Question

I have a byte array. It contains 24 bit signed integers stored lsb to msb. The array could hold up to 4mb of data. The integers will be converted to 32 bit signed integers to be used in the application. I would like to hear about possible strategies for conversion and sampling of this data.

One thing I need to do with the data is graph it. With sequential sampling, I am worried about loosing some of the important peaks and valleys in the data. I also want to do some calculations to determine the highest and lowest values.

Given what I need to do, are there any algorithms or ways of doing things that will help me achieve my goal quickly and efficiently?

Answer 1

If your input has to be 3 byte ints, then you can convert to 4 byte ints as follows:

byte[] input = new byte[] {1, 2, 3, 4, 5, 6, 7, 8, 9}; //sample data
byte[] buffer = new byte[4]; //4 byte buffer for conversion from 3-> 4 byte int
int[] output = new int[input.Length / 3];

for (int i = 0, j = 0; i < input.Length; i += 3, j++)
{
    Buffer.BlockCopy(input, i, buffer, 0, 3);

    int signed32 = BitConverter.ToInt32(buffer, 0);

    output[j] = signed32;
}

Edit

Fixed block copy for little endian.