Description:
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While writing an IMAP server I needed to parse mime mails 
serverside (it's a feature of imap servers).
Mailparse saved me, however part ids in mailparse do not 
match imap part ids.

Ref: RFC 3501 page 55

In IMAP, when a multipart is found at the root of the mail, 
or if its parent is a message/rfc822 part, it is "merged" 
with its parent.
For example my test email has the following ids:

mailparse:

1: multipart/mixed us-ascii
1.1: text/plain us-ascii 8bit
1.2: message/rfc822 us-ascii 8bit
1.2.1: multipart/mixed us-ascii 8bit
1.2.1.1: multipart/alternative us-ascii 8bit
1.2.1.1.1: text/plain iso-8859-1 8bit
1.2.1.1.2: text/html iso-8859-1 8bit
1.2.1.2: application/msword us-ascii

imap4rev1:

TEXT: multipart/mixed us-ascii
1: text/plain us-ascii 8bit
2: message/rfc822 us-ascii 8bit
2.TEXT: multipart/mixed us-ascii 8bit
2.1: multipart/alternative us-ascii 8bit
2.1.1: text/plain iso-8859-1 8bit
2.1.2: text/html iso-8859-1 8bit
2.2: application/msword us-ascii

A way to fetch imap part id (or to "switch" to imap part 
format) would be great (for now I have implemented a routine 
in php to generate imap part ids based on mail structure)