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porklib/Utils/Enum.php

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+<?php
+
+namespace MightyPork\Utils;
+
+use MightyPork\Exceptions\NotExistException;
+use ReflectionClass;
+
+/** Trait for checking if const is defined in class */
+trait Enum
+{
+    private static $cache_enum_constants = null;
+
+    /**
+     * Get all constants
+     *
+     * @param string $prefix required name prefix (filter)
+     * @return array name -> value array
+     */
+    public static function getConstants($prefix = '')
+    {
+        if (static::$cache_enum_constants != null) return static::$cache_enum_constants;
+
+        $map = (new ReflectionClass(static::class))->getConstants();
+        $selected = [];
+        foreach ($map as $k => $v) {
+            if ($prefix === '' || strpos($k, $prefix) === 0) {
+                $selected[$k] = $v;
+            }
+        }
+
+        static::$cache_enum_constants = $selected;
+        return $selected;
+    }
+
+    /**
+     * Check if a constant with a given value is defined in this class.
+     *
+     * @param mixed $value checked value
+     * @param string $prefix required name prefix
+     * @return bool
+     */
+    public static function isDefined($value, $prefix = '')
+    {
+        return in_array($value, static::getConstants($prefix));
+    }
+
+    /**
+     * Check if a constant with a given name is defined in this class.
+     *
+     * @param string $name checked name
+     * @param string $prefix required name prefix
+     * @return bool
+     */
+    public static function hasConstant($name, $prefix = '')
+    {
+        return array_key_exists($name, static::getConstants($prefix));
+    }
+
+    /**
+     * Get constant value dynamically by name
+     *
+     * @param string $name
+     * @return mixed
+     */
+    public static function forName($name)
+    {
+        return constant(static::class . '::' . $name);
+    }
+
+    /**
+     * Get constant name by it's value
+     *
+     * @param mixed $value
+     * @return string
+     */
+    public static function nameOf($value)
+    {
+        $k = array_search($value, static::getConstants());
+
+        if ($k == false)
+            throw new NotExistException("Invalid value '$value' for enum " . static::class);
+
+        return $k;
+    }
+}