我试图在Boost :: iostreams文档中遵循有限状态过滤器的示例。但是当我去使用过滤器我得到一个错误,指出:: imbue不可访问,因为'boost :: iostreams :: detail :: finite_state_filter_impl'使用'protected'从'my_fsm'继承。使用Boost :: iostreams两用过滤器
沮丧我将我的代码复制到boost示例中使用的测试中。测试编译并通过。我的结论是我可能错误地使用了以下定义的双重使用过滤器:
typedef io :: finite_state_filter my_fsm_filter;
我觉得只是推到一个filtered_stream可能不正确,但我找不到一个缺失的步骤。我相信肯定有必要包装过滤器,但是我没有找到任何示例(尽管我确信如果我深入探究用于测试升级代码的代码,它必须在某处)。
这里是一个位的示例代码:
#include <boost/mpl/vector.hpp>
#include <libs/iostreams/example/finite_state_filter.hpp>
namespace io = boost::iostreams;
struct my_fsm : io::finite_state_machine<my_fsm> {
BOOST_IOSTREAMS_FSM(my_fsm) // define skip and push.
typedef my_fsm self;
static const int beginline = 0;
static const int skipline = 1;
static const int dataline = 2;
typedef boost::mpl::vector <
row<beginline, is<'C'>, skipline, &self::skip>,
row<beginline, is_any, dataline, &self::push>,
row<skipline, is<'\n'>, beginline, &self::skip>,
row<skipline, is_any, skipline, &self::skip>,
row<dataline, is<'\n'>, beginline, &self::push>,
row<dataline, is_any, dataline, &self::push>
> transition_table;
};
typedef io::finite_state_filter<my_fsm> my_fsm_filter;
#include <iostream>
#include <string>
#include <boost/iostreams/device/file.hpp>
#include <boost/iostreams/filtering_stream.hpp>
#include <boost/iostreams/stream.hpp>
namespace io = boost::iostreams;
int main() {
io::stream<io::file_sink> out(io::file_sink("outputfile.txt"));
io::filtering_istream in;
my_fsm_filter infsm;
in.push(my_fsm_filter());
in.push(io::file_source("inputdata.txt"));
while (in) {
std::string line;
if(std::getline(in, line)) {
//std::cout << line << std::endl;
out << line << std::endl;
}
}
return 0;
}