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module;
#include <algorithm>
#include <boost/sml.hpp>
#include <span>
#include <string>
#include <vector>
export module ttwhy.scanners:ansi;
import :events;
namespace ttwhy::scanners::detail
{
/// Events
struct byte_received
{
char value;
};
struct timeout_expired
{
};
/// States
constexpr auto idle = boost::sml::state<class idle>;
constexpr auto escape_sequence = boost::sml::state<class escape_sequence>;
constexpr auto csi_sequence = boost::sml::state<class csi_sequence>;
constexpr auto ss3_sequence = boost::sml::state<class ss3_sequence>;
/// Actions
constexpr auto push_character = [](byte_received const & event, std::vector<input_event> & queue) {
queue.push_back(character_event{event.value});
};
constexpr auto push_backspace = [](std::vector<input_event> & queue) {
queue.push_back(control_event{control_key::backspace});
};
constexpr auto push_tab = [](std::vector<input_event> & queue) {
queue.push_back(control_event(control_key::tab));
};
constexpr auto push_enter = [](std::vector<input_event> & queue) {
queue.push_back(control_event(control_key::enter));
};
constexpr auto emit_timeout_escape = [](std::vector<input_event> & queue, std::string & buffer) {
queue.push_back(control_event{control_key::escape});
buffer.clear();
};
constexpr auto fallback_escape = [](byte_received const & event, std::vector<input_event> & queue) {
queue.push_back(control_event{control_key::escape});
if (event.value >= 0x20 && event.value <= 0x7e)
{
queue.push_back(character_event{event.value});
}
};
constexpr auto clear_csi = [](std::string & buffer) {
buffer.clear();
};
constexpr auto push_csi_parameter = [](byte_received const & event, std::string & buffer) {
buffer.push_back(event.value);
};
constexpr auto resolve_csi = [](byte_received const & event, std::string & buffer, std::vector<input_event> & queue) {
if (event.value == '~')
{
switch (buffer.at(0))
{
case '1':
case '7':
queue.push_back(navigation_event{navigation_key::home});
break;
case '2':
queue.push_back(navigation_event{navigation_key::insert_key});
break;
case '3':
queue.push_back(navigation_event{navigation_key::delete_key});
break;
case '4':
case '8':
queue.push_back(navigation_event{navigation_key::end});
break;
case '5':
queue.push_back(navigation_event{navigation_key::page_up});
break;
case '6':
queue.push_back(navigation_event{navigation_key::page_down});
break;
default:
}
}
else
{
switch (event.value)
{
case 'A':
queue.push_back(navigation_event{navigation_key::up});
break;
case 'B':
queue.push_back(navigation_event{navigation_key::down});
break;
case 'C':
queue.push_back(navigation_event{navigation_key::right});
break;
case 'D':
queue.push_back(navigation_event{navigation_key::left});
break;
case 'H':
queue.push_back(navigation_event{navigation_key::home});
break;
case 'F':
queue.push_back(navigation_event{navigation_key::end});
break;
default:
}
}
buffer.clear();
};
constexpr auto resolve_ss3 = [](byte_received const & event, std::vector<input_event> & queue) {
switch (event.value)
{
case 'A':
queue.push_back(navigation_event{navigation_key::up});
break;
case 'B':
queue.push_back(navigation_event{navigation_key::down});
break;
case 'C':
queue.push_back(navigation_event{navigation_key::right});
break;
case 'D':
queue.push_back(navigation_event{navigation_key::left});
break;
case 'H':
queue.push_back(navigation_event{navigation_key::home});
break;
case 'F':
queue.push_back(navigation_event{navigation_key::end});
break;
default:
}
};
/// Guards
constexpr auto is_backspace = [](byte_received e) {
return e.value == '\x08' || e.value == '\x7f';
};
constexpr auto is_tab = [](byte_received e) {
return e.value == '\x09';
};
constexpr auto is_enter = [](byte_received e) {
return e.value == '\x0a' || e.value == '\x0d';
};
constexpr auto is_escape = [](byte_received e) {
return e.value == '\x1b';
};
constexpr auto is_printable = [](byte_received e) {
return e.value >= 0x20 && e.value <= 0x7e;
};
constexpr auto is_csi_introducer = [](byte_received e) {
return e.value == '[';
};
constexpr auto is_ss3_introducer = [](byte_received e) {
return e.value == 'O';
};
constexpr auto is_invalid_introducer = [](byte_received e) {
return !(is_ss3_introducer(e) || is_csi_introducer(e));
};
constexpr auto is_csi_param = [](byte_received e) {
return e.value >= 0x20 && e.value <= 0x3f;
};
constexpr auto is_csi_terminator = [](byte_received e) {
return e.value >= 0x40 && e.value <= 0x7e;
};
/// Transitions
struct transition_table
{
auto operator()() const noexcept
{
using namespace boost::sml;
// clang-format off
return make_transition_table(
*idle + event<byte_received>[is_escape] = escape_sequence,
idle + event<byte_received>[is_backspace] / push_backspace = idle,
idle + event<byte_received>[is_tab] / push_tab = idle,
idle + event<byte_received>[is_enter] / push_enter = idle,
idle + event<byte_received>[is_printable] / push_character = idle,
escape_sequence + event<byte_received>[is_csi_introducer] / clear_csi = csi_sequence,
escape_sequence + event<byte_received>[is_ss3_introducer] = ss3_sequence,
escape_sequence + event<byte_received>[is_invalid_introducer] / fallback_escape = idle,
escape_sequence + event<timeout_expired> / emit_timeout_escape = idle,
csi_sequence + event<byte_received>[is_csi_param] / push_csi_parameter = csi_sequence,
csi_sequence + event<byte_received>[is_csi_terminator] / resolve_csi = idle,
csi_sequence + event<timeout_expired> / emit_timeout_escape = idle,
ss3_sequence + event<byte_received> / resolve_ss3 = idle,
ss3_sequence + event<timeout_expired> / emit_timeout_escape = idle
);
// clang-format on
}
};
} // namespace ttwhy::scanners::detail
export namespace ttwhy::scanners
{
struct ansi
{
explicit ansi(std::vector<input_event> & queue)
: m_state_machine{queue, m_csi_buffer}
{}
auto process(std::span<char const> buffer) -> void
{
std::ranges::for_each(buffer, [&](auto byte) { m_state_machine.process_event(detail::byte_received{byte}); });
}
auto timeout()
{
m_state_machine.process_event(detail::timeout_expired{});
}
[[nodiscard]] auto is_pending() const -> bool
{
return m_state_machine.is(detail::escape_sequence) || //
m_state_machine.is(detail::csi_sequence) || //
m_state_machine.is(detail::ss3_sequence);
}
private:
std::string m_csi_buffer{};
boost::sml::sm<detail::transition_table> m_state_machine;
};
} // namespace ttwhy::scanners
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