jellyfin-server/OpenSubtitlesHandler/MovieHasher.cs

using System;
using System.IO;
using System.Text;

namespace OpenSubtitlesHandler
{
    public class MovieHasher
    {
        public static byte[] ComputeMovieHash(Stream input)
        {
            using (input)
            {
                long lhash, streamsize;
                streamsize = input.Length;
                lhash = streamsize;

                long i = 0;
                byte[] buffer = new byte[sizeof(long)];
                while (i < 65536 / sizeof(long) && (input.Read(buffer, 0, sizeof(long)) > 0))
                {
                    i++;
                    lhash += BitConverter.ToInt64(buffer, 0);
                }

                input.Position = Math.Max(0, streamsize - 65536);
                i = 0;
                while (i < 65536 / sizeof(long) && (input.Read(buffer, 0, sizeof(long)) > 0))
                {
                    i++;
                    lhash += BitConverter.ToInt64(buffer, 0);
                }
                byte[] result = BitConverter.GetBytes(lhash);
                Array.Reverse(result);
                return result;
            }
        }

        public static string ToHexadecimal(byte[] bytes)
        {
            StringBuilder hexBuilder = new StringBuilder();
            for (int i = 0; i < bytes.Length; i++)
            {
                hexBuilder.Append(bytes[i].ToString("x2"));
            }
            return hexBuilder.ToString();
        }
    }
}