Array/Table save and load in LUA

Does anyone know how I would be able to save-to-file a Multi-Dimensional Array in LUA?

For example a rather large 2048x2048x10 array, all Integers. I "simply" want to be able to be able to save the array to a file like MMF does, and load it back into an array.

I think you will find this entire thread relevant to your situation (but it won't help you write array data to disk): http://www.clickteam.com/epicenter/ubbthreads.php?ubb=showflat&Number=157991#Post1579 91

You could use an MMF array to read from the lua array, then save that MMF array to disk (and vice versa for loading it). But yes thats quite the nifty array you put together!

wow i thought 500 x 500 x 10 was big lol.
The way I do it is 'share' the values with an MMF array.
Which means when you want to save, loop through each index and write into an mmf array and then save that. Then do the reverse when loading.
Basically as Pixeltheif said.

What I would like to see is the ability for lua to read/write directly to an MMF array, but doubt that will happen. Could make MMF unstable.

zellix shared some information with my on the subject. It might get added.

Aye, but running in MMF, you'll want to have VERY optimized code if you want this to take less than 5 minutes to write/read the array each time. I didn't notice how large your array was when you listed it- even in a binary array with the minimum size, 2048 * 2048 * 10 size of integers will requires 160 megabytes of memory for the application, and then 160 megabytes on the harddrive to write to

Scratch what I said about using an array class- with something this horrendously large, you'll want to use the Binary Object of MMF2, and simply write the values to memory in the binary data rather than allocating such a ridiculously big array in MMF2 (which probably wouldn't even work for 160 megabytes)

Quote:

---

zellix shared some information with my on the subject. It might get added.

---

after rereading the size, I think being able to export to a binary object instead of an array object might be more fitting here. Especially as your array.dll is already storing the data as an unformatted binary string anyway, isn't it? So it shouldn't be hard at all to export, hehe

MMF arrays, if my information is correct, should store numbers as compactly as array.dll, or the binary object. What you don't get is flexibility over the width of the numeric type.

Of course, an import/export for array.dll itself wouldn't be bad either.

Ya, the size of my array might sound obscene, but I assure you it is for the server-side only, and the client side arrays will not be so massive (atleast if I do it correctly) then again, 160MB these days in memory isn't that much, especially if it is the game's foundation. I even toyed with a 4096x4096x10 array, but maybe later, because that is just huge ha.

But, referring to passing the values to and from lua<->MMF I have done that, and with that size of an array, it is very very slow. I optimized it the best I could to my knowledge and it was still taking minutes, which would be unacceptable in most cases. I will try this array.dll out though, had no clue about it.

Why don´t write your own save/load function?
Something like that:

Code:

---


 function load(pfad)
 local text=""
 local char=""
 local n=1
 local temp={}
 
 file = io.open (pfad,"r")
 if file==nil then
        return(nil)
 end
 content = file:read("*a")
 file:close()

 for i=1,string.len(content) do
  char=(string.char(string.byte(content,i) ))
 
  if char~="|" then
    text=text..char
  else
  temp[n]=tonumber(text)
  n=n+1
  text=""
  end
 
 end

 return(temp)
end


function save(pfad,Array)
 file = io.open (pfad,"w")

 for i=1, table.getn(Array) do
  file:write(tostring(Array[i]).."|")
 end

 file:close()
end

---

Well the existing MMF array saves and loads almost instantly, even at 160mb sizes. It also already has pre-sizing built in. Overall, if Retriever is able to link it in LUA like other MMF objects, it seems like the best choice. Looking at the structure of the MMF Array, it doesn't look as bad as I thought, and looks quite efficient actually. I do agree the downside to it is not being able to specify the value type, but that doesn't seem to be too big of a deal.

But the save/load in LUA you posted is appreciated. It actually looks more straight-forward than the others I encountered and is good to have knowledge of.

I have tried adding limited support for modifying MMF Array objects directly to the experimental MMFI: http://www.clickteam.com/epicenter/ubbthreads.php?ubb=showflat&Number=176317#Post1763 17

mmfi.dll is a significant departure from the MMF Interface that's build directly into XLua itself, but I will not be adding new object support to the build-in interface.

TYTYTYTYTY :D

So how exactly do you reference an MMF array? I checked the Documentation and couldn't find it. I saw adding an object via it's Fixed ID, but array's don't have IDs? I am probably just blind though.

Arrays do have fixed IDs. They are accessed from the expression menu. There are other ways to get at them but in this case a fixed ID would be the most straightforward.