class Encoder {
static void appendNumericBytes(String content, BitVector bits) {
int length = content.length();
int i = 0;
while (i < length) {
int num1 = content.charAt(i) - '0';
if (i + 2 < length) {
// Encode three numeric letters in ten bits.
int num2 = content.charAt(i + 1) - '0';
int num3 = content.charAt(i + 2) - '0';
bits.appendBits(num1 * 100 + num2 * 10 + num3, 10);
i += 3;
} else if (i + 1 < length) {
// Encode two numeric letters in seven bits.
int num2 = content.charAt(i + 1) - '0';
bits.appendBits(num1 * 10 + num2, 7);
i += 2;
} else {
// Encode one numeric letter in four bits.
bits.appendBits(num1, 4);
i++;
}
}
}
}
