misc/efgcvt_r.c

   1 /* [efg]cvt -- compatibility functions for floating point formatting,
   2    reentrent versions.
   3 Copyright (C) 1995 Free Software Foundation, Inc.
   4 This file is part of the GNU C Library.
   5
   6 The GNU C Library is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU Library General Public License as
   8 published by the Free Software Foundation; either version 2 of the
   9 License, or (at your option) any later version.
  10
  11 The GNU C Library is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 Library General Public License for more details.
  15
  16 You should have received a copy of the GNU Library General Public
  17 License along with the GNU C Library; see the file COPYING.LIB.  If
  18 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21 #include <errno.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <ctype.h>
  25 #include <math.h>
  26
  27 int
  28 fcvt_r (value, ndigit, decpt, sign, buf, len)
  29      double value;
  30      int ndigit, *decpt, *sign;
  31      char *buf;
  32      size_t len;
  33 {
  34   int n, i;
  35
  36   if (buf == NULL)
  37     {
  38       errno = EINVAL;
  39       return -1;
  40     }
  41
  42   *sign = value < 0.0;
  43   if (*sign)
  44     value = - value;
  45
  46   n = snprintf (buf, len, "%.*f", ndigit, value);
  47   if (n < 0)
  48     return -1;
  49
  50   i = 0;
  51   while (i < n && isdigit (buf[i]))
  52     ++i;
  53   *decpt = i;
  54   do
  55     ++i;
  56   while (! isdigit (buf[i]));
  57   memmove (&buf[i - *decpt], buf, n - (i - *decpt));
  58
  59   return 0;
  60 }
  61
  62 int
  63 ecvt_r (value, ndigit, decpt, sign, buf, len)
  64      double value;
  65      int ndigit, *decpt, *sign;
  66      char *buf;
  67      size_t len;
  68 {
  69   ndigit -= (int) floor (log10 (value));
  70   if (ndigit < 0)
  71     ndigit = 0;
  72   return fcvt_r (value, ndigit, decpt, sign, buf, len);
  73 }