support utf8 search input

1 files changed, 33 insertions, 12 deletions

diff --git a/main.lua b/main.lua
index 560a376..74f7178 100644
--- a/main.lua
+++ b/main.lua
@@ -57,6 +57,23 @@ local function strip(str)
 	return (str:gsub('^%s*(.-)%s*$', '%1'))
 end
 
+local function utf8_seek(str, pos, n)
+	local step = n > 0 and 1 or -1
+	local test = n > 0
+		and function() return pos > #str end
+		or function() return pos <= 1 end
+
+	while n ~= 0 and not test() do
+		repeat
+			pos = pos + step
+		until test() or bit.band(str:byte(pos), 0xc0) ~= 0x80
+
+		n = n - step
+	end
+
+	return pos
+end
+
 local function read_json_file(fn)
 	local f = io.open(script_dir .. '/' .. fn, 'r')
 	if not f then
@@ -553,7 +570,7 @@ local function update_search_matches()
 	update_search_osd()
 end
 
-local function search_input_text(event)
+local function search_input_char(event)
 	if event.event ~= 'down' and event.event ~= 'repeat' then
 		return
 	end
@@ -561,30 +578,32 @@ local function search_input_text(event)
 	local menu = menus[depth]
 	local bc, ac = split_search_text()
 	menu.search_text = bc .. event.key_text .. ac
-	menu.search_cursor = menu.search_cursor + 1
+	menu.search_cursor = menu.search_cursor + #event.key_text
 	update_search_matches()
 end
 
 local function search_input_bs()
 	local menu = menus[depth]
-	if menu.search_cursor == 1 then
+	if menu.search_cursor <= 1 then
 		return
 	end
 
-	local bc, ac = split_search_text()
-	menu.search_text = bc:sub(1, -2) .. ac
-	menu.search_cursor = menu.search_cursor - 1
+	local pos = utf8_seek(menu.search_text, menu.search_cursor, -1)
+	menu.search_text = menu.search_text:sub(1, pos - 1) ..
+		menu.search_text:sub(menu.search_cursor)
+	menu.search_cursor = pos
 	update_search_matches()
 end
 
 local function search_input_del()
 	local menu = menus[depth]
-	if menu.search_cursor == #menu.search_text + 1 then
+	if menu.search_cursor > #menu.search_text then
 		return
 	end
 
-	local bc, ac = split_search_text()
-	menu.search_text = bc .. ac:sub(2)
+	menu.search_text = menu.search_text:sub(1, menu.search_cursor - 1) ..
+		menu.search_text:sub(
+			utf8_seek(menu.search_text, menu.search_cursor, 1))
 	update_search_matches()
 end
 
@@ -600,11 +619,13 @@ local function set_search_cursor(pos)
 end
 
 local function search_cursor_left()
-	set_search_cursor(menus[depth].search_cursor - 1)
+	local menu = menus[depth]
+	set_search_cursor(utf8_seek(menu.search_text, menu.search_cursor, -1))
 end
 
 local function search_cursor_right()
-	set_search_cursor(menus[depth].search_cursor + 1)
+	local menu = menus[depth]
+	set_search_cursor(utf8_seek(menu.search_text, menu.search_cursor, 1))
 end
 
 local function search_cursor_start()
@@ -674,7 +695,7 @@ end
 function bind_search_keys()
 	unbind_keys()
 
-	bind_key('ANY_UNICODE', search_input_text, {complex=true})
+	bind_key('ANY_UNICODE', search_input_char, {complex=true})
 	bind_key('BS', search_input_bs, {repeatable=true})
 	bind_key('DEL', search_input_del, {repeatable=true})