generate_helper.hpp

#pragma once
 
#include "telnetpp/element.hpp"
 
namespace telnetpp::detail {
 
//* =========================================================================
//* =========================================================================
template <class Continuation>
constexpr void generate_escaped(telnetpp::bytes data, Continuation &&cont)
{
    telnetpp::bytes::iterator begin = data.begin();
    telnetpp::bytes::iterator current = data.begin();
    telnetpp::bytes::iterator end = data.end();
 
    // If we come across an 0xFF byte in the data, then it must be repeated.
    // We do this by splitting the span into two, one of which ends with the
    // 0xFF byte and the second that begins with it.  In this way, the byte is
    // duplicated without requiring any extra allocations.
    while (current != end)
    {
        if (*current == telnetpp::iac)
        {
            cont({begin, current + 1});
            begin = current;
        }
 
        ++current;
    }
 
    if (begin != end)
    {
        cont({begin, end});
    }
}
 
//* =========================================================================
//* =========================================================================
template <class Continuation>
constexpr void generate_command(telnetpp::command cmd, Continuation &&cont)
{
    telnetpp::byte const data[] = {telnetpp::iac, cmd.value()};
 
    cont(data);
}
 
//* =========================================================================
//* =========================================================================
template <class Continuation>
constexpr void generate_negotiation(
    telnetpp::negotiation neg, Continuation &&cont)
{
    telnetpp::byte const data[] = {
        telnetpp::iac, neg.request(), neg.option_code()};
 
    cont(data);
}
 
//* =========================================================================
//* =========================================================================
template <class Continuation>
constexpr void generate_subnegotiation(
    telnetpp::subnegotiation sub, Continuation &&cont)
{
    telnetpp::byte const preamble[] = {
        telnetpp::iac, telnetpp::sb, sub.option()};
 
    constexpr telnetpp::byte const postamble[] = {telnetpp::iac, telnetpp::se};
 
    cont(preamble);
    generate_escaped(sub.content(), cont);
    cont(postamble);
}
 
}  // namespace telnetpp::detail