/**
* Update this hash with the given data.
*
* <p>A state may be passed into this method so that we can add padding and finalize a md5 hash
* without limiting our ability to update more data later.
*
* <p>If length bytes are not available to be hashed, as many bytes as possible will be hashed.
*
* @param state Which state is updated.
* @param buffer Array of bytes to be hashed.
* @param offset Offset to buffer array.
* @param length number of bytes to hash.
*/
private void update(MD5State state, byte buffer[], int offset, int length) {
finalState.valid = false;
// if length goes beyond the end of the buffer, cut it short.
if ((length + offset) > buffer.length) {
length = buffer.length - offset;
}
// compute number of bytes mod 64
// this is what we have sitting in a buffer
// that have not been hashed yet
int index = (int) (state.bitCount >>> 3) & 0x3f;
// add the length to the count (translate bytes to bits)
state.bitCount += length << 3;
int partlen = 64 - index;
int i = 0;
if (length >= partlen) {
System.arraycopy(buffer, offset, state.buffer, index, partlen);
transform(state, decode(state.buffer, 64, 0));
for (i = partlen; (i + 63) < length; i += 64) {
transform(state, decode(buffer, 64, i));
}
index = 0;
}
// buffer remaining input
if (i < length) {
for (int start = i; i < length; i++) {
state.buffer[index + i - start] = buffer[i + offset];
}
}
}
