31 lines
1.2 KiB
Text
31 lines
1.2 KiB
Text
zipalign -- zip archive alignment tool
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usage: zipalign [-f] [-v] <align> infile.zip outfile.zip
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-f : overwrite existing outfile.zip
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-v : verbose output
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<align> is in bytes, e.g. "4" provides 32-bit alignment
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infile.zip is an existing Zip archive
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outfile.zip will be created
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The purpose of zipalign is to ensure that all uncompressed data starts
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with a particular alignment relative to the start of the file. This
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allows those portions to be accessed directly with mmap() even if they
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contain binary data with alignment restrictions.
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Some data needs to be word-aligned for easy access, others might benefit
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from being page-aligned. The adjustment is made by altering the size of
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the "extra" field in the zip Local File Header sections. Existing data
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in the "extra" fields may be altered by this process.
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Compressed data isn't very useful until it's uncompressed, so there's no
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need to adjust its alignment.
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Alterations to the archive, such as renaming or deleting entries, will
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potentially disrupt the alignment of the modified entry and all later
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entries. Files added to an "aligned" archive will not be aligned.
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By default, zipalign will not overwrite an existing output file. With the
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"-f" flag, an existing file will be overwritten.
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