  96     return I2N(1);
  97   }
  98   return I2N(0);
  99 }
 100
 101 OBJECT float_coerce(STATE, OBJECT value) {
 102   if(FIXNUM_P(value)) {
 103     return float_new(state, (double)N2I(value));
 104   } else if(BIGNUM_P(value)) {
 105     return float_new(state, bignum_to_double(state, value));
 106   }
 107   return value;
 108 }