1                 : /* nearzero.c: bcmath library file. */
       2                 : /*
       3                 :     Copyright (C) 1991, 1992, 1993, 1994, 1997 Free Software Foundation, Inc.
       4                 :     Copyright (C) 2000 Philip A. Nelson
       5                 : 
       6                 :     This library is free software; you can redistribute it and/or
       7                 :     modify it under the terms of the GNU Lesser General Public
       8                 :     License as published by the Free Software Foundation; either
       9                 :     version 2 of the License, or (at your option) any later version.
      10                 : 
      11                 :     This library is distributed in the hope that it will be useful,
      12                 :     but WITHOUT ANY WARRANTY; without even the implied warranty of
      13                 :     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      14                 :     Lesser General Public License for more details.  (COPYING.LIB)
      15                 : 
      16                 :     You should have received a copy of the GNU Lesser General Public
      17                 :     License along with this library; if not, write to:
      18                 : 
      19                 :       The Free Software Foundation, Inc.
      20                 :       59 Temple Place, Suite 330
      21                 :       Boston, MA 02111-1307 USA.
      22                 : 
      23                 :     You may contact the author by:
      24                 :        e-mail:  philnelson@acm.org
      25                 :       us-mail:  Philip A. Nelson
      26                 :                 Computer Science Department, 9062
      27                 :                 Western Washington University
      28                 :                 Bellingham, WA 98226-9062
      29                 :        
      30                 : *************************************************************************/
      31                 : 
      32                 : #include <config.h>
      33                 : #include <stdio.h>
      34                 : #include <assert.h>
      35                 : #include <stdlib.h>
      36                 : #include <ctype.h>
      37                 : #include <stdarg.h>
      38                 : #include "bcmath.h"
      39                 : #include "private.h"
      40                 : 
      41                 : /* In some places we need to check if the number NUM is almost zero.
      42                 :    Specifically, all but the last digit is 0 and the last digit is 1.
      43                 :    Last digit is defined by scale. */
      44                 : 
      45                 : char
      46                 : bc_is_near_zero (num, scale)
      47                 :      bc_num num;
      48                 :      int scale;
      49              14 : {
      50                 :   int  count;
      51                 :   char *nptr;
      52                 : 
      53                 :   /* Error checking */
      54              14 :   if (scale > num->n_scale)
      55               0 :     scale = num->n_scale;
      56                 : 
      57                 :   /* Initialize */
      58              14 :   count = num->n_len + scale;
      59              14 :   nptr = num->n_value;
      60                 : 
      61                 :   /* The check */
      62              14 :   while ((count > 0) && (*nptr++ == 0)) count--;
      63                 : 
      64              14 :   if (count != 0 && (count != 1 || *--nptr != 1))
      65              11 :     return FALSE;
      66                 :   else
      67               3 :     return TRUE;
      68                 : }
      69                 :