public static final int stringPositiveSize(final int x) {
        for (int i = 0;; i++) {
            if (x <= sizeTable[i]) {
                return i + 1;
            }
        }
    }
All possible chars for representing a number as a String
metamorphosis-commons/src/main/java/com/taobao/metamorphosis/network/ByteUtils.java