contrib/groff-1.19/src/libs/libgroff/iftoa.c

   1 /* Copyright (C) 1989, 1990, 1991, 1992, 2000, 2004
   2    Free Software Foundation, Inc.
   3      Written by James Clark (jjc@jclark.com)
   4
   5 This file is part of groff.
   6
   7 groff is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 groff is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License along
  18 with groff; see the file COPYING.  If not, write to the Free Software
  19 Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
  20
  21 #define INT_DIGITS 19           /* enough for 64-bit integer */
  22
  23 #ifdef __cplusplus
  24 extern "C" {
  25 #endif
  26
  27 char *if_to_a(int i, int decimal_point)
  28 {
  29   /* room for a -, INT_DIGITS digits, a decimal point, and a terminating '\0' */
  30   static char buf[INT_DIGITS + 3];
  31   char *p = buf + INT_DIGITS + 2;
  32   int point = 0;
  33   buf[INT_DIGITS + 2] = '\0';
  34   /* assert(decimal_point <= INT_DIGITS); */
  35   if (i >= 0) {
  36     do {
  37       *--p = '0' + (i % 10);
  38       i /= 10;
  39       if (++point == decimal_point)
  40         *--p = '.';
  41     } while (i != 0 || point < decimal_point);
  42   }
  43   else {                        /* i < 0 */
  44     do {
  45       *--p = '0' - (i % 10);
  46       i /= 10;
  47       if (++point == decimal_point)
  48         *--p = '.';
  49     } while (i != 0 || point < decimal_point);
  50     *--p = '-';
  51   }
  52   if (decimal_point > 0) {
  53     char *q;
  54     /* there must be a dot, so this will terminate */
  55     for (q = buf + INT_DIGITS + 2; q[-1] == '0'; --q)
  56       ;
  57     if (q[-1] == '.') {
  58       if (q - 1 == p) {
  59         q[-1] = '0';
  60         q[0] = '\0';
  61       }
  62       else
  63         q[-1] = '\0';
  64     }
  65     else
  66       *q = '\0';
  67   }
  68   return p;
  69 }
  70
  71 #ifdef __cplusplus
  72 }
  73 #endif