method

mode

v1_9_2_180 - Show latest stable - 0 notes - Class: BigDecimal

mode(p1, p2 = v2) public

Controls handling of arithmetic exceptions and rounding. If no value is supplied, the current value is returned.

Six values of the mode parameter control the handling of arithmetic exceptions:

BigDecimal::EXCEPTION_NaN BigDecimal::EXCEPTION_INFINITY BigDecimal::EXCEPTION_UNDERFLOW BigDecimal::EXCEPTION_OVERFLOW BigDecimal::EXCEPTION_ZERODIVIDE BigDecimal::EXCEPTION_ALL

For each mode parameter above, if the value set is false, computation continues after an arithmetic exception of the appropriate type. When computation continues, results are as follows:

EXCEPTION_NaN	NaN
EXCEPTION_INFINITY	+infinity or -infinity
EXCEPTION_UNDERFLOW	0
EXCEPTION_OVERFLOW	+infinity or -infinity
EXCEPTION_ZERODIVIDE	+infinity or -infinity

One value of the mode parameter controls the rounding of numeric values: BigDecimal::ROUND_MODE. The values it can take are:

ROUND_UP	round away from zero
ROUND_DOWN	round towards zero (truncate)
ROUND_HALF_UP	round up if the appropriate digit >= 5, otherwise truncate (default)
ROUND_HALF_DOWN	round up if the appropriate digit >= 6, otherwise truncate
ROUND_HALF_EVEN	round towards the even neighbor (Banker’s rounding)
ROUND_CEILING	round towards positive infinity (ceil)
ROUND_FLOOR	round towards negative infinity (floor)

Show source

static VALUE
BigDecimal_mode(int argc, VALUE *argv, VALUE self)
{
    VALUE which;
    VALUE val;
    unsigned long f,fo;

    if(rb_scan_args(argc,argv,"11",&which,&val)==1) val = Qnil;

    Check_Type(which, T_FIXNUM);
    f = (unsigned long)FIX2INT(which);

    if(f&VP_EXCEPTION_ALL) {
        /* Exception mode setting */
        fo = VpGetException();
        if(val==Qnil) return INT2FIX(fo);
        if(val!=Qfalse && val!=Qtrue) {
            rb_raise(rb_eTypeError, "second argument must be true or false");
            return Qnil; /* Not reached */
        }
        if(f&VP_EXCEPTION_INFINITY) {
            VpSetException((unsigned short)((val==Qtrue)?(fo|VP_EXCEPTION_INFINITY):
                           (fo&(~VP_EXCEPTION_INFINITY))));
        }
        fo = VpGetException();
        if(f&VP_EXCEPTION_NaN) {
            VpSetException((unsigned short)((val==Qtrue)?(fo|VP_EXCEPTION_NaN):
                           (fo&(~VP_EXCEPTION_NaN))));
        }
        fo = VpGetException();
        if(f&VP_EXCEPTION_UNDERFLOW) {
            VpSetException((unsigned short)((val==Qtrue)?(fo|VP_EXCEPTION_UNDERFLOW):
                           (fo&(~VP_EXCEPTION_UNDERFLOW))));
        }
        fo = VpGetException();
        if(f&VP_EXCEPTION_ZERODIVIDE) {
            VpSetException((unsigned short)((val==Qtrue)?(fo|VP_EXCEPTION_ZERODIVIDE):
                           (fo&(~VP_EXCEPTION_ZERODIVIDE))));
        }
        fo = VpGetException();
        return INT2FIX(fo);
    }
    if(VP_ROUND_MODE==f) {
        /* Rounding mode setting */
        fo = VpGetRoundMode();
        if(val==Qnil) return INT2FIX(fo);
        Check_Type(val, T_FIXNUM);
        if(!VpIsRoundMode(FIX2INT(val))) {
            rb_raise(rb_eTypeError, "invalid rounding mode");
            return Qnil;
        }
        fo = VpSetRoundMode((unsigned long)FIX2INT(val));
        return INT2FIX(fo);
    }
    rb_raise(rb_eTypeError, "first argument for BigDecimal#mode invalid");
    return Qnil;
}

mode

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