ceph/src/boost/libs/property_tree/examples/custom_data_type.cpp

   1 // ----------------------------------------------------------------------------
   2 // Copyright (C) 2002-2006 Marcin Kalicinski
   3 //
   4 // Distributed under the Boost Software License, Version 1.0.
   5 // (See accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt)
   7 //
   8 // For more information, see www.boost.org
   9 // ----------------------------------------------------------------------------
  10
  11 // This example shows what need to be done to customize data_type of ptree.
  12 //
  13 // It creates my_ptree type, which is a basic_ptree having boost::any as its data
  14 // container (instead of std::string that standard ptree has).
  15
  16 #include <boost/property_tree/ptree.hpp>
  17 #include <boost/any.hpp>
  18 #include <list>
  19 #include <string>
  20 #include <iostream>
  21
  22 // Custom translator that works with boost::any instead of std::string
  23 template <class Ext, class Int = boost::any>
  24 struct variant_translator
  25 {
  26     typedef Ext external_type;
  27     typedef Int internal_type;
  28
  29     external_type
  30     get_value(const internal_type &value) const
  31     {
  32         return boost::any_cast<external_type>(value);
  33     }
  34     internal_type
  35     put_value(const external_type &value) const
  36     {
  37         return value;
  38     }
  39 };
  40
  41 int main()
  42 {
  43
  44     using namespace boost::property_tree;
  45
  46     // Property_tree with boost::any as data type
  47     // Key type:        std::string
  48     // Data type:       boost::any
  49     // Key comparison:  default (std::less<std::string>)
  50     typedef basic_ptree<std::string, boost::any> my_ptree;
  51     my_ptree pt;
  52
  53     // Put/get int value
  54     typedef variant_translator<int> int_tran;
  55     pt.put("int value", 3, int_tran());
  56     int int_value = pt.get<int>("int value", int_tran());
  57     std::cout << "Int value: " << int_value << "\n";
  58
  59     // Put/get string value
  60     typedef variant_translator<std::string> string_tran;
  61     pt.put<std::string>("string value", "foo bar", string_tran());
  62     std::string string_value = pt.get<std::string>(
  63         "string value"
  64       , string_tran()
  65     );
  66     std::cout << "String value: " << string_value << "\n";
  67
  68     // Put/get list<int> value
  69     typedef std::list<int> intlist;
  70     typedef variant_translator<intlist> intlist_tran;
  71     int list_data[] = { 1, 2, 3, 4, 5 };
  72     pt.put<intlist>(
  73         "list value"
  74       , intlist(
  75             list_data
  76           , list_data + sizeof(list_data) / sizeof(*list_data)
  77         )
  78       , intlist_tran()
  79     );
  80     intlist list_value = pt.get<intlist>(
  81         "list value"
  82       , intlist_tran()
  83     );
  84     std::cout << "List value: ";
  85     for (intlist::iterator it = list_value.begin(); it != list_value.end(); ++it)
  86         std::cout << *it << ' ';
  87     std::cout << '\n';
  88 }