in encode/java/src/main/java/com/aliyun/darabonba/encode/Encoder.java [177:188]
private int encodeOutLength(int srclen) {
int len = 0;
if (doPadding) {
len = 4 * ((srclen + 2) / 3);
} else {
int n = srclen % 3;
len = 4 * (srclen / 3) + (n == 0 ? 0 : n + 1);
}
if (linemax > 0) // line separators
len += (len - 1) / linemax * newline.length;
return len;
}