cpmirror/Assets/Mirror/Core/Tools/DeltaCompression.cs

// manual delta compression for some types.
//    varint(b-a)
// Mirror can't use Mirror II's bit-tree delta compression.
using System.Runtime.CompilerServices;

namespace Mirror
{
    public static class DeltaCompression
    {
        // delta (usually small), then zigzag varint to support +- changes
        // parameter order: (last, current) makes most sense (Q3 does this too).
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void Compress(NetworkWriter writer, long last, long current) =>
            Compression.CompressVarInt(writer, current - last);

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static long Decompress(NetworkReader reader, long last) =>
            last + Compression.DecompressVarInt(reader);

        // delta (usually small), then zigzag varint to support +- changes
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void Compress(NetworkWriter writer, Vector3Long last, Vector3Long current)
        {
            Compress(writer, last.x, current.x);
            Compress(writer, last.y, current.y);
            Compress(writer, last.z, current.z);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static Vector3Long Decompress(NetworkReader reader, Vector3Long last)
        {
            long x = Decompress(reader, last.x);
            long y = Decompress(reader, last.y);
            long z = Decompress(reader, last.z);
            return new Vector3Long(x, y, z);
        }
    }
}