From 261cc9abf81ef52c26de1b1eaa3c9744457edf91 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sat, 15 Oct 2016 15:54:45 -0400
Subject: [PATCH] adjust cursor movement to optionally allow moving to EOL

---
 src/core/PieceTable.cc  | 19 ++++++++++++++-----
 src/core/PieceTable.h   |  4 ++--
 src/gui/Window.cc       | 14 +++++++-------
 test/src/test_Buffer.cc |  2 +-
 4 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/src/core/PieceTable.cc b/src/core/PieceTable.cc
index 6b45e5b..599bd49 100644
--- a/src/core/PieceTable.cc
+++ b/src/core/PieceTable.cc
@@ -138,7 +138,7 @@ bool PieceTable::Cursor::go_start_of_line()
     return rv;
 }
 
-bool PieceTable::Cursor::go_end_of_line()
+bool PieceTable::Cursor::go_end_of_line(bool allow_on_eol)
 {
     if (!iterator.valid())
         return false;
@@ -148,11 +148,14 @@ bool PieceTable::Cursor::go_end_of_line()
             (iterator.piece->next != iterator.piece_table->end_piece))
     {
         iterator.go_next_piece();
-        rv = true;
     }
     uint32_t current_column = column;
     iterator.go_end_of_piece();
     calculate_column();
+    if (!allow_on_eol)
+    {
+        go_left(1);
+    }
     if (column != current_column)
         rv = true;
     return rv;
@@ -214,7 +217,7 @@ bool PieceTable::Cursor::go_left(int n)
     return true;
 }
 
-bool PieceTable::Cursor::go_right(int n)
+bool PieceTable::Cursor::go_right(int n, bool allow_on_eol)
 {
     if (!iterator.valid())
         return false;
@@ -222,7 +225,13 @@ bool PieceTable::Cursor::go_right(int n)
     {
         return false;
     }
+    Iterator iterator_2 = iterator;
     iterator.go_next_position();
+    if ((!allow_on_eol) && is_end_of_line())
+    {
+        iterator = iterator_2;
+        return false;
+    }
     uint32_t chr = *iterator;
     if (chr == '\t')
     {
@@ -307,7 +316,7 @@ void PieceTable::Cursor::calculate_column()
     while ((tmp_cursor.iterator.piece != iterator.piece) ||
             (tmp_cursor.iterator.offset < iterator.offset))
     {
-        tmp_cursor.go_right(1);
+        tmp_cursor.go_right(1, true);
     }
     column = tmp_cursor.column;
 }
@@ -317,7 +326,7 @@ void PieceTable::Cursor::forward_to_column(uint32_t c)
     int32_t diff = abs((int32_t)(c - column));
     if (diff == 0)
         return;
-    while (go_right(1))
+    while (go_right(1, false))
     {
         int32_t new_diff = abs((int32_t)(c - column));
         if (new_diff > diff)
diff --git a/src/core/PieceTable.h b/src/core/PieceTable.h
index 4849fc6..4e2acf8 100644
--- a/src/core/PieceTable.h
+++ b/src/core/PieceTable.h
@@ -102,11 +102,11 @@ public:
         Cursor(PieceTable * pt);
 
         bool go_start_of_line();
-        bool go_end_of_line();
+        bool go_end_of_line(bool allow_on_eol);
         bool go_up(int n, uint32_t desired_column);
         bool go_down(int n, uint32_t desired_column);
         bool go_left(int n);
-        bool go_right(int n);
+        bool go_right(int n, bool allow_on_eol);
         bool operator==(const Cursor & c)
         {
             return (c.line == line) && (c.column == column);
diff --git a/src/gui/Window.cc b/src/gui/Window.cc
index dce0f1b..12e8d0a 100644
--- a/src/gui/Window.cc
+++ b/src/gui/Window.cc
@@ -300,7 +300,7 @@ void Window::cursor_move(int which)
         m_target_column = m_cursor->column;
         break;
     case CURSOR_RIGHT:
-        moved = m_cursor->go_right(1);
+        moved = m_cursor->go_right(1, false);
         m_target_column = m_cursor->column;
         break;
     case CURSOR_UP:
@@ -314,7 +314,7 @@ void Window::cursor_move(int which)
         m_target_column = 0u;
         break;
     case CURSOR_EOL:
-        moved = m_cursor->go_end_of_line();
+        moved = m_cursor->go_end_of_line(false);
         m_target_column = 0x7FFFFFFFu;
         break;
     }
@@ -329,7 +329,7 @@ void Window::cursor_move(int which)
         case CURSOR_UP:
             {
                 PieceTable::Cursor c = *m_cursor;
-                c.go_end_of_line();
+                c.go_end_of_line(false);
                 row_offset = m_cursor->column / m_columns - c.column / m_columns - 1 - current_row_offset;
             }
             break;
@@ -337,7 +337,7 @@ void Window::cursor_move(int which)
             {
                 PieceTable::Cursor c = *m_cursor;
                 c.go_up(1, 0u);
-                c.go_end_of_line();
+                c.go_end_of_line(false);
                 row_offset = c.column / m_columns - current_row_offset + 1 + m_cursor->column / m_columns;
             }
             break;
@@ -347,7 +347,7 @@ void Window::cursor_move(int which)
         case CURSOR_EOL:
             {
                 PieceTable::Cursor c = *m_cursor;
-                c.go_end_of_line();
+                c.go_end_of_line(false);
                 row_offset = c.column / m_columns - current_row_offset;
             }
             break;
@@ -373,7 +373,7 @@ std::pair<int, PieceTable::Cursor> Window::calculate_start_position()
         if (cursor.go_up(1, 0u))
         {
             PieceTable::Cursor c = cursor;
-            c.go_end_of_line();
+            c.go_end_of_line(false);
             row -= c.column / m_columns + 1;
         }
         else
@@ -424,7 +424,7 @@ void Window::draw_buffer()
                     (character != '\t'))
                 draw_buffer_character(screen_column, screen_row, character);
         }
-        if (!cursor.go_right(1))
+        if (!cursor.go_right(1, false))
         {
             bool last_row = !cursor.go_down(1, 0);
             if (last_vertical_crosshair_row < row)
diff --git a/test/src/test_Buffer.cc b/test/src/test_Buffer.cc
index 1f4b8f9..a667ab0 100644
--- a/test/src/test_Buffer.cc
+++ b/test/src/test_Buffer.cc
@@ -30,7 +30,7 @@ TEST(BufferTest, allows_navigating_using_cursors)
     ASSERT_EQ((uint32_t)'H', **cursor);
     cursor->go_up(1, cursor->column);
     ASSERT_EQ((uint32_t)'H', **cursor);
-    cursor->go_right(1);
+    cursor->go_right(1, false);
     ASSERT_EQ((uint32_t)'e', **cursor);
     cursor->go_down(1, cursor->column);
     ASSERT_EQ((uint32_t)'h', **cursor);