Large GZIP archives

[NickHarmer]

It was recently reported to me that GZIP archives containing files larger than 4GB do not extract correctly using SevenZipSharp.

As we are all aware, the 7-zip EXE does not correctly report the Size of GZIP archives if they are bigger than 4GB, but it DOES correctly extract them. SevenZipSharp apparently does not.

I have a 14GB GZip archive containing a 15GB disk image file. WinRAR reports the file's packed and unpacked sizes correctly, and extracts the file.

7-zip (19 and 21 alpha) report the size incorrectly. 'Packed Size' is the size of the archive itself (which I guess is correct since it should only contain one file). Unpacked size (which should be 15,502,147,584 bytes) is reported as 2,617,245,696 bytes (which is the actual size truncated to a 32-bit quantity). However, the 7-zip EXE does correctly extract the entire file.

SevenZipSharp reports 'Size' as the 32-bit truncated value, but only extracts that much data when you call extractor.ExtractArchive(folder)

[squid-box]

I've looked into this a little, but I'm at a disadvantage since I don't have a ready supply of 4GB+ sized files. I created a 16GB dummy file that I gzip'ed - and 7z/SevenZipSharp shows it as having original size 0 bytes. It can be properly extracted using both 7z and SevenZipSharp though.

• Can you provide some example gzip (big ask, but I can't reproduce it myself with the generated file)?
• Are you using the 32 or 64 bit 7z dll?

[NickHarmer]

Hi - I'll try to look at this again next week.

Deadlines ... !