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prodigga/ForceSetByteArraySize.cs

Last active November 19, 2023 09:45
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ForceSetByteArraySize.cs
private static unsafe void ForceSetByteArrayLength(ref byte[] targetArray, long length)
{
if (length != 0)
{
fixed (byte* targetArrayPtr = &targetArray[0])
{
byte* lengthPtr = (byte*)&(length);
targetArrayPtr[-8] = lengthPtr[0];
targetArrayPtr[-7] = lengthPtr[1];
targetArrayPtr[-6] = lengthPtr[2];
targetArrayPtr[-5] = lengthPtr[3];
targetArrayPtr[-4] = lengthPtr[4];
targetArrayPtr[-3] = lengthPtr[5];
targetArrayPtr[-2] = lengthPtr[6];
targetArrayPtr[-1] = lengthPtr[7];
}
}
}
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Lol I don't recommend anyone actually use this. Was just a fun experiment.

You have your nice big buffer, you'd love to feed the API a Span<> or ArraySegment, but this API doesn't support it. What to do?

Pull the bytes out of your buffer into an array of the right size? and generate garbage?! Disgusting.

How about we just modify the Length int that describes the length of the underlying array (myArray.Length <- this guy!) to make the array (and the consumers) think the array is of that exact length..! Definitely not disgusting at all, nope. Don't forget to revert the value of length once you are done..!

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