json.h

/* Copyright 2011 Eeli Reilin. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, 
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation 
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ''AS IS'' AND ANY EXPRESS OR 
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 
 * EVENT SHALL EELI REILIN OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation 
 * are those of the authors and should not be interpreted as representing 
 * official policies, either expressed or implied, of Eeli Reilin.
 */

/**
 * \file json.h
 */

#ifndef JSON_H
#define JSON_H

#include <QVariant>
#include <QString>

namespace QtJson
{

/**
 * \enum JsonToken
 */
enum JsonToken
{
        JsonTokenNone = 0,
        JsonTokenCurlyOpen = 1,
        JsonTokenCurlyClose = 2,
        JsonTokenSquaredOpen = 3,
        JsonTokenSquaredClose = 4,
        JsonTokenColon = 5,
        JsonTokenComma = 6,
        JsonTokenString = 7,
        JsonTokenNumber = 8,
        JsonTokenTrue = 9,
        JsonTokenFalse = 10,
        JsonTokenNull = 11
};

/**
 * \class Json
 * \brief A JSON data parser
 *
 * Json parses a JSON data into a QVariant hierarchy.
 */
class Json
{
        public:
                /**
                 * Parse a JSON string
                 *
                 * \param json The JSON data
                 */
                static QVariant parse(const QString &json);

                /**
                 * Parse a JSON string
                 *
                 * \param json The JSON data
                 * \param success The success of the parsing
                 */
                static QVariant parse(const QString &json, bool &success);

                /**
                * This method generates a textual JSON representation
                *
                * \param data The JSON data generated by the parser.
                * \param success The success of the serialization
                */
                static QByteArray serialize(const QVariant &data);

                /**
                * This method generates a textual JSON representation
                *
                * \param data The JSON data generated by the parser.
                * \param success The success of the serialization
                *
                * \return QByteArray Textual JSON representation
                */
                static QByteArray serialize(const QVariant &data, bool &success);

        private:
                /**
                 * Parses a value starting from index
                 *
                 * \param json The JSON data
                 * \param index The start index
                 * \param success The success of the parse process
                 *
                 * \return QVariant The parsed value
                 */
                static QVariant parseValue(const QString &json, int &index,
                                                                   bool &success);

                /**
                 * Parses an object starting from index
                 *
                 * \param json The JSON data
                 * \param index The start index
                 * \param success The success of the object parse
                 *
                 * \return QVariant The parsed object map
                 */
                static QVariant parseObject(const QString &json, int &index,
                                                                           bool &success);

                /**
                 * Parses an array starting from index
                 *
                 * \param json The JSON data
                 * \param index The starting index
                 * \param success The success of the array parse
                 *
                 * \return QVariant The parsed variant array
                 */
                static QVariant parseArray(const QString &json, int &index,
                                                                           bool &success);

                /**
                 * Parses a string starting from index
                 *
                 * \param json The JSON data
                 * \param index The starting index
                 * \param success The success of the string parse
                 *
                 * \return QVariant The parsed string
                 */
                static QVariant parseString(const QString &json, int &index,
                                                                        bool &success);

                /**
                 * Parses a number starting from index
                 *
                 * \param json The JSON data
                 * \param index The starting index
                 *
                 * \return QVariant The parsed number
                 */
                static QVariant parseNumber(const QString &json, int &index);

                /**
                 * Get the last index of a number starting from index
                 *
                 * \param json The JSON data
                 * \param index The starting index
                 *
                 * \return The last index of the number
                 */
                static int lastIndexOfNumber(const QString &json, int index);

                /**
                 * Skip unwanted whitespace symbols starting from index
                 *
                 * \param json The JSON data
                 * \param index The start index
                 */
                static void eatWhitespace(const QString &json, int &index);

                /**
                 * Check what token lies ahead
                 *
                 * \param json The JSON data
                 * \param index The starting index
                 *
                 * \return int The upcoming token
                 */
                static int lookAhead(const QString &json, int index);

                /**
                 * Get the next JSON token
                 *
                 * \param json The JSON data
                 * \param index The starting index
                 *
                 * \return int The next JSON token
                 */
                static int nextToken(const QString &json, int &index);
};


} //end namespace

#endif //JSON_H