123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134 |
- /*
- * Copyright Andrey Semashev 2007 - 2015.
- * Distributed under the Boost Software License, Version 1.0.
- * (See accompanying file LICENSE_1_0.txt or copy at
- * http://www.boost.org/LICENSE_1_0.txt)
- */
- #include <cstddef>
- #include <string>
- #include <utility>
- #include <iostream>
- #include <boost/mpl/vector.hpp>
- #include <boost/log/attributes/value_extraction.hpp>
- #include <boost/log/attributes/attribute_value_impl.hpp>
- #include <boost/log/utility/value_ref.hpp>
- namespace logging = boost::log;
- namespace attrs = boost::log::attributes;
- //[ example_attr_value_extraction
- void print_value(logging::attribute_value const& attr)
- {
- // Extract a reference to the stored value
- logging::value_ref< int > val = logging::extract< int >(attr);
- // Check the result
- if (val)
- std::cout << "Extraction succeeded: " << val.get() << std::endl;
- else
- std::cout << "Extraction failed" << std::endl;
- }
- //]
- //[ example_attr_value_extraction_multiple_types
- void print_value_multiple_types(logging::attribute_value const& attr)
- {
- // Define the set of expected types of the stored value
- typedef boost::mpl::vector< int, std::string > types;
- // Extract a reference to the stored value
- logging::value_ref< types > val = logging::extract< types >(attr);
- // Check the result
- if (val)
- {
- std::cout << "Extraction succeeded" << std::endl;
- switch (val.which())
- {
- case 0:
- std::cout << "int: " << val.get< int >() << std::endl;
- break;
- case 1:
- std::cout << "string: " << val.get< std::string >() << std::endl;
- break;
- }
- }
- else
- std::cout << "Extraction failed" << std::endl;
- }
- //]
- //[ example_attr_value_extraction_visitor
- struct hash_visitor
- {
- typedef std::size_t result_type;
- result_type operator() (int val) const
- {
- std::size_t h = val;
- h = (h << 15) + h;
- h ^= (h >> 6) + (h << 7);
- return h;
- }
- result_type operator() (std::string const& val) const
- {
- std::size_t h = 0;
- for (std::string::const_iterator it = val.begin(), end = val.end(); it != end; ++it)
- h += *it;
- h = (h << 15) + h;
- h ^= (h >> 6) + (h << 7);
- return h;
- }
- };
- void hash_value(logging::attribute_value const& attr)
- {
- // Define the set of expected types of the stored value
- typedef boost::mpl::vector< int, std::string > types;
- // Extract the stored value
- logging::value_ref< types > val = logging::extract< types >(attr);
- // Check the result
- if (val)
- std::cout << "Extraction succeeded, hash value: " << val.apply_visitor(hash_visitor()) << std::endl;
- else
- std::cout << "Extraction failed" << std::endl;
- }
- //]
- #if 0
- //[ example_attr_value_extraction_visitor_rec
- void hash_value(logging::record_view const& rec, logging::attribute_name name)
- {
- // Define the set of expected types of the stored value
- typedef boost::mpl::vector< int, std::string > types;
- // Extract the stored value
- logging::value_ref< types > val = logging::extract< types >(name, rec);
- // Check the result
- if (val)
- std::cout << "Extraction succeeded, hash value: " << val.apply_visitor(hash_visitor()) << std::endl;
- else
- std::cout << "Extraction failed" << std::endl;
- }
- //]
- #endif
- int main(int, char*[])
- {
- print_value(attrs::make_attribute_value(10));
- print_value_multiple_types(attrs::make_attribute_value(10));
- print_value_multiple_types(attrs::make_attribute_value(std::string("Hello")));
- hash_value(attrs::make_attribute_value(10));
- hash_value(attrs::make_attribute_value(std::string("Hello")));
- return 0;
- }
|