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Annotation of embedaddon/php/ext/bcmath/libbcmath/src/compare.c, revision 1.1

1.1     ! misho       1: /* compare.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: /* Compare two bc numbers.  Return value is 0 if equal, -1 if N1 is less
        !            43:    than N2 and +1 if N1 is greater than N2.  If USE_SIGN is false, just
        !            44:    compare the magnitudes. */
        !            45: 
        !            46:  int
        !            47: _bc_do_compare (n1, n2, use_sign, ignore_last)
        !            48:      bc_num n1, n2;
        !            49:      int use_sign;
        !            50:      int ignore_last;
        !            51: {
        !            52:   char *n1ptr, *n2ptr;
        !            53:   int  count;
        !            54: 
        !            55:   /* First, compare signs. */
        !            56:   if (use_sign && n1->n_sign != n2->n_sign)
        !            57:     {
        !            58:       if (n1->n_sign == PLUS)
        !            59:        return (1);     /* Positive N1 > Negative N2 */
        !            60:       else
        !            61:        return (-1);    /* Negative N1 < Positive N1 */
        !            62:     }
        !            63: 
        !            64:   /* Now compare the magnitude. */
        !            65:   if (n1->n_len != n2->n_len)
        !            66:     {
        !            67:       if (n1->n_len > n2->n_len)
        !            68:        {
        !            69:          /* Magnitude of n1 > n2. */
        !            70:          if (!use_sign || n1->n_sign == PLUS)
        !            71:            return (1);
        !            72:          else
        !            73:            return (-1);
        !            74:        }
        !            75:       else
        !            76:        {
        !            77:          /* Magnitude of n1 < n2. */
        !            78:          if (!use_sign || n1->n_sign == PLUS)
        !            79:            return (-1);
        !            80:          else
        !            81:            return (1);
        !            82:        }
        !            83:     }
        !            84: 
        !            85:   /* If we get here, they have the same number of integer digits.
        !            86:      check the integer part and the equal length part of the fraction. */
        !            87:   count = n1->n_len + MIN (n1->n_scale, n2->n_scale);
        !            88:   n1ptr = n1->n_value;
        !            89:   n2ptr = n2->n_value;
        !            90: 
        !            91:   while ((count > 0) && (*n1ptr == *n2ptr))
        !            92:     {
        !            93:       n1ptr++;
        !            94:       n2ptr++;
        !            95:       count--;
        !            96:     }
        !            97:   if (ignore_last && count == 1 && n1->n_scale == n2->n_scale)
        !            98:     return (0);
        !            99:   if (count != 0)
        !           100:     {
        !           101:       if (*n1ptr > *n2ptr)
        !           102:        {
        !           103:          /* Magnitude of n1 > n2. */
        !           104:          if (!use_sign || n1->n_sign == PLUS)
        !           105:            return (1);
        !           106:          else
        !           107:            return (-1);
        !           108:        }
        !           109:       else
        !           110:        {
        !           111:          /* Magnitude of n1 < n2. */
        !           112:          if (!use_sign || n1->n_sign == PLUS)
        !           113:            return (-1);
        !           114:          else
        !           115:            return (1);
        !           116:        }
        !           117:     }
        !           118: 
        !           119:   /* They are equal up to the last part of the equal part of the fraction. */
        !           120:   if (n1->n_scale != n2->n_scale)
        !           121:     {
        !           122:       if (n1->n_scale > n2->n_scale)
        !           123:        {
        !           124:          for (count = n1->n_scale-n2->n_scale; count>0; count--)
        !           125:            if (*n1ptr++ != 0)
        !           126:              {
        !           127:                /* Magnitude of n1 > n2. */
        !           128:                if (!use_sign || n1->n_sign == PLUS)
        !           129:                  return (1);
        !           130:                else
        !           131:                  return (-1);
        !           132:              }
        !           133:        }
        !           134:       else
        !           135:        {
        !           136:          for (count = n2->n_scale-n1->n_scale; count>0; count--)
        !           137:            if (*n2ptr++ != 0)
        !           138:              {
        !           139:                /* Magnitude of n1 < n2. */
        !           140:                if (!use_sign || n1->n_sign == PLUS)
        !           141:                  return (-1);
        !           142:                else
        !           143:                  return (1);
        !           144:              }
        !           145:        }
        !           146:     }
        !           147: 
        !           148:   /* They must be equal! */
        !           149:   return (0);
        !           150: }
        !           151: 
        !           152: 
        !           153: /* This is the "user callable" routine to compare numbers N1 and N2. */
        !           154: 
        !           155: int
        !           156: bc_compare (n1, n2)
        !           157:      bc_num n1, n2;
        !           158: {
        !           159:   return _bc_do_compare (n1, n2, TRUE, FALSE);
        !           160: }
        !           161: