[gtksourceview/wip/chergert/vim: 226/293] add rot13 command

[Christian Hergert <chergert src gnome org>]

commit 03ce8477462d2be81781435b96ebbb448e3436be
Author: Christian Hergert <chergert redhat com>
Date:   Tue Nov 2 14:58:33 2021 -0700

    add rot13 command

 gtksourceview/vim/gtk-source-vim-command.c | 50 ++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
---
diff --git a/gtksourceview/vim/gtk-source-vim-command.c b/gtksourceview/vim/gtk-source-vim-command.c
index 0e126881..3ede431c 100644
--- a/gtksourceview/vim/gtk-source-vim-command.c
+++ b/gtksourceview/vim/gtk-source-vim-command.c
@@ -315,6 +315,55 @@ gtk_source_vim_command_downcase (GtkSourceVimCommand *self)
        return gtk_source_vim_command_change_case (self, GTK_SOURCE_CHANGE_CASE_LOWER);
 }
 
+static char *
+rot13 (const char *str)
+{
+       GString *ret = g_string_new (NULL);
+
+       for (const char *c = str; *c; c = g_utf8_next_char (c))
+       {
+               gunichar ch = g_utf8_get_char (c);
+
+               if ((ch >= 65 && ch < 90) || (ch >= 97 && ch < 122))
+               {
+                       if (g_ascii_tolower (ch) < 'n')
+                               g_string_append_c (ret, ch + 13);
+                       else
+                               g_string_append_c (ret, ch - 13);
+               }
+               else
+               {
+                       g_string_append_unichar (ret, ch);
+               }
+       }
+
+       return g_string_free (ret, FALSE);
+}
+
+static void
+gtk_source_vim_command_rot13 (GtkSourceVimCommand *self)
+{
+       GtkSourceBuffer *buffer;
+       GtkTextIter iter;
+       GtkTextIter selection;
+       char *text;
+       char *new_text;
+
+       buffer = gtk_source_vim_state_get_buffer (GTK_SOURCE_VIM_STATE (self), &iter, &selection);
+       text = gtk_text_iter_get_slice (&iter, &selection);
+       new_text = rot13 (text);
+
+       gtk_source_vim_state_begin_user_action (GTK_SOURCE_VIM_STATE (self));
+       gtk_text_buffer_delete (GTK_TEXT_BUFFER (buffer), &iter, &selection);
+       gtk_text_buffer_insert (GTK_TEXT_BUFFER (buffer), &iter, new_text, -1);
+       gtk_source_vim_state_end_user_action (GTK_SOURCE_VIM_STATE (self));
+
+       gtk_source_vim_state_set_can_repeat (GTK_SOURCE_VIM_STATE (self), TRUE);
+
+       g_free (text);
+       g_free (new_text);
+}
+
 static void
 gtk_source_vim_command_undo (GtkSourceVimCommand *self)
 {
@@ -556,6 +605,7 @@ gtk_source_vim_command_class_init (GtkSourceVimCommandClass *klass)
        ADD_COMMAND ("toggle-case",    gtk_source_vim_command_toggle_case);
        ADD_COMMAND ("upcase",         gtk_source_vim_command_upcase);
        ADD_COMMAND ("downcase",       gtk_source_vim_command_downcase);
+       ADD_COMMAND ("rot13",          gtk_source_vim_command_rot13);
 #undef ADD_COMMAND
 }