src/libs/libgroff/iftoa.c

   1 /* Copyright (C) 1989, 1990, 1991, 1992, 2000 Free Software Foundation, Inc.
   2      Written by James Clark (jjc@jclark.com)
   3
   4 This file is part of groff.
   5
   6 groff is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 2, or (at your option) any later
   9 version.
  10
  11 groff is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License along
  17 with groff; see the file COPYING.  If not, write to the Free Software
  18 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
  19
  20 #define INT_DIGITS 19           /* enough for 64-bit integer */
  21
  22 char *if_to_a(i, decimal_point)
  23      int i, decimal_point;
  24 {
  25   /* room for a -, INT_DIGITS digits, a decimal point, and a terminating '\0' */
  26   static char buf[INT_DIGITS + 3];
  27   char *p = buf + INT_DIGITS + 2;
  28   int point = 0;
  29   buf[INT_DIGITS + 2] = '\0';
  30   /* assert(decimal_point <= INT_DIGITS); */
  31   if (i >= 0) {
  32     do {
  33       *--p = '0' + (i % 10);
  34       i /= 10;
  35       if (++point == decimal_point)
  36         *--p = '.';
  37     } while (i != 0 || point < decimal_point);
  38   }
  39   else {                        /* i < 0 */
  40     do {
  41       *--p = '0' - (i % 10);
  42       i /= 10;
  43       if (++point == decimal_point)
  44         *--p = '.';
  45     } while (i != 0 || point < decimal_point);
  46     *--p = '-';
  47   }
  48   if (decimal_point > 0) {
  49     char *q;
  50     /* there must be a dot, so this will terminate */
  51     for (q = buf + INT_DIGITS + 2; q[-1] == '0'; --q)
  52       ;
  53     if (q[-1] == '.') {
  54       if (q - 1 == p) {
  55         q[-1] = '0';
  56         q[0] = '\0';
  57       }
  58       else
  59         q[-1] = '\0';
  60     }
  61     else
  62       *q = '\0';
  63   }
  64   return p;
  65 }