TTCOMP
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.
Software
Sample files
- Universal Dial UP Modem Driver CD → SOFTWARE/BITWARE/.../*.??$
- https://telparia.com/fileFormatSamples/archive/ttcomp/
