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/*
*
* (c) Vladi Belperchinov-Shabanski "Cade" <cade@biscom.net> 1998-2003
*
* SEE `README',`LICENSE' OR `COPYING' FILE FOR LICENSE AND OTHER DETAILS!
*
* $Id: eval.cpp,v 1.5 2003/01/21 19:56:35 cade Exp $
*
*/
#include <math.h>
#include <vstring.h>
#include "eval.h"
/*
This is *very* old code and I'm not sure if it works at all
after the last rewrite :)
*/
int EvalResult;
double Eval( const char* a_exp )
{
VString exp = a_exp;
str_cut_spc( exp );
int ps = 0; // pos of the +/-/:/* signs
int prior = 0; // priority flag
int par = 0; // brackets flag
int z = 0; // pos counter
while ( z < str_len( exp ) )
{
switch ( exp[z] ) {
case '(': par++; break;
case ')': par--; break;
case '+': if ((par == 0) && (prior < 20)) { prior = 20; ps = z; } break;
case '-': if ((par == 0) && (prior < 20)) { prior = 20; ps = z; } break;
case '*': if ((par == 0) && (prior < 10)) { prior = 10; ps = z; } break;
case '/': if ((par == 0) && (prior < 10)) { prior = 10; ps = z; } break;
case '%': if ((par == 0) && (prior < 10)) { prior = 10; ps = z; } break;
}
z++;
}
if (ps != 0)
{
VString p1;
VString p2;
str_copy( p1, exp, 0, ps );
str_copy( p1, exp, ps );
double res = 0.0;
switch (exp[ps]) {
case '+': res = (Eval(p1)+Eval(p2)); break;
case '-': res = (Eval(p1)-Eval(p2)); break;
case '*': res = (Eval(p1)*Eval(p2)); break;
case '/': res = (Eval(p1)/Eval(p2)); break;
case '%': res = (fmod(Eval(p1),Eval(p2))); break;
}
return res;
}
else
{ // well ... constant/function/brackets
int bp = str_find( exp, '(' );
if ( bp >= 0 )
if ( bp > 0 )
{ // function
VString fname;
str_copy( fname, exp, 0, bp );
VString p1;
str_copy( p1, exp, bp+1, str_rfind( exp, ')' ) - bp - 1 );
double res = 0.0;
if (strcasecmp(fname, "sin") == 0) {res = sin(Eval(p1));} else
if (strcasecmp(fname, "cos") == 0) {res = cos(Eval(p1));} else
if (strcasecmp(fname, "tan") == 0) {res = sin(Eval(p1))/cos(Eval(p1));} else
if (strcasecmp(fname, "atan") == 0) {res = atan(Eval(p1));} else
if (strcasecmp(fname, "asin") == 0) {res = asin(Eval(p1));} else
if (strcasecmp(fname, "acos") == 0) {res = acos(Eval(p1));} else
// degree/radians/grads conversions...
if (strcasecmp(fname, "r2d") == 0) {res = Eval(p1)*180/M_PI;} else
if (strcasecmp(fname, "d2r") == 0) {res = Eval(p1)*M_PI/180;} else
if (strcasecmp(fname, "r2g") == 0) {res = Eval(p1)*200/M_PI;} else
if (strcasecmp(fname, "g2r") == 0) {res = Eval(p1)*M_PI/200;} else
if (strcasecmp(fname, "d2g") == 0) {res = Eval(p1)*400/360;} else
if (strcasecmp(fname, "g2d") == 0) {res = Eval(p1)*360/400;} else
if (strcasecmp(fname, "random") == 0) {res = random() % long(Eval(p1));} else
if (strcasecmp(fname, "abs") == 0) {res = fabs(Eval(p1));} else
if (strcasecmp(fname, "int") == 0) {res = floor(Eval(p1)+0.5);} else
if (strcasecmp(fname, "sqrt") == 0) {res = sqrt(Eval(p1));} else
if (strcasecmp(fname, "exp") == 0) {res = ::exp(Eval(p1));} else
if (strcasecmp(fname, "ln") == 0) {res = log(Eval(p1));} else
if (strcasecmp(fname, "lg") == 0) {res = log10(Eval(p1));} else
// if (strcasecmp(fname, "") == 0) {} else
EvalResult = 10;
if (EvalResult == 10)
return 0;
else
return res;
}
else
{ // brackets
VString p1;
str_copy( p1, exp, 1, str_len( exp ) - 2 );
double res = Eval( p1 );
return res;
}
else
{ // constant
if ( strcasecmp( exp, "pi" ) == 0 ) { return M_PI; } else
if ( strcasecmp( exp, "e" ) == 0 ) { return M_E; } else
return atof ( exp );
}
}
//return 0;
}
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