> On Mar 30, 2017, at 6:40 PM, Steve Bird <[email protected]> wrote: > >> On Mar 30, 2017, at 8:25 PM, Carl Hoefs <[email protected]> >> wrote: >> >> I have megabytes of raw legacy science datasets that I'm trying to read into >> my app and ingest into an array of doubles. The data is supposed to be >> organized as a stream of 8-byte doubles. I do not know how these datasets >> were generated, so I don't know what format (big/little endian, byte >> swapped, etc) they are in. >> Here is a hex dump of 4 binary doubles: >> >> 49BF7DE372533C05 A8C02FE3135B4F09 86C22FE37E630B05 27C2C4E3E258BA08 > > A few minutes of LabVIEW work shows some semi-reasonable values if you swap > bytes: > BF49E37D5372053C = -0.000790058 > C0A8E32F5B13094F = -3185.59 > > Do you know that those values are wrong?
Alternating byte-swapping is a good hint that you're looking at a PDP-11 / VAX format. There are two different 64-bit VAX formats, though, and neither is identical to IEEE even after correcting for the byte order. Simply shuffling VAX bytes and interpreting as an IEEE double would be misleadingly close but still wrong. -- Greg Parker [email protected] <mailto:[email protected]> Runtime Wrangler _______________________________________________ Cocoa-dev mailing list ([email protected]) 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
