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Annotation of embedaddon/php/ext/bcmath/libbcmath/src/add.c, revision 1.1.1.1

1.1       misho       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: {
                     51:   bc_num sum = NULL;
                     52:   int cmp_res;
                     53:   int res_scale;
                     54: 
                     55:   if (n1->n_sign == n2->n_sign)
                     56:     {
                     57:       sum = _bc_do_add (n1, n2, scale_min);
                     58:       sum->n_sign = n1->n_sign;
                     59:     }
                     60:   else
                     61:     {
                     62:       /* subtraction must be done. */
                     63:       cmp_res = _bc_do_compare (n1, n2, FALSE, FALSE);  /* Compare magnitudes. */
                     64:       switch (cmp_res)
                     65:        {
                     66:        case -1:
                     67:          /* n1 is less than n2, subtract n1 from n2. */
                     68:          sum = _bc_do_sub (n2, n1, scale_min);
                     69:          sum->n_sign = n2->n_sign;
                     70:          break;
                     71:        case  0:
                     72:          /* They are equal! return zero with the correct scale! */
                     73:          res_scale = MAX (scale_min, MAX(n1->n_scale, n2->n_scale));
                     74:          sum = bc_new_num (1, res_scale);
                     75:          memset (sum->n_value, 0, res_scale+1);
                     76:          break;
                     77:        case  1:
                     78:          /* n2 is less than n1, subtract n2 from n1. */
                     79:          sum = _bc_do_sub (n1, n2, scale_min);
                     80:          sum->n_sign = n1->n_sign;
                     81:        }
                     82:     }
                     83: 
                     84:   /* Clean up and return. */
                     85:   bc_free_num (result);
                     86:   *result = sum;
                     87: }
                     88: