local function timeTest(str, f, ...)
  local clock = os.clock()
  local r = f(...)
  print(str, os.clock()-clock)
  return r
end

function main()
  local obj = {}
  for i=1,1000 do
    obj[i] = {}
    for j=1,100,3 do
      obj[i][j] = math.random()
      obj[i][j+1] = "n:"..math.random()
      obj[i][j+2] = (math.random()>0.5 and true or false)
    end
  end
  
  local s = ""
  local _obj
  print("Testing:")
  --s = timeTest("serialize():", serialize, obj)
  --_obj = timeTest("unserialize():", unserialize, s)
  
  --print()
  --s = timeTest("serialization.serialize():", serialization.serialize, obj)
  --_obj = timeTest("serialization.unserialize():", serialization.unserialize, s)
  
  --print()
  s = timeTest("table.toString():", table.toString, obj)
  _obj = timeTest("table.fromString():", table.fromString, s)
end

-- ********************************************************************************** --
-- **   Serialize table to string                                                  ** --
-- **                                                                              ** --
-- **   Modified version of http://l...content-available-to-author-only...s.org/wiki/SaveTableToFile              ** --
-- **                                                                              ** --
-- ********************************************************************************** --
 
-- declare local variables
--// exportstring( string )
--// returns a "Lua" portable version of the string
local function exportstring( s )
  return string.format("%q", s)
end
 
local insert  = table.insert
local tostring= tostring
local ipairs  = ipairs
local pairs   = pairs
local type    = type
 
--// The Save Function
function table.toString(tbl)
  if type(tbl) ~= 'table' then return "" end -- Argument not a table
 
  local charS,charE = "   ","\n"
  local s_tbl = {}
 
  -- initiate variables for save procedure
  local tables,lookup = { tbl },{ [tbl] = 1 }
  insert(s_tbl, "return {"..charE )
 
  for idx,t in ipairs( tables ) do
    insert(s_tbl, "-- Table: {"..idx.."}"..charE )
    insert(s_tbl, "{"..charE )
    local thandled = {}
 
    for i,v in ipairs( t ) do
      thandled[i] = true
      local stype = type( v )
      -- only handle value
      if stype == "table" then
        if not lookup[v] then
          insert( tables, v )
          lookup[v] = #tables
        end
        insert(s_tbl, charS.."{"..lookup[v].."},"..charE )
      elseif stype == "string" then
        insert(s_tbl,  charS..exportstring( v )..","..charE )
      elseif stype == "number" or stype == "boolean" then
        insert(s_tbl,  charS..tostring( v )..","..charE )
      end
    end
 
    for i,v in pairs( t ) do
      -- escape handled values
      if (not thandled[i]) then
 
        local str = ""
        local stype = type( i )
        -- handle index
        if stype == "table" then
          if not lookup[i] then
            insert( tables,i )
            lookup[i] = #tables
          end
          str = charS.."[{"..lookup[i].."}]="
        elseif stype == "string" then
          str = charS.."["..exportstring( i ).."]="
        elseif stype == "number" or stype == "boolean" then
          str = charS.."["..tostring( i ).."]="
        end
 
        if str ~= "" then
          stype = type( v )
          -- handle value
          if stype == "table" then
            if not lookup[v] then
              insert( tables,v )
              lookup[v] = #tables
            end
            insert(s_tbl, str.."{"..lookup[v].."},"..charE )
          elseif stype == "string" then
            insert(s_tbl, str..exportstring( v )..","..charE )
          elseif stype == "number" or stype == "boolean" then
            insert(s_tbl, str..tostring( v )..","..charE )
          end
        end
      end
    end
    insert(s_tbl, "},"..charE )
  end
  insert(s_tbl, "}" )
 
  return table.concat(s_tbl)
end
 
--// The Load Function
function table.fromString(s)
  if not s then return end -- Argument not string
  local ftables = loadstring(s)
  if not ftables then return end -- String cant be parsed into function
  local tables = ftables()
  for idx = 1,#tables do
    local tolinki = {}
    for i,v in pairs( tables[idx] ) do
      if type( v ) == "table" then
        tables[idx][i] = tables[v[1]]
      end
      if type( i ) == "table" and tables[i[1]] then
        insert( tolinki,{ i,tables[i[1]] } )
      end
    end
    -- link indices
    for _,v in ipairs( tolinki ) do
      tables[idx][v[2]],tables[idx][v[1]] =  tables[idx][v[1]],nil
    end
  end
  return tables[1]
end



