Add ArrayFlattener class

src/libraries/ArrayFlattener.php

@@ -0,0 +1,99 @@
+<?php
+
+namespace CarlBennett\MVC\Libraries;
+
+use \DateTime;
+
+final class ArrayFlattener {
+
+  const DELIMITER = '_';
+  const MAX_DEPTH = 4;
+
+  /**
+   * __construct()
+   * We set this to private so code cannot instantiate this class.
+   * This class is entirely static and meant to be used that way.
+   */
+  private function __construct() {}
+
+  /**
+   * flatten()
+   * Flattens an array or object into a string.
+   *
+   * @param $thing The array or object to be flattened.
+   *
+   * @return string The flattened thing.
+   */
+  public static function flatten( &$thing ) {
+    $buffer = '';
+
+    if ( is_object( $thing ) ) {
+      $vars = get_object_vars( $thing );
+    } else {
+      $vars = &$thing;
+    }
+
+    foreach ( $vars as $key => $value ) {
+      self::__flatten( $buffer, $key, $value, 0 );
+    }
+
+    return $buffer;
+  }
+
+  /**
+   * __flatten()
+   * Does the grunt work of flatten().
+   *
+   * @param &$buffer The string buffer that will be returned by flatten().
+   * @param &$key The name of the current key being processed.
+   * @param &$value The key's value, can be anything.
+   * @param $depth The current depth level, not to exceed MAX_DEPTH.
+   *
+   * @return void
+   */
+  private static function __flatten( &$buffer, &$key, &$value, $depth ) {
+    if ( $depth >= self::MAX_DEPTH ) {
+      // exceeded maximum recursion depth
+      $buffer .= $key . PHP_EOL;
+      return;
+    }
+
+    if ( is_null( $value ) ) {
+      $buffer .= $key . ' null' . PHP_EOL;
+      return;
+    }
+
+    if ( is_bool( $value ) ) {
+      $buffer .= $key . ' ' . ( $value ? 'true' : 'false' ) . PHP_EOL;
+      return;
+    }
+
+    if ( is_scalar( $value ) ) {
+      $buffer .= $key . ' ' . (string) $value . PHP_EOL;
+      return;
+    }
+
+    if ( $value instanceof DateTime ) {
+      $buffer .= $key . '_iso '  . $value->format( 'r' ) . PHP_EOL;
+      $buffer .= $key . '_unix ' . $value->format( 'U' ) . PHP_EOL;
+      return;
+    }
+
+    if ( is_object( $value ) ) {
+      $keys = get_object_vars( $value );
+    } else {
+      $keys = &$value;
+    }
+
+    if ( empty( $keys ) ) {
+      $buffer .= $key . PHP_EOL;
+      return;
+    }
+
+    foreach ( $keys as $_key => $_value ) {
+      $__key = $key . self::DELIMITER . $_key;
+      self::__flatten( $buffer, $__key, $_value, $depth++ );
+    }
+  }
+
+}