Thai cp874 (Windows 874) to UTF-8

Iguana will support languages encoded in UTF-8, unfortunately some systems use cp874 (Windows 874) and Thai language users cannot pipe inbound data to Iguana because of encoding mismatch.

Apparently it is easy to transcode from cp874 to UTF-8 using pretty trivial module offered below.

Say your inbound data comes in files encoded in cp874.

In Iguana channel Source component Translator script read this file content in binary mode (AKA ‘rb’)

Pipe the content of file through below module calling function cp874toUTF8()

utf8sOutData = transcode.cp874toUTF8(cp874InData)

Push UTF-8 result, calling queue.push{}, to Iguana queue for further normal processing by Filter or Destination component of the channel.

transcode={}

function transcode.convert(Data, Map)
   local j = 1
   local p = {}

   for i=1, #Data do
   local C = Map[Data:byte(i)]
   if C then
         p[#p+1] = Data:sub(j,i-1)
         p[#p+1] = C
         j = i + 1
      end
   end
   p[#p+1] = Data:sub(j,#Data)
   return table.concat(p)
end

function transcode.cp874toUTF8(D)
   local D2=''
   local d1=string.char(0xe0)..string.char(0xb8)
   local d2=string.char(0xe0)..string.char(0xb9)

   local cp874CodeSet={
      [128]='172',[133]='166',[145]='152',
      [146]='153',[147]='156',[148]='157',
      [149]='162',[150]='147',[151]='148'
   }
   
   local cp874List={128,133,145,146,147,148,149,150,151}
   
   local function din(n)
      for k,v in ipairs(cp874List) do
         if n==v then return true end
      end
   end
   
   for i=1,#D do
      if string.byte(D,i) < 0x80 then
         D2=D2..D:sub(i,i)
      elseif string.byte(D,i) > 0x9f then
         if string.byte(D,i) < 0xe0 then
            D2=D2..d1..
            string.char(string.byte(D,i)-0x20)
         elseif string.byte(D,i) > 0xdf and string.byte(D,i) < 0xfc then
            D2=D2..d2..
            string.char(string.byte(D,i)-0x60)
         elseif din(string.byte(D,i)) then
            D2=D2..
            transcode.convert(
               string.byte(D,i),cp874CodeSet)
         end
      end
      
   end
   
   return D2
end

Let me know if it works for you. Comments needed. Happy transcoding.