text: // util/base64.h
  
  /*    Copyright 2009 10gen Inc.
   *
   *    This program is free software: you can redistribute it and/or  modify
   *    it under the terms of the GNU Affero General Public License, version 3,
   *    as published by the Free Software Foundation.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    GNU Affero General Public License for more details.
   *
   *    You should have received a copy of the GNU Affero General Public License
   *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
   *
   *    As a special exception, the copyright holders give permission to link the
   *    code of portions of this program with the OpenSSL library under certain
   *    conditions as described in each individual source file and distribute
   *    linked combinations including the program with the OpenSSL library. You
   *    must comply with the GNU Affero General Public License in all respects
   *    for all of the code used other than as permitted herein. If you modify
   *    file(s) with this exception, you may extend this exception to your
   *    version of the file(s), but you are not obligated to do so. If you do not
   *    wish to do so, delete this exception statement from your version. If you
   *    delete this exception statement from all source files in the program,
   *    then also delete it in the license file.
   */
  
  #pragma once
  
  #include <sstream>
  #include <string>
  
  #include "mongo/base/string_data.h"
  
  namespace mongo {
  namespace base64 {
  
  void encode(std::stringstream& ss, const char* data, int size);
  std::string encode(const char* data, int size);
  std::string encode(const std::string& s);
  
  void decode(std::stringstream& ss, const std::string& s);
  std::string decode(const std::string& s);
  
  bool validate(StringData);
  
  /**
   * Calculate how large a given input would expand to.
   * Effectively: ceil(inLen * 4 / 3)
   */
  constexpr size_t encodedLength(size_t inLen) {
      return static_cast<size_t>((inLen + 2.5) / 3) * 4;
  }
  
  }  // namespace base64
  }  // namespace mongo
  