zipalign -- zip archive alignment tool

usage: zipalign [-f] [-v] infile.zip outfile.zip zipalign -c [-v] infile.zip

-c : check alignment only (does not modify file) -f : overwrite existing outfile.zip -p : page align stored shared object files -v : verbose output is in bytes, e.g. "4" provides 32-bit alignment infile.zip is an existing Zip archive outfile.zip will be created

The purpose of zipalign is to ensure that all uncompressed data starts with a particular alignment relative to the start of the file. This allows those portions to be accessed directly with mmap() even if they contain binary data with alignment restrictions.

Some data needs to be word-aligned for easy access, others might benefit from being page-aligned. The adjustment is made by altering the size of the "extra" field in the zip Local File Header sections. Existing data in the "extra" fields may be altered by this process.

Compressed data isn't very useful until it's uncompressed, so there's no need to adjust its alignment.

Alterations to the archive, such as renaming or deleting entries, will potentially disrupt the alignment of the modified entry and all later entries. Files added to an "aligned" archive will not be aligned.

By default, zipalign will not overwrite an existing output file. With the "-f" flag, an existing file will be overwritten.

You can use the "-c" flag to test whether a zip archive is properly aligned.

The "-p" flag aligns any file with a ".so" extension, and which is stored uncompressed in the zip archive, to a 4096-byte page boundary. This facilitates directly loading shared libraries from inside a zip archive.