feet, miles, and inches converter

<?php function distance($curlen,$type,$totype,$on){ 
    //Check to see if the first value is an interger 
    if(!is_int($curlen)){ 
        return 'Wrong input type for first value'; 
        exit; 
    } 
    //Make sure second value is either f,i, or m 
    if($type!="f"&&$type!="i"&&$type!="m"){ 
        return 'Wrong input type for second value'; 
        exit; 
    } 
    //Make sure third value is either f,i, or m 
    if($totype!="f"&&$totype!="i"&&$totype!="m"){ 
        return 'Wrong input type for third value'; 
        exit; 
    } 
    //Make sure fourth value is either 1 or 2 
    if($on!=1&&$on!=2){ 
        return 'Wrong input type for fourth value'; 
        exit; 
    } 
    //If it passes the above, get the current type 
    switch($type){ 
        //if it is an i do the math 
        case "i": 
            if($totype=="f"){ 
                $len = $curlen / 12; 
                if($on==1){ 
                    return number_format(round($len,1)).' FT'; 
                }else{ 
                    return number_format(round($len,1)); 
                } 
            }elseif($totype=="m"){ 
                $len = $curlen / 63360; 
                if($on==1){ 
                    return number_format(round($len,1)).' MI'; 
                }else{ 
                    return number_format(round($len,1)); 
                } 
            } 
        break; 
        //if it is an f do the math 
        case "f": 
            if($totype=="i"){ 
                $len = $curlen * 12; 
                if($on==1){ 
                    return number_format(round($len,1)).' IN'; 
                }else{ 
                    return number_format(round($len,1)); 
                } 
            }elseif($totype=="m"){ 
                $len = $curlen / 5280; 
                if($on==1){ 
                    return number_format(round($len,1)).' MI'; 
                }else{ 
                    return number_format(round($len,1)); 
                } 
            } 
        break; 
        //if it is an m do the math 
        case "m": 
            if($totype=="i"){ 
                $len = $curlen * 63360; 
                if($on==1){ 
                    return number_format(round($len,1)).' IN'; 
                }else{ 
                    return number_format(round($len,1)); 
                } 
            }elseif($totype=="f"){ 
                $len = $curlen * 5280; 
                if($on==1){ 
                    return number_format(round($len,1)).' FT'; 
                }else{ 
                    return number_format(round($len,1)); 
                } 
            } 
        break; 
    } 
} 
//position 1 = distance numaric numbers only no commas 
//position 2 = current lenght type of position 1 
//position 3 = convert lenght type of position 1 and 2 
//position 4 = FT,MI,IN extentions on or off :: 1=on : 2=off 
//m = miles 
//f = feet 
//i = inches echo distance(123,"m","f",1); ?>

Need to convert miles to feet, or feet to mile or even inches? Using this function you can convert one to the other.