feat: Distribute library as a native PHP extension

.gitignore

@@ -4,6 +4,8 @@ composer.lock
 clover.xml
 junit-logfile.xml
 tmp/
+.php-version
+.vscode/
 
 # Agents
 .agents/

extension/.gitignore

@@ -0,0 +1,3 @@
+vendor/
+composer.lock
+build/

extension/array_diff_multidimensional.php

@@ -0,0 +1,70 @@
+<?php
+
+use native_types;
+
+function array_diff_multidimensional(array $array1, mixed $array2, bool $strict = true): array {
+    if (!is_array($array2)) {
+        return $array1;
+    }
+
+    if (count($array1) === 0 || $array1 === $array2) {
+        return [];
+    }
+
+    $result = [];
+    $epsilon = defined('PHP_FLOAT_EPSILON') ? PHP_FLOAT_EPSILON : 2.2204460492503E-16;
+
+    foreach ($array1 as $key => $value) {
+        // Use isset for better performance, fall back to array_key_exists for null values
+        if (!isset($array2[$key]) && !array_key_exists($key, $array2)) {
+            $result[$key] = $value;
+            continue;
+        }
+
+        $value2 = $array2[$key];
+
+        if (is_array($value)) {
+            if (empty($value)) {
+                if (!is_array($value2) || !empty($value2)) {
+                    $result[$key] = $value;
+                }
+                continue;
+            }
+
+            // Only recurse if both are arrays
+            if (is_array($value2)) {
+                $recursiveArrayDiff = array_diff_multidimensional($value, $value2, $strict);
+                if (!empty($recursiveArrayDiff)) {
+                    $result[$key] = $recursiveArrayDiff;
+                }
+            } else {
+                $result[$key] = $value;
+            }
+            continue;
+        }
+
+        // Handle scalar value comparison optimization
+        if ($strict) {
+            // Strict comparison - optimize float handling
+            if (is_float($value) && is_float($value2)) {
+                // Use epsilon comparison for float precision
+                if (abs($value - $value2) > $epsilon) {
+                    $result[$key] = $value;
+                }
+            } elseif ($value !== $value2) {
+                $result[$key] = $value;
+            }
+        } else {
+            // Loose comparison - convert if either is float
+            if (is_float($value) || is_float($value2)) {
+                if ((string) $value != (string) $value2) {
+                    $result[$key] = $value;
+                }
+            } elseif ($value != $value2) {
+                $result[$key] = $value;
+            }
+        }
+    }
+
+    return $result;
+}

extension/composer.json

@@ -0,0 +1,6 @@
+{
+    "require-dev": {
+        "php": "^8.5",
+        "swoole/typephp": "^0.7.0"
+    }
+}

extension/project.yml

@@ -0,0 +1,74 @@
+# Output file path (equivalent to -o/--output)
+output: build/array_diff_multidimensional
+
+# If you only need to specify the artifact name, you can also use name
+# name does not change the output directory
+# name: myapp
+
+# Build mode: bin (executable) / lib (dynamic library) / ext (PHP extension)
+# Under WASM, you can also use library to generate a Component with a WIT export interface
+mode: ext
+
+# Optimization level, parallel jobs, and debug switch
+optimize: 2
+job: 8
+debug: false
+
+# Source list (files or directories)
+sources:
+  - array_diff_multidimensional.php
+
+# Ignored files or directories
+ignore:
+  - tests/
+  - vendor/
+
+# Build directory (relative paths are resolved relative to the directory containing this YAML file)
+build-dir: build/out
+
+# C++ standard version
+cxx-std: c++20
+
+# Target CPU / cross-compilation platform
+march: native
+# target-platform: x86_64-unknown-linux-gnu
+
+# WASI 0.2 output: only component or browser is allowed
+# wasm: component
+# wasm-browser-dir: generated
+# library mode can configure the WIT identifier
+# wasm-package: app:calculator@1.0.0
+# wasm-world: calculator
+
+# Custom C++ compiler (gcc/g++/clang/clang++, etc.)
+cpp-compiler: clang++
+
+# Additional C++ compilation options
+cxx-flags:
+  - -fvisibility=hidden
+  - -Wno-unused-parameter
+
+# Additional linker options
+ld-flags:
+  - -lcurl
+  - -lssl
+
+# Additional C++ header search paths (equivalent to -I)
+include-paths:
+  - /opt/mylib/include
+  - ../shared/headers
+
+# Preprocessor macro definitions (equivalent to -D)
+defines:
+  - ENABLE_LOGGING=1
+  - DEBUG_LEVEL=3
+
+# Runtime / build behavior
+sanitize: address
+profile: false
+no-literal-strings: false
+no-progress: true
+no-console: false
+dry: false
+lto: true
+format: true