I have to process a large byte array that is passed to my function. I need to copy the content from this incoming byte array in smaller "chunks" to an outbound byte array.
For every "chunk" of data created in the outbound array, I need to call a web service.
Upon return, I need to resume looping through the incoming byte array, continuing to pass a whole or partial chunk of data until the complete incoming array is processed (i.e. sent to the web service in chunks).
I am very new to C# and I am struggling with a loop that works. I know how to call the web service to handle a "chunk" but I can't get the looping correct. Here is a sketch of the pathetic mess I currently have:
int chunkSize = 10000;
byte[] outboundBuffer = new byte[chunkSize];
while (BytesRead > 0)
{
long i = 0;
foreach (byte x in incomingArray)
{
BytesRead += 1;
outboundBuffer[i] = incomingArray[i]
i++;
}
uploadObject.Size = BytesRead;
uploadObject.MTOMPayload = outboundBuffer;
// call web service here and pass the uploadObject
// get next "chunk" until incomingArray is fully processed
}
I know this is a mess and won't work; could someone sketch a proper loop to get this done? Thanks very much.
You might want to look into Array.Copy or Buffer.BlockCopy; this will clean things up a bit, since you won't have to copy all of the bytes individually:
int incomingOffset = 0;
while(incomingOffset < incomingArray.Length)
{
int length =
Math.Min(outboundBuffer.Length, incomingArray.Length - incomingOffset);
// Changed from Array.Copy as per Marc's suggestion
Buffer.BlockCopy(incomingArray, incomingOffset,
outboundBuffer, 0,
length);
incomingOffset += length;
// Transmit outbound buffer
}
You probably want Buffer.BlockCopy
(the rawest of the copies; ideally suitable for byte[]
).
Of course, the other option is to use a MemoryStream
in place of the outbound array, and just Write
to it each time, then call ToArray()
or GetBuffer()
on the MemoryStream
(with GetBuffer()
, you need to watch the length; with ToArray()
it is trimmed for you automatically):
MemoryStream ms = new MemoryStream();
byte[] buffer = new byte[BUFFER_SIZE];
int bytesReceived;
while((bytesReceived = GetNextChunk(buffer, 0, BUFFER_SIZE)) > 0) {
ms.Write(incomingArray, 0, bytesReceived);
}
byte[] final = ms.ToArray();
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