Add Buffer::iterator_at_line{begin,end}(size_t line) overloads

src/buffer.cc

@@ -97,6 +97,11 @@ BufferIterator Buffer::iterator_at_line_begin(const BufferIterator& iterator) co
     return BufferIterator(*this, { iterator.line(), 0 });
 }
 
+BufferIterator Buffer::iterator_at_line_begin(size_t line) const
+{
+    return BufferIterator(*this, clamp({ (int)line, 0 }));
+}
+
 BufferIterator Buffer::iterator_at_line_end(const BufferIterator& iterator) const
 {
     BufferPos line = iterator.line();
@@ -104,6 +109,13 @@ BufferIterator Buffer::iterator_at_line_end(const BufferIterator& iterator) cons
     return ++BufferIterator(*this, { line, line_length(line) - 1 });
 }
 
+BufferIterator Buffer::iterator_at_line_end(size_t line) const
+{
+    line = std::min(line, (size_t)line_count()-1);
+    assert(line_length(line) > 0);
+    return ++BufferIterator(*this, { (int)line, line_length(line) - 1 });
+}
+
 BufferIterator Buffer::begin() const
 {
     return BufferIterator(*this, { 0, 0 });

src/buffer.hh

@@ -161,11 +161,15 @@ public:
     // returns an iterator pointing to the first character of the line
     // iterator is on
     BufferIterator iterator_at_line_begin(const BufferIterator& iterator) const;
+    // the same but taking a line number instead of an iterator
+    BufferIterator iterator_at_line_begin(size_t line) const;
 
     // returns an iterator pointing to the character after the last of the
     // line iterator is on (which is the first of the next line if iterator is
     // not on the last one)
     BufferIterator iterator_at_line_end(const BufferIterator& iterator) const;
+    // the same but taking a line number instead of an iterator
+    BufferIterator iterator_at_line_end(size_t line) const;
 
     const String& line_content(size_t l) const { return m_lines[l].content; }