PKHeX/PKHeX.Core/MysteryGifts/DataMysteryGift.cs

using System;

namespace PKHeX.Core;

/// <summary>
/// Mystery Gift backed by serialized fields from ROM/SAV data, rather than observed specifications.
/// </summary>
public abstract class DataMysteryGift : MysteryGift
{
    public readonly byte[] Data;

    protected DataMysteryGift(byte[] data) => Data = data;

    /// <summary>
    /// Returns an array for exporting outside the program (to disk, etc).
    /// </summary>
    public virtual byte[] Write() => Data;

    public override int GetHashCode()
    {
        int hash = 17;
        foreach (var b in Data)
            hash = (hash * 31) + b;
        return hash;
    }

    /// <summary>
    /// Creates a deep copy of the <see cref="MysteryGift"/> object data.
    /// </summary>
    public override MysteryGift Clone()
    {
        byte[] data = (byte[])Data.Clone();
        var result = GetMysteryGift(data);
        if (result == null)
            throw new ArgumentException(nameof(MysteryGift));
        return result;
    }

    public override bool Empty => Data.AsSpan().IndexOfAnyExcept<byte>(0) == -1;
}