local function serializeImpl( t, tTracking )  
  local sType = type(t)
  if sType == "table" then
    if tTracking[t] ~= nil then
      error( "Cannot serialize table with recursive entries" )
    end
    tTracking[t] = true
    
    local result = "{"
    for k,v in pairs(t) do
      result = result..("["..serializeImpl(k, tTracking).."]="..serializeImpl(v, tTracking)..",")
    end
    result = result.."}"
    return result
    
  elseif sType == "string" then
    return string.format( "%q", t )
  
  elseif sType == "number" or sType == "boolean" or sType == "nil" then
    return tostring(t)
    
  else
    error( "Cannot serialize type "..sType )
    
  end
end

function serialize( t )
  local tTracking = {}
  return serializeImpl( t, tTracking )
end

function unserialize( s )
  local func, e = loadstring( "return "..s, "serialize" )
  if not func then
    return s
  else
    --setfenv( func, {} )
    return func()
  end
end


serialization = {}

-- Important: pretty formatting will allow presenting non-serializable values
-- but may generate output that cannot be unserialized back.
function serialization.serialize(value, pretty)
  local kw =  {["and"]=true, ["break"]=true, ["do"]=true, ["else"]=true,
               ["elseif"]=true, ["end"]=true, ["false"]=true, ["for"]=true,
               ["function"]=true, ["goto"]=true, ["if"]=true, ["in"]=true,
               ["local"]=true, ["nil"]=true, ["not"]=true, ["or"]=true,
               ["repeat"]=true, ["return"]=true, ["then"]=true, ["true"]=true,
               ["until"]=true, ["while"]=true}
  local id = "^[%a_][%w_]*$"
  local ts = {}
  local function s(v, l)
    local t = type(v)
    if t == "nil" then
      return "nil"
    elseif t == "boolean" then
      return v and "true" or "false"
    elseif t == "number" then
      if v ~= v then
        return "0/0"
      elseif v == math.huge then
        return "math.huge"
      elseif v == -math.huge then
        return "-math.huge"
      else
        return tostring(v)
      end
    elseif t == "string" then
      return string.format("%q", v):gsub("\\\n","\\n")
    elseif t == "table" and pretty and getmetatable(v) and getmetatable(v).__tostring then
      return tostring(v)
    elseif t == "table" then
      if ts[v] then
        if pretty then
          return "recursion"
        else
          error("tables with cycles are not supported")
        end
      end
      ts[v] = true
      local i, r = 1, nil
      local f
      if pretty then
        local ks, sks, oks = {}, {}, {}
        for k in pairs(v) do
          if type(k) == "number" then
            table.insert(ks, k)
          elseif type(k) == "string" then
            table.insert(sks, k)
          else
            table.insert(oks, k)
          end
        end
        table.sort(ks)
        table.sort(sks)
        for _, k in ipairs(sks) do
          table.insert(ks, k)
        end
        for _, k in ipairs(oks) do
          table.insert(ks, k)
        end
        local n = 0
        f = table.pack(function()
          n = n + 1
          local k = ks[n]
          if k ~= nil then
            return k, v[k]
          else
            return nil
          end
        end)
      else
        f = table.pack(pairs(v))
      end
      for k, v in table.unpack(f) do
        if r then
          r = r .. "," .. (pretty and ("\n" .. string.rep(" ", l)) or "")
        else
          r = "{"
        end
        local tk = type(k)
        if tk == "number" and k == i then
          i = i + 1
          r = r .. s(v, l + 1)
        else
          if tk == "string" and not kw[k] and string.match(k, id) then
            r = r .. k
          else
            r = r .. "[" .. s(k, l + 1) .. "]"
          end
          r = r .. "=" .. s(v, l + 1)
        end
      end
      ts[v] = nil -- allow writing same table more than once
      return (r or "{") .. "}"
    else
      if pretty then
        return tostring(t)
      else
        error("unsupported type: " .. t)
      end
    end
  end
  local result = s(value, 1)
  local limit = type(pretty) == "number" and pretty or 10
  if pretty then
    local truncate = 0
    while limit > 0 and truncate do
      truncate = string.find(result, "\n", truncate + 1, true)
      limit = limit - 1
    end
    if truncate then
      return result:sub(1, truncate) .. "..."
    end
  end
  return result
end

function serialization.unserialize(data)
  --checkArg(1, data, "string")
  local result, reason = load("return " .. data, "=data", _, {math={huge=math.huge}})
  if not result then
    return nil, reason
  end
  local ok, output = pcall(result)
  if not ok then
    return nil, output
  end
  return output
end


main()