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//
// Copyright (c) 2021 Dmitry Arkhipov (grisumbras@gmail.com)
//
// 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)
//
// Official repository: https://github.com/boostorg/json
//
// tag::doc_forward_conversion_1[]
namespace boost {
namespace json {
class value;
struct value_from_tag;
template< class T >
struct try_value_to_tag;
template< class T1, class T2 >
struct result_for;
template< class T >
void value_from( T&& t, value& jv );
template< class T >
typename result_for< T, value >::type
try_value_to( const value& jv );
}
}
// end::doc_forward_conversion_1[]
// tag::doc_forward_conversion_3[]
namespace boost {
namespace json {
class value;
struct value_from_tag;
template< class T >
struct try_value_to_tag;
template< class T1, class T2 >
struct result_for;
template< class T, class Context >
void value_from( T&& t, value& jv, const Context& ctx );
template< class T, class Context >
typename result_for< T, value >::type
try_value_to( const value& jv, const Context& ctx );
}
}
// end::doc_forward_conversion_3[]
#include "doc_types.hpp"
#include <system_error>
// tag::doc_forward_conversion_2[]
namespace user_ns
{
template< class JsonValue >
void tag_invoke(
const boost::json::value_from_tag&, JsonValue& jv, const ip_address& addr )
{
const unsigned char* b = addr.begin();
jv = { b[0], b[1], b[2], b[3] };
}
template< class JsonValue >
typename boost::json::result_for< ip_address, JsonValue >::type
tag_invoke(
const boost::json::try_value_to_tag< ip_address >&,
const JsonValue& jv )
{
using namespace boost::json;
if( !jv.is_array() )
return make_error_code( std::errc::invalid_argument );
auto const& arr = jv.get_array();
if( arr.size() != 4 )
return make_error_code( std::errc::invalid_argument );
auto oct1 = try_value_to< unsigned char >( arr[0] );
if( !oct1 )
return make_error_code( std::errc::invalid_argument );
auto oct2 = try_value_to< unsigned char >( arr[1] );
if( !oct2 )
return make_error_code( std::errc::invalid_argument );
auto oct3 = try_value_to< unsigned char >( arr[2] );
if( !oct3 )
return make_error_code( std::errc::invalid_argument );
auto oct4 = try_value_to< unsigned char >( arr[3] );
if( !oct4 )
return make_error_code( std::errc::invalid_argument );
return ip_address{ *oct1, *oct2, *oct3, *oct4 };
}
}
// end::doc_forward_conversion_2[]
// tag::doc_forward_conversion_3[]
namespace user_ns
{
struct as_string
{ };
template< class JsonValue >
void
tag_invoke(
const boost::json::value_from_tag&, JsonValue& jv,
const ip_address& addr,
const as_string& )
{
auto& js = jv.emplace_string();
js.resize( 4 * 3 + 3 + 1 ); // XXX.XXX.XXX.XXX\0
auto it = addr.begin();
auto n = std::snprintf(
js.data(), js.size(), "%hhu.%hhu.%hhu.%hhu", it[0], it[1], it[2], it[3] );
js.resize(n);
}
template< class JsonValue >
typename boost::json::result_for< ip_address, JsonValue >::type
tag_invoke(
const boost::json::try_value_to_tag< ip_address >&,
const JsonValue& jv,
const as_string& )
{
const auto* js = jv.if_string();
if( ! js )
return make_error_code( std::errc::invalid_argument );
unsigned char octets[4];
int result = std::sscanf(
js->data(), "%hhu.%hhu.%hhu.%hhu", octets, octets + 1, octets + 2, octets + 3 );
if( result != 4 )
return make_error_code( std::errc::invalid_argument );
return ip_address( octets[0], octets[1], octets[2], octets[3] );
}
}
// end::doc_forward_conversion_3[]
#include <boost/json/value_from.hpp>
#include <boost/json/value_to.hpp>
#include "test_suite.hpp"
namespace boost {
namespace json {
class doc_forward_conversion
{
public:
void
run()
{
value jv{ 212, 115, 81, 22 };
auto const addr = value_to< user_ns::ip_address >( jv );
BOOST_TEST( get<0>(addr) == 212 );
BOOST_TEST( get<1>(addr) == 115 );
BOOST_TEST( get<2>(addr) == 81 );
BOOST_TEST( get<3>(addr) == 22 );
value const jv2 = value_from( addr );
BOOST_TEST( jv == jv2 );
jv = value_from( addr, user_ns::as_string() );
BOOST_TEST( jv.is_string() );
string const& js = jv.get_string();
BOOST_TEST( js == "212.115.81.22" );
auto const addr2 = value_to< user_ns::ip_address >(
jv, user_ns::as_string() );
BOOST_TEST( get<0>(addr2) == 212 );
BOOST_TEST( get<1>(addr2) == 115 );
BOOST_TEST( get<2>(addr2) == 81 );
BOOST_TEST( get<3>(addr2) == 22 );
}
};
TEST_SUITE(doc_forward_conversion, "boost.json.doc_forward_conversion");
} // namespace json
} // namespace boost
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