/* compare.c: bcmath library file. */ /* Copyright (C) 1991, 1992, 1993, 1994, 1997 Free Software Foundation, Inc. Copyright (C) 2000 Philip A. Nelson This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. (COPYING.LIB) You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to: The Free Software Foundation, Inc. 59 Temple Place, Suite 330 Boston, MA 02111-1307 USA. You may contact the author by: e-mail: philnelson@acm.org us-mail: Philip A. Nelson Computer Science Department, 9062 Western Washington University Bellingham, WA 98226-9062 *************************************************************************/ #include <config.h> #include <stdio.h> #include <assert.h> #include <stdlib.h> #include <ctype.h> #include <stdarg.h> #include "bcmath.h" #include "private.h" /* Compare two bc numbers. Return value is 0 if equal, -1 if N1 is less than N2 and +1 if N1 is greater than N2. If USE_SIGN is false, just compare the magnitudes. */ int _bc_do_compare (n1, n2, use_sign, ignore_last) bc_num n1, n2; int use_sign; int ignore_last; { char *n1ptr, *n2ptr; int count; /* First, compare signs. */ if (use_sign && n1->n_sign != n2->n_sign) { if (n1->n_sign == PLUS) return (1); /* Positive N1 > Negative N2 */ else return (-1); /* Negative N1 < Positive N1 */ } /* Now compare the magnitude. */ if (n1->n_len != n2->n_len) { if (n1->n_len > n2->n_len) { /* Magnitude of n1 > n2. */ if (!use_sign || n1->n_sign == PLUS) return (1); else return (-1); } else { /* Magnitude of n1 < n2. */ if (!use_sign || n1->n_sign == PLUS) return (-1); else return (1); } } /* If we get here, they have the same number of integer digits. check the integer part and the equal length part of the fraction. */ count = n1->n_len + MIN (n1->n_scale, n2->n_scale); n1ptr = n1->n_value; n2ptr = n2->n_value; while ((count > 0) && (*n1ptr == *n2ptr)) { n1ptr++; n2ptr++; count--; } if (ignore_last && count == 1 && n1->n_scale == n2->n_scale) return (0); if (count != 0) { if (*n1ptr > *n2ptr) { /* Magnitude of n1 > n2. */ if (!use_sign || n1->n_sign == PLUS) return (1); else return (-1); } else { /* Magnitude of n1 < n2. */ if (!use_sign || n1->n_sign == PLUS) return (-1); else return (1); } } /* They are equal up to the last part of the equal part of the fraction. */ if (n1->n_scale != n2->n_scale) { if (n1->n_scale > n2->n_scale) { for (count = n1->n_scale-n2->n_scale; count>0; count--) if (*n1ptr++ != 0) { /* Magnitude of n1 > n2. */ if (!use_sign || n1->n_sign == PLUS) return (1); else return (-1); } } else { for (count = n2->n_scale-n1->n_scale; count>0; count--) if (*n2ptr++ != 0) { /* Magnitude of n1 < n2. */ if (!use_sign || n1->n_sign == PLUS) return (-1); else return (1); } } } /* They must be equal! */ return (0); } /* This is the "user callable" routine to compare numbers N1 and N2. */ int bc_compare (n1, n2) bc_num n1, n2; { return _bc_do_compare (n1, n2, TRUE, FALSE); }