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POC# StructLayout/FieldOffset and indexing in arrays
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copied!<p>I'm having a bit of a problem using FieldOffset correctly with arrays. The code below is an example where it doesn't work correctly for me:</p> <pre><code>[StructLayout(LayoutKind.Explicit)] public struct IndexStruct { [FieldOffset(0)] public byte[] data; [FieldOffset(0)] public short[] idx16; [FieldOffset(0)] public int[] idx32; } </code></pre> <p>If I for example sets the array named "data" to a serialized byte array and then try to retrieve data as shorts using the "idx16" field the indexing is still aligned as a byte[]. Meaning that idx16<a href="https://stackoverflow.com/questions/619041/what-is-the-fastest-way-to-convert-a-float-to-a-byte/619307#619307">1</a> fetches the second byte in data, not the second 16bit word (byte 2 and 3). If I do the inverse I index shorts instead of bytes, meaning that the offset alignment is inherited from the source data. My question, is there a way to work around this? I know that I can compensate the index value by multiplying with the size of the element, but is there another way?</p> <p><a href="https://stackoverflow.com/questions/619041/what-is-the-fastest-way-to-convert-a-float-to-a-byte/619307#619307">Here</a> is an answer I found here on StackOverflow, but when trying that code it turned out that it wasn't working properly. Tried it out using a Unit test in VS with the following code without any success: </p> <pre><code>[TestMethod()] public void SumTest() { float[] fArr = {2.0f, 0.5f, 0.0f, 1.0f}; MemoryStream ms = new MemoryStream(); for (int i = 0; i < fArr.Length; i++) { ms.Write(BitConverter.GetBytes(fArr[i]), 0, sizeof(float)); } byte[] buff = ms.ToArray(); double expected = 3.5f; double actual = Sum(buff); Assert.AreEqual(expected, actual); } </code></pre> <p>Many thanks in advance!</p>

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