Here is a wrapper class for the Compression API. This requires Windows 8 or newer.
It is used here in a simple demo, which creates a 2.5MB file test.txt which is then read back and run through compression and written out as comp.bin, and then that is read back and run through decompression and written as the expanded.txt file.
Writing the before and after files makes it easy to run WinDiff to verify results.
There is some work remaining to be done but the essentials are all working.
Caveat:
Programs that use this system DLL may be flagged as a trojan horse by antivirus software, even by Windows Defender. Malware droppers have gotten out of control so all security suites are tightening these things up a lot. When they see a VB6 program they turn on quite a few other checks, and your suspicion score can rise quickly. Blame the miscreants who started using VB6 to create their monsters.
It is used here in a simple demo, which creates a 2.5MB file test.txt which is then read back and run through compression and written out as comp.bin, and then that is read back and run through decompression and written as the expanded.txt file.
Writing the before and after files makes it easy to run WinDiff to verify results.
There is some work remaining to be done but the essentials are all working.
Caveat:
Programs that use this system DLL may be flagged as a trojan horse by antivirus software, even by Windows Defender. Malware droppers have gotten out of control so all security suites are tightening these things up a lot. When they see a VB6 program they turn on quite a few other checks, and your suspicion score can rise quickly. Blame the miscreants who started using VB6 to create their monsters.