Run length encoding (RLE) with patterns more than a character long

[hasanchik]

Hi there,

So when I do post it’s mostly just some really weird undebuggable stuff. Except every time I did end up debugging it. But here’s something I can’t debug: my creativity (lol)

Ok but seriously i’m having difficulty making a RLE system that scans patterns of multiple characters. Here is the problem (more like problem solving) i’m having:
A conventional RLE system only scans individual repeating characters. This type of RLE is very easy to code.

aaavvvvccccassss = 3a4v4ca4s

But let’s say we have a repeating pattern of characters. Without manually defining how long a pattern is how would one be able to

XAXAXAGMGMGMLALLALLALLALBLOLBLOL = XA|4|GM|3|LAL|4|BLOL|2|

Specifically the problem i’m having is to find out what the pattern is. LALLAL could be the pattern, but LAL is just more efficient. I’m hoping you can give me a starting point to work upon.

(PS: I haven’t used regex or things like that before, so if this can be easily done with it please do tell me)

[hasanchik]

--Run length encode
--Found solution to my pattern length finding problems
--Amount pointer comes AFTER all of the data
--Please feed this functions LISTS
function encodingLibrary.RLEncode(itemTable: {any}) : string
	table.insert(itemTable, "placeholderencode")
	local finalString = ""
	local currentFindingPattern = itemTable[1]
	local lastFindingPattern = itemTable[1]
	local repeatingPatterns = 0
	for i, currentFindingPattern in pairs(itemTable) do
		if currentFindingPattern == lastFindingPattern then
			repeatingPatterns += 1
		else
			--if repeatingPatterns > 1 then
				--this list's id is nothing to save on a bit of space 
			finalString ..= lastFindingPattern .. "{,".. encodingLibrary.ToHigherbase(repeatingPatterns) .."}"
			--end
			repeatingPatterns = 1
		end
		--print(currentFindingPattern, lastFindingPattern, repeatingPatterns, finalString)
		lastFindingPattern = currentFindingPattern
	end
	return finalString
end

--Somehow made this work all in one run
function encodingLibrary.RLDecode(_string : string) : {any}
	local finalTable = {}
	local currentCharacter = ""
	local currentString = ""
	local tableType = ""
	local repeatAmount = ""
	local i = 0
	--print(_string)
	while i < string.len(_string) do
		i += 1
		currentCharacter = string.sub(_string, i, i)
		--print(currentCharacter)
		--print(tableType)
		local contentateString = true
		if currentCharacter == "{" then
			if tableType == "justRepeat" then --There is only one data table for every item.
			--	currentString ..= currentCharacter
			end
			tableType = "undefined"
		elseif currentCharacter == "}" then
			contentateString = false
			currentString ..= currentCharacter
			if tableType == "repeat" then
				repeatAmount = encodingLibrary.Tobase10(repeatAmount)
				currentString = string.sub(currentString, 1, string.len(currentString)-3-string.len(repeatAmount))
				for i = 1, repeatAmount do
					table.insert(finalTable, currentString)
				end
				repeatAmount = ""
				currentString = ""
				tableType = ""
			end
		elseif tableType == "undefined" then
			if currentCharacter == "," then
				tableType = "repeat"
			else
				tableType = "notRepeat"
			end
		elseif tableType == "repeat" then
			repeatAmount ..= currentCharacter
		end
		if contentateString then
			currentString ..= currentCharacter
		end
	end
	return finalTable
end