CODEWITHSUNDEEP
windowsoperating-systemdeflate
Luke
Luke

Reputation: 161

How does Windows decide whether to use Deflate or Deflate64 for zipping files?

Windows Explorer uses the Deflate64 compression method for its zip files, rather than Deflate. Is this behaviour consistent across "current" Windows versions?

I tried one way. I created one zip file whose size is 2.69 GB, and one folder whose size is more than 1.23.

After zipping both of them, the zip file was created using Deflate64 and its size was 3.19 GB.

I would like to know how Windows decides whether to zip the file using Deflate64 or Deflate? What are the conditions required to create Deflate64 zip files?

Upvotes: 1

Views: 1635

Answers (1)

Mark Adler
Mark Adler

Reputation: 112502

See this note:

Windows 7/8/10 all use Deflate64. The cutoff in zip size where it switches from Deflate to Deflate64 appears to be 2 gigs. The number of files within the zip is irrelevant to the compression type chosen e.g. one 2.5 gig file will be Deflate64’ed the same as five 0.5 gig files.

Upvotes: 0

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