first version of af oda in lua

scripts/1-af.lua

@@ -0,0 +1,81 @@
+_Af_Oda_id = nil
+_Af_Oda_state = 0
+_Af_Oda_len = 0
+_Af_Oda_afs = {}
+
+---@param freq number
+---@return table
+local function encode_af(freq)
+    local out = {}
+    if(freq >= 87.6 and freq <= 107.9) then
+        table.insert(out, math.tointeger((freq * 10) - 875))
+    elseif freq >= 64.1 and freq <= 88.0 then
+        table.insert(out, math.tointeger((freq * 10) - 384))
+    elseif freq >= 153 and freq <= 279 then
+        table.insert(out, 250) -- LFMF incoming
+        table.insert(out, (freq - 153) / 9 + 1)
+    elseif freq >= 531 and freq <= 1602 then
+        table.insert(out, 250) -- LFMF incoming
+        table.insert(out, (freq - 531) / 9 + 16)
+    end
+    return out
+end
+
+local function get_next_af_oda_group()
+    local af = {0, 0, 0, 0}
+    local num_entries = #_Af_Oda_afs
+
+    local i = 1
+    if _Af_Oda_state == 0 then
+        af[1] = 224 + math.min(_Af_Oda_len, 25)
+        _Af_Oda_state = 1
+        i = 2
+    end
+
+    while i <= 4 do
+        if _Af_Oda_state <= num_entries then
+            af[i] = _Af_Oda_afs[_Af_Oda_state]
+            _Af_Oda_state = _Af_Oda_state + 1
+        else af[i] = 205 end
+        i = i + 1
+    end
+
+    if _Af_Oda_state > num_entries then _Af_Oda_state = 0 end
+
+    local b = (7 << 12)
+    for j = 1, 4 do
+        local bit8 = (math.tointeger(af[j]) >> 8) & 0x01
+        b = b | (bit8 << (j - 1))
+    end
+
+    return b, ((math.tointeger(af[1]) & 0xFF) << 8) | (math.tointeger(af[2]) & 0xFF), ((math.tointeger(af[3]) & 0xFF) << 8) | (math.tointeger(af[4]) & 0xFF)
+end
+
+local function init_af_oda()
+    if _Af_Oda_id == nil then
+        _Af_Oda_id = register_oda(7, false, 0x6365, 0)
+        set_oda_handler(_Af_Oda_id, function()
+            local b, c, d = get_next_af_oda_group()
+            return true, b, c, d
+        end)
+    end
+end
+
+---Sets the AFs included in the ODA
+---@param afs table List of numbers (e.g., {98.1, 102.5})
+function set_rds_af_oda(afs)
+    _Af_Oda_afs = {}
+    _Af_Oda_len = #afs
+    for _, f in ipairs(afs) do
+        local codes = encode_af(f)
+        for _, code in ipairs(codes) do
+            table.insert(_Af_Oda_afs, code)
+        end
+    end
+    _Af_Oda_state = 0
+    if _Af_Oda_id == nil then init_af_oda() end
+end
+
+function on_state()
+    init_af_oda()
+end