libquadmath/quadmath_io.c

   1 #include "quadmath.h"
   2 #include <stdio.h>
   3 #include <string.h>
   4
   5 #define ABS(x) ((x) >= 0 ? (x) : -(x))
   6
   7
   8
   9 static void
  10 format (char * res, const __float128 x, size_t n)
  11 {
  12   char buffer[1024];
  13   char *p;
  14
  15   memset (buffer, 0, sizeof(buffer));
  16
  17   g_Qfmt (buffer, &x, n + 1, sizeof(buffer) - 3);
  18   p = buffer + (*buffer == '-' ? 1 : 0);
  19
  20   // The sign is the easiest part
  21   res[0] = (signbitq (x) ? '-' : '+');
  22
  23   if (*p == '.')
  24   {
  25     // We have a number smaller than 1, without exponent
  26     int exp = 0;
  27     char *c;
  28
  29     for (c = p+1; *c == '0'; c++)
  30       exp++;
  31
  32     // We move the string "exp" characters left
  33     size_t l = strlen (p+1+exp);
  34     memcpy (res + 2, p + 1 + exp, l);
  35     memset (res + 2 + l, '0', n - l + 1);
  36     sprintf (res + n + 3, "e-%02d", exp + 1);
  37
  38     res[1] = res[2];
  39     res[2] = '.';
  40
  41     return;
  42   }
  43
  44   // Now, do we already have an exponent
  45   char *c;
  46   for (c = p; *c && *c != 'e'; c++)
  47     ;
  48   if (*c)
  49   {
  50     int exp = strtol (c + 1, NULL, 10);
  51
  52     size_t l = c - p;
  53
  54     memcpy (res + 1, p, l);
  55     if (l <= n + 1)
  56       memset (res + 1 + l, '0', (int) n - l + 2);
  57
  58     sprintf (res + n + 3, "e%c%02d", exp >= 0 ? '+' : '-', ABS(exp));
  59
  60     return;
  61   }
  62   else
  63   {
  64     // If we have no exponent, normalize and add the exponent
  65     for (c = p; *c && *c != '.'; c++)
  66       ;
  67
  68     res[1] = *p;
  69     res[2] = '.';
  70
  71     size_t l = c - p;
  72     memcpy (res + 3, p + 1, l);
  73     size_t l2 = strlen (c + 1);
  74     memcpy (res + 2 + l, c + 1, l2);
  75     memset (res + 2 + l + l2, '0', n - (l + l2) + 1);
  76     sprintf (res + n + 3, "e+%02d", l - 1);
  77
  78     return;
  79   }
  80 }
  81
  82
  83 void
  84 quadmath_dtoaq (char *s, size_t size, size_t n, __float128 x)
  85 {
  86   char buffer[1024];
  87   memset (buffer, 0, sizeof(buffer));
  88   format (buffer, x, n);
  89   memcpy (s, buffer, size);
  90 }