public static function initBignum($how = NULL)
{
/* Check to see if PHP is running in a 32-bit environment and if so,
use GMP or BC Math if available. */
if ($how === NULL) {
if (self::$bignum != self::bigChoose) {
// determination has already been made
return self::$bignum;
} else {
if (PHP_INT_SIZE >= 8) {
self::$bignum = self::bigNative;
} else {
if (function_exists("gmp_add")) {
self::$bignum = self::bigGMP;
} else {
if (function_exists("bcadd")) {
self::$bignum = self::bigBC;
} else {
if (class_exists("\\phpseclib\\Math\\BigInteger", 0)) {
// phpseclib v2.x
self::$bignum = self::bigSecLib;
self::$secLib = "\\phpseclib\\Math\\BigInteger";
} else {
if (class_exists("Math_BigInteger", 0)) {
// phpseclib v1.x
self::$bignum = self::bigSecLib;
self::$secLib = "Math_BigInteger";
} else {
self::$bignum = self::bigNot;
}
}
}
}
}
}
} else {
switch ($how) {
case self::bigChoose:
self::$bignum = $how;
return self::initBignum();
case self::bigNot:
break;
case self::bigNative:
if (PHP_INT_SIZE < 8) {
throw new UUIDException("Bignum method is not available.", 801);
}
break;
case self::bigGMP:
if (!function_exists("gmp_add")) {
throw new UUIDException("Bignum method is not available.", 801);
}
break;
case self::bigBC:
if (!function_exists("bcadd")) {
throw new UUIDException("Bignum method is not available.", 801);
}
break;
case self::bigSecLib:
if (class_exists("\\phpseclib\\Math\\BigInteger", 0)) {
//v2.x
self::$secLib = "\\phpseclib\\Math\\BigInteger";
} else {
if (class_exists("Math_BigInteger", 0)) {
//v1.x
self::$secLib = "Math_BigInteger";
} else {
throw new UUIDException("Bignum method is not available.", 801);
}
}
break;
default:
throw new UUIDException("Bignum method not implemented.", 901);
}
self::$bignum = $how;
}
return self::$bignum;
}