From 1862d867f6439f6146c46a00a6b3f34d6c404574 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sat, 24 Dec 2016 14:41:25 -0500
Subject: [PATCH] Fix Buffer::Iterator::go_previous_line()

---
 src/core/Buffer-Iterator.cc | 18 ++++++++----------
 test/files/blank_lines.txt  |  5 +++++
 test/src/test_Buffer.cc     | 25 +++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 10 deletions(-)
 create mode 100644 test/files/blank_lines.txt

diff --git a/src/core/Buffer-Iterator.cc b/src/core/Buffer-Iterator.cc
index 23ff99f..2a0b901 100644
--- a/src/core/Buffer-Iterator.cc
+++ b/src/core/Buffer-Iterator.cc
@@ -153,18 +153,16 @@ bool Buffer::Iterator::go_right_in_line(bool allow_eol)
 bool Buffer::Iterator::go_previous_line()
 {
     Iterator i2 = *this;
-    i2.go_back();
-    while (i2.valid() && (*i2 != '\n'))
+    while (i2.valid())
     {
         i2.go_back();
-    }
-    i2.go_back();
-    if (i2.valid())
-    {
-        m_line--;
-        m_offset = i2.m_offset;
-        go_start_of_line();
-        return true;
+        if (*i2 == '\n')
+        {
+            i2.go_start_of_line();
+            m_line--;
+            m_offset = i2.m_offset;
+            return true;
+        }
     }
     return false;
 }
diff --git a/test/files/blank_lines.txt b/test/files/blank_lines.txt
new file mode 100644
index 0000000..7af78dc
--- /dev/null
+++ b/test/files/blank_lines.txt
@@ -0,0 +1,5 @@
+abc
+
+def
+
+end
diff --git a/test/src/test_Buffer.cc b/test/src/test_Buffer.cc
index 7ee5ad5..1fd5c1a 100644
--- a/test/src/test_Buffer.cc
+++ b/test/src/test_Buffer.cc
@@ -67,3 +67,28 @@ TEST(BufferTest, allows_navigating_using_iterators)
     EXPECT_EQ(0u, iterator->line());
     ASSERT_EQ((uint32_t)'H', **iterator);
 }
+
+TEST(BufferTest, allows_navigating_using_iterators2)
+{
+    Buffer b("test/files/blank_lines.txt");
+    auto iterator = b.add_iterator();
+
+    EXPECT_EQ(0u, iterator->line());
+    EXPECT_EQ((uint32_t)'a', **iterator);
+
+    EXPECT_TRUE(iterator->go_next_line());
+    EXPECT_EQ(1u, iterator->line());
+    EXPECT_EQ((uint32_t)'\n', **iterator);
+
+    EXPECT_TRUE(iterator->go_next_line());
+    EXPECT_EQ(2u, iterator->line());
+    EXPECT_EQ((uint32_t)'d', **iterator);
+
+    EXPECT_TRUE(iterator->go_previous_line());
+    EXPECT_EQ(1u, iterator->line());
+    EXPECT_EQ((uint32_t)'\n', **iterator);
+
+    EXPECT_TRUE(iterator->go_previous_line());
+    EXPECT_EQ(0u, iterator->line());
+    EXPECT_EQ((uint32_t)'a', **iterator);
+}