On 28.06.2011, at 21:57, Thomas Engelmeier wrote: > > On 28.06.2011, at 21:37, Charles Srstka wrote: > >> On Jun 28, 2011, at 12:00 PM, Jens Alfke wrote: >> >>> Another way (that I often use) is to define a C struct that matches the >>> fields and layout of the header, then cast the bytes to a pointer to that >>> struct and read the fields. It makes your code look a lot cleaner, but you >>> have to be careful to (a) make sure the compiler packs the struct fields >>> properly, and (b) you byte-swap all integer/float fields appropriately. >> >> It’s my understanding that reading/writing a struct directly to/from a file >> is considered poor practice, because of the two things you mentioned: endian >> issues, and the fact that you don’t know how the compiler will align the >> fields — and even if you test that, you don’t know that it’s not going to >> change in some future version of clang or gcc, or that Apple’s not going to >> switch to a new architecture or something in which the compilers will emit >> different output. > > - the endian issue you'll have to deal with anyway > - regarding struct alignment: > the 80ies file format had tons of of serialized struct data which usually > better end up in a struct. > Well, streamed reading has bad performance, so you'd not want to use it in > image (or movie) manipulation code.
P.S.: unless the structs have variable length data in the middle, i.e. can not be read in one read anyway. IIRC the PS structures are not organized that way, though. _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
