misc/efgcvt.c

   1 /* [efg]cvt -- compatibility functions for floating point formatting
   2 Copyright (C) 1995 Free Software Foundation, Inc.
   3 This file is part of the GNU C Library.
   4
   5 The GNU C Library is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 License, or (at your option) any later version.
   9
  10 The GNU C Library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include <ctype.h>
  23 #include <math.h>
  24
  25 char *
  26 fcvt (value, ndigit, decpt, sign)
  27      double value;
  28      int ndigit, *decpt, *sign;
  29 {
  30   static char buf[100];
  31   int n, i;
  32
  33   *sign = value < 0.0;
  34   if (*sign)
  35     value = - value;
  36
  37   n = snprintf (buf, sizeof buf, "%.*f", ndigit, value);
  38   if (n < 0)
  39     return NULL;
  40
  41   i = 0;
  42   while (i < n && isdigit (buf[i]))
  43     ++i;
  44   *decpt = i;
  45   do
  46     ++i;
  47   while (! isdigit (buf[i]));
  48   memmove (&buf[i - *decpt], buf, n - (i - *decpt));
  49
  50   return buf;
  51 }
  52
  53 char *
  54 ecvt (value, ndigit, decpt, sign)
  55      double value;
  56      int ndigit, *decpt, *sign;
  57 {
  58   ndigit -= (int) floor (log10 (value));
  59   if (ndigit < 0)
  60     ndigit = 0;
  61   return fcvt (value, ndigit, decpt, sign);
  62 }
  63
  64 char *
  65 gcvt (value, ndigit, buf)
  66      double value;
  67      int ndigit;
  68      char *buf;
  69 {
  70   sprintf (buf, "%.*g", ndigit, value);
  71   return buf;
  72 }