PersistentMap/PersistentOrderedMap/KeyStrategies/StandardStrategy.cs

namespace PersistentOrderedMap;

using System.Runtime.CompilerServices;
/// <summary>
/// A universal key strategy for any type that relies on standard comparisons 
/// (IComparable, IComparer, or custom StringComparers) without SIMD prefixes.
/// </summary>
public readonly struct StandardStrategy<K> : IKeyStrategy<K>
{
    private readonly IComparer<K> _comparer;

    // If no comparer is provided, it defaults to Comparer<K>.Default
    // which automatically uses IComparable<K> if the type implements it.

    public StandardStrategy()
    {
        _comparer = Comparer<K>.Default;
    }

    public StandardStrategy(IComparer<K>? comparer)
    {
        _comparer = comparer ?? Comparer<K>.Default;
    }
    // Tell the B-Tree to skip SIMD routing and just use LinearSearch
    public bool UsesPrefixes => false;
    public bool UseBinarySearch => true;
    // This will never be called because UsesPrefixes is false, 
    // but we must satisfy the interface.
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public long GetPrefix(K key) => 0;

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public int Compare(K x, K y)
    {
        return _comparer.Compare(x, y);
    }
}
public readonly struct StandardStrategy2<K, TComparer> : IKeyStrategy<K>
    where TComparer : struct, IComparer<K>
                      {
                          private readonly TComparer _comparer;

                          public StandardStrategy2(TComparer comparer) => _comparer = comparer;

                          public bool UsesPrefixes => false;
                          public bool UseBinarySearch => true;

[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int Compare(K x, K y) => _comparer.Compare(x, y);

                          public long GetPrefix(K key) => 0;
    }