Add search function

src/row_op.c

@@ -18,6 +18,18 @@ int editorRowCxToRx(erow *row, int cursor_x) {
   return render_x;
 }
 
+int editorRowRxToCx(erow *row, int rx) {
+  int cur_rx = 0;
+  int cx;
+  for (cx = 0; cx < row->size; cx++) {
+    if (row->chars[cx] == '\t')
+      cur_rx += (E.constantes.TAB_LENGTH - 1) - (cur_rx % E.constantes.TAB_LENGTH);
+    cur_rx++;
+    if (cur_rx > rx) return cx;
+  }
+  return cx;
+}
+
 /**
  * \fn editorUpdateRow(erow *row)
  * \brief Copy content of \p row in \p row->render.