bson/src/main/org/bson/internal/UnsignedLongs.java
private static boolean overflowInParse(final long current, final int digit, final int radix) {
        if (current >= 0) {
            if (current < MAX_VALUE_DIVS[radix]) {
                return false;
            }
            if (current > MAX_VALUE_DIVS[radix]) {
                return true;
            }
            // current == maxValueDivs[radix]
            return (digit > MAX_VALUE_MODS[radix]);
        }

        // current < 0: high bit is set
        return true;
    }
private static boolean overflowInParse(final long current, final int digit, final int radix) {
        if (current >= 0) {
            if (current < MAX_VALUE_DIVS[radix]) {
                return false;
            }
            if (current > MAX_VALUE_DIVS[radix]) {
                return true;
            }
            // current == maxValueDivs[radix]
            return (digit > MAX_VALUE_MODS[radix]);
        }

        // current < 0: high bit is set
        return true;
    }
number.