DisplayBuffer: add range and compute_range methods

1 files changed, 22 insertions, 0 deletions

diff --git a/src/display_buffer.cc b/src/display_buffer.cc
index 4b4847cb..5b8aaff3 100644
--- a/src/display_buffer.cc
+++ b/src/display_buffer.cc
@@ -17,4 +17,26 @@ DisplayLine::iterator DisplayLine::split(iterator it, BufferIterator pos)
     return m_atoms.insert(it, std::move(atom));
 }
 
+void DisplayBuffer::compute_range()
+{
+    m_range.first  = BufferIterator();
+    m_range.second = BufferIterator();
+    for (auto& line : m_lines)
+    {
+        for (auto& atom : line)
+        {
+            if (not atom.content.has_buffer_range())
+                continue;
+
+            if (not m_range.first.is_valid() or m_range.first > atom.content.begin())
+                m_range.first = atom.content.begin();
+
+            if (not m_range.second.is_valid() or m_range.second < atom.content.end())
+                m_range.second = atom.content.end();
+        }
+    }
+    assert(m_range.first.is_valid() and m_range.second.is_valid());
+    assert(m_range.first <= m_range.second);
+}
+
 }