NdsKey1KeyTable.cs

using System.Buffers.Binary;
 
namespace NdsForge;

public sealed class NdsKey1KeyTable
{
    public const int ByteLength = 0x1048;

    private readonly uint[] _words;

    public NdsKey1KeyTable(ReadOnlySpan<byte> data)
    {
        if (data.Length != ByteLength)
        {
            throw new ArgumentException($"A DS KEY1 table must contain exactly 0x{ByteLength:X} bytes.", nameof(data));
        }
 
        _words = new uint[ByteLength / sizeof(uint)];
        for (int index = 0; index < _words.Length; index++)
        {
            _words[index] = BinaryPrimitives.ReadUInt32LittleEndian(data[(index * sizeof(uint))..]);
        }
    }

    public byte[] Export()
    {
        var data = new byte[ByteLength];
        for (int index = 0; index < _words.Length; index++)
        {
            BinaryPrimitives.WriteUInt32LittleEndian(data.AsSpan(index * sizeof(uint)), _words[index]);
        }
 
        return data;
    }

    internal uint[] CreateWorkingWords() => (uint[])_words.Clone();
}