lua add ability to use custom kbd layouts

bring custom keyboard layouts to lua
conversion to the proper format requires create_kbd_layout.lua
just pass a lua string with your desired layout

Change-Id: I14a392410846311a4f3cf8dda0e88d39834d0418

apps/plugins/lua/include_lua/create_kbd_layout.lua

@@ -0,0 +1,81 @@
+--create keyboard layout
+--BILGUS 4/2021
+local function encode_short(n)
+    return string.char(bit.band(0x00FF, n), bit.rshift(bit.band(0xFF00, n), 8))
+end
+
+function utf8decode(str)
+    local INVALID = 0xfffd
+    local t = {}
+    local function check_char(c)
+        local tail = false
+        local code
+        c = string.byte(c)
+        if (c <= 0x7f) or (c >= 0xc2) then
+            -- Start of new character
+            if (c < 0x80) then        -- U-00000000 - U-0000007F, 1 string.byte
+                code = c;
+            elseif (c < 0xe0) then   -- U-00000080 - U-000007FF, 2 string.bytes
+                tail = 1;
+                code = bit.band(c, 0x1f)
+            elseif (c < 0xf0) then   -- U-00000800 - U-0000FFFF, 3 string.bytes
+                tail = 2;
+                code = bit.band(c, 0x0f)
+            elseif (c < 0xf5) then -- U-00010000 - U-001FFFFF, 4 string.bytes
+                tail = 3;
+                code = bit.band(c, 0x07)
+            else
+                -- Invalid size
+                code = 0xfffd;
+            end
+
+            while tail and c ~= 0 do
+                tail = tail - 1
+                if bit.band(c, 0xc0) == 0x80 then
+                    -- Valid continuation character
+                    code = bit.bor(bit.lshift(code, 6),bit.band(c, 0x3f))
+                else
+                    -- Invalid continuation char
+                    code = INVALID;
+                    break;
+                end
+            end
+        else
+            -- Invalid UTF-8 char
+            code = INVALID;
+        end
+        -- currently we don't support chars above U-FFFF
+        t[#t + 1 ] = encode_short((code < 0x10000) and code or 0xfffd)
+    end
+    str:gsub(".", check_char) -- run check function for every char
+    return table.concat(t)
+end
+
+function create_keyboard_layout(s_layout)
+    local insert = table.insert
+    lines = {}
+
+    local t={}
+    for str in string.gmatch(s_layout, "([^\n]+)") do
+        local len = string.len(str)
+        lines[#lines + 1] =
+        table.concat({encode_short(len), utf8decode(str)})
+    end
+    lines[#lines + 1] = encode_short(0xFEFF)
+
+    return table.concat(lines)
+end
+
+--[[
+local name = "Test_KBD_LAYOUT_" .. tostring(1)
+local test = create_keyboard_layout("ABCDEFGHIJKLM\nNOPQRSTUVWXYZ\n0123456789")
+local file = io.open('/' .. name, "w+") -- overwrite, rb ignores the 'b' flag
+file:write(test)-- write the layout to the file now
+file:close()
+
+if not file then
+    rb.splash(rb.HZ, "Error opening /" .. name)
+    return
+end
+rb.kbd_input(name, test)
+]]