PKHeX/PKHeX.Core/Editing/PKM/LegalMoveInfo.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

37 lines
1.4 KiB
C#

using System;
using System.Buffers;
namespace PKHeX.Core;
public sealed class LegalMoveInfo
{
// Use a bool array instead of a HashSet; we have a limited range of moves.
// This implementation is faster (no hashcode or bucket search) with lower memory overhead (1 byte per move ID).
private readonly bool[] AllowedMoves = new bool[(int)Move.MAX_COUNT + 1];
/// <summary>
/// Checks if the requested <see cref="move"/> is legally able to be learned.
/// </summary>
/// <param name="move">Move to check if can be learned</param>
/// <returns>True if can learn the move</returns>
public bool CanLearn(int move) => AllowedMoves[move];
/// <summary>
/// Reloads the legality sources to permit the provided legal info.
/// </summary>
/// <param name="la">Details of analysis, moves to allow</param>
public bool ReloadMoves(LegalityAnalysis la)
{
var rent = ArrayPool<bool>.Shared.Rent(AllowedMoves.Length);
var span = rent.AsSpan(0, AllowedMoves.Length);
LearnPossible.Get(la.Entity, la.EncounterOriginal, la.Info.EvoChainsAllGens, span);
// check prior move-pool to not needlessly refresh the data set
bool diff = !span.SequenceEqual(AllowedMoves);
if (diff) // keep
span.CopyTo(AllowedMoves);
span.Clear();
ArrayPool<bool>.Shared.Return(rent);
return diff;
}
}