Saving/Loading simple tables with a game

[Gedemon]

Not fully tested, so use it carefully, I've no idea of the size limit and performance on large table.

I tested it by saving/loading a table with all plots coordinates of a small map and some data for each plot.

In a lua file loaded as an <UserInterface> component (as GameConfiguration.SetValue doesn't exist in scripts contexts):

-----------------------------------------------------------------------------------------
--    FILE:     SaveLoad.lua
--  Gedemon (2017)
--  Loading/Saving simple tables with the game file using Pickle Table for serialization
--  http://lua-users.org/wiki/PickleTable
-----------------------------------------------------------------------------------------

----------------------------------------------
-- Pickle.lua
-- A table serialization utility for lua
-- Steve Dekorte, http://www.dekorte.com, Apr 2000
-- Freeware
----------------------------------------------

function pickle(t)
  return Pickle:clone():pickle_(t)
end

Pickle = {
  clone = function (t) local nt={}; for i, v in pairs(t) do nt[i]=v end return nt end
}

function Pickle:pickle_(root)
  if type(root) ~= "table" then
    error("can only pickle tables, not ".. type(root).."s")
  end
  self._tableToRef = {}
  self._refToTable = {}
  local savecount = 0
  self:ref_(root)
  local s = ""

  while #(self._refToTable) > savecount do
    savecount = savecount + 1
    local t = self._refToTable[savecount]
    s = s.."{\n"
    for i, v in pairs(t) do
        s = string.format("%s[%s]=%s,\n", s, self:value_(i), self:value_(v))
    end
    s = s.."},\n"
  end

  return string.format("{%s}", s)
end

function Pickle:value_(v)
  local vtype = type(v)
  if     vtype == "string" then return string.format("%q", v)
  elseif vtype == "number" then return v
  elseif vtype == "boolean" then return tostring(v)
  elseif vtype == "table" then return "{"..self:ref_(v).."}"
  else --error("pickle a "..type(v).." is not supported")
  end
end

function Pickle:ref_(t)
  local ref = self._tableToRef[t]
  if not ref then
    if t == self then error("can't pickle the pickle class") end
    table.insert(self._refToTable, t)
    ref = #(self._refToTable)
    self._tableToRef[t] = ref
  end
  return ref
end

----------------------------------------------
-- unpickle
----------------------------------------------

function unpickle(s)
  if type(s) ~= "string" then
    error("can't unpickle a "..type(s)..", only strings")
  end
  local gentables = loadstring("return "..s)
  local tables = gentables()

  for tnum = 1, #(tables) do
    local t = tables[tnum]
    local tcopy = {}; for i, v in pairs(t) do tcopy[i] = v end
    for i, v in pairs(tcopy) do
      local ni, nv
      if type(i) == "table" then ni = tables[i[1]] else ni = i end
      if type(v) == "table" then nv = tables[v[1]] else nv = v end
      t[i] = nil
      t[ni] = nv
    end
  end
  return tables[1]
end



-----------------------------------------------------------------------------------------
-- Load / Save
-- Using Civ6 GameConfiguration
-----------------------------------------------------------------------------------------

-- save
function SaveTableToSlot(t, sSlotName)
    local s = pickle(t)
    GameConfiguration.SetValue(sSlotName, s)
end

-- load
function LoadTableFromSlot(sSlotName)
    local s = GameConfiguration.GetValue(sSlotName)
    if s then
        local t = unpickle(s)
        return t
    else
        print("ERROR: can't load table from ".. tostring(sSlotName))
    end
end

function Initialize()
    ExposedMembers.SaveTableToSlot = SaveTableToSlot
    ExposedMembers.LoadTableFromSlot = LoadTableFromSlot
end
Initialize()

usage (from any context) :
> ExposedMembers.SaveTableToSlot(t, "myTable")
> t = ExposedMembers.LoadTableFromSlot("myTable")


When to save if you can't do it at specific times ?

-- this Lua event is called when listing files on the save/load menu
function SaveMyTable()
    ExposedMembers.SaveTableToSlot(myTable, "myTable")
end
LuaEvents.FileListQueryComplete.Add( SaveMyTable )

-- could get the quicksave key here
function OnInputHandler( pInputStruct:table )
    local uiMsg = pInputStruct:GetMessageType();
    if uiMsg == KeyEvents.KeyDown then
        if pInputStruct:GetKey() == Keys.VK_F5 then -- but the binding can be changed...
            ExposedMembers.SaveTableToSlot(myTable, "myTable")
        end
    end
    -- pInputStruct:IsShiftDown() and pInputStruct:IsAltDown()
end
ContextPtr:SetInputHandler( OnInputHandler, true )

-- Or on this event for quick save
function OnInputAction( actionID )
    if actionID == Input.GetActionId("QuickSave") then
        ExposedMembers.SaveTableToSlot(myTable, "myTable")
    end
end
Events.InputActionTriggered.Add( OnInputAction )

 

[FearSunn]

Thank you @Gedemon for this code snippet! It is lightweight and works perfectly! Exactly what I needed for one of my mods.

 

[Tiramisu]

Yes, this is a very valuable tool for modders. The code works well, but you have forgot to put "Add" in the last line. So it should be

Events.InputActionTriggered.Add( OnInputAction )

to catch quicksave-events.
I guess forgetting the "Add"-statement is a common mistake for Lua-modders.

 

[Gedemon]

Yes, common, thanks, edited.

 

[TheMarshmallowBear]

OH MY GOD I NEEDED THIS. I've been trying and looking EVERYWHERE and it was right under my nose! This is perfect! Thank you Gedemon!

 

[Gedemon]

there is an official method to save/load table, the serializer from Firaxis is faster as it runs in gamecore

-- ===========================================================================
--    Serialize custom data in the custom data table.
--    key        must be a string
--    value    can be anything
-- ===========================================================================
function WriteCustomData( key:string, value )
    local pParameters :table = UI.GetGameParameters():Add("CustomData");
    if pParameters ~= nil then
        pParameters:Remove( key );
        local pData:table = pParameters:Add( key );
        pData:AppendValue( value );
    else
        UI.DataError("Could not write CustomData: ",key,value);
    end
end

-- ===========================================================================
--    Read back custom data, returns NIL if not found.
--    key        must be a string
--    RETURNS: all values from the associated key (or nil if key isn't found)
-- ===========================================================================
function ReadCustomData( key:string )
    local pParameters    :table = UI.GetGameParameters():Get("CustomData");
    local kReturn        :table = {};
    if pParameters ~= nil then
        local pValues:table = pParameters:Get( key );       
        -- No key or empty key?  Return nil...
        if pValues == nil then
            return nil;
        end
        local count:number = pValues:GetCount();
        if count == 0 then
            return nil;
        end
        for i = 1, count, 1 do
            local value = pValues:GetValueAt(i-1);
            table.insert(kReturn, value);
        end
    else
        return nil;
    end
    return unpack(kReturn);
end