1 (?:Content- # start of content header
2 (?:Type: (?>\s*) # rest of c/t header
3 [\w-]+/[\w-]+ # content-type (any)
4 |Disposition: (?>\s*) # content-disposition hdr
5 attachment) # content-disposition
6 ;(?>\s*) # ; space or newline
7 (?:file)?name= # filename=/name=
8 |begin (?>\s+) [0-7]{3,4} (?>\s+)) # begin octal-mode
9 (\"[^\"]+\. # quoted filename.
10 (?:vb[se] # list of extns
22 |[\w.-]+\. # unquoted filename.ext
23 (?:vb[se] # list of extns
33 ) # end of filename capture
34 [\s;] # trailing ;/space/newline