From 36e4dacdf5e33b9d92ea59124ef67a040b5392cb Mon Sep 17 00:00:00 2001
From: Maxime Coste <frrrwww@gmail.com>
Date: Thu, 28 Jun 2012 14:26:01 +0200
Subject: [PATCH] Fix BufferIterator::on_erase and tweak Buffer

---
 src/buffer.cc              |  3 ++-
 src/buffer_iterator.inl.hh | 14 +++++++-------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/src/buffer.cc b/src/buffer.cc
index 30cf6d38..4c29837a 100644
--- a/src/buffer.cc
+++ b/src/buffer.cc
@@ -152,7 +152,7 @@ void Buffer::end_undo_group()
     if (m_current_undo_group.empty())
         return;
 
-    m_history.push_back(m_current_undo_group);
+    m_history.push_back(std::move(m_current_undo_group));
     m_history_cursor = m_history.end();
 
     m_current_undo_group.clear();
@@ -277,6 +277,7 @@ void Buffer::insert(const BufferIterator& pos, const String& content)
 void Buffer::erase(const BufferIterator& pos, BufferSize length)
 {
     BufferIterator end = pos + length;
+    assert(end.is_valid());
     String prefix = m_lines[pos.line()].content.substr(0, pos.column());
     String suffix = m_lines[end.line()].content.substr(end.column());
     Line new_line = { m_lines[pos.line()].start, prefix + suffix };
diff --git a/src/buffer_iterator.inl.hh b/src/buffer_iterator.inl.hh
index bcb83ab0..2ae412e7 100644
--- a/src/buffer_iterator.inl.hh
+++ b/src/buffer_iterator.inl.hh
@@ -32,6 +32,7 @@ inline BufferIterator& BufferIterator::operator=(const BufferIterator& iterator)
 {
     m_buffer = iterator.m_buffer;
     m_coord = iterator.m_coord;
+    assert(is_valid());
     return *this;
 }
 
@@ -90,18 +91,17 @@ inline void BufferIterator::on_erase(const BufferCoord& begin,
     if (m_coord < begin)
         return;
 
-    BufferCoord measure;
-    measure.line = end.line - begin.line;
-    measure.column = end.column - (measure.line == 0 ? begin.column : 0);
     if (m_coord <= end)
         m_coord = begin;
     else
     {
-        m_coord.line -= measure.line;
-        if (measure.line > 0 and begin.line == m_coord.line)
-            m_coord.column += begin.column;
         if (end.line == m_coord.line)
-            m_coord.column -= measure.column;
+        {
+            m_coord.line = begin.line;
+            m_coord.column = begin.column + m_coord.column - end.column;
+        }
+        else
+            m_coord.line -= end.line - begin.line;
     }
 
     if (is_end())