Convert a VERY LARGE binary file into a Base64String incrementally

Question

I need help converting a VERY LARGE binary file (ZIP file) to a Base64String and back again. The files are too large to be loaded into memory all at once (they throw OutOfMe

Answer 1

Use this code:

public void ConvertLargeFile(string source , string destination)
{
    using (FileStream inputStream = new FileStream(source, FileMode.Open, FileAccess.Read))
    { 

        int buffer_size = 30000; //or any multiple of 3

        byte[] buffer = new byte[buffer_size];
        int bytesRead = inputStream.Read(buffer, 0, buffer.Length);
        while (bytesRead > 0)
        {
            byte[] buffer2 = buffer;

            if(bytesRead < buffer_size)
            {
                buffer2 = new byte[bytesRead];
                Buffer.BlockCopy(buffer, 0, buffer2, 0, bytesRead);
            }

            string base64String = System.Convert.ToBase64String(buffer2);
            File.AppendAllText(destination, base64String);

            bytesRead = inputStream.Read(buffer, 0, buffer.Length);

        }
    }
}