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/* 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);
}
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