////////////////////////////////////////////////////////////////////////////////
/// @brief utility functions for json objects
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2014 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// 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.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
/// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany
/// @author Copyright 2012-2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGODB_BASICS_JSON__UTILITIES_H
#define ARANGODB_BASICS_JSON__UTILITIES_H 1

#include "Basics/Common.h"
#include "Basics/json.h"

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// --SECTION--                                                  public functions
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////////////////////////////////////////////////////////////////////////////////
/// @brief compare two json values
///
/// the values are first compared by their types, and only by their values if
/// the types are the same
/// returns -1 if lhs is smaller than rhs, 0 if lhs == rhs, and 1 if rhs is
/// greater than lhs.
///
/// If useUTF8 is set to true, strings will be converted using proper UTF8,
/// otherwise, strcmp is used, so it should only be used to test for equality
/// in this case.
////////////////////////////////////////////////////////////////////////////////

int TRI_CompareValuesJson (TRI_json_t const*, 
                           TRI_json_t const*,
                           bool useUTF8 = true);

////////////////////////////////////////////////////////////////////////////////
/// @brief check if two json values are the same
////////////////////////////////////////////////////////////////////////////////

bool TRI_CheckSameValueJson (TRI_json_t const*, 
                             TRI_json_t const*);

////////////////////////////////////////////////////////////////////////////////
/// @brief uniquify a sorted json list into a new array
///
/// it is a prerequisite that the input list is already sorted.
/// otherwise the result is unpredictable.
////////////////////////////////////////////////////////////////////////////////

TRI_json_t* TRI_UniquifyArrayJson (TRI_json_t const*);

////////////////////////////////////////////////////////////////////////////////
/// @brief sorts a json array in place
////////////////////////////////////////////////////////////////////////////////

TRI_json_t* TRI_SortArrayJson (TRI_json_t*);

////////////////////////////////////////////////////////////////////////////////
/// @brief checks if a JSON struct has duplicate attribute names
////////////////////////////////////////////////////////////////////////////////

bool TRI_HasDuplicateKeyJson (TRI_json_t const*);

////////////////////////////////////////////////////////////////////////////////
/// @brief merge two JSON documents into one
////////////////////////////////////////////////////////////////////////////////

TRI_json_t* TRI_MergeJson (TRI_memory_zone_t*,
                           TRI_json_t const*,
                           TRI_json_t const*,
                           bool,
                           bool);

////////////////////////////////////////////////////////////////////////////////
/// @brief compute a hash value for a JSON document.
////////////////////////////////////////////////////////////////////////////////

uint64_t TRI_HashJson (TRI_json_t const* json);

////////////////////////////////////////////////////////////////////////////////
/// @brief compute a hash value for a JSON document, using fasthash64.
/// This is slightly faster than the FNV-based hashing
////////////////////////////////////////////////////////////////////////////////

uint64_t TRI_FastHashJson (TRI_json_t const* json);

////////////////////////////////////////////////////////////////////////////////
/// @brief compute a hash value for a JSON document depending on a list
/// of attributes.
////////////////////////////////////////////////////////////////////////////////

uint64_t TRI_HashJsonByAttributes (TRI_json_t const* json,
                                   char const *attributes[],
                                   int nrAttributes,
                                   bool docComplete,
                                   int* error);

////////////////////////////////////////////////////////////////////////////////
/// @brief hasher for JSON value
////////////////////////////////////////////////////////////////////////////////

namespace triagens {
  namespace basics {

    struct JsonHash {
      inline size_t operator() (TRI_json_t const* value) const {
        return TRI_FastHashJson(value);
      }
    };

////////////////////////////////////////////////////////////////////////////////
/// @brief equality comparator for JSON values
////////////////////////////////////////////////////////////////////////////////

    struct JsonEqual {    
      inline bool operator() (TRI_json_t const* lhs,
                              TRI_json_t const* rhs) const {

        return (TRI_CompareValuesJson(lhs, rhs, false) == 0);
      }
    };

////////////////////////////////////////////////////////////////////////////////
/// @brief less comparator for JSON values
////////////////////////////////////////////////////////////////////////////////

    template<bool useUtf8>
    struct JsonLess {    
      inline bool operator() (TRI_json_t const* lhs,
                              TRI_json_t const* rhs) const {

        return TRI_CompareValuesJson(lhs, rhs, useUtf8) < 0;
      }
    };

  }
}

#endif

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