This compresses multiple files in parallel, and will split up larger
files (5MB+) into smaller chunks (1MB) to compress in parallel.
There is a small size overhead to recombine the chunks, but it's only a
few bytes per chunk, so for a 1MB chunk, it's minimal.
Rough numbers, with everything in the page cache, this can compress
~4GB (1000 files) down to 1GB in 6.5 seconds, instead of 120 seconds with
the non-parallel soong_jar and 150 seconds with zip.
Go's DEFLATE algorithm is still a bit worse than zip's -- about 3.5%
larger file sizes, but for most of our "dist" targets that is fine.
Change-Id: Ie4886c7d0f954ace46e599156e35fea7e74d6dd7
This doesn't do any decompression / recompression, but just copies over
the already compressed contents. So it's similar to zip -U, but allows
rewriting of the paths.
The first expected usecase is to replace img_from_target_files during
the build, since it does the equivalent of this:
zip2zip -i <target-files.zip> -o <img.zip> OTA/android-info.txt:android-info.txt IMAGES/*:.
Except it decompresses and recompresses the images, which takes over a
minute instead of a few seconds.
Change-Id: I88d0df188635088783223873f78e193272dbdf1c
In preparation to patch in some custom functionality (parallel
compression and zero-decompress zip to zip copying)
Change-Id: I96a36efc09c715f6b55290af40ebfdde9ae72e33
