Compression - Revision history

213.127.36.131: fixed link

2016-10-22T23:22:39Z

fixed link

← Older revision		Revision as of 23:22, 22 October 2016
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	Crediar re'ed the decompression from the code and translated it to C code.		Crediar re'ed the decompression from the code and translated it to C code.

	You can download a tool with the source to decompress data from any given offset [http://~~crediar~~.~~no-ip~~.~~com~~/td-v0.1-cred.rar here].		You can download a tool with the source to decompress data from any given offset [http://www.terranigma.be/td-v0.1-cred.rar here].

Nethraz: added missing detail to the game's algorithm

2016-03-06T17:35:01Z

added missing detail to the game's algorithm

← Older revision		Revision as of 17:35, 6 March 2016
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	##* Call the position at which the match is found '''best_offset''' and the length of the match '''best_length'''.		##* Call the position at which the match is found '''best_offset''' and the length of the match '''best_length'''.
	##* If there are multiple matches of the same length, use the one with the highest offset.		##* If there are multiple matches of the same length, use the one with the highest offset.
	## if '''2 <= best_length <= 5''' and '''best_offset''' is no less than '''inpus_pos-0x100''', then encode the match using mode '''00'''.~~<br />~~else if '''best_length <= 2''', then encode the current input byte as literal and set '''best_length = 1'''.~~<br />~~else if '''best_length <= 9''', then encode the match using mode '''01'''.~~<br />~~else encode the match using mode '''01L'''.		## if '''input_pos + best_length > input_size''', then '''best_length''' = '''input_size - input_pos'''
			## Encode the match:
			##* if '''2 <= best_length <= 5''' and '''best_offset''' is no less than '''inpus_pos-0x100''', then encode the match using mode '''00'''.
			##* else if '''best_length <= 2''', then encode the current input byte as literal and set '''best_length = 1'''.
			##* else if '''best_length <= 9''', then encode the match using mode '''01'''.
			##* else encode the match using mode '''01L'''.
	## '''inpus_pos''' += '''best_length'''		## '''inpus_pos''' += '''best_length'''

Nethraz: described exact compression of game data

2016-03-06T17:12:43Z

described exact compression of game data

← Older revision		Revision as of 17:12, 6 March 2016
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	In the table, each '''cc''' stands for a control code bit. The second data byte is divided into 5+3 bits for mode '''01'''.		In the table, each '''cc''' stands for a control code bit. The second data byte is divided into 5+3 bits for mode '''01'''.

			== Compression used for the Game ==

			In general there is more than one way to compress a chunk of data with the given format.
			But the game's developers used a very specific ''greedy'' algorithm to compress all the data in the game.
			It can be reproduced with the following algorithm:

			# Append 0x100 zero bytes to the (uncompressed) input data. These don't count into '''input_size''' and are only there for padding!
			# Output the header, using 00, '''input_size''', input[0]
			# '''input_pos''' = 1
			# While there is still input to process, repeat the following:
			## Find the longest match of data for the current input_pos:
			##* Look in the range '''max(0,input_pos-0x2000)..(input_pos-1)''' for a match of up to '''0x100''' bytes.
			##* Call the position at which the match is found '''best_offset''' and the length of the match '''best_length'''.
			##* If there are multiple matches of the same length, use the one with the highest offset.
			## if '''2 <= best_length <= 5''' and '''best_offset''' is no less than '''inpus_pos-0x100''', then encode the match using mode '''00'''.<br />else if '''best_length <= 2''', then encode the current input byte as literal and set '''best_length = 1'''.<br />else if '''best_length <= 9''', then encode the match using mode '''01'''.<br />else encode the match using mode '''01L'''.
			## '''inpus_pos''' += '''best_length'''

	== Tool ==		== Tool ==

Nethraz: described compression in detail

2016-02-18T22:35:12Z

described compression in detail

@@ Line 1: / Line 1: @@
 Terranigma uses a compression for most of the data.
-I re'ed it from the code and translated it to C code. So there won't be a real explanation on how it works.
+== Format ==
 You can download a tool with the source to decompress data from any given offset [http://crediar.no-ip.com/td-v0.1-cred.rar here].

Crediar: added TD download

2012-04-11T06:58:09Z

added TD download

← Older revision		Revision as of 06:58, 11 April 2012
Line 3:		Line 3:
	I re'ed it from the code and translated it to C code. So there won't be a real explanation on how it works.		I re'ed it from the code and translated it to C code. So there won't be a real explanation on how it works.

	You can download a tool with the source to decompress data from any given offset here ~~(soon)~~.		You can download a tool with the source to decompress data from any given offset [http://crediar.no-ip.com/td-v0.1-cred.rar here].

Crediar: Created page with "Terranigma uses a compression for most of the data. I re'ed it from the code and translated it to C code. So there won't be a real explanation on how it works. You can downl..."

2012-04-10T12:56:01Z

Created page with "Terranigma uses a compression for most of the data. I re'ed it from the code and translated it to C code. So there won't be a real explanation on how it works. You can downl..."

New page

Terranigma uses a compression for most of the data.

I re'ed it from the code and translated it to C code. So there won't be a real explanation on how it works.

You can download a tool with the source to decompress data from any given offset here (soon).