[Xapian-tickets] [Xapian] #673: Use IEEE-754 interchange format?

[Xapian]

#673: Use IEEE-754 interchange format?
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 Reporter:  olly            |             Owner:  nobody
     Type:  defect          |            Status:  new
 Priority:  normal          |         Milestone:  1.5.0
Component:  Backend-Remote  |           Version:
 Severity:  normal          |        Resolution:
 Keywords:  GoodFirstBug    |        Blocked By:
 Blocking:                  |  Operating System:  All
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Comment (by olly):

 A slightly more concrete plan:

 * Using little-endian IEEE-754 format makes most sense as that's the
 dominant format for current platforms (notably used by x86, x86-64, and
 common configurations of arm).  For these platforms we then just need to
 copy the bytes in the new versions of `serialise_double()` and
 `unserialise_double()`.

 * For platforms with big-endian IEEE-754 we just need to byte-swap when
 doing that copying.  There's already a helper `do_bswap()` which handles
 this efficiently (by using compiler built-ins or similar where available).

 * For the (currently rare) platforms using a non-IEEE-754 format we'll
 need a pair of utility functions to convert between the native format and
 little-endian IEEE-754 format.  The current `serialise_double()` and
 `unserialise_double()` should provide some hints as to how to implement
 those.

 I'd suggest getting this working for IEEE-754 platforms first, then
 worrying about the others as a second step.

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Ticket URL: <https://trac.xapian.org/ticket/673#comment:4>
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