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/*
Ousía
Copyright (C) 2014, 2015 Benjamin Paaßen, Andreas Stöckel
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _OUSIA_VARIANT_CONVERTER_HPP_
#define _OUSIA_VARIANT_CONVERTER_HPP_
namespace ousia {
// Forward declaration
class Logger;
class RttiBase;
class Variant;
enum class VariantType : int16_t;
/**
* The VariantConverter class is used to convert a variant to a certain
* prespecified type. The functions ensure that the variant has the requested
* type, even if the conversion fails.
*/
class VariantConverter {
public:
/**
* Enumeration used to define the mode of conversion -- either only safe
* conversions (without any data loss) are performed, or all possible
* conversions are tried (with possible data loss).
*/
enum class Mode { SAFE, ALL };
/**
* Converts the given variant to a boolean. If the "mode" parameter is set
* to Mode::SAFE, only booleans can be converted to booleans. For all other
* types the conversion fails. If "mode" is set to Mode::ALL, nullptr
* values and zero numeric values are treated as "false", all other values
* are treated as "true".
*
* @param var is instance of the Variant class that should be converted to
* the requested type.
* @param logger is a reference to the logger instance into which messages
* should be logged.
* @param mode is the conversion mode. See method description for the exact
* effect.
*/
static bool toBool(Variant &var, Logger &logger, Mode mode = Mode::SAFE);
/**
* Converts the given variant to an integer. If the "mode" parameter is set
* to Mode::SAFE, only integers can be converted to integers. For all other
* types the conversion fails. If "mode" is set to Mode::ALL, booleans are
* converted to 0, 1, nullptr is converted to 0, doubles are truncated,
* strings are parsed and truncated, arrays with one element are converted
* to an integer. Conversion fails for objects, functions, maps and arrays
* with zero or more than one entry.
*
* @param var is instance of the Variant class that should be converted to
* the requested type.
* @param logger is a reference to the logger instance into which messages
* should be logged.
* @param mode is the conversion mode. See method description for the exact
* effect.
*/
static bool toInt(Variant &var, Logger &logger, Mode mode = Mode::SAFE);
/**
* Converts the given variant to a double. If the "mode" parameter is set
* to Mode::SAFE, only integers and doubles can be converted to doubles. For
* all other types the conversion fails. If "mode" is set to Mode::ALL,
* booleans are converted to 0.0, 1.0, nullptr is converted to 0.0, strings
* are parsed, arrays with one element are converted to a double.
* Conversion fails for objects, functions, maps and arrays with zero or
* more than one entry.
*
* @param var is instance of the Variant class that should be converted to
* the requested type.
* @param logger is a reference to the logger instance into which messages
* should be logged.
* @param mode is the conversion mode. See method description for the exact
* effect.
*/
static bool toDouble(Variant &var, Logger &logger, Mode mode = Mode::SAFE);
/**
* Converts the given variant to a double. If the "mode" parameter is set
* to Mode::SAFE, all primitive types can be converted to strings. For
* all other types the conversion fails. If "mode" is set to Mode::ALL,
* maps and arrays are converted to a JSON representation, objects and
* functions are converted to an informative string containing their pointer
* and type.
*
* @param var is instance of the Variant class that should be converted to
* the requested type.
* @param logger is a reference to the logger instance into which messages
* should be logged.
* @param mode is the conversion mode. See method description for the exact
* effect.
*/
static bool toString(Variant &var, Logger &logger, Mode mode = Mode::SAFE);
static bool convert(Variant &var, VariantType requestedType,
const RttiBase &rttiType, Logger &logger,
Mode mode = Mode::SAFE);
static bool convert(Variant &var, VariantType requestedType,
Logger &logger, Mode mode = Mode::SAFE);
};
}
#endif /* _OUSIA_VARIANT_CONVERTER_HPP_ */
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