<?php
/*
 * Copyright 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Collection of static utility methods used for convenience across
 * the client library.
 *
 * @author Chirag Shah <chirags@google.com>
 */
class Google_Utils {
  public static function urlSafeB64Encode($data) {
    $b64 = base64_encode($data);
    $b64 = str_replace(array('+', '/', '\r', '\n', '='),
                       array('-', '_'),
                       $b64);
    return $b64;
  }

  public static function urlSafeB64Decode($b64) {
    $b64 = str_replace(array('-', '_'),
                       array('+', '/'),
                       $b64);
    return base64_decode($b64);
  }

  /**
   * Misc function used to count the number of bytes in a post body, in the world of multi-byte chars
   * and the unpredictability of strlen/mb_strlen/sizeof, this is the only way to do that in a sane
   * manner at the moment.
   *
   * This algorithm was originally developed for the
   * Solar Framework by Paul M. Jones
   *
   * @link   http://solarphp.com/
   * @link   http://svn.solarphp.com/core/trunk/Solar/Json.php
   * @link   http://framework.zend.com/svn/framework/standard/trunk/library/Zend/Json/Decoder.php
   * @param  string $str
   * @return int The number of bytes in a string.
   */
  static public function getStrLen($str) {
    $strlenVar = strlen($str);
    $d = $ret = 0;
    for ($count = 0; $count < $strlenVar; ++ $count) {
      $ordinalValue = ord($str{$ret});
      switch (true) {
        case (($ordinalValue >= 0x20) && ($ordinalValue <= 0x7F)):
          // characters U-00000000 - U-0000007F (same as ASCII)
          $ret ++;
          break;

        case (($ordinalValue & 0xE0) == 0xC0):
          // characters U-00000080 - U-000007FF, mask 110XXXXX
          // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
          $ret += 2;
          break;

        case (($ordinalValue & 0xF0) == 0xE0):
          // characters U-00000800 - U-0000FFFF, mask 1110XXXX
          // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
          $ret += 3;
          break;

        case (($ordinalValue & 0xF8) == 0xF0):
          // characters U-00010000 - U-001FFFFF, mask 11110XXX
          // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
          $ret += 4;
          break;

        case (($ordinalValue & 0xFC) == 0xF8):
          // characters U-00200000 - U-03FFFFFF, mask 111110XX
          // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
          $ret += 5;
          break;

        case (($ordinalValue & 0xFE) == 0xFC):
          // characters U-04000000 - U-7FFFFFFF, mask 1111110X
          // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
          $ret += 6;
          break;
        default:
          $ret ++;
      }
    }
    return $ret;
  }

  /**
   * Normalize all keys in an array to lower-case.
   * @param array $arr
   * @return array Normalized array.
   */
  public static function normalize($arr) {
    if (!is_array($arr)) {
      return array();
    }

    $normalized = array();
    foreach ($arr as $key => $val) {
      $normalized[strtolower($key)] = $val;
    }
    return $normalized;
  }
}