root/trunk/samples/lzw.md

module lzw

function main(vararg)
{
    if(#vararg < 2)
    {
        writefln("Usage: mdcl lzw.md inputFile outputFile")
        return
    }
    
    local input = io.File(vararg[0], io.FileMode.In)
    local output = io.File(vararg[1], io.FileMode.OutNew)
    local dict = {}
    local w = ""
    local code
    
    for(code = 0; code < 128; code++)
        dict[toString(toChar(code))] = code
    
    local shortCount = 0
    output.writeInt(0)
    
    for(local i = 0, local size = input.size(); i < size; i++)
    {
        local k = input.readChar()
    
        local wk = w ~ k
    
        if(wk in dict)
            w = wk
        else
        {
            output.writeShort(dict[w])
            shortCount++
            dict[wk] = code
            code++
            w = toString(k)
        }
    }
    
    output.flush()
    output.position(0)
    output.writeInt(shortCount)
    
    input.close()
    output.close()
}