Merge branch 'trunk' into feature/socket-syscalls

src/usr/editor.rs

@@ -236,6 +236,31 @@ impl Editor {
  self.highlighted.clear();
  }
 
+ // Align cursor that is past the end of the line, to the end
+ // of the line.
+ //
+ // If the cursor is somewhere on the long line on the second
+ // screen in the following diagram, going down should move
+ // the cursor to the end of the short line and display the
+ // first screen instead of the second screen.
+ //
+ // +----------------------------+----------------------------+
+ // | | |
+ // | This is a loooooooooooooooo|oooooong line |
+ // | This is a short line | ^ |
+ // | ^ | |
+ // +----------------------------+----------------------------+
+ fn align_cursor(&mut self) {
+ let x = self.offset.x + self.cursor.x;
+ let y = self.offset.y + self.cursor.y;
+ let eol = self.lines[y].chars().count();
+ if x > eol {
+ let n = self.cols();
+ self.offset.x = (eol / n) * n;
+ self.cursor.x = eol % n;
+ }
+ }
+
  pub fn run(&mut self) -> Result<(), ExitCode> {
  print!("\x1b[2J\x1b[1;1H"); // Clear screen and move cursor to top
  self.print_screen();
@@ -317,9 +342,9 @@ impl Editor {
  self.cursor.y -= 1
  } else if self.offset.y > 0 {
  self.offset.y -= 1;
- self.print_screen();
  }
- self.cursor.x = self.next_pos(self.cursor.x, self.cursor.y);
+ self.align_cursor();
+ self.print_screen();
  },
  'B' if csi => { // Arrow Down
  let is_eof = self.offset.y + self.cursor.y == self.lines.len() - 1;
@@ -328,12 +353,12 @@ impl Editor {
  if is_bottom || is_eof {
  if !is_eof {
  self.offset.y += 1;
- self.print_screen();
  }
  } else {
  self.cursor.y += 1;
  }
- self.cursor.x = self.next_pos(self.cursor.x, self.cursor.y);
+ self.align_cursor();
+ self.print_screen();
  }
  },
  'C' if csi => { // Arrow Right
@@ -344,8 +369,8 @@ impl Editor {
  csi = false;
  continue
  } else if self.cursor.x == self.cols() - 1 {
- self.cursor.x = self.offset.x;
  self.offset.x += self.cols();
+ self.cursor.x -= self.cols() - 1;
  self.print_screen();
  } else {
  self.cursor.x += 1;
@@ -358,10 +383,10 @@ impl Editor {
  csi = false;
  continue;
  } else if self.cursor.x == 0 {
- self.cursor.x = self.offset.x - 1;
  self.offset.x -= self.cols();
+ self.cursor.x += self.cols() - 1;
+ self.align_cursor();
  self.print_screen();
- self.cursor.x = self.next_pos(self.cursor.x, self.cursor.y);
  } else {
  self.cursor.x -= 1;
  }
@@ -521,20 +546,6 @@ impl Editor {
  Ok(())
  }
 
- // Move cursor past end of line to end of line or left of the screen
- fn next_pos(&self, x: usize, y: usize) -> usize {
- let eol = self.lines[self.offset.y + y].chars().count();
- if eol <= self.offset.x + x {
- if eol <= self.offset.x {
- 0
- } else {
- eol - 1
- }
- } else {
- x
- }
- }
-
  fn rows(&self) -> usize {
  sys::console::rows() - 1 // Leave out one line for status line
  }