working towards sim uart-like device support

bdpi/uart_sim_device.c

@@ -0,0 +1,53 @@
+#include <sys/select.h>
+#include <termios.h>
+#include <unistd.h>
+#include <stdio.h>
+
+static struct termios oldt, newt;
+
+void init_terminal() {
+    // Get terminal attributes
+    tcgetattr(STDIN_FILENO, &oldt);
+    newt = oldt;
+
+    // Set terminal to raw mode (no echo, non-canonical)
+    newt.c_lflag &= ~(ICANON | ECHO);
+    tcsetattr(STDIN_FILENO, TCSANOW, &newt);
+}
+
+void restore_terminal() {
+    // Restore terminal to its old state
+    tcsetattr(STDIN_FILENO, TCSANOW, &oldt);
+}
+
+char get_char_from_terminal() {
+    char c = getchar();
+    return c;
+}
+
+int is_char_available() {
+    struct timeval tv;
+    fd_set read_fd_set;
+
+    // Don't wait at all, not even a microsecond
+    tv.tv_sec = 0;
+    tv.tv_usec = 0;
+
+    // Watch stdin (fd 0) to see when it has input
+    FD_ZERO(&read_fd_set);
+    FD_SET(0, &read_fd_set);
+
+    // Check if there's any input available
+    if (select(1, &read_fd_set, NULL, NULL, &tv) == -1) {
+        perror("select");
+        return 0;  // 0 indicates no characters available
+    }
+
+    if (FD_ISSET(0, &read_fd_set)) {
+        // Character is available
+        return 1;
+    } else {
+        // No character available
+        return 0;
+    }
+}