From a025219a21254c8970e19a90bf31148d351f6579 Mon Sep 17 00:00:00 2001
From: _ov4 <ov4@ov4.org>
Date: Mon, 21 Sep 2026 11:55:10 +0000
Subject: add raw input echo

---
 include/line/mode.h      |  53 ++++---------------
 module-test/line_test.cc |  14 ++---
 src/line/mode.cc         | 130 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 146 insertions(+), 51 deletions(-)
 create mode 100644 src/line/mode.cc

diff --git a/include/line/mode.h b/include/line/mode.h
index 8811e66..2baad81 100644
--- a/include/line/mode.h
+++ b/include/line/mode.h
@@ -1,59 +1,28 @@
 #pragma once
 
-#include <unistd.h>
 #include <termios.h>
-#include <stdlib.h>
+#include <string>
 
 using namespace std; // TODO: remove
 
 namespace ov4
 {
 
-inline termios attr;
-
-void disable_raw()
-{
-    tcsetattr(STDIN_FILENO, TCSAFLUSH, &attr);
-}
-
-void enable_raw()
+struct T_position
 {
-    termios attr_raw;
-    tcgetattr(STDIN_FILENO, &attr);
-    tcgetattr(STDIN_FILENO, &attr_raw);
-
-    // LOCAL
+    int row;
+    int col;
+};
 
-    // disable
-    // echo
-    // canonical
-    // signal
-    // disable post-input processing, aka control-V
-    attr_raw.c_lflag &= ~(ECHO | ICANON | ISIG | IEXTEN);
-
-    // INPUT
-
-    // disable 
-    // software flow control, aka control-S/Q
-    // \n and \r conversion
-    attr_raw.c_iflag &= ~(IXON | ICRNL);
-
-    // OUTPUT
+inline termios attr;
 
-    // disable
-    // post-output processing
-    attr_raw.c_oflag &= ~(OPOST);
+void disable_raw();
+void enable_raw();
 
-    // misc
-    attr_raw.c_iflag &= ~(BRKINT | INPCK | ISTRIP);
-    attr_raw.c_cflag |= ~(CS8);
+void clear_below();
 
-    atexit(disable_raw);
+std::string readline();
 
-    // TCSAFLUSH
-    // the change shall occur after all output written to fildes is transmitted
-    // and all input so far received but not read shall be discarded before the change is made
-    tcsetattr(STDIN_FILENO, TCSAFLUSH, &attr_raw);
-}
+T_position get_cursor_position();
 
 }
diff --git a/module-test/line_test.cc b/module-test/line_test.cc
index 7bc16df..d71d088 100644
--- a/module-test/line_test.cc
+++ b/module-test/line_test.cc
@@ -2,6 +2,7 @@
  * test line editor
    $ g++ \
    module-test/line_test.cc \
+   src/line/mode.cc \
    -std=c++26 -Iinclude -Ithird_party/magic_enum/include \
    -O0 -ggdb3 -fno-omit-frame-pointer -fno-inline -D_GLIBCXX_ASSERTIONS \
    -o module-test/line_test.out
@@ -11,6 +12,7 @@
 
 #include <iostream>
 #include <print>
+#include <unistd.h>
 
 #include "line/mode.h"
 
@@ -20,14 +22,8 @@ using namespace ov4;
 int main()
 {
     enable_raw();
-    char c;
-    while (read(STDIN_FILENO, &c, 1) == 1)
-    {
-        if (c == 'q') break;
-        if (iscntrl(c))
-            print("control: {}\r\n", static_cast<unsigned char>(c));
-        else
-            print("entered: {}\r\n", c);
-    }
+    string s = readline();
+    disable_raw();
+    cout << s << endl;
     return 0;
 }
diff --git a/src/line/mode.cc b/src/line/mode.cc
new file mode 100644
index 0000000..83eda67
--- /dev/null
+++ b/src/line/mode.cc
@@ -0,0 +1,130 @@
+#include "line/mode.h"
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <iostream>
+#include <print>
+
+using namespace std;
+
+namespace ov4
+{
+
+void disable_raw()
+{
+    tcsetattr(STDIN_FILENO, TCSAFLUSH, &attr);
+}
+
+void enable_raw()
+{
+    termios attr_raw;
+    tcgetattr(STDIN_FILENO, &attr);
+    tcgetattr(STDIN_FILENO, &attr_raw);
+
+    // LOCAL
+
+    // disable
+    // echo
+    // canonical
+    // signal
+    // disable post-input processing, aka control-V
+    attr_raw.c_lflag &= ~(ECHO | ICANON | ISIG | IEXTEN);
+
+    // INPUT
+
+    // disable 
+    // software flow control, aka control-S/Q
+    // \n and \r conversion
+    attr_raw.c_iflag &= ~(IXON | ICRNL);
+
+    // OUTPUT
+
+    // disable
+    // post-output processing
+    attr_raw.c_oflag &= ~(OPOST);
+
+    // misc
+    attr_raw.c_iflag &= ~(BRKINT | INPCK | ISTRIP);
+    attr_raw.c_cflag |= ~(CS8);
+
+    atexit(disable_raw);
+
+    // TCSAFLUSH
+    // the change shall occur after all output written to fildes is transmitted
+    // and all input so far received but not read shall be discarded before the change is made
+    tcsetattr(STDIN_FILENO, TCSAFLUSH, &attr_raw);
+}
+
+void clear_below()
+{
+    print("\x1b[0J");
+}
+
+string readline()
+{
+    string buffer;
+    char c;
+    while (read(STDIN_FILENO, &c, 1) == 1)
+    {
+        if (c == 'Q') break;
+        else if (c == 'C') 
+        {
+            clear_below();
+        }
+        else if (c == 'R')
+        {
+            get_cursor_position();
+        }
+        else if (iscntrl(c))
+        {
+            print("control: {}\r\n", static_cast<unsigned char>(c));
+            fflush(stdout);
+            if (c == 13) // \n
+            {
+                //print("line: {}\r\n", buffer);
+                return buffer;
+            }
+        }
+        else
+        {
+            print("{}", c);
+            buffer += c;
+            fflush(stdout);
+        }
+    }
+    return buffer;
+}
+
+T_position get_cursor_position()
+{
+    char c;
+    string buffer;
+    T_position pos;
+    int row, col;
+    tcflush(STDIN_FILENO, TCIFLUSH);
+    cout << "\x1b[6n" << flush;
+    while (read(STDIN_FILENO, &c, 1) == 1)
+    {
+        if (c == 'R') break;
+        buffer += c;
+    }
+    if (buffer.size() <= 2 || buffer[0] != '\x1b' || buffer[1] != '[')
+    {
+        pos.row = -1;
+        pos.col = -1;
+        return pos;
+    }
+    if ((sscanf(buffer.c_str(), "\x1b[%d;%d", &row, &col)) != 2)
+    {
+        pos.row = -1;
+        pos.col = -1;
+        return pos;
+    }
+    pos.row = row;
+    pos.col = col;
+    print("row {}, col {}\r\n", row, col);
+    fflush(stdout);
+    return pos;
+} 
+
+}
-- 
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