1                 : /* add.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                 : 
      42                 : /* Here is the full add routine that takes care of negative numbers.
      43                 :    N1 is added to N2 and the result placed into RESULT.  SCALE_MIN
      44                 :    is the minimum scale for the result. */
      45                 : 
      46                 : void
      47                 : bc_add (n1, n2, result, scale_min)
      48                 :      bc_num n1, n2, *result;
      49                 :      int scale_min;
      50              21 : {
      51              21 :   bc_num sum = NULL;
      52                 :   int cmp_res;
      53                 :   int res_scale;
      54                 : 
      55              21 :   if (n1->n_sign == n2->n_sign)
      56                 :     {
      57              20 :       sum = _bc_do_add (n1, n2, scale_min);
      58              20 :       sum->n_sign = n1->n_sign;
      59                 :     }
      60                 :   else
      61                 :     {
      62                 :       /* subtraction must be done. */
      63               1 :       cmp_res = _bc_do_compare (n1, n2, FALSE, FALSE);  /* Compare magnitudes. */
      64               1 :       switch (cmp_res)
      65                 :         {
      66                 :         case -1:
      67                 :           /* n1 is less than n2, subtract n1 from n2. */
      68               1 :           sum = _bc_do_sub (n2, n1, scale_min);
      69               1 :           sum->n_sign = n2->n_sign;
      70               1 :           break;
      71                 :         case  0:
      72                 :           /* They are equal! return zero with the correct scale! */
      73               0 :           res_scale = MAX (scale_min, MAX(n1->n_scale, n2->n_scale));
      74               0 :           sum = bc_new_num (1, res_scale);
      75               0 :           memset (sum->n_value, 0, res_scale+1);
      76               0 :           break;
      77                 :         case  1:
      78                 :           /* n2 is less than n1, subtract n2 from n1. */
      79               0 :           sum = _bc_do_sub (n1, n2, scale_min);
      80               0 :           sum->n_sign = n1->n_sign;
      81                 :         }
      82                 :     }
      83                 : 
      84                 :   /* Clean up and return. */
      85              21 :   bc_free_num (result);
      86              21 :   *result = sum;
      87              21 : }
      88                 :