On 12/30/05, Xavier Noria <[EMAIL PROTECTED]> wrote: > Even if gzipped files have always more than 0 bytes, wouldn't it be > true than all empty gzipped files have the same size, and that non- > empty gzipped files are greater than that minimum? In this Mac that > size seems to be 24 bytes.
Nope. Gzipped files have a header which may include filename. $ touch foo $ ls -l foo -rw-r--r-- 1 me mine 0 Dec 30 2005 foo $ gzip foo $ ls -l foo.gz -rw-r--r-- 1 me mine 24 Dec 30 18:04 foo.gz $ touch foobar $ ls -l foobar -rw-r--r-- 1 me mine 0 Dec 30 2005 foobar $ gzip foobar $ ls -l foobar.gz -rw-r--r-- 1 me mine 27 Dec 30 18:04 foobar.gz Well - it looks like an empty gzipped file with a name takes C<21 + length($name)> but that's not reliable since the header size may vary. $ touch foo $ ls -l foo -rw-r--r-- 1 me mine 0 Dec 30 2005 foo $ gzip -n foo # omit name from header $ ls -l foo.gz -rw-r--r-- 1 me mine 20 Dec 30 2005 foo.gz To be true, in gzip file specifications, there is a field with the size of the uncompressed data - but that's what zlib/zcat/Compress::Zlib access for us to know the file is empty. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
