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#ifndef APT_HELPER_TEESTREAM_H
#define APT_HELPER_TEESTREAM_H
/* 'basic' implementation of a streambuf which passes the output
to two 'real' streambufs emulating '| tee' on the shell
The main use is streaming debug output to std::clog as well as
a logfile easily, so don't expect that to be a bulletproof
implementation. */
#include <apt-pkg/macros.h>
#include <iostream>
template <typename CharT, typename Traits = std::char_traits<CharT>
> class basic_teebuf: public std::basic_streambuf<CharT, Traits>
{
public:
basic_teebuf(std::basic_streambuf<CharT, Traits> * const sb1,
std::basic_streambuf<CharT, Traits> * const sb2)
: s1(sb1), s2(sb2) {}
protected:
virtual std::streamsize xsputn(const CharT* s, std::streamsize c) override
{
return s2->sputn(s, s1->sputn(s, c));
}
// overflow is the fallback of sputc which is non-virtual
typedef typename Traits::int_type int_type;
int_type overflow(int_type ch = Traits::eof()) override
{
auto const eof = Traits::eof();
if (Traits::eq_int_type(ch, Traits::eof()) == true)
return eof;
auto const r1 = s1->sputc(Traits::to_char_type(ch));
auto const r2 = s2->sputc(Traits::to_char_type(ch));
return Traits::eq_int_type(r1, eof) ? r1: r2;
}
void imbue(const std::locale& loc) override
{
s1->pubimbue(loc);
s2->pubimbue(loc);
}
int sync() override
{
auto const r1 = s1->pubsync();
auto const r2 = s2->pubsync();
return r1 == 0 ? r2 : r1;
}
private:
std::basic_streambuf<CharT, Traits> * const s1;
std::basic_streambuf<CharT, Traits> * const s2;
};
template <typename CharT, typename Traits = std::char_traits<CharT>
> class basic_teeostream: public std::basic_ostream<CharT, Traits>
{
public:
basic_teeostream(std::basic_ostream<CharT, Traits> &o1, std::basic_ostream<CharT, Traits> &o2) :
std::basic_ostream<CharT, Traits>(&tbuf), tbuf(o1.rdbuf(), o2.rdbuf()) {}
private:
basic_teebuf<CharT, Traits> tbuf;
};
#endif
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