Major update

- Add an IO system to hijack a bit of the terminal.
- Other minor fixes.

src/internal/io/io.cc

@@ -0,0 +1,81 @@
+#include "internal/io/io.h"
+
+namespace bed::internal::io {
+termios IO::orig_termios{};
+bool IO::cleaned = false;
+
+IO::IO() {
+  if (tcgetattr(STDIN_FILENO, &orig_termios) == -1)
+    throw fatal_error("Can't get terminal state.", 1);
+  atexit(cleanup);
+  struct termios raw = orig_termios;
+  raw.c_iflag &= ~(BRKINT | ISTRIP | IXON);
+  raw.c_cflag |= (CS8);
+  raw.c_lflag &= ~(ECHO | ICANON | ISIG);
+  raw.c_cc[VMIN] = 1;
+  raw.c_cc[VTIME] = 0;
+  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1)
+    throw fatal_error("Can't set terminal state.", 1);
+  std::string os = "\x1b[?2004h";
+  write_all(STDOUT_FILENO, os.c_str(), os.size());
+}
+
+IO::~IO() {
+  cleanup();
+}
+
+void IO::enable_mouse() {
+  const char *seq = "\x1b[?1000h";
+  write_all(STDOUT_FILENO, seq, 8);
+}
+
+void IO::disable_mouse() {
+  const char *seq = "\x1b[?1000l";
+  write_all(STDOUT_FILENO, seq, 8);
+}
+
+std::pair<uint16_t, uint16_t> IO::terminal_size() {
+  struct winsize ws{};
+  if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1)
+    throw fatal_error("Can't get terminal size.", 1);
+  return {ws.ws_row, ws.ws_col};
+}
+
+std::pair<uint16_t, uint16_t> IO::cursor_position() {
+  write_all(STDOUT_FILENO, "\x1b[6n", 4);
+  std::string response;
+  char c;
+  if (read(STDIN_FILENO, &c, 1) != 1 || c != '\x1b')
+    throw fatal_error("Invalid cursor position response.", 1);
+  if (read(STDIN_FILENO, &c, 1) != 1 || c != '[')
+    throw fatal_error("Invalid cursor position response.", 1);
+  while (true) {
+    if (read(STDIN_FILENO, &c, 1) != 1)
+      throw fatal_error("Invalid cursor position response.", 1);
+    if (c == 'R')
+      break;
+    response += c;
+  }
+  unsigned row;
+  unsigned col;
+  if (sscanf(response.c_str(), "%u;%u", &row, &col) != 2)
+    throw fatal_error("Invalid cursor position response.", 1);
+  return {(uint16_t)row, (uint16_t)col};
+}
+
+void IO::cleanup() {
+  if (cleaned)
+    return;
+  std::string os = "\x1b[?2004l";
+  write_all(STDOUT_FILENO, os.c_str(), os.size());
+  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &orig_termios) == -1)
+    perror("Can't clean up terminal.");
+  cleaned = true;
+}
+
+void IO::move_cursor(uint16_t row, uint16_t col) {
+  char buf[32];
+  int n = snprintf(buf, sizeof(buf), "\x1b[%u;%uH", row, col);
+  write_all(STDOUT_FILENO, buf, n);
+}
+} // namespace bed::internal::io