1 files changed, 114 insertions, 0 deletions

diff --git a/src/ui/list_input.h b/src/ui/list_input.h
new file mode 100644
index 0000000..aad3ae4
--- /dev/null
+++ b/src/ui/list_input.h
@@ -0,0 +1,114 @@
+/*
+   This file is part of GNUnet.
+   Copyright (C) 2022 GNUnet e.V.
+
+   GNUnet is free software: you can redistribute it and/or modify it
+   under the terms of the GNU Affero General Public License as published
+   by the Free Software Foundation, either version 3 of the License,
+   or (at your option) any later version.
+
+   GNUnet is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+   SPDX-License-Identifier: AGPL3.0-or-later
+ */
+/*
+ * @author Tobias Frisch
+ * @file ui/list_input.h
+ */
+
+#ifndef UI_LIST_INPUT_H_
+#define UI_LIST_INPUT_H_
+
+#include <stdbool.h>
+#include <stdlib.h>
+
+#define list_input_reset(list) { \
+  (list)->line_index = 0;       \
+  (list)->selected = NULL;      \
+}
+
+#define list_input_select(list, line_width, item) {              \
+  const bool selected = (                                       \
+      ((list)->line_selected >= (list)->line_index) &&          \
+      ((list)->line_selected < (list)->line_index + line_width) \
+  );                                                            \
+                                                                \
+  (list)->line_index += line_width;                             \
+                                                                \
+  if (selected)                                                 \
+    (list)->selected = item;                                    \
+}
+
+#define list_input_event(list, key) {                          \
+  int count = (list)->line_index;                             \
+                                                              \
+  switch (key)                                                \
+  {                                                           \
+    case KEY_UP:                                              \
+    {                                                         \
+      (list)->line_selected--;                                \
+      break;                                                  \
+    }                                                         \
+    case KEY_DOWN:                                            \
+    {                                                         \
+      (list)->line_selected++;                                \
+      break;                                                  \
+    }                                                         \
+    default:                                                  \
+      break;                                                  \
+  }                                                           \
+                                                              \
+  if ((list)->line_selected < 0)                              \
+    (list)->line_selected = 0;                                \
+  else if ((list)->line_selected >= count)                    \
+    (list)->line_selected = count - 1;                        \
+                                                              \
+  if ((list)->window)                                         \
+  {                                                           \
+    const int height = getmaxy((list)->window);               \
+    const int y = (list)->line_selected - (list)->line_offset; \
+                                                              \
+    if (y < 0)                                                \
+      (list)->line_offset += y;                                \
+    else if (y + 1 >= height)                                 \
+      (list)->line_offset += y + 1 - height;                   \
+                                                              \
+    if ((list)->line_offset < 0)                               \
+      (list)->line_offset = 0;                                 \
+    else if ((list)->line_offset >= count)                     \
+      (list)->line_offset = count - 1;                         \
+  }                                                           \
+}
+
+#define list_input_print_(list, line_width, yes_res, no_res)     \
+  const bool selected = (                                       \
+      ((list)->line_selected >= (list)->line_index) &&          \
+      ((list)->line_selected < (list)->line_index + line_width) \
+  );                                                            \
+                                                                \
+  const int y = (list)->line_index - (list)->line_offset; {      \
+                                                                \
+  (list)->line_index += line_width;                             \
+                                                                \
+  if (y + line_width < 1)                                       \
+    return yes_res;                                             \
+                                                                \
+  const int height = getmaxy((list)->window);                   \
+                                                                \
+  if (y >= height)                                              \
+    return no_res;                                              \
+}
+
+#define list_input_print_gnunet(list, line_width) \
+    list_input_print_(list, line_width, GNUNET_YES, GNUNET_NO)
+
+#define list_input_print(list, line_width) \
+    list_input_print_(list, line_width, , )
+
+#endif /* UI_LIST_INPUT_H_ */