Kompressor/Kompressor/FileReadAllBytesPatch.cs

using System.IO;
using System.IO.Compression;
using HarmonyLib;

namespace Kompressor
{
    [HarmonyPatch(typeof(File), "ReadAllBytes")]
    public class FileReadAllBytesPatch
    {
        public static void Postfix(string path, ref byte[] __result)
        {
            if (!path.EndsWith("GameSave.GC")) return; // not a save file; do nothing
            for (byte i = 0; i < MyPlugin.COMPRESSION_FRAME_START.Length; i++)
            {
                if (__result[i] != MyPlugin.COMPRESSION_FRAME_START[i])
                {
                    // Don't do anything; not compressed
                    return;
                }
            }
            GamecraftModdingAPI.Utility.Logging.MetaLog($"Reading compressed save from {path}");
            // remove frame at start of file
            byte[] compressedResult = new byte[__result.Length - MyPlugin.COMPRESSION_FRAME_START.Length];
            for (long i = MyPlugin.COMPRESSION_FRAME_START.Length; i < __result.Length; i++)
            {
                compressedResult[i - MyPlugin.COMPRESSION_FRAME_START.Length] = __result[i];
            }
            MemoryStream compressedData = new MemoryStream(compressedResult);
            // decompress
            GZipStream gzip = new GZipStream(compressedData, CompressionMode.Decompress, true);
            // update result
            MemoryStream decompressedData = new MemoryStream();
            byte[] buffer = new byte[1];
            int readCount = gzip.Read(buffer, 0, 1);
            while (readCount != 0)
            {
                decompressedData.Write(buffer, 0, 1);
                readCount = gzip.Read(buffer, 0, 1);
            }
            gzip.Close();
            byte[] newResult = new byte[decompressedData.Length];
            decompressedData.Seek(0, 0);
            decompressedData.Read(newResult, 0, (int)decompressedData.Length);
            GamecraftModdingAPI.Utility.Logging.MetaLog($"compressedData.Length: {compressedData.Length}");
            GamecraftModdingAPI.Utility.Logging.MetaLog($"decompressedData.Length: {decompressedData.Length}");
            GamecraftModdingAPI.Utility.Logging.MetaLog($"newResult: \"{System.Text.Encoding.UTF8.GetString(newResult)}\"");
            GamecraftModdingAPI.Utility.Logging.MetaLog($"Completed decompression of save");
            __result = newResult;
            compressedData.Close();
            decompressedData.Close();
        }
    }
}