Update Method
Feeds a chunk of data to the hash function.
Syntax
hashfunction.update(buffer_Buffer, [callback])
Callback
The 'callback' parameter specifies a function which will be called when the operation completes (or an error is encountered). If the 'callback' parameter is not specified, then the method will block and will not return until the operation completes (or an error is encountered).
The callback for this method is defined as:
function(err){ }
'err' is the error that occurred. If there was no error, then 'err' is 'null'.
'err' has 2 properties which hold detailed information:
err.code err.message
Remarks
This method feeds Buffer to the hash function. Call this methodrepeatedly to pass your data to the hash function chunk by chunk.
Remember to initialize the hash function with an Reset call beforestarting to feed data with this method. After the whole volume ofdata has been sent, complete the calculation and obtain the resultingmessage digest with a Finish call.