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Pods/Realm/include/core/realm/util/base64.hpp 3.05 KB
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  /*************************************************************************
   *
   * Copyright 2016 Realm 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.
   *
   **************************************************************************/
  
  #ifndef REALM_UTIL_BASE64_HPP
  #define REALM_UTIL_BASE64_HPP
  
  #include <vector>
  #include <realm/string_data.hpp>
  #include <realm/util/optional.hpp>
  
  namespace realm {
  namespace util {
  
  
  /// base64_encode() encodes the bnary data in \param in_buffer of size \param in_buffer_size .
  /// The encoded data is placed in \param out_buffer . The size of \param \out_buffer is passed in
  /// \param out_buffer_size . The output buffer out_buffer must be
  /// large enough to hold the base64 encoded data. The size can be obtained from the function
  /// base64_encoded_size. out_buffer_size is only used to assert that the output buffer is
  /// large enough.
  size_t base64_encode(const char *in_buffer, size_t in_buffer_size, char* out_buffer, size_t out_buffer_size) noexcept;
  
  /// base64_encoded_size() returns the exact size of the base64 encoded
  /// data as a function of the size of the input data.
  inline size_t base64_encoded_size(size_t in_buffer_size) noexcept
  {
      return 4 * ((in_buffer_size + 2) / 3);
  }
  
  
  /// Decode base64-encoded string in input, and places the result in out_buffer.
  /// The length of the out_buffer must be at least 3 * input.size() / 4.
  ///
  /// The input must be padded base64 (i.e. the number of non-whitespace
  /// characters in the input must be a multiple of 4). Whitespace (spaces, tabs,
  /// newlines) is ignored.
  ///
  /// The algorithm stops when the first character not in the base64 character
  /// set is encountered, or when the end of the input is reached.
  ///
  /// \returns the number of successfully decoded bytes written to out_buffer, or
  /// none if the whole input was not valid base64.
  Optional<size_t> base64_decode(StringData input, char* out_buffer, size_t out_buffer_len) noexcept;
  
  /// Return an upper bound on the decoded size of a Base64-encoded data
  /// stream of length \a base64_size. The returned value is suitable for
  /// allocation of buffers containing decoded data.
  inline size_t base64_decoded_size(size_t base64_size) noexcept
  {
      return (base64_size * 3 + 3) / 4;
  }
  
  
  
  /// base64_decode_to_vector() is a convenience function that decodes \param
  /// encoded and returns the result in a std::vector<char> with the correct size.
  /// This function returns none if the input is invalid.
  Optional<std::vector<char>> base64_decode_to_vector(StringData encoded);
  
  } // namespace util
  } // namespace realm
  
  #endif // REALM_UTIL_BASE64_HPP