gnu/usr.bin/groff/libgroff/iftoa.cc

   1 /*-
   2  * This code is derived from software copyrighted by the Free Software
   3  * Foundation.
   4  *
   5  * Modified 1991 by Donn Seeley at UUNET Technologies, Inc.
   6  */
   7
   8 #ifndef lint
   9 static char sccsid[] = "@(#)iftoa.cc    6.3 (Berkeley) 5/8/91";
  10 #endif /* not lint */
  11
  12 /* Copyright (C) 1989, 1990 Free Software Foundation, Inc.
  13      Written by James Clark (jjc@jclark.uucp)
  14
  15 This file is part of groff.
  16
  17 groff is free software; you can redistribute it and/or modify it under
  18 the terms of the GNU General Public License as published by the Free
  19 Software Foundation; either version 1, or (at your option) any later
  20 version.
  21
  22 groff is distributed in the hope that it will be useful, but WITHOUT ANY
  23 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  24 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  25 for more details.
  26
  27 You should have received a copy of the GNU General Public License along
  28 with groff; see the file LICENSE.  If not, write to the Free Software
  29 Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
  30
  31 #include "lib.h"
  32
  33 const char *iftoa(int i, int decimal_point)
  34 {
  35   /* room for a -, 10 digits, a decimal point, and a terminating '\0' */
  36   static char buf[INT_DIGITS + 3];
  37   char *p = buf + INT_DIGITS + 2;
  38   int point = 0;
  39   buf[INT_DIGITS + 2] = '\0';
  40   /* assert(decimal_point <= INT_DIGITS); */
  41   if (i >= 0) {
  42     do {
  43       *--p = '0' + (i % 10);
  44       i /= 10;
  45       if (++point == decimal_point)
  46         *--p = '.';
  47     } while (i != 0 || point < decimal_point);
  48   }
  49   else {                        /* i < 0 */
  50     do {
  51       *--p = '0' - (i % 10);
  52       i /= 10;
  53       if (++point == decimal_point)
  54         *--p = '.';
  55     } while (i != 0 || point < decimal_point);
  56     *--p = '-';
  57   }
  58   if (decimal_point > 0) {
  59     char *q;
  60     /* there must be a dot, so this will terminate */
  61     for (q = buf + INT_DIGITS + 2; q[-1] == '0'; --q)
  62       ;
  63     if (q[-1] == '.') {
  64       if (q - 1 == p) {
  65         q[-1] = '0';
  66         q[0] = '\0';
  67       }
  68       else
  69         q[-1] = '\0';
  70     }
  71     else
  72       *q = '\0';
  73   }
  74   return p;
  75 }