Add cursor movements to move to SOL and EOL.

src/core/PieceTable.cc

@@ -122,28 +122,39 @@ PieceTable::Cursor::Cursor(PieceTable * pt) : iterator(pt)
     init_column();
 }
 
-void PieceTable::Cursor::go_start_of_line()
+bool PieceTable::Cursor::go_start_of_line()
 {
+    bool rv = false;
     while (iterator.valid() &&
             (!iterator.piece->prev->eol()) &&
             (iterator.piece->prev != iterator.piece_table->start_piece))
     {
         iterator.go_prev_piece();
+        rv = true;
     }
+    if (iterator.offset != 0u)
+        rv = true;
     iterator.offset = 0u;
     init_column();
+    return rv;
 }
 
-void PieceTable::Cursor::go_end_of_line()
+bool PieceTable::Cursor::go_end_of_line()
 {
+    bool rv = false;
     while (iterator.valid() &&
             (!iterator.piece->eol()) &&
             (iterator.piece->next != iterator.piece_table->end_piece))
     {
         iterator.go_next_piece();
+        rv = true;
     }
+    uint32_t current_column = column;
     iterator.go_end_of_piece();
     calculate_column();
+    if (column != current_column)
+        rv = true;
+    return rv;
 }
 
 bool PieceTable::Cursor::go_up(int n, uint32_t desired_column)

src/core/PieceTable.h

@@ -110,8 +110,8 @@ public:
 
         Cursor(PieceTable * pt);
 
-        void go_start_of_line();
-        void go_end_of_line();
+        bool go_start_of_line();
+        bool go_end_of_line();
         bool go_up(int n, uint32_t desired_column);
         bool go_down(int n, uint32_t desired_column);
         bool go_left(int n);