lua fix yellow and add temploader

temp loader allows some lua requires to be loaded and
later garbage collected unfortunately the module needs to be formatted
in such a way to pass back a call table in order to keep the functions
within from being garbage collected too early

BE AWARE this bypasses the module loader which would allow code reuse
so if you aren't careful this memory saving tool could spell disaster
for free RAM if you load the same code multiple times

Change-Id: I0b6f81e481b8c779edbd620c8403794f8353926f

4 files changed, 102 insertions, 58 deletions

diff --git a/apps/plugins/lua/include_lua/create_kbd_layout.lua b/apps/plugins/lua/include_lua/create_kbd_layout.lua
index bb3ab297ca..3d8f343cc9 100644
--- a/apps/plugins/lua/include_lua/create_kbd_layout.lua
+++ b/apps/plugins/lua/include_lua/create_kbd_layout.lua
@@ -1,74 +1,82 @@
 --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
+-- kbdlayout = require("create_kbd_layout")
+-- local layout = kbdlayout.create_keyboard_layout("abcd")
+local _kbdlayout = {} do
 
-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
+    local function encode_short(n)
+        return string.char(bit.band(0x00FF, n), bit.rshift(bit.band(0xFF00, n), 8))
+    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))
+    local 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 continuation char
-                    code = INVALID;
-                    break;
+                    -- 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
-        else
-            -- Invalid UTF-8 char
-            code = INVALID;
+            -- currently we don't support chars above U-FFFF
+            t[#t + 1 ] = encode_short((code < 0x10000) and code or 0xfffd)
         end
-        -- currently we don't support chars above U-FFFF
-        t[#t + 1 ] = encode_short((code < 0x10000) and code or 0xfffd)
+        str:gsub(".", check_char) -- run check function for every char
+        return table.concat(t)
     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 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)
+        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)
+        return table.concat(lines)
+    end
+    _kbdlayout.create_keyboard_layout = create_keyboard_layout
+    _kbdlayout.utf8decode = utf8decode
 end
 
+
 --[[
 local name = "Test_KBD_LAYOUT_" .. tostring(1)
-local test = create_keyboard_layout("ABCDEFGHIJKLM\nNOPQRSTUVWXYZ\n0123456789")
+local test = _kbdlayout.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()
@@ -79,3 +87,4 @@ if not file then
 end
 rb.kbd_input(name, test)
 ]]
+return _kbdlayout
diff --git a/apps/plugins/lua/include_lua/temploader.lua b/apps/plugins/lua/include_lua/temploader.lua
new file mode 100644
index 0000000000..69eae468a8
--- /dev/null
+++ b/apps/plugins/lua/include_lua/temploader.lua
@@ -0,0 +1,30 @@
+--[[
+temp loader allows some lua requires to be loaded and later garbage collected
+unfortunately the module needs to be formatted in such a way to pass back a 
+call table in order to keep the functions within from being garbage collected 
+too early
+
+BE AWARE this bypasses the module loader which would allow code reuse
+so if you aren't careful this memory saving tool could spell disaster
+for free RAM if you load the same code multiple times
+--]]
+
+
+local function tempload(modulename)
+  --http://lua-users.org/wiki/LuaModulesLoader
+  local errmsg = ""
+  -- Find source
+  local modulepath = string.gsub(modulename, "%.", "/")
+  for path in string.gmatch(package.path, "([^;]+)") do
+    local filename = string.gsub(path, "%?", modulepath)
+    local file = io.open(filename, "r")
+    if file then
+      -- Compile and return the module
+      return assert(loadstring(assert(file:read("*a")), filename))()
+    end
+    errmsg = errmsg.."\n\tno file '"..filename.."' (temp loader)"
+  end
+  return errmsg
+end
+
+return tempload
diff --git a/apps/plugins/lua/lua.make b/apps/plugins/lua/lua.make
index eada6b370f..60dfd24cdd 100644
--- a/apps/plugins/lua/lua.make
+++ b/apps/plugins/lua/lua.make
@@ -22,7 +22,8 @@ LUA_INCLUDELIST := $(addprefix $(LUA_BUILDDIR)/,audio.lua blit.lua color.lua \
 						math_ex.lua print.lua timer.lua playlist.lua pcm.lua \
 						sound.lua rbcompat.lua rbsettings.lua poly_points.lua \
 						printtable.lua printmenus.lua printsubmenu.lua \
-						menubuttons.lua menucoresettings.lua create_kbd_layout.lua)
+						menubuttons.lua menucoresettings.lua create_kbd_layout.lua \
+                        temploader.lua)
 
 ifndef APP_TYPE
     ROCKS += $(LUA_BUILDDIR)/lua.rock
diff --git a/apps/plugins/lua/rocklib.c b/apps/plugins/lua/rocklib.c
index 050fbc73b2..2672d446fc 100644
--- a/apps/plugins/lua/rocklib.c
+++ b/apps/plugins/lua/rocklib.c
@@ -153,7 +153,7 @@ RB_WRAP(kbd_input)
 
     const char *input = lua_tostring(L, 1);
     size_t layout_len;
-    const char *layout = lua_tolstring(L, 2, &layout_len);
+    const unsigned char *layout = lua_tolstring(L, 2, &layout_len);
     char *buffer = luaL_prepbuffer(&b);
 
     if(input != NULL)
@@ -161,8 +161,12 @@ RB_WRAP(kbd_input)
     else
         buffer[0] = '\0';
 
-    if(layout_len <= 1 || (unsigned short)layout[layout_len - 1] != 0xFFFE)
+    if(layout_len <= 2 ||
+       layout[layout_len - 1] != 0xFE ||
+       layout[layout_len - 2] != 0xFF)
+    {
         layout = NULL;
+    }
 
     if(!rb->kbd_input(buffer, LUAL_BUFFERSIZE, (unsigned short *)layout))
     {