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--- trrntzipui [2020/11/26 18:23] – johnsanc
+++ trrntzipui [2024/04/10 19:08] (current) – johnsanc
@@ Line 19: / Line 19: @@
 |2007-05-09|First code commit. (by shindakun)|
-**__The TorrentZipped Files Comments__**
-The .ZIP file comments in the End of Central directory is used to check the validity of the torrentzipped
-file.
-The comment must be formatted as the 22 bytes of TORRENTZIPPED-XXXXXXXX
-The XXXXXXXX is the CRC32 of the central directory records stored as hexadecimal upper case text.
-(the CRC32 of the bytes in the file between Start Of Central Directory & End Of Central Directory)
-This comment ensures that if any change is made to the files within the zip this checksum will no longer
-match the byte data in the central directory, and in this way we can check the validity of a torrentzip file.
-**__File Order with a TorrentZip__**
-For the creation of consistent torrentzipped files, the file order is also very important.
-Files must be sorted by filename using a lower case sort. (Unicode values.)
-**__Directory separator character__**
-As zips only store files (not directories), files in directories are represented by storing a relative path to
-the filename. For example file ‘test1.rom’ in directory ‘set1’ would be stored with a filename of
-‘set1/test1.rom’. Some zipping programs will store this as ‘set1\test1.rom’.
-This leads to a possible naming inconsistency. The zip file format state “All slashes should be forward
-slashes ‘/’ as opposed to backwards slashes ‘\’ “. So Torrentzip will change all ‘\’ character to ‘/’.
-(This must be done before sorting, to ensure that the sort is performed correctly.)
-**__Directory Entries and Empty Directories__**
-A directory entry is stored in a zip by adding a file entry ending in a directory separator character with a
-zero size and CRC. So directory ‘set1’ would be stored as a zero length, zero CRC file called ‘set1/’.
-Some zip programs when adding the previously mentioned file ‘set1/test1.rom’ will also add the
-directory ‘set1/’, this creates an inconsistency problem. In this example the ‘set1/’ directory entry is
-unnecessary, as the filename ‘set1/test1.rom’ implies the existents of the ‘set1/’ directory. To resolve
-this inconsistency un-needed directories should be removed from the zip, the only needed directory
-entries are empty directories that are not implied by any file entries.
-Example:
-^Filename^Size^CRC^
-|set1/|0|00000000|
-|set1/test1.rom|1024|53AC4D0|
-|set2/|0|00000000|
-The set1/ entry should be removed, as it is implied by the set1/test1.rom file. The set2/ entry should be
-kept to create the empty directory, as removing it would completely remove the set2 directory.
-Latest ZIP files format specifications can be found here [[https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT|https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT]]