// Copyright (C) 2009-2015 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef BASE64_H
#define BASE64_H 1

#include <stdint.h>
#include <string>
#include <vector>

//
// Note: this helper module isn't specific to the DNS protocol per se.
// We should probably move this to somewhere else, possibly in some common
// utility area.
//

namespace isc {
namespace util {
namespace encode {

/// \brief Encode binary data in the base64 format.
///
/// This function returns a new \c std::string object that stores a text
/// encoded in the base64 format for the given \c binary %data.
/// The resulting string will be a valid, canonical form of base64
/// representation as specified in RFC4648.
///
/// If memory allocation for the returned string fails, a corresponding
/// standard exception will be thrown.  This function never throws exceptions
/// otherwise.
///
/// \param binary A vector object storing the data to be encoded. 
/// \return A newly created string that stores base64 encoded value for binary.
std::string encodeBase64(const std::vector<uint8_t>& binary);

/// \brief Decode a text encoded in the base64 format into the original %data.
///
/// The \c input argument must be a valid string represented in the base64
/// format as specified in RFC4648.  Space characters (spaces, tabs, newlines)
/// can be included in \c input and will be ignored.  Without spaces, the
/// length of string must be a multiple of 4 bytes with necessary paddings.
/// Also it must be encoded using the canonical encoding (see RFC4648).
/// If any of these conditions is not met, an exception of class
/// \c isc::BadValue will be thrown.
///
/// If \c result doesn't have sufficient capacity to store all decoded %data
/// and memory allocation fails, a corresponding standard exception will be
/// thrown.  If the caller knows the necessary length (which can in theory
/// be calculated from the input string), this situation can be avoided by
/// reserving sufficient space for \c result beforehand.
///
/// Any existing %data in \c result will be removed.  This is the case in some
/// of the cases where an exception is thrown; that is, this function only
/// provides the basic exception guarantee.
///
/// \param input A text encoded in the base64 format.
/// \param result A vector in which the decoded %data is to be stored.
void decodeBase64(const std::string& input, std::vector<uint8_t>& result);

} // namespace encode
} // namespace util
} // namespace isc

#endif  // BASE64_H

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