From fb5d7b6714d265aae844ce8f7df35d675505026f Mon Sep 17 00:00:00 2001
From: Jun Mukai <mukai@google.com>
Date: Fri, 16 Mar 2018 13:34:53 -0700
Subject: [PATCH 1/2] fix crashes on prev_boundary

Fixes #38, #39
---
 src/grapheme.rs | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/grapheme.rs b/src/grapheme.rs
index c07fc8c..e7a3161 100644
--- a/src/grapheme.rs
+++ b/src/grapheme.rs
@@ -624,6 +624,9 @@ impl GraphemeCursor {
         if self.offset == 0 {
             return Ok(None);
         }
+        if self.offset == chunk_start {
+            return Err(GraphemeIncomplete::PrevChunk);
+        }
         let mut iter = chunk[..self.offset - chunk_start].chars().rev();
         let mut ch = iter.next().unwrap();
         loop {
@@ -647,6 +650,7 @@ impl GraphemeCursor {
                     self.decide(true);
                 } else {
                     self.resuming = true;
+                    self.cat_after = Some(gr::grapheme_category(ch));
                     return Err(GraphemeIncomplete::PrevChunk);
                 }
             }
@@ -659,3 +663,19 @@ impl GraphemeCursor {
         }
     }
 }
+
+#[test]
+fn test_grapheme_cursor_prev_boundary() {
+    let s = "abcd";
+    let mut c = GraphemeCursor::new(3, s.len(), true);
+    assert_eq!(c.prev_boundary(&s[2..], 2), Err(GraphemeIncomplete::PrevChunk));
+    assert_eq!(c.prev_boundary(&s[..2], 0), Ok(Some(2)));
+}
+
+#[test]
+fn test_grapheme_cursor_prev_boundary_chunk_start() {
+    let s = "abcd";
+    let mut c = GraphemeCursor::new(2, s.len(), true);
+    assert_eq!(c.prev_boundary(&s[2..], 2), Err(GraphemeIncomplete::PrevChunk));
+    assert_eq!(c.prev_boundary(&s[..2], 0), Ok(Some(1)));
+}

From 1f2f59149e82c8177c0f3154fb5d383b6a9a795e Mon Sep 17 00:00:00 2001
From: Jun Mukai <mukai@google.com>
Date: Mon, 19 Mar 2018 17:22:12 -0700
Subject: [PATCH 2/2] fix typo contained through manual merge

---
 src/grapheme.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/grapheme.rs b/src/grapheme.rs
index b815dd2..f6062f7 100644
--- a/src/grapheme.rs
+++ b/src/grapheme.rs
@@ -669,6 +669,7 @@ impl GraphemeCursor {
     }
 }
 
+#[test]
 fn test_grapheme_cursor_ris_precontext() {
     let s = "\u{1f1fa}\u{1f1f8}\u{1f1fa}\u{1f1f8}\u{1f1fa}\u{1f1f8}";
     let mut c = GraphemeCursor::new(8, s.len(), true);