callback_stream.h

#pragma once
 
#include <iostream>
#include <string>
 
#include <cgv/signal/signal.h>
 
namespace cgv {
    namespace signal {
 
struct callback_streambuf : public std::streambuf
{
    cgv::signal::signal<const std::string&>& write;
 
    callback_streambuf(cgv::signal::signal<const std::string&>& _write) : write(_write)
    {
    }
    std::streambuf *setbuf(char_type *buf, std::streamsize n)
    {
        setp(buf,buf+n-1);
        return this;
    }
    int_type overflow(int_type c)
    {
        if (c != std::char_traits<char>::eof()) {
            *pptr() = c;
            pbump(1);
        }
        int num = static_cast<int>(pptr()-pbase());
        std::string text(pbase(),num);
        write(text);
        pbump(-num);
        return c;
    }
    int sync()
    {
        int num = static_cast<int>(pptr()-pbase());
        std::string text(pbase(),num);
        write(text);
        pbump(-num);
        return num;
    }
};
 
class callback_stream : public std::ostream
{
protected:
    callback_streambuf buf;
    char buffer[256];
public:
    cgv::signal::signal<const std::string&> write;
    callback_stream() : std::ostream(0), buf(write)
    {
        buf.setbuf(buffer,256);
        init(&buf);
    }
};
 
    }
}