NumberVisitor.h

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/*
 * Copyright 2009 Savarese Software Research Corporation
 *
 * 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
 *
 *     https://www.savarese.com/software/ApacheLicense-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 __SSRC_WSPR_UTILITY_NUMBER_VISITOR_H
#define __SSRC_WSPR_UTILITY_NUMBER_VISITOR_H

#include <ssrc/wispers/utility/Properties.h>

__BEGIN_NS_SSRC_WSPR_UTILITY

template<typename T>
class NumberVisitor : public boost::static_visitor<void> {
  mutable T _value;

public:

  NumberVisitor(T value) : _value(value) { }

  const T get() const {
    return _value;
  }

  void operator()(bool v) const {
    _value = v;
  }

  void operator()(std::int32_t v) const {
    _value = v;
  }

  void operator()(std::uint32_t v) const {
    _value = v;
  }

  void operator()(std::int64_t v) const {
    _value = v;
  }

  void operator()(std::uint64_t v) const {
    _value = v;
  }

  void operator()(double v) const {
    _value = v;
  }

  template<typename V>
  void operator()(V & v) const { }
};

template<typename T, typename V>
const T get_number(const V & variant,
                   const T & default_value = T())
{
  NumberVisitor<T> nv(default_value);
  boost::apply_visitor(nv, variant);
  return nv.get();
}

template<typename T>
const T get_number(const Properties & properties,
                   const T & default_value = T())
{
  if(properties.is_null())
    return default_value;
  return get_number(*properties.value(), default_value);
}

template<typename T, typename... P>
const T get_number(const Properties & properties,
                   const T & default_value,
                   const P & ...p)
{
  const Properties *node = properties.find(p...);

  if(node != 0)
    return get_number(*node, default_value);

  return default_value;
}

__END_NS_SSRC_WSPR_UTILITY

#endif