dovecot - May 2010 - mdbox: What format is the file "storage/dovecot.map.index" in? (Dovecot 2.0beta5)

I am looking at "mdbox" under Dovecot 2.0beta5.

Looking at the documentation for "mdbox" I saw that we had a directory
"storage" containing files "m.#" where "#" is an
integer and a map file
("dovecot.map.index").

I think I expected the map file to be a plain text file with one record 
per line, but in fact it appears to contain binary data.

According to the wiki ( http://wiki.dovecot.org/MailboxFormat/dbox ) the 
records go as:

- map_uid: Unique growing 32 bit number for the message.

- refcount: 16 bit reference counter for this message. Each time the 
message is copied the refcount is increased.

- file_id: File number containing the message. For example if file_id=5, 
the message is in file m.5.

- offset: Offset to message within the file.

- size: Space used by the message in the file, including all metadata.

The map file I have here is 1688 bytes in size (and I think there are 64 
messages stored). Prime factors of 1688 are 2^3 x 211, so I think it is 
something other than just a straight array of fixed-size structures.

Still, I can always look at the source if I really want to know :-)

Regards,

Bill

It's the same format as other dovecot.index* files. You can look at its
contents with:

doveadm dump storage/dovecot.map.index