From c2336a8a22a5ddf26b33a53f914bf0d5397a6553 Mon Sep 17 00:00:00 2001
From: _ov4 <ov4@ov4.org>
Date: Tue, 22 Sep 2026 02:52:22 +0000
Subject: add cursor moving limit pos

---
 src/line/cursor.cc | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/line/mode.cc   | 68 ++-------------------------------------
 2 files changed, 96 insertions(+), 65 deletions(-)
 create mode 100644 src/line/cursor.cc

(limited to 'src/line')

diff --git a/src/line/cursor.cc b/src/line/cursor.cc
new file mode 100644
index 0000000..ce01466
--- /dev/null
+++ b/src/line/cursor.cc
@@ -0,0 +1,93 @@
+#include "line/cursor.h"
+
+#include <print>
+#include <iostream>
+#include <string>
+#include <unistd.h>
+#include <cstdio>
+#include <cstdlib>
+#include <termios.h>
+
+using namespace std;
+
+namespace ov4
+{
+
+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;
+} 
+
+void print_override(const std::string &s)
+{
+    print("\r");
+    fflush(stdout);
+    print("{}", s);
+    fflush(stdout);
+    cursor_col = s.size()+1;
+    line_end_pos = cursor_col;
+}
+
+void move_cursor(char c)
+{
+    switch (c)
+    {
+        // case 'A':
+        //     print("\x1b[A");
+        //     fflush(stdout);
+        //     cursor_row--;
+        //     break;
+        // case 'B':
+        //     print("\x1b[B");
+        //     fflush(stdout);
+        //     cursor_row++;
+        //     break;
+        case 'C':
+            if (cursor_col < line_end_pos)
+            {
+                print("\x1b[C");
+                fflush(stdout);
+                cursor_col++;
+            }
+            break;
+        case 'D':
+            if (cursor_col > 1)
+            {
+                print("\x1b[D");
+                fflush(stdout);
+                cursor_col--;
+            }
+            break;
+        default:
+            return;
+    }
+}
+
+}
diff --git a/src/line/mode.cc b/src/line/mode.cc
index 3ddd067..c4b9972 100644
--- a/src/line/mode.cc
+++ b/src/line/mode.cc
@@ -5,6 +5,8 @@
 #include <iostream>
 #include <print>
 
+#include "line/cursor.h"
+
 using namespace std;
 
 namespace ov4
@@ -96,31 +98,7 @@ string readline()
                 if (read(STDIN_FILENO, seq + 1, 1) != 1)
                     continue;
 
-                switch (seq[1])
-                {
-                    case 'A':
-                        print("\x1b[A");
-                        fflush(stdout);
-                        cursor_row--;
-                        break;
-                    case 'B':
-                        print("\x1b[B");
-                        fflush(stdout);
-                        cursor_row++;
-                        break;
-                    case 'C':
-                        print("\x1b[C");
-                        fflush(stdout);
-                        cursor_col--;
-                        break;
-                    case 'D':
-                        print("\x1b[D");
-                        fflush(stdout);
-                        cursor_col++;
-                        break;
-                    default:
-                        return "ERROR";
-                }
+                move_cursor(seq[1]);
             }
         }
 
@@ -134,45 +112,5 @@ string readline()
     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;
-} 
-
-void print_override(const std::string &s)
-{
-    print("\r");
-    fflush(stdout);
-    print("{}", s);
-    fflush(stdout);
-    cursor_col = s.size()+1;
-}
 
 }
-- 
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