PKHeX/PKHeX.Core/Legality/Evolutions/Reversal/EvolutionReverseLookup.cs
Kurt 9166d0eb64
Refactoring: Move Source (Legality) (#3560)
Rewrites a good amount of legality APIs pertaining to:
* Legal moves that can be learned
* Evolution chains & cross-generation paths
* Memory validation with forgotten moves

In generation 8, there are 3 separate contexts an entity can exist in: SW/SH, BD/SP, and LA. Not every entity can cross between them, and not every entity from generation 7 can exist in generation 8 (Gogoat, etc). By creating class models representing the restrictions to cross each boundary, we are able to better track and validate data.

The old implementation of validating moves was greedy: it would iterate for all generations and evolutions, and build a full list of every move that can be learned, storing it on the heap. Now, we check one game group at a time to see if the entity can learn a move that hasn't yet been validated. End result is an algorithm that requires 0 allocation, and a smaller/quicker search space.

The old implementation of storing move parses was inefficient; for each move that was parsed, a new object is created and adjusted depending on the parse. Now, move parse results are `struct` and store the move parse contiguously in memory. End result is faster parsing and 0 memory allocation.

* `PersonalTable` objects have been improved with new API methods to check if a species+form can exist in the game.
* `IEncounterTemplate` objects have been improved to indicate the `EntityContext` they originate in (similar to `Generation`).
* Some APIs have been extended to accept `Span<T>` instead of Array/IEnumerable
2022-08-03 16:15:27 -07:00

44 lines
1.3 KiB
C#

using System.Collections.Generic;
using System.Diagnostics;
namespace PKHeX.Core;
/// <summary>
/// Object storing a reversal path for evolution nodes.
/// </summary>
public class EvolutionReverseLookup : IEvolutionLookup
{
private readonly EvolutionNode[] Nodes;
private readonly int MaxSpecies;
private readonly Dictionary<int, int> KeyLookup;
public EvolutionReverseLookup(IEnumerable<(int Key, EvolutionLink Value)> links, int maxSpecies)
{
MaxSpecies = maxSpecies;
KeyLookup = new Dictionary<int, int>(maxSpecies);
var nodes = new EvolutionNode[maxSpecies * 2];
int ctr = maxSpecies + 1;
foreach (var (key, value) in links)
{
var index = key <= MaxSpecies ? key : KeyLookup.TryGetValue(key, out var x) ? x : KeyLookup[key] = ctr++;
ref var node = ref nodes[index];
node.Add(value);
}
Nodes = nodes;
Debug.Assert(KeyLookup.Count < maxSpecies);
}
private int GetIndex(int key)
{
if (key <= MaxSpecies)
return key;
return KeyLookup.TryGetValue(key, out var index) ? index : 0;
}
public ref EvolutionNode this[int key] => ref Nodes[GetIndex(key)];
}
public interface IEvolutionLookup
{
ref EvolutionNode this[int key] { get; }
}