Processing messages from a byte[] buffer, prepending leftover bytes to the next buffer

Question

I have a byte array of 256 (byte[256]) and I have a stream of byte data coming in which I am reading with the 256 Buffer size on my byte array.

I parse the byte array and extract 2 "Messages" from the byte array...leaving 13 bytes in the array un-processed.

Question how do I get the 13 bytes attached to the next 256 byte array that comes in so I can process the "partial bytes" from the first byte array with the second byte array in the fastest possible way?

Example:

    [256 Array]
    [+++++++++++++++++++] (1st Buffer)
    [**************] (Processed in the first iteration...)
                   [----] (Remaining from the 1st Buffer)
                   [----][++++++++++++++++++++](Old Buff + New Buff256[])
                   [-----+++++++++++++++++++++] <---- (THIS)
                  (How do I get this Combination to process in the most
                  efficient manner so I am not missing messages that may
                  have been chopped off by my buffer size from the old buffer)

Thanks in advance guys.

Welcome! Any code to show? What research have you done? This will help us help you. Good luck! — , May 27 '16 at 02:40
@Valmorgal It looks like there is a solution [here](http://stackoverflow.com/questions/8221136/fifo-queue-buffer-specialising-in-byte-streams) — Dmitry Nogin, May 27 '16 at 03:15

score 3 · Accepted Answer · answered May 27 '16 at 02:43

3

Declare a buffer of 512 bytes instead of 256.

When you are ready to receive another 256 bytes, check if you have any left-overs in the buffer. If you do, copy them to the start of the buffer.

Then receive your 256 bytes, putting them after the left-overs.

Assuming your messages are all smaller than 256 bytes each, you shouldn't overrun your buffer.

answered May 27 '16 at 02:43

Blorgbeard

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@blogbeard Thanks for the reply. I'm looking for a fast implementation to do exactly what you are saying. To put the left over bytes at the beginning of the new buffer. – Valmorgal May 27 '16 at 13:08
Well, how fast do you need it? Why is this not fast enough? – Blorgbeard May 27 '16 at 22:07

Processing messages from a byte[] buffer, prepending leftover bytes to the next buffer

1 Answers1