Add search function

src/file_io.c

@@ -110,3 +110,21 @@ void editorSave() {
     free(buf);
     editorSetStatusMessage("Can't save! I/O error: %s", strerror(errno));
 }
+
+void editorFind() {
+  char *query = editorPrompt("Search: %s (ESC to cancel)");
+  if (query == NULL) return;
+  int i;
+  for (i = 0; i < E.numrows; i++) {
+    erow *row = &E.row[i];
+    char *match = strstr(row->render, query);
+    if (match) {
+      E.cursor_y = i;
+      E.cursor_x = editorRowRxToCx(row, match - row->render);
+      E.row_offset = E.numrows;
+      break;
+    }
+  }
+  free(query);
+}
+