The most efficient way to replace one sequence of bytes with some other sequence

Question

What is the most efficient way to replace one sequence of bytes (e.g. 67 67 67) with some other sequence of bytes (e.g. 90). Sequences can have different lengths.

Answer 1

Here is a short application that does what you need:

    static void Main(string[] args)
    {
        byte [] bArray = new byte[] {11, 67, 67, 67, 33, 34, 67, 67, 11, 33, 67, 67, 67, 67};

        byte[] result = Replace(bArray, new byte[] {67, 67, 67}, new byte[] {90});

        foreach (byte b in result)
        {
            Console.WriteLine(b);
        }
    }

    private static byte [] Replace(byte[] input, byte[] pattern, byte[] replacement)
    {
        if (pattern.Length == 0)
        {
            return input;
        }

        List<byte> result = new List<byte>();

        int i;

        for (i = 0; i <= input.Length - pattern.Length; i++)
        {
            bool foundMatch = true;
            for (int j = 0; j < pattern.Length; j++)
            {
                if (input[i + j] != pattern[j])
                {
                    foundMatch = false;
                    break;
                }
            }

            if (foundMatch)
            {
                result.AddRange(replacement);
                i += pattern.Length - 1;
            }
            else
            {
                result.Add(input[i]);
            }
        }

        for (; i < input.Length; i++ )
        {
            result.Add(input[i]);
        }

        return result.ToArray();
    }