feat: Initial commit + Position & FieldBitMap classes

.gitignore

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+vendor/

composer.json

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+{
+  "name": "overflowerror/php-chess",
+  "description": "description",
+  "minimum-stability": "stable",
+  "license": "MIT",
+  "authors": [
+    {
+      "name": "overflowerror",
+      "email": "email@example.com"
+    }
+  ],
+  "require-dev": {
+    "phpunit/phpunit": "^10.5"
+  },
+  "autoload": {
+    "psr-4": {
+      "Game\\": "./src/Game/"
+    }
+  }
+}

phpunit.xml

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+<?xml version="1.0" encoding="utf-8" ?>
+<phpunit bootstrap="./vendor/autoload.php"
+         displayDetailsOnTestsThatTriggerDeprecations="true"
+         displayDetailsOnTestsThatTriggerErrors="true"
+         displayDetailsOnTestsThatTriggerNotices="true"
+         displayDetailsOnTestsThatTriggerWarnings="true">
+    <testsuites>
+        <testsuite name="The project's test suite">
+            <directory>./tests</directory>
+        </testsuite>
+    </testsuites>
+</phpunit>

src/Game/FieldBitMap.php

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+<?php
+
+namespace Game;
+
+if (gettype(2147483648) == "double") {
+    die("need 64 bit integers");
+}
+
+class FieldBitMap {
+    private int $map = 0;
+
+    public function __construct(array|int $argument) {
+        if (gettype($argument) == "array") {
+            foreach ($argument as $position) {
+                $this->add($position);
+            }
+        } else {
+            $this->map = $argument;
+        }
+    }
+
+    public function getBitForPosition(Position $position): int {
+        return $position->file * 8 + $position->rank;
+    }
+
+    public function add(Position $position): void {
+        if ($position->isValid()) {
+            $this->map |= 1 << $this->getBitForPosition($position);
+        }
+    }
+
+    public function intersect(FieldBitMap $map): FieldBitMap {
+        return new FieldBitMap($this->map & $map->map);
+    }
+
+    public function union(FieldBitMap $map): FieldBitMap {
+        return new FieldBitMap($this->map | $map->map);
+    }
+
+    public function isEmpty(): bool {
+        return $this->map == 0;
+    }
+
+    public function has(Position $position): bool {
+        return ($this->map & (1 << $this->getBitForPosition($position))) != 0;
+    }
+
+    public function getPositions(): array {
+        $result = [];
+
+        for ($i = 0; $i < 64; $i++) {
+            if ($this->map & (1 << $i)) {
+                $result[] = new Position(floor($i / 8), $i % 8);
+            }
+        }
+
+        return $result;
+    }
+
+    public function getMap(): int {
+        return $this->map;
+    }
+
+    public static function full(): FieldBitMap {
+        return new FieldBitMap(-1);
+    }
+
+    public static function empty(): FieldBitMap {
+        return new FieldBitMap(0);
+    }
+}

src/Game/Position.php

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+<?php
+
+namespace Game;
+
+class Position {
+    public int $file;
+    public int $rank;
+
+    public function __construct($file, $rank) {
+        $this->rank = $rank;
+        $this->file = $file;
+    }
+
+    public function isValid(): bool {
+        return
+            $this->file >= 0 && $this->file < 8 &&
+            $this->rank >= 0 && $this->rank < 8;
+    }
+
+    public function __toString(): string {
+        return ["a", "b", "c", "d", "e", "f", "g", "h"][$this->file] . ($this->rank + 1);
+    }
+}

tests/Game/FieldBitMapTest.php

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+<?php
+declare(strict_types=1);
+
+use Game\FieldBitMap;
+use Game\Position;
+use PHPUnit\Framework\TestCase;
+
+final class FieldBitMapTest extends TestCase {
+
+    public function testEmptyMapHasPositions() {
+        $subject = FieldBitMap::empty();
+
+        $this->assertTrue($subject->isEmpty());
+        $this->assertEmpty($subject->getPositions());
+    }
+
+    public function testFullMapHasAllPositions() {
+        $subject = FieldBitMap::full();
+
+        $this->assertFalse($subject->isEmpty());
+        $this->assertCount(64, $subject->getPositions());
+    }
+
+    public function testMapPositionsAreRetained() {
+        $positions = [
+            new Position(0, 0),
+            new Position(3, 4),
+            new Position(7, 7),
+        ];
+
+        $subject = new FieldBitMap($positions);
+
+        $this->assertFalse($subject->isEmpty());
+        $this->assertEquals($positions, $subject->getPositions());
+    }
+
+}

tests/Game/PositionTest.php

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+<?php
+declare(strict_types=1);
+
+use Game\Position;
+use PHPUnit\Framework\TestCase;
+
+final class PositionTest extends TestCase {
+
+    public function testIsValid_default_min() {
+        $subject = new Position(0, 0);
+        $this->assertTrue($subject->isValid());
+    }
+
+    public function testIsValid_default_max() {
+        $subject = new Position(7, 7);
+        $this->assertTrue($subject->isValid());
+    }
+
+    public function testIsValid_fileTooHigh() {
+        $subject = new Position(8, 7);
+        $this->assertFalse($subject->isValid());
+    }
+
+    public function testIsValid_RankTooHigh() {
+        $subject = new Position(7, 8);
+        $this->assertFalse($subject->isValid());
+    }
+
+    public function testIsValid_fileTooLow() {
+        $subject = new Position(-1, 0);
+        $this->assertFalse($subject->isValid());
+    }
+
+    public function testIsValid_RankTooLow() {
+        $subject = new Position(0, -1);
+        $this->assertFalse($subject->isValid());
+    }
+
+    public function testToString() {
+        $subject = new Position(4, 5);
+
+        $this->assertEquals("e6", strval($subject));
+    }
+}