From 576cabea93171711e27b697092934ee324ba121f Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Wed, 28 Jul 2021 18:58:57 +0200
Subject: [PATCH] WIP

---
 zed/src/editor/display_map.rs | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/zed/src/editor/display_map.rs b/zed/src/editor/display_map.rs
index c3b45bee66b89f528bde48b7d9f841b9a7ea2814..5e41412bf165d92aeb6f97d52c2a726013eae332 100644
--- a/zed/src/editor/display_map.rs
+++ b/zed/src/editor/display_map.rs
@@ -107,6 +107,39 @@ impl DisplayMapSnapshot {
         self.buffer_snapshot.max_point().row + 1
     }
 
+    pub fn prev_row_boundary(&self, mut display_point: DisplayPoint) -> (DisplayPoint, Point) {
+        *display_point.column_mut() = 0;
+        let mut point = display_point.to_buffer_point(self, Bias::Left);
+        while point.column != 0 {
+            point.column = 0;
+            display_point = point.to_display_point(self);
+            if display_point.column() != 0 {
+                *display_point.column_mut() = 0;
+                point = display_point.to_buffer_point(self, Bias::Left);
+            }
+        }
+
+        (display_point, point)
+    }
+
+    pub fn next_row_boundary(&self, mut display_point: DisplayPoint) -> (DisplayPoint, Point) {
+        *display_point.row_mut() += 1;
+        *display_point.column_mut() = 0;
+        let mut point = display_point.to_buffer_point(self, Bias::Right);
+        while point.column != 0 {
+            point.column = 0;
+            point.row += 1;
+            display_point = point.to_display_point(self);
+            if display_point.column() != 0 {
+                *display_point.row_mut() += 1;
+                *display_point.column_mut() = 0;
+                point = display_point.to_buffer_point(self, Bias::Right);
+            }
+        }
+
+        (display_point, point)
+    }
+
     pub fn max_point(&self) -> DisplayPoint {
         DisplayPoint(self.wraps_snapshot.max_point())
     }