gnu/dist/groff/src/libs/libgroff/iftoa.c

   1 /*      $NetBSD$        */
   2
   3 /* Copyright (C) 1989, 1990, 1991, 1992, 2000, 2004
   4    Free Software Foundation, Inc.
   5      Written by James Clark (jjc@jclark.com)
   6
   7 This file is part of groff.
   8
   9 groff is free software; you can redistribute it and/or modify it under
  10 the terms of the GNU General Public License as published by the Free
  11 Software Foundation; either version 2, or (at your option) any later
  12 version.
  13
  14 groff is distributed in the hope that it will be useful, but WITHOUT ANY
  15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17 for more details.
  18
  19 You should have received a copy of the GNU General Public License along
  20 with groff; see the file COPYING.  If not, write to the Free Software
  21 Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
  22
  23 #define INT_DIGITS 19           /* enough for 64-bit integer */
  24
  25 #ifdef __cplusplus
  26 extern "C" {
  27 #endif
  28
  29 char *if_to_a(int i, int decimal_point)
  30 {
  31   /* room for a -, INT_DIGITS digits, a decimal point, and a terminating '\0' */
  32   static char buf[INT_DIGITS + 3];
  33   char *p = buf + INT_DIGITS + 2;
  34   int point = 0;
  35   buf[INT_DIGITS + 2] = '\0';
  36   /* assert(decimal_point <= INT_DIGITS); */
  37   if (i >= 0) {
  38     do {
  39       *--p = '0' + (i % 10);
  40       i /= 10;
  41       if (++point == decimal_point)
  42         *--p = '.';
  43     } while (i != 0 || point < decimal_point);
  44   }
  45   else {                        /* i < 0 */
  46     do {
  47       *--p = '0' - (i % 10);
  48       i /= 10;
  49       if (++point == decimal_point)
  50         *--p = '.';
  51     } while (i != 0 || point < decimal_point);
  52     *--p = '-';
  53   }
  54   if (decimal_point > 0) {
  55     char *q;
  56     /* there must be a dot, so this will terminate */
  57     for (q = buf + INT_DIGITS + 2; q[-1] == '0'; --q)
  58       ;
  59     if (q[-1] == '.') {
  60       if (q - 1 == p) {
  61         q[-1] = '0';
  62         q[0] = '\0';
  63       }
  64       else
  65         q[-1] = '\0';
  66     }
  67     else
  68       *q = '\0';
  69   }
  70   return p;
  71 }
  72
  73 #ifdef __cplusplus
  74 }
  75 #endif