Merge branch 'release/1.3.7'

Author: Alexander Perechnev

ChessKit.podspec

@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |spec|
   spec.name         = "ChessKit"
-  spec.version      = "1.3.6"
+  spec.version      = "1.3.7"
   spec.summary      = "Lightweight and fast chess framework written in Swift."
 
   spec.description  = "Lightweight and fast chess framework written in Swift. ChessKit is used as a base freamework for Ladoga chess engine."

README.md

@@ -42,7 +42,7 @@ target 'MyApp' do
 end
 ```
 
-## Gettings Started
+## Getting Started
 
 ChessKit is well covered by [documentation](https://aperechnev.github.io/ChessKit/). But anyway here you can find an example describing how to start working with ChessKit faster.
 

Sources/ChessKit/Game.swift

@@ -209,12 +209,43 @@ public class Game {
                 .filter { $0.color != self.position.state.turn }
         }
 
-        if piece.kind == .rook {
-            let kind: PieceKind = move.from.file == 0 ? .queen : .king
-            
-            self.position.state.castlings = self.position.state.castlings
-                .filter { $0.color != self.position.state.turn || $0.kind != kind }
+        self.position.state.castlings = self.position.state.castlings.filter {
+            // filter should return true if we should not exclude
+            // filter should return false if we should exclude current castling
+            // $0 is one of KQkq pieces (white K, white Q, black k, black q)
+            // castlingColorAndSideToExclude returns piece if move from/to is at some of 4 corners
+            // if castlingColorAndSideToExclude returns piece
+            // for either "from" or for "to" square - we have to exclude casling
+            var excludeBecauseOfFrom = false
+            var excludeBecauseOfTo = false
+            if let colorAndSideToExclude = castlingColorAndSideToExclude(square: move.from) {
+                excludeBecauseOfFrom = $0.color == colorAndSideToExclude.color && $0.kind == colorAndSideToExclude.kind
+            }
+            if let colorAndSideToExclude = castlingColorAndSideToExclude(square: move.to) {
+                excludeBecauseOfTo = $0.color == colorAndSideToExclude.color && $0.kind == colorAndSideToExclude.kind
+            }
+            return !(excludeBecauseOfFrom || excludeBecauseOfTo)
+        }
+    }
+    
+    private func castlingColorAndSideToExclude(square: Square) -> Piece? {
+        // is A1?
+        if square.file == 0 && square.rank == 0 {
+            return Piece(kind: .queen, color: .white)
+        }
+        // is H1?
+        if square.file == 7 && square.rank == 0 {
+            return Piece(kind: .king, color: .white)
+        }
+        // is A8?
+        if square.file == 0 && square.rank == 7 {
+            return Piece(kind: .queen, color: .black)
+        }
+        // is H8?
+        if square.file == 7 && square.rank == 7 {
+            return Piece(kind: .king, color: .black)
         }
+        return nil
     }
 
     // MARK: Utilities

Sources/ChessKit/Rules/StandardRules.swift

@@ -169,6 +169,11 @@ public class StandardRules: Rules {
             nextPosition.board[move.to] = nextPosition.board[move.from]
             nextPosition.board[move.from] = nil
 
+            // if move is en passant capture - remove captured pawn from board
+            if let enPassantCapturedPawn = self.squareOfEnPassantCapturedPawn(move: move, position: position) {
+                nextPosition.board[enPassantCapturedPawn] = nil
+            }
+            
             if self.isIllelgalCastling(move: move, position: position) {
                 return false
             }
@@ -179,6 +184,16 @@ public class StandardRules: Rules {
         return moves.filter(filter)
     }
 
+    private func squareOfEnPassantCapturedPawn(move: Move, position: Position) -> Square? {
+        guard let enPassant = position.state.enPasant else {
+            return nil
+        }
+        if move.to.file == enPassant.file && move.to.rank == enPassant.rank {
+            return Square(file: enPassant.file, rank: enPassant.rank == 2 ? 3 : 4)
+        }
+        return nil
+    }
+    
     private func enumeratedPieces(for position: Position) -> [(Square, Piece)] {
         return position.board.enumeratedPieces()
             .filter { $0.1.color == position.state.turn }

Tests/ChessKitTests/Performance/BoardPerformanceTests.swift

@@ -0,0 +1,38 @@
+//
+//  BoardPerformanceTests.swift
+//  ChessKitTests
+//
+//  Created by Alexander Perechnev on 25.08.2021.
+//
+
+import XCTest
+@testable import ChessKit
+
+class BoardPerformanceTests: XCTestCase {
+    
+    private let board = Board()
+    private let range = 0 ..< 100_000
+    
+    private let coordinate = "e4"
+    private let square = Square(coordinate: "e4")
+    private let index = Square(coordinate: "e4").index
+    
+    func testAccessByCoordinatePerformance() throws {
+        self.measure {
+            range.forEach { _ in let _ = board["e4"] }
+        }
+    }
+    
+    func testAccessBySquarePerformance() throws {
+        self.measure {
+            range.forEach { _ in let _ = board[square] }
+        }
+    }
+    
+    func testAccessByIndexPerformance() throws {
+        self.measure {
+            range.forEach { _ in let _ = board[index] }
+        }
+    }
+
+}

Tests/ChessKitTests/Rules/Standard/PawnMovesTests.swift

@@ -54,6 +54,10 @@ class PawnMovesTests: XCTestCase {
         self.assert(fen: "rnbqkbnr/ppp1pppp/8/8/3pP1P1/7P/PPPP1P2/RNBQKBNR b KQkq e3 0 3",
                     moves: "d4d3 d4e3",
                     coordinate: "d4")
+        
+        self.assert(fen: "8/8/3p2k1/P2Pr1Pp/3R2KP/8/8/8 w - h6 0 2",
+                moves: "g5h6",
+                coordinate: "g5")
     }
 
     private func assert(fen: String, moves: String, coordinate: String) {