TTCOMP

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m (Jsummers moved page TTComp archive to TTCOMP: Less-bad name)
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|formattype=electronic
 
|formattype=electronic
 
|subcat=Compression
 
|subcat=Compression
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|extensions={{ext|ttc}}, others
 
}}
 
}}
'''TTComp archive''' is a compressed file format. It was apparently used by some software installation utilities. It uses [[PKWARE DCL Implode]] compression.
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'''TTCOMP''' is the informal name of a file compression utility developed by SWFTE International. Its compressed file format is just a raw blob of [[PKWARE DCL Implode]]-compressed data. The name "TTCOMP" has sometimes been used (misused?) for any file compressed in such a manner, even if it has nothing to do with the TTCOMP software.
  
Though it may be called an "archive" format, it appears to store nothing more than a stream of compressed data.
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The TTCOMP software has been passed around in the form of a pair of files named "TTCOMP.EXE" and "TTDECOMP.EXE", though there's no evidence that this is an official distribution. The software is included in SWFTE's ''Typecase'' product, and maybe some other SWFTE products, but the files are named "COMPR.EXE" and "DECOMPR.EXE". Typecase does not appear to ever use the name "TTCOMP", and it's not clear where it came from. Someone may have derived it from the '''.TTC''' filename extension that Typecase uses for compressed [[TrueType]] fonts.
  
 
== Identification ==
 
== Identification ==
The first byte of a TTComp file indicates the type of compression:
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Refer to [[PKWARE DCL Implode#Identification]] for how to identify PKWARE DCL Implode format in general.
* <code>0x00</code>: binary compression
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* <code>0x01</code>: ASCII compression
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The second byte of a TTComp file specifies the size of the dictionary as follows:
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TTCOMP.EXE/COMPR.EXE appears to only ever use binary compression, and a 4K dictionary. TTDECOMP.EXE/DECOMPR.EXE can decompress all six modes. So, you could declare that TTCOMP files always start with bytes {{magic|0x00 0x06}}, or you could account for the other modes as well.
* <code>0x04</code>: 1024 bytes
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* <code>0x05</code>: 2048 bytes
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* <code>0x06</code>: 4096 bytes
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Most TTComp files begin with bytes <code>0x00 0x06</code> indicating binary compression and a 4K dictionary.
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== Software ==
 
== Software ==
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* [https://archive.org/details/UniversalDialUPModemDriverCD Universal Dial UP Modem Driver CD] → SOFTWARE/BITWARE/.../*.??$
 
* [https://archive.org/details/UniversalDialUPModemDriverCD Universal Dial UP Modem Driver CD] → SOFTWARE/BITWARE/.../*.??$
 
* https://telparia.com/fileFormatSamples/archive/ttcomp/
 
* https://telparia.com/fileFormatSamples/archive/ttcomp/
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[[Category:PKWARE]]

Revision as of 14:33, 20 July 2021

File Format
Name TTCOMP
Ontology
Extension(s) .ttc, others

TTCOMP is the informal name of a file compression utility developed by SWFTE International. Its compressed file format is just a raw blob of PKWARE DCL Implode-compressed data. The name "TTCOMP" has sometimes been used (misused?) for any file compressed in such a manner, even if it has nothing to do with the TTCOMP software.

The TTCOMP software has been passed around in the form of a pair of files named "TTCOMP.EXE" and "TTDECOMP.EXE", though there's no evidence that this is an official distribution. The software is included in SWFTE's Typecase product, and maybe some other SWFTE products, but the files are named "COMPR.EXE" and "DECOMPR.EXE". Typecase does not appear to ever use the name "TTCOMP", and it's not clear where it came from. Someone may have derived it from the .TTC filename extension that Typecase uses for compressed TrueType fonts.

Identification

Refer to PKWARE DCL Implode#Identification for how to identify PKWARE DCL Implode format in general.

TTCOMP.EXE/COMPR.EXE appears to only ever use binary compression, and a 4K dictionary. TTDECOMP.EXE/DECOMPR.EXE can decompress all six modes. So, you could declare that TTCOMP files always start with bytes 0x00 0x06, or you could account for the other modes as well.

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Sample files

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