/*  sdfexpac.cpp  by K.Tsuru  */
// function ID 3317  DRADIX
/**************************************************************************
SDouble class
It provides a function which checks the argument x is proper or not, i.e.
it returns whether the exponential function exp(x) occurs an overflow/underflow
 error or not by an integer value.

From the condition "exp(x) < DRADIX^DRADIX_EXP_MAX" the range of 'x' must be
within
 |x| < DFIGURES*log(10)*DRADIX_EXP_MAX = 301759.17...
***************************************************************************/
#ifndef SN_H
#include "sn.h"
#endif

static const double xMax = (double)DFIGURES * M_LN10 * (double)DRADIX_EXP_MAX;
     // = 301759.17...

SNManager::SNErrorFlag ExpArgCheck(const SDouble& x, int funcID) {
    double iX = doubleD(x, 0);
    SNManager::SNErrorFlag err = x.SNError();

    if( fabs(iX) < xMax ) return x.NO_ERR;
    err = (x.Sign() > 0) ? x.OVERFLOW_ERR : x.UNDERFLOW_ERR;    

    if (funcID > 0) {
        x.Puts(5, 20);
        x.SetError(err, " exp(x) \"x\" has above value.", funcID);
    }
    return err;
}