Club Amiga de Montreal - CAM/CAM_CD_1.iso/files/211.lha/Spiff/compare.c

C/C++ Source or Header | 1996-02-14 | 3.9 KB | 210 lines

/*                        Copyright (c) 1988 Bellcore
**                            All Rights Reserved
**       Permission is granted to copy or use this program, EXCEPT that it
**       may not be sold for profit, the copyright notice must be reproduced
**       on copies, and credit should be given to Bellcore where it is due.
**       BELLCORE MAKES NO WARRANTY AND ACCEPTS NO LIABILITY FOR THIS PROGRAM.
*/


#ifndef lint
static char rcsid[]= "$Header: compare.c,v 1.1 88/09/15 11:33:53 daniel Rel $";
#endif

#include "misc.h"
#include "flagdefs.h"
#include "tol.h"
#include "token.h"
#include "line.h"
#include "float.h"
#include "compare.h"

#include <ctype.h>

X_com(a,b,flags)
int a,b,flags;
{
    K_token atmp,btmp;

    atmp = K_gettoken(0,a);
    btmp = K_gettoken(1,b);
    if(flags & U_BYTE_COMPARE)
    {
        return(_X_strcmp(K_gettext(atmp),K_gettext(btmp),flags));
    }
    else
    {
        return(_X_cmptokens(atmp,btmp,flags));
    }
#ifndef lint
    Z_fatal("this line should never be reached in com");
    return(-1);    /* Z_fatal never returns, but i need a this line
                here to stop lint from complaining */
#endif
}

/*
**    same as strcmp() except that case can be optionally ignored
*/
static int
_X_strcmp(s1,s2,flags)
char *s1,*s2;
int flags;
{
    if (flags & U_NO_CASE)
    {

        for (;('\0' != s1) && ('\0' !=  *s2);s1++,s2++)
        {
            if(isalpha(*s1) && isalpha(*s2))
            {
                if(tolower(*s1) != tolower(*s2))
                {
                    return(1);
                }
            }
            else
            {
                if(*s1!=*s2)
                {
                    return(1);
                }
            }
        }
        return(*s1 != *s2);
    }
    else
    {
        return(strcmp(s1,s2));
    }
}


/*
**    routine to compare two tokens
*/
static int
_X_cmptokens(p1,p2,flags)
K_token p1, p2;
int flags;
{
    if (K_gettype(p1) !=  K_gettype(p2))
    {
        return(1);
    }

    switch (K_gettype(p1))
    {
        case K_LIT:
            return(_X_strcmp(K_gettext(p1),K_gettext(p2),flags));
        case K_FLO_NUM:
            return(_X_floatdiff(K_getfloat(p1),
                       K_getfloat(p2),
                       T_picktol(K_gettol(p1),
                             K_gettol(p2))));
        default:
            Z_fatal("fell off switch in _X_cmptokens");
            return(-1);    /* Z_fatal never returns, but i need a this line
                        here to stop lint from complaining */
    }

}

/*
**    compare two F_floats using a tolerance
*/
static int
_X_floatdiff(p1,p2,the_tol)
F_float p1,p2;
T_tol the_tol;
{
    F_float diff, float_tmp;
    T_tol tol_tmp;

    /*
    **     check for null tolerance list
    */
    if (T_isnull(the_tol))
    {
        Z_fatal("_X_floatdiff called with a null tolerance");
    }

    /*
    **    look for an easy answer. i.e -- check
    **        to see if any of the tolerances are of type T_IGNORE
    **        or if the numbers are too small to exceed an absolute
    **        tolerance.
    **        if so, return immediately
    */
    for(tol_tmp=the_tol; !(T_isnull(tol_tmp)) ;tol_tmp=T_getnext(tol_tmp))
    {
        if ((T_IGNORE == T_gettype(tol_tmp)) ||
            /*
            **    take a look at the exponents before you bother
            **    with the mantissas
            */
            ((T_ABSOLUTE == T_gettype(tol_tmp))
                   && !F_zerofloat(T_getfloat(tol_tmp))
                   && (F_getexp(p1) <
                    F_getexp(T_getfloat(tol_tmp))-1)
                   && (F_getexp(p2) <
                    F_getexp(T_getfloat(tol_tmp))-1)))
        {
                return(0);
        }
    }


    /*
    **    ok, we're going to have to do some arithmetic, so
    **        first find the magnitude of the difference
    */
    if (F_getsign(p1) != F_getsign(p2))
    {
        diff = F_floatmagadd(p1,p2);
    }
    else
    {
        diff = F_floatsub(p1,p2);
    }

    /*
    **    now check to see if the difference exceeds any tolerance
    */
    for(tol_tmp=the_tol; !(T_isnull(tol_tmp)) ;tol_tmp=T_getnext(tol_tmp))
    {
        float_tmp = T_getfloat(tol_tmp);

        if (T_gettype(tol_tmp) == T_ABSOLUTE)
        {
            /* do nothing */
        }
        else if (T_gettype(tol_tmp) == T_RELATIVE)
        {
            if (F_floatcmp(p1,p2) > 0)
            {
                float_tmp = F_floatmul(p1, float_tmp);
            }
            else
            {
                float_tmp = F_floatmul(p2, float_tmp);
            }
        }
        else
        {
            Z_fatal("bad value for type of tolerance in floatdiff");
        }
        /*
        **    if we pass this tolerance, then we're done
        */
        if (F_floatcmp(diff,float_tmp) <= 0)
        {
            return(0);
        }
    }
    /*
    **    all of the tolerances were exceeded
    */
    return(1);
}